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Cited by 1,274Electrocatalysts for Energy ConversionFuel Cells and Related MaterialsCatalytic Processes in Materials Science

Carbon-Supported Pt-Based Alloy Electrocatalysts for the Oxygen Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells: Particle Size, Shape, and Composition Manipulation and Their Impact to Activity

Open access
Wang, Yan-Jie, Zhao, Nana, Fang, Baizeng, Li, Hui, Bi, Xiaotao T., Wang, Haijiang·2015·Chemical Reviews
DOI 10.1021/cr500519c
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Abstract

A scientific review addresses the current development of size-dependent, shape-selected, and composition-controlled carbon-supported Pt-alloy electrocatalysts for enhancing electrochemical catalytic performance in polymer electrolyte membrane fuel cells (PEMFCs). It starts with an overview of carbon support in carbon-supported Pt-alloy electrocatalysts and proceeds to the theoretical studies on the impact of Pt-alloy particle size, shape, and composition, and the experimental research on the particle size, shape, and composition of Pt-alloy catalysts. It particularly emphasizes on strategies to control particle size, shape, composition, and their impacts on catalyst activity toward the oxygen reduction reaction.

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Crossref · 10.1021/cr500519c

Cites

408 of 408 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

16 of 289 cited sources checked · 6 supported · 2 flagged · accuracy not yet measured

  • Premisecitation

    The adsorption properties of Pt may be altered by alloying Pt, which is closely related to ORR.

    “The formation of Ptalloying can result in two key changes favorable to the enhancement of Pt-alloy catalysts.One is that the alloying of Pt might change the electronic properties of Pt while the other is that the adsorption properties of Pt may be altered by alloying Pt, which is closely related to ORR. 133”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [133] Bing Y., 2010, Chem. Soc. Rev. source
  • Premisecitation

    Alloying of Pt might change the electronic properties of Pt.

    “The formation of Ptalloying can result in two key changes favorable to the enhancement of Pt-alloy catalysts.One is that the alloying of Pt might change the electronic properties of Pt while the other is that the adsorption properties of Pt may be altered by alloying Pt, which is closely related to ORR. 133”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [133] Bing Y., 2010, Chem. Soc. Rev. source
  • Premisecitation

    pH control is another strategy that can help to control particle size in the synthesis of Pt-based nanoparticle catalysts.

    “In addition to the use of protecting agents, pH control is another strategy that can help to control particle size in the synthesis of Pt-based nanoparticle catalysts.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [223] Shimazaki Y., 2005, J. Colloid Interface Sci. source
    • cites [224] Abedini A., 2013, Nanoscale Res. Lett. source

      The 'Effects of synthesis parameters' section says that pH during irradiation synthesis helps determine metallic nanoparticle size, supporting the general strategy. The paper does not establish this specifically for Pt-based nanoparticle catalysts; its 'Effect of pH of the medium' section discusses copper ions and silver clusters instead. No page numbers are available in our copy. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
  • Premisecitation

    Controlling the composition by fine-tuning the stoichiometric ratio of all metal precursors had direct impacts on the ORR activity, selectivity, and durability of Pt-alloy catalysts.

    “It was found that controlling the composition by fine-tuning the stoichiometric ratio of all the metal precursors (i.e., the ratio of Pt to other metals) had direct impacts on the ORR activity, the selectivity, and the durability of Pt-alloy catalysts.147,[425][426][427][428][429][430]”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [147] Stamenkovic V. R., 2007, Science source
    • cites [425] Zhang S., 2014, J. Am. Chem. Soc. source

      The introduction (p. 3) links alloy composition to desirable ORR catalytic properties, including activity, durability and selectivity. The experiments (pp. 3–5), however, tune Ni core size rather than the Pt-to-other-metal precursor ratio; they report activity differences and a stability test, but do not show that fine-tuning precursor stoichiometry directly changes selectivity or durability. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [426] Hernández-Fernández P., 2007, J. Phys. Chem. C source
  • Premisecitation

    After dealloying, the Pt:Cu molar ratio changed from 0.3 to 1.8 due to removal of copper.

    “They found that after dealloying the Pt:Cu molar ratio had changed from 0.3 to 1.8 due to the removal of copper in the dealloying process.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [281] Dutta I., 2010, J. Phys. Chem. C source
  • May combine two claims. 100
  • Classified as probably not a substantial claim. 47
  • The quote only partly states this claim. 4

  • May combine two claims.

    Premisecitation

    High-temperature heat treatment can cause agglomeration of particles, reduction of specific surface area, and broadening of particle size distribution.

    “However, high-temperature heat treatment can cause agglomeration of particles, reduction of specific surface area, and broadening of particle size distribution.”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [234] Singh B., 2012, ECS J. Solid State Sci. Technol. source

      In “Glucose electro-oxidation studies” (page unavailable), the paper says heat treatment can increase particle size and thereby reduce catalyst active area, supporting the surface-area concern in substance. It does not establish that high-temperature treatment causes agglomeration or broadens the particle-size distribution; it reports treatment at 450 °C without agglomeration and cites improved particle distribution at 400–550 °C. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [235] Sheng W., 2011, J. Electrochem. Soc. source

      In the XPS results section (page not provided), the paper reports that increasing heat-treatment temperature from 300°C to 600°C caused no substantial change in Pt nanoparticle size or dispersion. It describes the resulting particles as well dispersed, contrary to attributing heat-induced agglomeration and a broadened size distribution to this study. The passage does not report a reduction in specific surface area from heat treatment. (LLM, conf=0.83)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [236] Chandan A., 2013, J. Power Sources source

  • May combine two claims.

    Premisecitation

    Dealloying resulted in an increase in mass activity from 0.21 to 0.29 A mg-1 Pt at 0.90 V, and an increase in specific activity from 300 to 580 A cm-2 Pt.

    “Dealloying resulted in an increase in mass activity from 0.21 to 0.29 A mg -1 Pt at 0.90 V, and an increase in specific activity from 300 to 580 A cm -2 Pt .”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [281] Dutta I., 2010, J. Phys. Chem. C source

      The Results and Discussion (RDE measurements; page unavailable) say that dealloying increased mass activity but that specific activity at 0.90 V slightly trailed the annealed sample—not that it rose from 300 to 580. The catalyst-development discussion (page unavailable) reports a dealloyed mass activity of 0.34 A/mg Pt, rather than the claimed 0.29 A/mg Pt. (LLM, conf=0.90)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Detailed degradation mechanisms revealed the transportation of Pt ions through liquid and/or ionomer and the transportation of electrons through carbon support.

    “The detailed degradation mechanisms 116,117 revealed the transportation of Pt ions through liquid and/or ionomer and the transportation of electrons through carbon support, respectively.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [116] Paulus U. A., 2002, Electrochim. Acta source
    • cites [117] Ralph T. R., 2002, Platinum Met. Rev. source

      The Carbon black Supports passage (section labeled References; page unavailable) says the carbon support must provide high electrical conductivity, which supports the electron-transport part in general. The Stability passage describes base-metal ions leaching into the membrane, not Pt ions moving through liquid or ionomer. Neither passage establishes the claimed detailed degradation mechanism. (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    McBreen and Mukerjee found that alloying with Ru can cause electronic effects on Pt such as an increase in the number of Pt d band vacancies and a decrease in the Pt-Pt distance.

    “They found that alloying with Ru can cause electronic effects on the Pt such as an increase in the number of Pt d band vacancies and a decrease in the Pt-Pt distance.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [81] McBreen J., 1995, J. Electrochem. Soc. source

  • May combine two claims.

    Premisecitation

    In Pt alloys, Pt tends to congregate in the first layer and then be induced to form a surface strain, which strongly influences its reactivity, depending on the type of transition metal(s) in the alloy.

    “In Pt alloys, Pt tends to congregate in the first layer and then be induced to form a surface strain, which strongly influences its reactivity, depending on the type of transition metal(s) in the alloy.133”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [133] Bing Y., 2010, Chem. Soc. Rev. source

  • May combine two claims.

    Premisecitation

    High reaction temperature and a high degree of solute supersaturation can accelerate nucleation.

    “High reaction temperature and a high degree of solute supersaturation (i.e., the ratio of saturation solute concentrations to equilibrium solute concentration) can accelerate nucleation.”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [194] Volmer M., 1926, Phys. C

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [195] Volmer, M. Kinetic der Phasbildung, Dresden, Steinfopff, Leipzig , 1939.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [196] Becker R., 1935, Ann. Phys. source

      In the crystal-growth discussion (page unavailable), the paper says that, unless supersaturation is too high, a considerable time elapses before a new nucleus forms. That supports the supersaturation part for vapor, but the copy does not establish that high reaction temperature accelerates nucleation or address supersaturation defined by solute concentrations. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Sui et al. successfully synthesized PtFe nanotubes using AAO membrane as a hard template.

    “Sui et al. 334 successfully synthesized PtFe nanotubes using AAO membrane as a hard template.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [334] Sui Y. C., 2004, Appl. Phys. Lett. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    PEO segments in PEO-PPO-PEO triblock copolymer were able to reduce metal ions, forming cavities (pseudocrown ethers) binding PdCl4 2- from starting precursors; bound PdCl4 2- ions might then be reduced via oxidation of oxyethylene segments by the metal center.

    “Shao's group believed that PEO segments in the PEO-PPO-PEO triblock copolymer were able to reduce metal ions, thus forming cavities (pseudocrown ethers) binding PdCl 42-from the starting precursors: the bound PdCl 4 2-ions might then be reduced via oxidation of the oxyethylene segments by the metal center.311,312”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [311] Alexandridis P., 2011, Eur. Polym. J. source

      Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [312] Piao Y., 2007, Small source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Carbon-supported Pt-alloy systems are known as solid solutions of Pt and other metal(s), among which carbon-supported Pt-based bimetallic alloys are popular electrocatalysts in PEMFCs.

    “Carbon-supported Pt-alloy systems are known as solid solutions of Pt and other metal(s), among which carbonsupported Pt-based bimetallic alloys are popular electrocatalysts in PEMFCs.13,57,396,397”
    Quote in the paperNot a substantial claim1 of 4 sources checked
    • cites [13] Gasteiger H. A., 2005, Appl. Catal. B: Environ. source
    • cites [57] Yu X., 2007, J. Power Sources source
    • cites [396] Brouzgou A., 2012, Appl. Catal. B Environ. source
    • cites [397] Kulesza P. J., 2013, Electrochim. Acta source

      Section 4 says Pt and Ru can form a solid solution in a binary alloy, depending on their ratio; it does not say that Pt alloys generally are solid solutions. Sections 1 and 3 discuss Pt-based bimetallic electrocatalysts for fuel-cell reactions, but do not establish that carbon-supported Pt-based bimetallic alloys are popular in PEMFCs. Section 7 discusses a carbon-supported Pt–ceria material for PEMFCs, not a bimetallic alloy. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    The composition of Pt increased from 20 to 29 wt % while Cu content decreased from 20 to 5.4 wt %.

    “The composition of Pt increased from 20 to 29 wt % while the Cu content decreased from 20 to 5.4 wt %.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [281] Dutta I., 2010, J. Phys. Chem. C source

      In Results and Discussion, under “Synthesis and Chemical Characterization” (page not available), the paper says dealloying removed a significant fraction of Cu and raised the Pt/Cu molar ratio from 0.3 to 1.8. That supports the reported change in composition, but the available passage does not give the claimed weight percentages; it points to Table 1 for metal contents. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    At cathode loading of 0.077-0.37 mg Pt cm-2 in the MEA, tested current density was dependent on factors such as temperature, pressure, and relative humidity.

    “At the cathode loading of 0.077-0.37mg Pt cm -2 in the MEA, the tested current density was found to be dependent on some factors such as temperature, pressure, and relative humidity (RH).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Among synthesis approaches, wet chemical synthesis has been employed the most.

    “Among these approaches, wet chemical synthesis has been employed the most.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Addition of another metal to Pt can form a Pt alloy and alter the availability of active surface sites (the ensemble effect) or the binding strength of reactants, intermediates, products, and spectator species (the electronic and/or strain effect).

    “Alloying has become an attractive strategy to develop advanced Pt-based electrocatalysts, [23][24][25][26][27][28][29] in which the addition of another metal can form a Pt alloy 30 and thus alter the availability of active surface sites (the ensemble effect) or the binding strength of reactants, intermediates, products, and spectator species (the electronic and/or strain effect).31”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [30] Maroun F., 2001, Science source
    • cites [31] Burch R., 1982, Acc. Chem. Res. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Polymer electrolyte membrane fuel cells (PEMFCs) are among the most promising candidates for the reliable and efficient conversion of hydrogen into electric power in automotive, distributed power generation, and portable electronic applications on a large scale.

    “Polymer electrolyte membrane fuel cells (PEMFCs) are among the most promising candidates for the reliable and efficient conversion of hydrogen, produced from fossil or renewable sources, into electric power in automotive, distributed power generation, and portable electronic applications on a large scale.[2][3][4][5][6][7][8][9][10][11]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2][3][4][5][6][7][8][9][10][11]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    The specific surface area of the support and the oxygen surface groups affected the particle size, dispersion, and catalytic performance of carbon-supported Pt-Pd catalysts.

    “They concluded that the specific surface area of the support as well as the oxygen surface groups affected the particle size and dispersion and catalytic performance.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [107] Limpattayanate S., 2014, Renew. Energy source

  • May combine two claims.

    Premisecitation

    Carbon support is not a mere inert material; it can alter the system's Galvani potential, raise the electronic density in the catalysts, and lower the Fermi level, which favor electron transfer at the electrode-electrolyte interface and accelerate electrode processes.

    “It is well-known that carbon support is not a mere inert material 69 and it can alter the system's Galvani potential, raise the electronic density in the catalysts, and lower the Fermi level, which favor the electron transfer at the electrodeelectrolyte interface and thus accelerate the electrode processes.57,70”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [69] Calderón J. C., 2012, Int. J. Hydrogen Energy source
    • cites [57] Yu X., 2007, J. Power Sources source
    • cites [70] Zenyuk I. V., 2012, J. Phys. Chem. C source

  • May combine two claims.

    Premisecitation

    Vulcan carbon provided significantly higher active surface area for Pt-Pd nanoparticles than HSAG graphite, probably due to a good interaction of Pt-Pd with Vulcan than with HSAG, even though HSAG had a higher surface area.

    “It was concluded that Vulcan carbon provided significantly higher active surface area probably due to a good interaction of Pt-Pd with Vulcan than with HSAG even though the later had a higher surface area than the former.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [109] Gamez, A.; Richard, D.; Gallezot, P.InResume des Journees d’Etude Piles a Combustible;Paris, France, 1999; p401.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    X-ray photoelectron spectroscopy (XPS) studies showed Pt as an electron donor to carbon and their interaction was dependent on the Fermi-level of electrons in both Pt and carbon.

    “This was further supported by X-ray photoelectron spectroscopy (XPS) studies that showed Pt as an electron donor to carbon and their interaction was dependent on the Fermi-level of electrons in both Pt and carbon.74”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [74] Coloma F., 1996, Appl. Catal., A source

  • May combine two claims.

    Premisecitation

    The surface physicochemical properties and structure of carbon materials play an important role on the activity and stability of resultant carbon-supported Pt-alloy catalysts because the interaction between carbon and Pt-alloy can modify the physicochemical and electronic structure of Pt-alloy, which in turn influences catalytic activity and durability.

    “The surface physicochemical properties and the structure of carbon materials play an important role on the activity and the stability of the resultant carbon supported Ptalloy catalysts because the interaction between carbon and Ptalloy can modify the physicochemical and electronic structure of Pt-alloy which in turn influences the catalytic activity and durability.[61][62][63][64][65]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [61][62][63][64][65]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Antolini et al. found a further shift to higher energy values for the Pt 4f7/2 of PtRu/C by 0.2-0.3 eV with respect to pure Pt/C because of an enhanced Pt-carbon interaction or smaller Pt particle size.

    “They found a further shift to higher energy values for the Pt 4f 7/2 of PtRu/C by 0.2-0.3eV with respect to pure Pt/C because of an enhanced Ptcarbon interaction or smaller Pt particle size.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [79] Antolini E., 2001, J. Solid State Electrochem. source

  • May combine two claims.

    Premisecitation

    The interaction between Pt-alloy and carbon support affects the growth, structure, and dispersion of Pt-alloy nanoparticles on the carbon support and is closely related to the size, shape, and composition of Pt-alloy nanoparticles.

    “In the research on carbon-supported Pt-alloy catalysts, more and more attention has been paid to the interaction between Pt-alloy and carbon support which affects the growth, the structure, and the dispersion of Pt-alloy nanoparticles on the carbon support 57,[66][67][68] and is closely related to the size, shape, and composition of Pt-alloy nanoparticles.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites 57,[66][67][68]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    According to Bogotski and Snudkin, the rise in electron density on Pt-alloy could be attributed to carbon support synergism based on changes in the electronic state of Pt after its deposition, thus enhancing electrocatalytic activity.

    “According to Bogotski and Snudkin, 84 however, the rise in electron density on Pt-alloy could be attributed to carbon support synergism on the basis of changes in the electronic state of Pt after its deposition, thus enhancing the electrocatalytic activity.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [84] Bogotski V. S., 1984, Electrochim. Acta source

  • May combine two claims.

    Premisecitation

    Among three carbon supports (Hicon Black, multiwalled carbon nanotubes, and Vulcan XC-72) for Pt-Pd catalysts, Pt-Pd/Vulcan XC-72 showed better catalyst dispersion, smaller particle size (~6.78 nm), a higher Pt:Pd ratio (49.6:50.4), and the highest ORR activity under PEM fuel cell testing.

    “With all three carbon-supported Pt-Pd catalysts being prepared by a seeding and impregnation method, the Pt-Pd/Vulcan XC-72 showed a better catalyst dispersion, smaller particle size (∼6.78nm), a higher Pt:Pd ratio ( 49.6:50.4),and the highest ORR activity under the PEM fuel cell testing condition.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [107] Limpattayanate S., 2014, Renew. Energy source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Goodenough and Manoharan concluded that the synergistic catalytic effect in a carbon-supported PtRu system could be attributed to an intra-alloy electron transfer from Ru to Pt.

    “After the observation by using a combination of XPS, extended X-ray absorption fine structure (EXAFS), and ESR measurements on a carbon-supported PtRu system, Goodenough and Manoharan 80 concluded that the synergistic catalytic effect could be attributed to an intra-alloy electron transfer from Ru to Pt.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80] Goodenough J. B., 1989, Chem. Mater. source

  • May combine two claims.

    Interpretationcitation

    Electrons in a carbon-supported Pt-alloy system have been proved to transfer not only within Pt-alloy, but also from Pt-alloy to carbon.

    “It can be concluded from the discussion above that the electrons in a carbon supported Pt-alloy system have been proved to transfer not only within Pt-alloy, but also from Ptalloy to carbon.[71][72][73][74][75][76][77][78]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [71][72][73][74][75][76][77][78]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    The carbon support may modify the electronic character of the Pt-alloy and influence the shape and distribution of the deposited Pt-alloy particles.

    “The carbon support may not only modify the electronic character of the Pt-alloy 52 but also influence the shape and distribution of the deposited Pt-alloy particles.102,103”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [52] Antolini E., 2009, Appl. Catal., B source
    • cites [102] Trogadas P., 2014, Carbon source
    • cites [103] Augustine R. L., 1996 source

  • May combine two claims.

    Interpretationcitation

    The strong wetting interaction for the alloy can modify the morphology of particles at the metal-carbon interface, likely altering the alloy electronic structure and contributing to the 1.8-fold enhanced ORR activity over pure Pt.

    “The strong wetting interaction for the alloy can modify the morphology of the particles at the metalcarbon interface, likely altering the alloy electronic structure and contributing to the 1.8 fold enhanced ORR activity over pure Pt.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [83] Slanac D. A., 2012, Electrochim. Acta source

  • May combine two claims.

    Premisecitation

    The reported oxidation of carbon support may cause severe sintering/agglomeration of Pt-alloy nanoparticles under long-term fuel cell operation and thus decrease the electrocatalytic surface area, resulting in degradation of the catalyst and decrease of catalytic activity and fuel cell performance.

    “Inspite of the positive impact of carbon on the catalytic activity, the reported oxidation of carbon support may cause a severe sintering/agglomeration of Pt-alloy nanoparticles under longterm fuel cell operation 110,111 and thus the decrease of electrocatalytic surface area, resulting in the degradation of catalyst and the decrease of catalytic activity and fuel cell performance.3,[112][113][114]”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [110] Kou R., 2011, J. Am. Chem. Soc. source
    • cites [111] Siburian R., 2014, Int. Res. J. Pure Appl. Chem. source
    • cites 3,[112][113][114]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Well-defined shapes of Pt-based nanocatalysts can mimic the catalytic property of the bulk metal but exhibit superior catalytic activity due to the manipulation of crystal facet that allows fine-tuning of both selectivity and reactivity for many major catalytic reactions.

    “Well-defined shapes of Pt-based nanocatalysts can mimic the catalytic property of the bulk metal but exhibit superior catalytic activity due to the manipulation of crystal facet 147,148 that allow the fine-tuning of both the selectivity and the reactivity for many major catalytic reactions, so as to achieve high catalytic performance.[149][150][151][152]”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [147] Stamenkovic V. R., 2007, Science source
    • cites [148] Chen J., 2009, Nano Today source
    • cites [149][150][151][152]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Many carbon-supported Pt-alloy catalysts (PtM/C, M = Co, Ni, Cu, Fe, Cr, Au, Pd, W, etc.) have been successfully synthesized.

    “To date, many carbon-supported Pt-alloy catalysts (PtM/C, M = Co, 159,160 Ni, 161 Cu, 159 Fe, [162][163][164] Cr, 165 Au, 166 Pd, 167,168 W, 169 etc.) have been successfully synthesized.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [159] Xiong L., 2005, J. Electrochem. Soc. source
    • cites [160] Kim J. W., 2011, Int. J. Hydrogen, Energy source
    • cites [161] Mukerjee S., 1995, J. Phys. Chem. source

  • May combine two claims.

    Premisecitation

    Pt supported carbon particles are prone to degradation during fuel starvation due to the reaction C + 2H2O → CO2 + 4H+ + 4e-, while the oxidation of carbon is catalyzed by the presence of Pt.

    “Pt supported carbon particles are prone to degradation during fuel starvation due to the reaction (C + 2H 2 O → CO 2 +4 H + +4 e -) while the oxidation of carbon is catalyzed by the presence of Pt. 118”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [118] Passalacqua, E.; Vivaldi, M.; Giordano, N.; Anotonucci, P. L.; Kinoshita, K. Proceedings of the 27th Intersociety Energy Conversion Engineering Conf. ; 1992; Vol.929294, pp3.425–3.431.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A nanostructure with high-index facets exhibits higher catalytic activity than common nanostructures with low-index facets because more atoms are added at the former's steps, edges, and kinks.

    “In addition, it is suggested that a nanostructure with high-index facets exhibits higher catalytic activity than common nanostructures with low-index facets because more atoms are added at the former's steps, edges, and kinks.148,[156][157][158]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites 148,[156][157][158]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Catalyst sintering or agglomeration is another problem for the reduction of fuel cell durability because sintering could reduce the electroactive surface area of the Pt catalyst, lower Pt utilization, and degrade its catalytic activity.

    “Also, catalyst sintering or agglomeration is another problem for the reduction of fuel cell durability because the catalyst sintering could reduce the electroactive surface area of the Pt catalyst, lower the Pt utilization, and degrade its catalytic activity.115”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [115] Garland, N.Fuel Cells Plenary; 2008 DOE Hydrogen Program Merit Review and Peer Evaluation Meeting, 2008.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisereasoning

    The carbon support can be converted to CO2 and Pt may be lost from the electrode, leading to loss of fuel cell performance.

    “The carbon support can be converted to CO 2 and Pt may be lost from the electrode, leading to loss of fuel cell performance.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    With increasing particle size, the catalytic rate per surface site of Au particles sharply increased, whereas a decrease was observed for Pt particles as the particle size decreased.

    “They found that, with increasing particle size, the catalytic rate per surface site of Au particles sharply increased, whereas a decrease was observed for Pt particles as the particle size decreased.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [131] Nørskov J. K., 2008, Chem. Soc. Rev. source
    • cites [132] Meier J., 2004, Chem. Phys. Lett. source

  • May combine two claims.

    Premisecitation

    The catalytic properties of Pt-bimetallic alloy catalysts were determined by the thickness of the Pt skeleton layer, which depended on the initial composition of the Pt-bimetallic alloy catalysts.

    “They found that the catalytic properties were determined by the thickness of the Pt skeleton layer, which depended on the initial composition of the Pt-bimetallic alloy catalysts.173”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [173] Wang C., 2011, Adv. Funct. Mater. source

  • May combine two claims.

    Premisecitation

    The relationship between electrocatalytic activity and alloy composition in Pt-alloy catalysts does not follow a simple monotonic trend, since the concentration of different alloying elements can substantially affect catalytic performance due to resulting changes in intrinsic properties such as electronic structure and surface segregation.

    “However, the relationship between electrocatalytic activity and alloy composition in Pt-alloy catalysts does not follow a simple monotonic trend, since the concentration of different alloying elements can substantially affect the catalytic performance due to the resulting changes in intrinsic properties (e.g., electronic structure and surface segregation).147,170”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [147] Stamenkovic V. R., 2007, Science source
    • cites [170] Wang C., 2012, ACS Catal. source

  • May combine two claims.

    Premisecitation

    Carbon-supported Pt alloy can achieve at least two to four times greater ORR activity compared to Pt/C catalysts, due to a positive shift in the onset potential for OHads formation on the alloy catalyst.

    “It has been reported that carbon-supported Pt alloy can achieve at least two to four times greater ORR activity compared to Pt/C catalysts, due to a positive shift in the onset potential for OH ads formation on the alloy catalyst.13,[123][124][125][126]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites 13,[123][124][125][126]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    With the addition of a metal M, the Pt content in the catalyst decreases, as does the cost of materials.

    “With the addition of a metal (M), the Pt content in the catalyst decreases, as does the cost of materials.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Moderately compressed {111} facets were most conducive to ORR on small nanoparticles, which could result in a compressive strain effect and thus enhance ORR activity.

    “The moderately compressed {111} facets were most conducive to ORR on small nanoparticles, which could result in the compressive strain effect and thus enhance the ORR activity.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [155] Wang J.-X., 2009, J. Am. Chem. Soc. source

  • May combine two claims.

    Interpretationreasoning

    As a result, the precious metal is prone to nucleate first and grow into separate nanoparticles or form Pt-rich regions in the product.

    “As a result, the precious metal is prone to nucleate first and grow into separate nanoparticles or form Pt-rich regions in the product.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [179] Chen M., 2004, J. Am. Chem. Soc. source
    • cites [180] Ahrenstorf K., 2008, Adv. Funct. Mater. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Steric stabilization can be achieved by coordination of sterically demanding nonionic surfactants or polymers that produce strong repulsion between particles and droplets as protective shields on a metallic surface.

    “Steric stabilization is the other mechanism (Figure 5B), 205 which can be achieved by the coordination of sterically demanding nonionic surfactants or polymers that produce strong repulsion between particles and droplets as protective shields on a metallic surface.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [205] L. D. Pachón L. D., 2008, Appl. Organometal. Chem. source

  • May combine two claims.

    Premisecitation

    The size of the CTAB-mediated Pt3Cox/C catalyst increased only slightly from 2.2 to 2.8 nm, because it had a lower annealing temperature of 250 °C, at which agglomeration was not induced.

    “However, the size of the CTABmediated Pt 3 Co x /C catalyst increased only slightly from 2.2 to 2.8 nm, because it had a lower annealing temperature of 250 °C, at which agglomeration was not induced.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [218] Kim J.-W., 2011, Int. J. Hydrogen Energy source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Electrostatic stabilization counterbalances van der Waals attraction by Coulomb repulsion between negatively charged colloidal particles.

    “Electrostatic stabilization is one of the mechanisms: the attraction of van der Waals forces is counterbalanced by the repulsion of the Coulomb forces acting between the negatively charged colloidal particles”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [206] Ozkar S., 2002, J. Am. Chem. Soc. source

  • May combine two claims.

    Premisecitation

    Kim et al. found that particle sizes of 40 wt% Pt3Cox/C were smaller than those of commercial 40 wt% Pt/C; when the amount of stabilizer was 15 times the total moles of Pt and Co, the order of sizes was commercial (3.3 nm) > SA-15 (2.7 nm) > TOAB-15 (2.5 nm) > OAM-15 (2.2 nm).

    “They found that the particle sizes of 40 wt % Pt 3 Co x /C were smaller than those of commercial 40 wt %Pt/C; when the amount of stabilizer was 15 times the total moles of Pt and Co, the order of sizes was commercial ( 3.3 nm) > SA-15 (2.7 nm) > TOAB-15 (2.5 nm) > OAM-15 (2.2 nm)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [218] Kim J.-W., 2011, Int. J. Hydrogen Energy source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The two main mechanisms for stabilization against aggregation are electrostatic stabilization and steric stabilization.

    “The two main mechanisms for stabilization against aggregation 205,206 are shown in Figure 5.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [205] L. D. Pachón L. D., 2008, Appl. Organometal. Chem. source
    • cites [206] Ozkar S., 2002, J. Am. Chem. Soc. source

  • May combine two claims.

    Premisecitation

    The average size of Pt-Ni particles obtained by Jeon et al. using SA as stabilizer was approximately 3.4 nm, regardless of heat treatment, since 300 °C was not sufficient to sinter carbon-supported Pt-Ni alloy nanoparticles and thus resulted in incomplete alloying (~35%).

    “The average size of the obtained Pt-Ni particles was approximately 3.4 nm, regardless of heat treatment, since 300 °C was not sufficient to sinter carbon-supported Pt-Ni alloy nanoparticles and thus resulted in incomplete alloying (∼35%).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [207] Jeon T.–Y., 2009, J. Phys. Chem. C source

  • May combine two claims.

    Premisecitation

    According to Lamer's plot, both a fast nucleation step and gradual growth on formed nuclei can result in a monodispersed and homogeneous alloy nanomaterial, which is advantageous for the synthesis of Pt-alloy nanoparticles with high catalytic activity.

    “According to Lamer's plot, 181 both a fast nucleation step and gradual growth on formed nuclei can result in a monodispersed and homogeneous alloy nanomaterial, which is particularly advantageous for the synthesis of Pt-alloy nanoparticles with high catalytic activity.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [181] Lamer V. K., 1950, J. Am. Chem. Soc. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Protective agents are used to stabilize nanostructured colloidal metal and prevent agglomeration.

    “In general, protective agents are used to stabilize nanostructured colloidal metal and prevent agglomeration.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [202] Bönnemann H., 2004, J. New Mater. Electrochem. Systems

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [203] Bönnemann H., 2004, Chem. Ind. source
    • cites [204] Zhou J., 2009, J. Colloid Interface Sci. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The three carboxyl anions of CA can be adsorbed onto the surface of metal particles and exert either hydrophobic or Coulombic effects on the particles, thereby stabilizing nanoparticles.

    “In particular, the three carboxyl anions of CA can be adsorbed onto the surface of metal particles and exert either hydrophobic or Coulombic effects on the particles, thereby stabilizing nanoparticles.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [211] Ozkar S., 2002, J. Am. Chem. Soc. source

  • May combine two claims.

    Interpretationcitation

    CTAB is the most appropriate stabilizer for the fabrication of the Pt3Cox/C catalyst because the dispersion of Pt-Co particles on the carbon support is much more uniform than in a commercial Pt/C catalyst.

    “It was thus concluded that CTAB is the most appropriate stabilizer for the fabrication of the Pt 3 Co x /C catalyst because the dispersion of Pt-Co particles on the carbon support is much more uniform than in a commercial Pt/C catalyst.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [218] Kim J.-W., 2011, Int. J. Hydrogen Energy source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    According to classical nucleation theory, three key variables control the rate of nucleation: temperature, surface free energy, and degree of supersaturation.

    “According to classical nucleation theory, three key variables control the rate of nucleation: temperature, surface free energy, and degree of supersaturation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [12] Peng Z., 2009, Nano Today source

  • May combine two claims.

    Premisecitation

    Some polymers, including PVP, bind too strongly to the nanoparticle surface to be removed, which can result in decreased catalytic performance.

    “However, some polymers, including PVP, bind too strongly bound to the nanoparticle surface to be removed, which can result in decreased catalytic performance.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [222] Li H., 2007, J. Phys. Chem. C source

  • May combine two claims.

    Premiseown data

    SA as stabilizer was helpful in protecting formed nanoparticles, which had a controlled size and shape, as no marked changes in their shape or size were observed during TEM analysis after heat treatment.

    “It should be mentioned that as a stabilizer, SA was helpful in protecting the formed nanoparticles, which had a controlled size and shape, as no marked changes in their shape or size were observed during the TEM analysis after heat treatment.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [207] Jeon T.–Y., 2009, J. Phys. Chem. C source

  • May combine two claims.

    Premisecitation

    Plane (111) has the lowest surface energy while plane (110) has the highest.

    “Plane (111) has the lowest surface energy while plane (110) has the highest.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [273] Yang H., 2008

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [274] Bönnemanna H., 2010, Appl. Organometal. Chem. source

  • May combine two claims.

    Interpretationreasoning

    Increasing the proportion of the second metal does not monotonically reduce the size of Pt-alloy nanoparticles; their size also often depends on reaction conditions (e.g., synthesis method and heat treatment), in addition to the type of second metal and its content.

    “Notably, increasing the proportion of the second metal does not monotonically reduce the size of Pt-alloy nanoparticles; their size also often depends on the reaction conditions (e.g., the synthesis method and heat treatment), in addition to the type of second metal and its content.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The degree of alloying can be controlled by adjusting the heat treatment temperature, even though high temperature may increase the particle size.

    “Therefore, the degree of alloying can be controlled by adjusting the heat treatment temperature, even though high temperature may increase the particle size.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    In contrast to the shapes of Pt nanoparticles, the shapes of Pt alloys seem to lack variety, probably because it is not easy to control particle shape in the synthesis of Pt alloys supported on carbon, and only a few expected shapes of Pt alloys can achieve high catalytic activity.

    “In contrast to the shapes of the Pt nanoparticles shown in Figure 12, 12 the shapes of the Pt alloys seem to lack variety, probably because, on the one hand, it is not easy to control particle shape in the synthesis of Pt alloys supported on carbon, and on the other hand, only a few of the expected shapes of Pt alloys can achieve high catalytic activity.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    When the amount of urea in the starting Pt-salt aqueous solution was increased, the size of the Pt complex species decreased, as did that of the metallic Pt nanoparticles.

    “It was found that when the amount of urea in the starting Pt-salt aqueous solution was increased the size of the Pt complex species decreased, as did that of the metallic Pt nanoparticles”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4] Fang B., 2009, J. Am. Chem. Soc. source

  • May combine two claims.

    Premiseown data

    Addition of Fe (at atomic ratios of Pt to Fe from 3:1 to 1:6) could effectively prevent Pt particles from agglomerating and decrease the particle size of Pt-Fe/C from 4.4 to 3.2 nm, based on the Pt(220) diffraction peak in XRD spectra.

    “It was observed that the addition of Fe (at atomic ratios of Pt to Fe from 3:1 to 1:6) could effectively prevent Pt particles from agglomerating and decrease the particle size of Pt-Fe/C from 4.4 to 3.2 nm, based on the Pt (220) diffraction peak in XRD spectra.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The area-specific ORR activities of Nafion-coated PtM/C catalysts in O2-saturated 0.1 M HClO4 were 1.3 to 1.8 times higher than that of Pt/C, with the ORR activity increasing in the order Pt/C < PtNi/C < PtFe/C < PtCo/C < PtV/C < PtCr/C.

    “The area-specific ORR activities of Nafion-coated PtM/ C catalysts in O 2 -saturated 0.1 M HClO 4 solution were found to be 1.3 to 1.8 times higher than that of Pt/C, with the ORR activity increasing in the order of Pt/C < PtNi/C < PtFe/C < PtCo/C < PtV/C < PtCr/C.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [255] Yano H., 2007, Langmuir source

  • May combine two claims.

    Premisecitation

    Electrocatalytic activity is shape-dependent, since the electrocatalytic reaction is sensitive to catalyst structure and the reaction rate varies significantly with catalyst shape and/or crystallographic facets.

    “Electrocatalytic activity is shape-dependent, since the electrocatalytic reaction is sensitive to catalyst structure and the reaction rate varies significantly with catalyst shape and/or crystallographic facets.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [267] Guo D.-J., 2012, Electroanalysis source
    • cites [268] Tang Y., 2013, Langmuir source
    • cites [269] Guo S., 2013, J. Am. Chem. Soc.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premiseown data

    Spherical Pd nanocrystals with an average particle size of 4.96 nm were observed in TEM images.

    “Spherical Pd nanocrystals with an average particle size of 4.96 nm were observed in TEM images.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Novel-shaped nanoparticles often exhibit unique physical and chemical properties.

    “Novel-shaped nanoparticles often exhibit unique physical and chemical properties.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Binary Pt-based nanocrystals are highly tunable and are superior to their monometallic counterparts.

    “Binary Ptbased nanocrystals have been extensively investigated since they are highly tunable and are superior to their monometallic counterparts.[300][301][302]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [300][301][302]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The morphology of nanocrystals can be well controlled once a capping agent is selectively adsorbed onto the surface of metal nanoparticles.

    “In other words, the morphology of the nanocrystals can be well controlled once a capping agent is selectively adsorbed onto the surface of the metal nanoparticles.272”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [272] Tao A. R., 2008, Small source

  • May combine two claims.

    Premisecitation

    Inorganic ions and other small molecules can prevent metal nanoparticle size from increasing and affect the shape of formed metal nanoparticles.

    “Similar to organic capping agents, inorganic ions and other small molecules can also prevent metal nanoparticle size from increasing and affect the shape of formed metal nanoparticles.[313][314][315][316][317][318][319][320]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [313][314][315][316][317][318][319][320]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Precise shape-controlled Pt-based alloy electrocatalysts have exhibited great potential to deliver superior ORR activity in PEMFCs and have become a leading focus of research.

    “In recent years, precise shape-controlled Pt-based alloy electrocatalysts have exhibited great potential to deliver superior ORR activity in PEMFCs and thus have become a leading focus of research.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    When hexadecylamine was used as a capping agent, a small portion of cubes was observed, while dodecylamine led to 100% truncated-octahedral Pt3Ni nanocrystals.

    “when hexadecylamine was used as a capping agent, a small portion of cubes was observed (Figure 15a,b) while the use of dodecylamine led to 100% truncated-octahedral nanocrystals of Pt 3 Ni, as shown in Figure 14c.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [288] Wu J., 2010, J. Am. Chem. Soc. source

  • May combine two claims.

    Premisecitation

    Wang et al. reported that a nanocube Pt catalyst was four times more active for the ORR than a Pt nanoparticle, since Pt{111} facets can provide optimal binding energy between platinum atoms and adsorbed species for ORR.

    “Wang et al. reported that a nanocube Pt catalyst was four times more active for the ORR than a Pt nanoparticle, since Pt{111} facets can provide optimal binding energy between platinum atoms and the adsorbed species for ORR.248,341”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [248] Markovic N. M., 1997, J. Electrochem. Soc. source
    • cites [341] Wang C., 2008, Angew. Chem., Int. Ed. source

  • May combine two claims.

    Premisecitation

    Wu et al. reported truncated-octahedral Pt3Ni catalysts with a particle size of 5-7 nm that had a dominant exposure of {111} facets.

    “Wu et al. 288 reported truncated-octahedral Pt 3 Ni (t,o-Pt 3 Ni) catalysts with a particle size of 5-7 nm that had a dominant exposure of {111} facets.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [288] Wu J., 2010, J. Am. Chem. Soc. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Shao's group used an aqueous solution to prepare a sub-10 nm bimetallic core-shell Pd@Pt nanocrystal.

    “In contrast to the nonhydrolytic system mentioned above, an aqueous solution was used by Shao's group 306 to prepare a sub-10 nm bimetallic core-shell Pd@Pt nanocrystal.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [306] Zhang G., 2013, J. Phys. Chem. C source

  • May combine two claims.

    Premisecitation

    Both chemical and physical templates can offer confined spaces and/or functionalized structures for the formation and growth of a Pt alloy.

    “Both chemical and physical templates can offer confined spaces and/or functionalized structures for the formation and growth of a Pt alloy.[327][328][329][330]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [327][328][329][330]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Shaped Pt-based alloy nanostructures often present unusually high catalytic activity.

    “In addition, shaped Pt-based alloy nanostructures often present unusually high catalytic activity.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    PVP was found to be suitable only as an alternative reducing agent, while formaldehyde had a negative effect on formation of regularly shaped PtPd nanocrystals due to possible strong adsorption of several intermediate species decomposed from formaldehyde on the (111) surface.

    “Moreover, PVP was found to be suitable only as an alternative reducing agent, while formaldehyde was found to have a negative effect on the formation of regularly shaped PtPd nanocrystals due to the possible strong adsorption of several intermediate chemical species, decomposed from formaldehyde, on the (111) surface.321,322”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [321] Huang X.-Q., 2009, J. Am. Chem. Soc. source
    • cites [322] Huang X.-Q., 2011, Nat. Nanotechnol. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Soft templates are more common in actual synthesis because they, especially surfactant molecules, can often provide hydrophilic heads and lipophilic long carbon tails favoring the formation of shape-controlled Pt alloys.

    “Compared to hard templates, soft templates are more common in actual synthesis because they, especially surfactant molecules, can often provide hydrophilic heads and lipophilic long carbon tails favoring the formation of shape-controlled Pt alloys.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Well-controlled shapes of Pt-based nanocatalysts can retain the catalytic property of the bulk metal and greatly enhance catalytic activity because the facet can increase the number of Pt active sites.

    “On the basis of the relationship between shape and facet in Pt-alloy nanocrystals, well-controlled shapes of Pt-based nanocatalysts can not only retain the catalytic property of the bulk metal but also greatly enhance the catalytic activity because the facet can increase the number of Pt active sites.34,148,[341][342][343][344][345]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites 34,148,[341][342][343][344][345]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Cheng et al. prepared nest-like Ni1-xPtx spheres of submicrometer sizes through a template-replacement route in which PSA was employed as a soft template.

    “Cheng et al. 335 prepared nest-like Ni 1-x Pt x spheres of submicrometer sizes through a template-replacement route in which poly(styrene-co-methacrylic acid) (PSA) was employed as a soft template.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [335] Cheng F., 2007, Inorg. Chem. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Organic capping agents play a significant role in the synthesis of shape-controlled colloidal metal nanoparticles.

    “It is well-known that organic capping agents play a significant role in the synthesis of shape-controlled colloidal metal nanoparticles.272”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [272] Tao A. R., 2008, Small source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Long hydrophobic carbon chains of organic capping agents provide a steric barrier that prevents direct contact between relatively high energy metallic surfaces and stabilizes metal nanoparticles.

    “In general, long hydrophobic carbon chains of organic capping agents can provide a steric barrier to prevent direct contact between relatively high energy metallic surfaces and therefore stabilize the metal nanoparticles.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Br- and I- in a solution of KBr and KI act as adsorption/protective agents on the surface of Pt-Pd alloy nanoparticles, favoring stabilization of the (100) facet and formation of monodispersed sub-10 nm Pt-Pd tetrahedrons and cubes.

    “Typically, inorganic ions such as Br -and I - in a solution of KBr and KI have proven to be as the adsorption/protective agents on the surface of Pt-Pd alloy nanoparticles, favoring the stabilization of the (100) facet and thus the formation of monodispersed sub-10 nm Pt-Pd tetrahedrons and cubes.320”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [320] Yin A.-X., 2011, J. Am. Chem. Soc. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    A capping agent can be selectively adsorbed onto a specific type of facet because different crystal facets have different atomic arrangement and electronic structures, which bring about relative growth rates along particular crystallographic directions.

    “A capping agent can be selectively adsorbed onto a specific type of facet, since different crystal facets have different atomic arrangement and electronic structures, which bring about the relative growth rates along particular crystallographic directions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisereasoning

    {111} facet has the lowest surface energy among low-index facets, so face-centered cubic crystals always tend to grow along the ⟨100⟩ direction into an octahedron-like shape.

    “Since {111} facet has the lowest surface energy among the low-index facets, facecentered cubic (fcc) of crystals always tends to grow along the ⟨100⟩ direction into an octahedron-like shape.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premiseown data

    Total noble mass-specific activity of Pt/Pd3Fe/C was about five times larger than that of Pt/C at 0.8 V, while Pt/Pd/C had an enhancement factor of 3.

    “the total noble mass-specific activity of Pt/Pd 3 Fe/C was about five times larger than that of Pt/C at 0.8 V, as depicted in Figure 18b, while Pt/Pd/C had an enhancement factor of 3.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Among Pt ML electrocatalysts, those using Pd as substrate were found to be most active and durable, exhibiting highest activity, even higher than Pt(111).

    “Among Pt ML electrocatalysts, those using Pd as the substrate were found to be the most active and durable, 358 exhibiting the highest activity, even higher than Pt (111).351,358”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [358] Sasaki K., 2010, Angew. Chem., Int. Ed. source
    • cites [351] Zhang J., 2005, Angew. Chem., Int. Ed. source

  • May combine two claims.

    Premisecitation

    Adsorption of CO on {100} facets was stronger than on {111} facets, which favors formation of the octahedral shape in the synthesis process.

    “The adsorption of CO on {100} facets was found to be stronger than on {111} facets, which favors the formation of the octahedral shape in the synthsis process.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [287] Wu J., 2011, Nano Lett. source

  • May combine two claims.

    Premisecitation

    Bulky 30 nm Pt3Ni{111} catalyst showed a 10-fold improvement in ORR activity compared to Pt{111} catalyst and was 90 times more active than current state-of-the-art Pt/C catalysts for PEMFCs.

    “Also, the bulky 30 nm Pt 3 Ni{111} catalyst showed a 10-fold improvement in ORR activity compared to Pt{111} catalyst and was 90 times more active than current state-of-theart Pt/C catalysts for PEMFCs.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [147] Stamenkovic V. R., 2007, Science source

  • May combine two claims.

    Premisecitation

    Specific activity of Pt-monolayer catalysts on 4 nm Pd and 4.6 nm Pd3Co cores was about 5- and 9-fold enhanced, respectively, over that of 3 nm Pt nanoparticles, while only 2- and 3-fold enhancements in specific activity can be attributed to nanosize- and lattice mismatch-induced contraction in {111} facets.

    “Their results showed that the specific activity of the Pt-monolayer catalysts on 4 nm Pd and 4.6 nm Pd 3 Co cores was about 5-and 9-fold enhanced, respectively, over that of 3 nm Pt nanoparticles while only the 2-and 3-fold enhancements in specific activity can be attributed to the nanosize-and lattice mismatch-induced contraction in {111} facets.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [155] Wang J.-X., 2009, J. Am. Chem. Soc. source

  • May combine two claims.

    Premisecitation

    According to XRD and HRTEM, the cubic shape was bound by {100} facets, while the octahedral shape was bound by {111} facets.

    “According to their results of XRD and HRTEM, the cubic shape was bound by the {100} facets, while the octahedral shape was bound by {111} facets.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [287] Wu J., 2011, Nano Lett. source

  • May combine two claims.

    Premisecitation

    Kang and Murray showed that cubic Mn-Pt nanocrystals gave higher ORR activity than spherical MnPt nanocrystals in H2SO4 while spherical nanocrystals were more active in HClO4.

    “Kang and Murray 346 showed that the cubic Mn-Pt nanocrystals gave a higher ORR activity than the spherical MnPt nanocrystals in H 2 SO 4 while the spherical nanocrystals were more active in HClO 4 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [346] Kang Y., 2010, J. Am. Chem. Soc. source

  • May combine two claims.

    Premisecitation

    Specific and mass activities of carbon-supported Pt3Ni nanooctahedra were ~7 and ~4 times higher, respectively, than those of commercial Pt/C catalysts.

    “Importantly, the specific and mass activities of carbon-supported Pt 3 Ni nanooctahedra were found to be ∼7 and ∼4 times, respectively, higher than those of the commercial Pt/C catalysts.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [286] Zhang J., 2010, Nano Lett. source

  • May combine two claims.

    Premisecitation

    Wu et al. used CO as gas reducing agent and made two Pt3Ni nanocrystals with octahedral and cubic morphologies.

    “Wu et al. 287 utilized CO as a gas reducing agent and made two Pt 3 Ni nanocrystals with octahedral and cubic morphologies.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [287] Wu J., 2011, Nano Lett. source

  • May combine two claims.

    Premisecitation

    Catalytic evaluation of facet-dependent Pt-alloy nanocrystals also depended on the reaction medium, in agreement with results on catalytic activity of single Pt nanocrystals.

    “This also suggested that the catalytic evaluation of facet-dependent Pt-alloy nanocrystals also depended on the reaction medium, which was in agreement with the results on the catalytic activity of single Pt nanocrystals.347,348”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [347] Markovic N. M., 1995, J. Phys. Chem. source
    • cites [348] Guo S., 2013, Angew. Chem., Int. Ed. source

  • May combine two claims.

    Interpretationcitation

    The ORR activity of Mn-Pt nanocrystals was higher on {111} facet than on {100} facet in HClO4, whereas the ORR activity was higher on {100} facet than on {111} facet in H2SO4.

    “This indicated that the ORR activity of Mn-Pt nanocrystals was higher on {111} facet than on {100} facet in HClO 4 , whereas the ORR activity was higher on {100} facet than on {111} facet in H 2 SO 4 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [346] Kang Y., 2010, J. Am. Chem. Soc. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    To make Pt-alloy nanoparticles with predetermined compositions, a strong reducing agent such as sodium borohydride, hydrazine, or hydrogen is often introduced to reduce all metal precursors simultaneously at proper rates (coreduction).

    “To make Pt-alloy nanoparticles with predetermined compositions, a strong reducing agentsuch as sodium borohydride, hydrazine, or hydrogenis often introduced to reduce all the metal precursors simultaneously at the proper rates (i.e., coreduction).406,[410][411][412][413][414]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites 406,[410][411][412][413][414]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Core-shell structured PtCo/C catalyst made using electroless deposition had similar crystallite size (~2.5 nm) as Pt/C catalyst based on XRD, and its intrinsic activity for ORR was two to four times higher than Pt/C.

    “It was found that the core-shell structured PtCo/C catalyst made using the above method had a similar crystallite size (∼2.5 nm) as that of Pt/C catalyst, based on XRD analysis, and its intrinsic activity for the ORR was found to be two to four times higher than that of Pt/C.227”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [227] Kristian N., 2010, Electrochim. Acta source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Counterions and solvents can change redox potentials and thus reduction reaction rates of given metal ions.

    “Interestingly, counterions and solvents can change the redox potentials and thus the reduction reaction rates of given metal ions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The ordered intermetallic phase was different from the disordered alloy phase, in which all columns have equal intensity and lack the (001) super period.

    “This ordered intermetallic phase was different from the disordered alloy phase, in which all columns have equal intensity and lack the (001) super period.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [376] Wang D., 2013, Nat. Mater. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Colloidal chemical synthesis method is most popular approach for producing carbon-supported PtM (M = Co, Cu, Fe, Ni, Pd, Ru, etc.) nanoparticle catalysts.

    “The colloidal chemical synthesis method is the most popular approach for producing carbonsupported PtM (M = Co, Cu, Fe, Ni, Pd, Ru, etc.) nanoparticle catalysts; [404][405][406][407][408][409]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [404][405][406][407][408][409]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Premisecitation

    Previous work reported low activities for ordered Pt-alloy catalysts such as Pt-Co catalysts due to particle sintering during high-temperature annealing.

    “Although previous work reported low activities for ordered Pt-alloy catalysts such as Pt-Co catalysts, due to particle sintering during high-temperature annealing, attention has recently been given to the ordered alloy phase of Pt intermetallic compounds in an effort to explore more active carbon-supported Pt-alloy catalysts with superior catalytic performance.264,420”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [264] Koh S., 2007, Electrochim. Acta source
    • cites [420] Watanabe M., 1994, J. Electrochem. Soc. source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The disadvantage of coreduction colloidal approach is that it is difficult to synthesize monodispersed alloy nanoparticles of controlled size and composition without using special agents (e.g., a template).

    “The disadvantage of the coreduction colloidal approach is that it is difficult to synthesize monodispersed alloy nanoparticles of controlled size and composition without using special agents (e.g., a template).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    These Pt3Co/C catalysts exhibited over 200% increase in mass activity and over 300% increase in specific activity when compared with disordered Pt3Co alloy nanoparticles as well as Pt/C particles.

    “These Pt 3 Co/C catalysts exhibited over 200% increase in mass activity and over 300% increase in specfic activity when compared with disordered Pt 3 Co alloy nanoparticles as well as Pt/C particles.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    According to theory of excess Gibbs free energy, high temperatures can result in entropy making more of a contribution than enthalpy to change in internal energy; consequently, excess free energy becomes negative, leading to formation of alloys.

    “According to the theory of excess Gibbs free energy, [194][195][196] high temperatures can result in entropy making more of a contribution than enthalpy to the change in internal energy; consequently, the excess free energy becomes negative, leading to the formation of alloys.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [194][195][196]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Pt should preferentially deposit onto metal particle core M in layer-by-layer fashion or Frank-van der Merwe model since lattice mismatch between Pt and M is small and sum of surface energy of depositing metal and interfacial energy is less than surface energy of M substrate metal.

    “In this way, Pt should be preferentially deposited onto the metal particle core M in a layer-by-layer fashion or Frank-van der Merwe (FM) model (see Figure 20), since the lattice mismatch between Pt and M is small, and the sum of the surface energy of the depositing metal and the interfacial energy is less than the surface energy of the M substrate metal.12,[372][373][374][375]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites 12,[372][373][374][375]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisenone given

    After heat treatment at 700 °C, mean particle size of synthesized Pt3Co/C was 5 nm, slightly smaller than value calculated from XRD results.

    “After heat treatment at 700 °C, the mean particle size of the synthesized Pt 3 Co/C was 5 nm, which was slightly smaller than the value calculated from XRD results.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    In electroless deposition method, pH value of synthesis solution determined Pt to Co ratio and thickness of Pt layer outside Co core.

    “In this method, the pH value of the synthesis solution determined the Pt to Co ratio and the thickness of the Pt layer outside of the Co core.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    To obtain chemically ordered Pt-Fe alloy phases, an annealing step was required at 800 °C under 8 vol % H2/Ar.

    “To obtain chemically ordered Pt-Fe alloy phases, an annealing step was required at 800 °C under 8 vol % H 2 /Ar.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [424] Prabhudev S., 2013, ACS Nano source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Lee et al. synthesized a monodispersed nanoparticle electrocatalyst of Pt-Ru supported on Vulcan carbon through coreduction of Pt(acac)2 and Ru(acac)3 using 1,2-hexadecanediol as reducing agent and oleic acid as surfactants.

    “Lee et al. 416 synthesized a monodispersed nanoparticle electrocatalyst of Pt-Ru supported on Vulcan carbon through the coreduction of platinum acetylacetonate (Pt(acac) 2 ) and ruthenium acetylacetonate (Ru(acac) 3 ) using 1,2-hexadecanediol as the reducing agent and oleic acid as the surfactants.417”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [416] Lee Y. H., 2006, Chem. Mater. source
    • cites [417] Liu Z., 2006, Chem. Mater. source

  • May combine two claims.

    Premisecitation

    Botton's group developed a wet impregnation technique to synthesize structurally ordered intermetallic core-shell Pt3Fe2/C alloy catalysts, with an ordered Pt3Fe2 core encapsulated within a bilayer Pt-rich shell.

    “Later, Botton's group developed a wet impregnation technique to synthesize a new structurally ordered intermetallic core-shell Pt 3 Fe 2 /C alloy catalysts, with an ordered Pt 3 Fe 2 core encapsulated within a bilayer Pt-rich shell.424”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [424] Prabhudev S., 2013, ACS Nano source

  • May combine two claims.

    Premisecitation

    To reduce Pt content and at same time substantially alter surface electronic properties and boost catalytic performance, non-Pt metals, especially non-noble metals, have often been employed.

    “To reduce the Pt content and, at the same time, substantially alter the surface electronic properties and boost catalytic performance, non-Pt metals, especially non-noble metals, have often been employed.403”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [403] Kim J., 2011, Electrochem. Solid-State Lett. source

  • May combine two claims. The quote only partly states this claim.

    Premisenone given

    For PtCo/C catalysts with nominal Pt:Co ratio 1:3, the specific activity at pH 2.5 (0.894 mA/cm2 Pt) is higher than at pH 4.0 (0.555) and pH 1.5 (0.497), and higher than Pt/C (0.230).

    “PtCo/C | 2.5 | 2.6 | 3.849 | 2.722 | 16.3 | 1:2.2 | 0.894”
    • Also stated in: § 8. CONCLUSIONS · plain
      “PtCo/C | 4.0 | 2.5 | 3.881 | 2.744 | 17.4 | 1:2.8 | 0.555”
    • Also stated in: § 8. CONCLUSIONS · plain
      “Pt/C | | 2.5 | 3.931 | 2.780 | 22.1 | | 0.230”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    To date, Pt-based catalysts have been considered the most practical for the ORR.

    “To date, Pt-based catalysts have been considered the most practical for the ORR.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Pd2@Pt1/C catalyst presented superior activity and durability in single H2/O2 fuel cell testing at very low Pt loadings (~0.15 mg Pd+Pt cm-2).

    “Furthermore, the Pd 2 @Pt 1 /C catalyst presented superior activity and durability in single H 2 /O 2 fuel cell testing at very low Pt loadings (∼0.15 mg Pd+Pt cm -2 ).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [306] Zhang G., 2013, J. Phys. Chem. C source

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Composition of Pt alloys can play an important role in balancing high catalytic activity and stability.

    “It is well-known that the composition of Pt alloys can play an important role in balancing high catalytic activity and stability.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    Use of metal alloys not only reduces noble metal content but also increases catalytic activity toward the ORR.

    “The use of metal alloys not only reduces the noble metal content but also increases the catalytic activity toward the ORR.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    When reaction time was increased to 42 h, near-surface Pt at.% increased from 30 to 41 even though size, shape, and bulk composition of the two Pt-Ni nanoparticles (Pt:Ni = 46:54) were identical.

    “When the reaction time was increased to 42 h, the near-surface Pt at.% increased from 30 to 41 even though the size, shape, and bulk composition of the two Pt-Ni nanoparticles (Pt:Ni = 46:54) were identical.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [433] Cui C., 2012, Nano Lett. source

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Nanoscale Pt-alloy phases and their corresponding structures (e.g., core-shell) can be successfully controlled by a high-throughput, combinatorial screening method that can identify combinations of alloy phases and compositions, thereby achieving an optimized balance between catalytic activity and stability.

    “From an engineering perspective, nanoscale Pt-alloy phases and their corresponding structures (e.g., the core-shell structure) can be successfully controlled by a high-throughput, combinatorial screening method that can identify the combinations of alloy phases and compositions, thereby achieving an optimized balance between catalytic activity and stability.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    At 80 °C, 100% RH, 3 bar abs, H2/O2, the current density is 0.65-1.31 A cm-2 at 0.6 V and the maximum power density is 885 mW cm-2.

    “(80 °C, 100% RH, 3 bar <abs>, H 2 /O 2 ): current density of 0.65-1.31A cm -2 at 0.6 V and maximum power density of 885 mW cm -2”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    All these factors dictate what materials and synthetic strategy will be selected, so as to achieve technological breakthroughs in the microstructure and performance of ORR catalysts.

    “All these factors dictate what materials and synthetic strategy will be selected, so as to achieve technological breakthroughs in the microstructure and performance of ORR catalysts.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The ORR at the cathode is the rate-determining step in the whole set of fuel cell reactions due to its sluggishness in comparison with the anode reaction.

    “The ORR at the cathode is the rate-determining step in the whole set of fuel cell reactions due to its sluggishness in comparison with the anode reaction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    At 110 °C, 25% RH, 1.5 bar, H2/O2, the current density is 0.5 A cm-2 at 0.6 V and the maximum power density is 700 mW cm-2.

    “110 °C, 25% RH, 1.5 bar, H 2 /O 2 ): current density of 0.5 A cm -2 at 0.6 V and maximum power densities of 700 mW cm -2”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Premisecitation

    Dealloyed binary PtM3 catalysts showed more than 3-fold improvement in ORR activity for M = Co, Cu, and close to a 3-fold improvement for M = Ni in terms of Pt-mass activity (~0.275 A mg-1 Pt) in single fuel cell tests, compared to a 45 wt % Pt/C reference cathode catalyst.

    “The dealloyed binary PtM 3 catalysts showed a more than 3-fold improvement in the ORR activity for M = Co, Cu, and close to a 3-fold improvement for M = Ni in terms of the Pt-mass activity (∼0.275A mg -1 Pt )i n single fuel”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [259] Remona A. M., 2011, J. Fuel Cell Sci. Technol. source

  • May combine two claims.

    Premisenone given

    At 80 °C, 33% RH, 3 bar abs, 1 M H2SO4, H2/O2, the current density is 1.0-1.4 A cm-2 at 0.6 V and the maximum power density is 840 mW cm-2.

    “(80 °C, 33% RH, 3 bar <abs>, 1 M H 2 SO 4 ,H 2 /O 2 ): current density of 1.0-1.4A cm -2 at 0.6 V and maximum power density of 840 mW cm -2”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Premisecitation

    For PtCo/C (3:1), increasing heat-treatment temperature from 600 to 1100 °C increases particle size from 3.83 to 8.63 nm.

    “2 | Co (3:1) | furnace (N 2 /10% H 2 ) | 600/2.5 700/2.5 | 3.83 2.95 | 3.855 3.876 | fcc, Pt 3 M | 61 c | 2000, 55”
    • Also stated in: § 8. CONCLUSIONS · plain
      “1100/2.5 | 8.63 | 3.868 | | 75 c |”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [2000]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [55] Min M., 2000, Electrochim. Acta source

  • May combine two claims.

    Interpretationreasoning

    Dissolution of nonprecious metal(s) is not beneficial to the stability of Pt-alloy and results in deteriorating fuel cell performance, particularly under long-term operation of fuel cells.

    “But this dissolution of nonprecious metal(s) is not beneficial to the stability of Pt-alloy and results in a deteriorating fuel cell performance, in particular under the long-term operation of fuel cells.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In a PEMFC, the cathode ORR is known 6 or more orders of magnitude slower than the anode hydrogen oxidation reaction and thus results in a limitation of overall fuel cell performance.

    “In a PEMFC, the cathode ORR is known 6 or more orders of magnitude slower than the anode hydrogen oxidation reaction 121,279 and thus results in a limitation of the overall fuel cell performance.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [121] Debe M. K., 2012, Nature source
    • cites [279] Li W., 2010, J. Power Sources source

  • May combine two claims.

    Premisecitation

    The degree of dealloying of Pt-Co and Pt-Ni binary systems was lower than that of Pt-Cu compounds, as evidenced by 15-20 at.% non-noble metals near the surface and in the bulk of dealloyed particles, whereas Pt-Cu formed core-shell structures with a Pt-rich surface and a Pt-Cu core under the same dealloying conditions.

    “The degree of dealloying of Pt-Co and Pt-Ni binary systems was lower than that of Pt-Cu compounds, as evidenced by the presence of around 15-20 at.% non-noble metals near the surface and in the bulk of the dealloyed particles, whereas under the same dealloying conditions, Pt-Cu formed core-shell structures with a Ptrich surface and a Pt-Cu core.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [259] Remona A. M., 2011, J. Fuel Cell Sci. Technol. source

  • May combine two claims.

    Premisecitation

    Pt content increased and catalytic activity decreased when catalyst dealloying time increased from 12 to 72 h for Pt1Ni3/C catalysts.

    “It was found that the Pt content increased and the catalytic activity decreased when the catalyst dealloying time increased from 12 to 72 h.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [434] Wagner, F. T.DOE Hydrogen and Fuel Cells Program: FY 2012, Annual Progress Report, V.D.12 High-Activity Dealloyed Catalysts, General Motors, LLC (GM).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Premisenone given

    Due to high cost and limited supply of Pt, reducing Pt loading in the catalyst layer and thus the cost of PEMFCs has become one of the key targets to achieve widespread commercialization.

    “However, due to the high cost and limited supply of Pt, reducing Pt loading in the catalyst layer and thus the cost of the PEMFCs has become one of the key targets to achieve their widespread commercialization.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Pt is costly and its supply is limited.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The most common strategy in Pt load reduction is alloying Pt with other metal elements to form Pt-alloy catalysts.

    “The most common strategy in Pt load reduction is alloying Pt with other metal elements to form Ptalloy catalysts.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Although size, shape, and composition of Pt-alloy nanoparticles are all key parameters in design and preparation of Pt-alloy nanocatalysts, a desirable particle shape has been recognized to play a more dominant role in improvement of ORR catalysis in PEMFCs.

    “Although the size, shape, and composition of Pt-alloy nanoparticles are all key parameters in the design and preparation of Pt-alloy nanocatalysts, a desirable particle shape (e.g., octahedral, tetrahedral, cubic, etc.) has been recognized to play a more dominant role in the improvement of ORR catalysis in PEMFCs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    At 130 °C, 100% RH, 3 bar, H2/O2, current density was 1.59 A cm-2 and maximum power density exceeded 1000 mW cm-2; after 1500 cycles, particle size of metal increased from 2.9 to 3.7 nm at 0.9-0.7 V/cell.

    “(3) (130 °C, 100% RH, 3 bar, H 2 /O 2 ): current density of 1.59 A cm -2 and maximum power density exceeding 1000 mW cm -2 .After 1500 cycles, the particle size of metal increased from 2.9 to 3.7 nm at 0.9-0.7 V/cell.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Increase of particle size and change of crystal parameters after degradation suggest that carbon-supported Pt-alloy catalyst should not only exhibit high ORR activity but also have physicochemical and electrochemical stability so that the catalyst can be utilized in commercial PEMFC with low PGM loading ≤0.125 mg cm-2.

    “The increase of particle size and the change of crystal parameters after the degradation suggest that the carbon supported Pt-alloy catalyst should not only be able to exhibit a high ORR activity but also have a physicochemical and electrochemical stability so that the catalyst can be utilized in the commercial PEMFC with a low PGM loading equal to or lower than 0.125 mg cm -2 .”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    RDE test results in 0.1 M HClO4 for catalysts with Pt:Pd molar ratios of 1:3, 1:2, 2:3, 1:1, and 1:2 revealed dependence on Pt shell morphology with Pd2@Pt1/C (1:2) having the highest mass activity and Pd1@Pt2/C (2:1) having the best area-specific activity; both values were significantly better than those of commercial Pt/C catalysts.

    “The RDE test results in 0.1 M HClO 4 for catalysts with Pt:Pd molar ratios of 1:3, 1:2, 2:3, 1:1, and 1:2 revealed dependence on the Pt shell morphology with Pd 2 @Pt 1 /C (molar ratio of Pt:Pd = 1:2) having the highest mass activity and Pd 1 @Pt 2 /C (molar ratio of Pt:Pd = 2:1) having the best area-specific activity; both values were significantly better than those of commercial Pt/C catalysts.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [306] Zhang G., 2013, J. Phys. Chem. C source

  • May combine two claims.

    Interpretationreasoning

    Although many scientists obtained carbon-supported Pt-alloy catalysts with two or more fold higher ORR activity by RDE than commercial Pt/C, performance of H2/O2 (or air)-PEMFCs with MEAs fabricated with these catalysts did not show direct correlation with RDE performance, and these catalysts still need improvement to meet commercial PEMFC requirements in cost, durability, power density, and Pt加载.

    “Although many scientists were able to obtain carbon supported Pt-alloy catalysts with a two or more fold higher ORR activity, measured by the rotating disk electrode (RDE) technique, than that of the commercial Pt/C, the performance of H 2 /O 2 (or air)-PEMFCs with MEAs fabricated with these catalysts did not show direct correlation with the performance obtained through RDE tests, and as a result,”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Catalytic activity of monodispersed Pt-alloy nanoparticle catalysts supported on carbon is often found to depend on Pt-alloy shape, and optimal ORR activity can be achieved by controlling this shape.

    “With more and more recent discoveries in the development of advanced Pt-based catalysts, the catalytic activity of monodispersed Pt-alloy nanoparticle catalysts supported on carbon is often found to depend on Ptalloy shape, and optimal ORR activity can be achieved by controlling this shape.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Core-shell structured Pt-alloy nanocatalysts have been proven capable of greatly enhancing not only ORR activity but also catalyst durability due to electronic and strain effects that arise on the nanostructured surface, which can be adjusted by selection of various materials and different synthesis routes.

    “Core-shell structured Pt-alloy nanocatalysts have been proven capable of greatly enhancing not only the ORR activity but also the catalyst durability due to the electronic and strain effects that arise on the nanostructured surface, which can be adjusted by the selection of various materials and different synthesis routes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Materials selection and synthesis methods both play a key role in formation of desirable catalyst structures with enhanced ORR activity.

    “This review reveals that materials selection and synthesis methods both play a key role in the formation of desirable catalyst structures with enhanced ORR activity.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    In wet chemical synthesis, chemistry of liquid-solid interfaces (e.g., chemical reactivity of crystal planes) plays an essential role in size- and direction-controlled growth of nanostructures for catalysts, under reaction conditions including protective agent, reaction medium, pH value, pressure, and temperature.

    “In wet chemical synthesis, the chemistry of liquid-solid interfaces (e.g., the chemical reactivity of crystal planes) plays an essential role in the size-and direction-controlled growth of nanostrucures for catalysts, under a set of reaction conditions that include protective agent, reaction medium, pH value, pressure, and temperature.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Premiseown data

    For Pt/C, increasing annealing temperature from 350 to 950 °C increases crystallite size from 2 to 13.8 nm.

    “Pt/C | 350 | 100:0 | 3.92 | 2 | 2.3 ± 0.8 | 6 ± 3”
    • Also stated in: § 8. CONCLUSIONS · plain
      “Pt/C | 950 | 100:0 | 3.92 | 13.8 | 9 ± 21 1 ± 3”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    After electrochemical treatment in 0.1 M HClO4, Pt-based mass activities increased 5-fold from Pt/C to Pt1Co3/C in the order Pt/C < Pt1Co1/C < Pt3Co1/C < Pt1Co3/C, with similar particle sizes of 3-4 nm.

    “After electrochemical treatment in 0.1 M HClO 4 , the Pt-based mass activities increased 5-fold from Pt/C to Pt 1 Co 3 /C in the order of Pt/C < Pt 1 Co 1 /C < Pt 3 Co 1 /C < Pt 1 Co 3 /C, with similar particle sizes of 3-4 nm.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [175] Oezaslan M., 2012, J. Electrochem. Soc. source
141 of 141

  • The paper relies on this without support.

    Very little theoretical work has been conducted to evaluate the effects of nanoparticle shape on ORR activity.

    “However, in contrast to the growing number of studies on the correlation between the size of spherical nanoparticles and their catalytic activity, very little theoretical work has been conducted to evaluate the effects of nanoparticle shape on ORR activity since these structures are not easily accessible.”

  • The authors state this as an assumption.

    The specific activity of a catalyst for the ORR is independent of particle size.

    “while the specific activity is assumed to be independent of the particle size.”

  • The paper relies on this without support.

    Pd is at least 50 times more abundant on earth than Pt.

    “it is at least 50 times more abundant on the earth than Pt”

  • The paper relies on this without support.

    Very small Pt-alloy particles (<2 nm) are significantly prone to agglomeration or corrosion under practical synthesis conditions.

    “very small particles (<2 nm) are significantly prone to agglomeration or corrosion under practical synthesis conditions.”

  • The paper relies on this without support.

    The high cost of Pt catalysts used in PEMFC electrodes represents about 30-40% of the total cost of the fuel cell.

    “One of the major factors limiting PEMFC commercialization is the high cost of Pt catalysts used in the electrodes, as this represents about 30-40% of the total cost of the fuel cell.”

  • The paper relies on this without support.

    Pt is costly and its supply is limited.

    “However, due to the high cost and limited supply of Pt, reducing Pt loading in the catalyst layer and thus the cost of the PEMFCs has become one of the key targets to achieve their widespread commercialization.”
6 of 6

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conflicting shares of fuel-cell cost

    Minor

    The introduction says Pt-based electrocatalysts account for over 55% of total cost, whereas Section 6 puts the Pt catalysts used in the electrodes at about 30-40% of the fuel cell's total cost.

  • Listed Pt:Pd ratios omit a catalyst subsequently compared

    Minor

    The stated ratio list repeats 1:2 and contains no 2:1 ratio, yet the same sentence evaluates a Pd1@Pt2/C catalyst explicitly identified as Pt:Pd = 2:1.

  • Two incompatible activity ranges for the synthesized PtM catalysts

    Minor

    One passage says the PtM/C catalysts achieved 3-4.5 times the mass activity of Pt/C. The next says the lowest-activity member of those synthesized catalysts achieved only about 1.5 times the activity of Pt.

  • Specific-activity value differs by a factor of 1,000

    Minor

    The narrative reports approximately 0.248 A/cm2 for the dealloyed Pt-Ni catalyst, while Table 8 gives 248 μA/cm2 for that catalyst. The table value equals 0.000248 A/cm2.

  • Highest-activity Pd@Pt composition is outside the stated series

    Minor

    The described series specifies x values of 1.0, 1.5, and 2.0, but the catalyst said to have the highest mass activity has x = 0.5.

  • Co alloy ratio conflicts with the catalysts identified

    Minor

    The stated Pt:Co ratio of 1:3 does not match either PtCo/C (1:1) or Pt3Co/C (3:1), the Co alloys identified in the same discussion and table.

6 of 6

Cites

Flagged first, then by citations

4 of the 412 references couldn’t be matched to a known paper.

Research works printed but not linked: 21

  1. Li Y. M., 2010, Nano Lett., 10, 1078
  2. Appleby, A. J.InThe Electrocatalysis of Fuel Cell Reactions;Dudley, R.; O’Grady, W.; Srinivasan, S., Eds.; The Electrochemical Society Softbound Proceedings Series, PV 79–2, Princeton, NJ, 1979; p23.
  3. Garland, N.Fuel Cells Plenary; 2008 DOE Hydrogen Program Merit Review and Peer Evaluation Meeting, 2008.
  4. Passalacqua, E.; Vivaldi, M.; Giordano, N.; Anotonucci, P. L.; Kinoshita, K. Proceedings of the 27th Intersociety Energy Conversion Engineering Conf. ; 1992; Vol.929294, pp3.425–3.431.
  5. Olveira S., 2014, Nanotechnology, 2014, 324089
  6. Mullin J. W., 1997, Crystallization
  7. Volmer M., 1926, Phys. C, 227, 119
  8. Bönnemann H., 2004, J. New Mater. Electrochem. Systems, 7, 93
  9. Ozkar S., 2002, J. Am. Chem. Soc., 124, 5796, 10.1021/ja012749v · DOI · Paper page
  10. Kim J.-W., 2011, Int. J. Hydrogen Energy, 36, 12088, 10.1016/j.ijhydene.2011.06.137 · DOI · Paper page
  11. Guo S., 2013, J. Am. Chem. Soc., 135, 13869
  12. Wu J., 2013, Acc. Chem. Res., 46, 1848, 10.1021/ar300359w · DOI · Paper page
  13. Yang H., 2008, Metal Nanoclusters in Catalysis and Materials Science: The Issue of Size Control. Part II: Methodologies
  14. Chen C., 2014, Science, 343, 1339, 10.1126/science.1249061 · DOI · Paper page
  15. Han L., 2014, Nature, 4, 6414
  16. Nilekar A. U., 2007, Top. Catal., 46, 276, 10.1007/s11244-007-9001-z · DOI · Paper page
  17. Okaya K., 2010, ACS Appl. Mater. Interfaces, 2, 888, 10.1021/am9008693 · DOI · Paper page
  18. Sarkar A., 2010, J. Phys. Chem. C, 114, 4725, 10.1021/jp908933r · DOI · Paper page
  19. Jalan V., 1983, J. Electrochem. Soc., 130, 2299, 10.1149/1.2119574 · DOI · Paper page
  20. Shimazaki Y., 2005, J. Colloid Interface Sci., 292, 122, 10.1016/j.jcis.2005.05.052 · DOI · Paper page
  21. Yang S.-C., 2008, Adv. Funct. Mater., 18, 1

Cited by

Sorted by citations

Related

Authors
Wang, Y.-J., Zhao, N., Fang, B., Li, H., Bi, X. T., & Wang, H.
Affiliations
  • University of British Columbia (CA)
  • Vancouver International Clean-Tech Research Institute Inc., 4475 Wayburne Drive, Burnaby, Canada V5G 4X4
  • National Research Council Canada (CA)
Corresponding author
  • Li, Hui
  • Bi, Xiaotao T.
  • Wang, Haijiang
ORCID
Venue
Chemical Reviews
Publisher
American Chemical Society (ACS)
Published
2015-04-14
Volume
115
Issue
9
Pages
3433-3467
ISSN
  • 0009-2665 (ISSN-L)
  • 1520-6890
DOI
10.1021/cr500519c
OpenAlex
W2039922946
Cited by
1,267
References
412
Citations by year
2026: 42 · 2025: 64 · 2024: 97 · 2023: 83 · 2022: 117 · 2021: 118 · 2020: 150 · 2019: 164 · 2018: 174 · 2017: 121 · 2016: 105 · 2015: 30 · 2014: 1
FWCI
4.71
Type
journal article
Language
en
Open access
Locations
  • Chemical Reviews (publishedVersion)
  • PubMed (publishedVersion)
  • NPARC (submittedVersion)
Funders
  • Vancouver International CleanTech Research Institute
  • Natural Sciences and Engineering Research Council of Canada (452756-13)
Topics
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Electrocatalysts for Energy Conversion
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Fuel Cells and Related Materials
  • Physical Sciences › Materials Science › Materials Chemistry › Catalytic Processes in Materials Science
Keywords
oxygen reduction reaction, proton exchange membrane fuel cells, carbon-supported catalysts, particle size effects, particle shape control, composition control, catalytic activity

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-11.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-11.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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