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Cited by 41Electrocatalysts for Energy ConversionAdvanced Photocatalysis TechniquesCO2 Reduction Techniques and Catalysts

Bimetallic Ni–Co selenide heterostructure aerogel for highly efficient overall water splitting

Open access
Liu, Hongchen, Yang, Fan, Chen, Fengjiang, Che, Sai, Chen, Neng, Xu, Chong, Wu, Ni, Wei, Wenkai +1 more·2023·Materials Chemistry Frontiers
DOI 10.1039/d2qm01082h
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Abstract

A high-performance NiSe 2 –CoSe 2 aerogel was prepared via facile gelation and selenium vapor deposition for efficient water splitting. Its heterostructure and aerogel morphology provided high intrinsic activity and abundant active sites, respectively.

AI snapshot

Written from the paper’s full text.

TL;DR

A bimetallic NiSe₂–CoSe₂ heterostructure aerogel was made by gelation and selenium vapor deposition and used as a bifunctional electrocatalyst for alkaline water splitting. The optimized 1:1, 400 °C sample showed low HER/OER overpotentials and a 1.56 V overall cell voltage at 10 mA cm⁻², matching Pt/C + RuO₂.

Key findings

  • The optimized NiSe₂–CoSe₂ aerogel required 65 mV overpotential for HER and 220 mV for OER at 10 mA cm⁻² in 1 M KOH; the two-electrode overall water splitting cell reached 10 mA cm⁻² at 1.56 V, equal to the Pt/C + RuO₂ device.
  • Stability tests retained 97% of initial HER current, 93% of initial OER current, and 91% of initial overall water splitting current after 40 h; gas evolution showed an H₂:O₂ ratio near 2:1, indicating nearly 100% Faradaic efficiency.
  • The heterostructure outperformed single selenides and the Ni–Co alloy aerogel: HER overpotentials were 131 mV for NiSe₂, 173 mV for CoSe₂, and 94 mV for Ni–Co; OER overpotentials were 304 mV, 289 mV, and 265 mV, respectively, while RuO₂ required 251 mV.
  • DFT attributed the improved HER to a Co site with ΔG_H* of −0.18 eV, closer to zero than Ni (−0.26 eV), Ni–Co (−0.32 eV), NiSe₂ (−0.40 eV), and CoSe₂ (−0.49 eV); for OER, the *OOH formation step had the largest barrier at 1.86 eV, with a 0.43 eV difference between the HO*→O* and O*→OOH* steps.

Methods

  • Synthesis: Ni–Co hydrogels were formed by NaBH₄ reduction and spontaneous gelation of mixed Ni²⁺/Co²⁺ solutions, freeze-dried into aerogels, then selenized with Se vapor at 400 °C for 120 min under Ar; Ni:Co ratios and selenization temperatures were varied for comparison.
  • Characterization: SEM, TEM/EDS, ICP-OES, XRD, and XPS were used to examine morphology, composition, crystalline phases, and surface chemical states.
  • Electrochemistry: carbon cloth electrodes were tested in 1 M KOH using a three-electrode setup for HER/OER and a two-electrode cell for overall water splitting; LSV, EIS, CV-derived double-layer capacitance, and chronoamperometry were used. DFT calculations employed DMol³ with GGA-PBE, effective core potentials, DNP basis sets, and constructed Ni–Co, NiSe₂, CoSe₂, and NiSe₂–CoSe₂ models.

Limitations

  • The paper does not state a dedicated limitations section.
  • Evident from the text: the DFT model was simplified to focus on the bimetallic selenide heterostructure, excluding surface oxidation and unselenized metal phases, so it may not fully represent the working catalyst surface.
  • Evident from the text: OER stability loss was partly attributed to catalyst detachment caused by oxygen bubble overflow, and the anodic catalyst transformed into hydroxides/oxyhydroxides during OER, indicating that the as-prepared selenide is not the sole active phase under operation.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1039/d2qm01082h

Cites

48 of 48 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

9 of 36 cited sources checked · 2 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Noble-metal catalysts currently give the best electrocatalytic water splitting performance at low operating voltage.

    “Currently, noble metal-based catalysts show the best performance for electrocatalytic water splitting with a low operating voltage.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [3] 3. J. Zhu, L. Hu, P. Zhao, L. Y. S. Lee and K. Y. Wong, Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles, Chem. Rev., 2020, 120, 851-918. source

      The section on supporting materials identifies platinum-group metals as the most effective catalysts for the hydrogen evolution reaction, citing their low overpotentials. The Conclusion and Perspective distinguishes that reaction from oxygen evolution, which also determines water-splitting efficiency. The cited evidence therefore supports the claim for hydrogen evolution, but not the broader claim that noble-metal catalysts give the best performance or low operating voltage for overall water splitting; page numbers were unavailable. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [4] 4. E. Fabbri, A. Habereder, K. Waltar, R. Ko ¨tz and T. J. Schmidt, Developments and perspectives of oxide-based catalysts for the oxygen evolution reaction, Catal. Sci. Tech- nol., 2014, 4, 3800-3821. source

      The Introduction describes high voltage efficiencies in acidic polymer-electrolyte water electrolysers, whose electrodes are generally catalysed by noble metals. Section 3.1 identifies RuO₂ as the most active single-metal oxide catalyst for those systems. The paper does not establish that noble-metal catalysts give the best low-voltage performance across electrocatalytic water-splitting systems generally. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Interpretationcitation

    In situ generated H2 from Ni/Co reduction and NaBH4 hydrolysis acts as a gas template that directs formation of the porous interconnected network.

    “During this step, the in situ generated H 2 gas from the reduction of Ni, Co elements and the hydrolysis of NaBH 4 served as the gas template, directing the formation of porous interconnected networks (Fig. S1, ESI †).31,32”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [31] 31. B. Zhang, F. Yang, X. Liu, N. Wu, S. Che and Y. Li, Phosphorus doped nickel-molybdenum aerogel for efficient overall water splitting, Appl. Catal., B, 2021, 298, 120494. source

      Section 3.1 (p. 3) says H₂ generated by NaBH₄ hydrolysis could serve as a gas template for porous, sponge-like aerogel structures, and describes an interconnected skeleton. It discusses Ni–Mo synthesis, not H₂ generated from Ni/Co reduction; its later mention of Ni–Co aerogels (Section 3.1, p. 4) does not establish that part of the claim. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [32] 32. L. Liu, L. X. Chen, A. J. Wang, J. Yuan, L. Shen and J. J. Feng, Hydrogen bubbles template-directed synthesis of self- supported AuPt nanowire networks for improved ethanol oxidation and oxygen reduction reactions, Int. J. Hydrogen Energy, 2016, 41, 8871-8880. source
  • Findingown data

    The NiSe2-CoSe2 aerogel had the lowest charge transfer resistance (12.16 Ω) among the tested aerogels, compared with NiSe2 (39.70 Ω), CoSe2 (59.51 Ω), and Ni-Co (25.87 Ω).

    “Compared with NiSe 2 (39.70 O), CoSe 2 (59.51 O), and Ni-Co (25.87 O) aerogels, the NiSe 2 -CoSe 2 showed the lowest R ct of 12.16 O, indicating the enhanced charge transfer ability offered by the heterostructure.”
    Quote in the paperSubstantial claim
  • Findingown data

    The XRD pattern of the cathodic NiSe2-CoSe2 aerogel after the stability test showed characteristic peaks of NiSe2, CoSe2, Ni, and Co identical to the unreacted sample.

    “The characteristic peaks of selenides (NiSe 2 and CoSe 2 ) and metal elements (Ni and Co) that are identical to the unreacted sample could be observed in the XRD pattern of the cathodic NiSe 2 -CoSe 2 aerogel, suggesting that the overall structure and composition of the tested hybrid was unaltered.”
    Quote in the paperSubstantial claim
  • Findingown data

    NiSe2-CoSe2 showed the best electron conductive performance among the prepared samples.

    “NiSe 2 -CoSe 2 showed the best electron conductive performance, which further supported the optimal preparation conditions.”
    Quote in the paperSubstantial claim
  • May combine two claims. 31
  • Classified as probably not a substantial claim. 6
  • The quote only partly states this claim. 1

  • May combine two claims.

    Interpretationcitation

    The shift and overlap of NiSe2 and CoSe2 XRD peaks at 30-40 degrees indicate lattice distortion from interaction between the two selenides and support heterostructure formation.

    “Compared with the standard cards, the shift and superposition of NiSe 2 and CoSe 2 characteristic peaks at 301-401 could be observed, which was attributed to the lattice distortion caused by the interaction between the two selenide crystals, thus proving the formation of a bimetallic selenide heterostructure.37,38”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [37] 37. B. Jansi Rani, G. Ravi, R. Yuvakkumar, B. Saravanakumar, M. Thambidurai, C. Dang and D. Velauthapillai, CoNiSe 2- Nanostructures for Clean Energy Production, ACS Omega, 2020, 5, 14702-14710. source

      The Results and Discussion XRD passage says all three samples matched their standard diffraction patterns, contrary to the claimed shift from the standard cards. It identifies a distinct hexagonal CoNiSe2 pattern and confirms binary selenide formation, but does not attribute that formation to overlapping NiSe2 and CoSe2 peaks or interaction-induced lattice distortion. Page numbers are unavailable in our copy. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [38] 38. C. Liu, T. Gong, J. Zhang, X. Zheng, J. Mao, H. Liu, Y. Li and Q. Hao, Engineering Ni2P-NiSe2 heterostructure interface for highly efficient alkaline hydrogen evolution, Appl. Catal., B, 2020, 262, 1-8. source

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

    Premisecitation

    A Ni-Mo-P aerogel has larger electrochemical surface area and better HER performance than nanowires of the same composition.

    “In contrast to the nanowires with the same composition, the Ni-Mo-P aerogel exhibits a larger electrochemical surface area and a better HER performance.31”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [31] 31. B. Zhang, F. Yang, X. Liu, N. Wu, S. Che and Y. Li, Phosphorus doped nickel-molybdenum aerogel for efficient overall water splitting, Appl. Catal., B, 2021, 298, 120494. source

      Section 3.2 reports better HER performance for a Ni-Mo aerogel than for Ni-Mo nanowires and attributes it to the aerogel’s higher surface area. It also reports strong HER performance for the Ni-Mo-P aerogel, but does not compare its HER performance or electrochemical surface area with Ni-Mo-P nanowires. The nanowire comparison therefore does not establish the claim for materials of the same Ni-Mo-P composition. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    The high cost and limited reserves of noble metals prevent their large-scale use.

    “However, high cost and low reserves dramatically prevent their large-scale application.3,4”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [3] 3. J. Zhu, L. Hu, P. Zhao, L. Y. S. Lee and K. Y. Wong, Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles, Chem. Rev., 2020, 120, 851-918. source
    • cites [4] 4. E. Fabbri, A. Habereder, K. Waltar, R. Ko ¨tz and T. J. Schmidt, Developments and perspectives of oxide-based catalysts for the oxygen evolution reaction, Catal. Sci. Tech- nol., 2014, 4, 3800-3821. source

  • May combine two claims.

    Findingcitation

    Ni-rich NiSe2-CoSe2-2:1 and NiSe2 aerogels form networks of small nanoparticles, whereas NiSe2-CoSe2-1:2 and CoSe2 consist of larger nanoparticles without a clear network skeleton.

    “Notably, the NiSe 2 -CoSe 2 -2 : 1 and NiSe 2 aerogels with a higher Ni content tended to form the network structure composed of comparatively small nanoparticles (Fig. S4(a) and (c), ESI †), while the NiSe 2 -CoSe 2 -1 : 2 and CoSe 2 were entirely comprised of larger nanoparticles without an appreciable network skeleton (Fig. S4(b) and (d), ESI †).35”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [35] 35. K. Deng, T. Ren, Y. Xu, S. Liu, Z. Dai, Z. Wang, X. Li, L. Wang and H. Wang, Transition metal M (M = Co, Ni, and Fe) and boron co-modulation in Rh-based aerogels for highly efficient and pH-universal hydrogen evolution electrocatalysis, J. Mater. Chem. A, 2020, 8, 5595-5600. source

      The Results and discussion section describes a network of small particles in RhCoB aerogels; its Fig. S4 concerns nitrogen adsorption, not images of nickel or cobalt selenides. Searches for NiSe2–CoSe2 compositions and their comparative nanoparticle morphology found no passage addressing the claimed materials. (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Efficient HER catalysts need moderate H* adsorption/desorption, while efficient OER catalysts need balanced O* binding between OH* and OOH*.

    “Basically, high performance electrocatalysts for the HER require moderate adsorption/desorption properties with H*, while high performance electrocatalysts for the OER need balanced binding energy of O* between OH* and OOH*.3,13”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [3] 3. J. Zhu, L. Hu, P. Zhao, L. Y. S. Lee and K. Y. Wong, Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles, Chem. Rev., 2020, 120, 851-918. source

      Section 3.6, “Hydrogen bonding energy” (page unavailable), says an ideal HER catalyst binds hydrogen neither too weakly nor too strongly, supporting the H* part. The Conclusion and Perspective mentions the importance of OER catalysts but does not describe balanced O* binding between OH* and OOH*; searches for those intermediates found no supporting passage. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [13] 13. J. Mohammed-ibrahim and H. Moussab, Tuning the electronic structure of the earth-abundant electrocatalysts for oxygen evolution reaction (OER) to achieve efficient alkaline water splitting -A review, J. Energy Chem., 2021, 56, 299-342. source

  • May combine two claims.

    Findingown data

    The Cdl value of the NiSe2-CoSe2 aerogel was 18.50 mF cm−2, higher than NiSe2 (3.64 mF cm−2), CoSe2 (3.25 mF cm−2), and Ni-Co (1.16 mF cm−2).

    “The C dl value of the NiSe 2 -CoSe 2 aerogel was calculated to be 18.50 mF cm À2 , which was higher than that of NiSe 2 (3.64 mF cm À2 ), CoSe 2 (3.25 mF cm À2 ), and Ni-Co (1.16 mF cm À2 ) aerogels, indicating that the heterostructure activated additional exposed active sites.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The NiSe2 aerogel has good crystallinity with distinct Ni and NiSe2 peaks, while CoSe2 aerogel crystallinity is poorer because of an amorphous surface oxide layer.

    “In addition, the NiSe 2 aerogel showed good crystallinity with distinct characteristic peaks of Ni and NiSe 2 , but the crystallinity of the CoSe 2 aerogel was comparatively poor due to the easy formation of an amorphous oxide layer on the surface.39,40”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [39] 39. A. Badruzzaman, A. Yuda, A. Ashok and A. Kumar, Recent advances in cobalt based heterogeneous catalysts for oxygen evolution reaction, Inorg. Chim. Acta, 2020, 511, 119854. source
    • cites [40] 40. V. D. Nithya, Recent advances in CoSe 2 electrocatalysts for hydrogen evolution reaction, Int. J. Hydrogen Energy, 2021, 46, 36080-36102. source

  • May combine two claims.

    Findingown data

    The NiSe2-CoSe2 aerogel device exhibited a potential of 1.56 V at 10 mA cm−2, equal to Pt/C + RuO2 (1.56 V).

    “The NiSe 2 -CoSe 2 aerogel device exhibited a low potential of 1.56 V@10 mA cm À2 , which was equal to the performance of Pt/C + RuO 2 (1.56 V).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    At 10 mA cm-2, the OER overpotential of NiSe2-CoSe2 is lower than those of NiSe2, CoSe2, Ni-Co, and commercial RuO2.

    “Benefiting from the rapid reconstruction, NiSe 2 -CoSe 2 exhibited the lowest overpotential of 220 mV@10 mA cm À2 , significantly better than that of NiSe 2 (304 mV), CoSe 2 (289 mV) and Ni-Co (265 mV).”
    • Also stated in: § Electrocatalytic activity towards OER and overall water splitting · boosted
      “Notably, the performance of the NiSe 2 -CoSe 2 aerogel was superior to the commercial RuO 2 (251 mV@10 mA cm À2 ), demonstrating that the selenide heterostructure possessed great application potential in the electrocatalytic OER process.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    NiSe2-CoSe2 has an OER Tafel slope of 99.57 mV dec-1, lower than NiSe2, CoSe2, and Ni-Co.

    “Besides, NiSe 2 -CoSe 2 exhibited a Tafel slope of 99.57mV dec À1 , lower than that of NiSe 2 (157.71mV dec À1 ), CoSe 2 (131.52 mV dec À1 ) and Ni-Co (109.47 mV dec À1”
    Quote in the paperSubstantial claim

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

    Findingcitation

    Pt/C has a HER overpotential of 34 mV at 10 mA cm-2, consistent with reported literature.

    “The Pt/C showed the lowest overpotential of 34 mV@10 mA cm À2 , which was consistent with the reported literature.44”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [44] 44. V. H. Hoa, D. T. Tran, D. C. Nguyen, D. H. Kim, N. H. Kim and J. H. Lee, Molybdenum and Phosphorous Dual Doping in Cobalt Monolayer Interfacial Assembled Cobalt Nano- wires for Efficient Overall Water Splitting, Adv. Funct. Mater., 2020, 30, 1-12. source

  • May combine two claims.

    Findingown data

    HRTEM and FFT show NiSe2 (220) planes at 0.212 nm and CoSe2 (220) planes at 0.207 nm, indicating formation of the NiSe2-CoSe2 heterostructure.

    “Based on the results of Fast Fourier Transform (FFT), the (220) crystal planes of NiSe 2 (0.212 nm, Fig. 2(c1)) and CoSe 2 (0.207 nm, Fig. 2(c2)) were observed, which preliminarily proved the formation of the NiSe 2 -CoSe 2 heterostructure.21,26”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [21] 21. D. Chen, Z. Xu, W. Chen, G. Chen, J. Huang, J. Huang, C. Song, C. Li and K. (Ken) Ostrikov, Just add water to split water: ultrahigh-performance bifunctional electrocatalysts fabricated using eco-friendly heterointerfacing of NiCo dis- elenides, J. Mater. Chem. A, 2020, 8, 12035-12044. source
    • cites [26] 26. X. Zhang, Y. Ding, G. Wu and X. Du, CoSe 2 @NiSe 2 nanoar- ray as better and efficient electrocatalyst for overall water splitting, Int. J. Hydrogen Energy, 2020, 45, 30611-30621. source

  • May combine two claims.

    Findingown data

    XPS shows Ni2+ and Co2+ peaks in NiSe2-CoSe2 shifted positively by 1.80 eV and 1.10 eV, indicating electronic structure regulation by selenization.

    “For NiSe 2 -CoSe 2 , the peaks of Ni 2+ and Co 2+ showed obvious positive shifts of 1.80 eV and 1.10 eV, respectively, indicating the electronic structure regulation due to selenization.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    After selenization to NiSe2-CoSe2, the OER oxidation onset voltage decreases to 1.23 V, indicating a surface that favors reconstruction and active-site generation.

    “As Ni-Co was further selenized to NiSe 2 -CoSe 2 , the onset voltage of oxidation decreased to 1.23 V, demonstrating that the bimetallic selenide heterostructure had the surface that favored to reconstruct and generate active sites with excellent OER performance.10”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] 10. X. Peng, Y. Yan, X. Jin, C. Huang, W. Jin, B. Gao and P. K. Chu, Recent advance and prospectives of electrocata- lysts based on transition metal selenides for efficient water splitting, Nano Energy, 2020, 78, 105234. source

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

    Findingcitation

    Air contact forms a thick oxide layer on the aerogel surface.

    “Because of contact with air, a thick oxide layer was formed on the surface of aerogel.34,36”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [34] 34. B. Cai and A. Eychmu ¨ller, Promoting Electrocatalysis upon Aerogels, Adv. Mater., 2019, 31, 1-16.

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

    • cites [36] 36. F. Chen, F. Yang, H. Liu, S. Che, G. Zhang, C. Xu and Y. Li, One-pot preparation of surface vulcanization Co-Fe bime- tallic aerogel for efficient sulfadiazine degradation, Chem. Eng. J., 2022, 430, 132904. source

  • May combine two claims.

    Findingown data

    NiSe2 aerogel had a HER overpotential of 131 mV at 10 mA cm−2, CoSe2 aerogel 173 mV, and Ni-Co aerogel 94 mV.

    “NiSe 2 aerogel (131 mV@10 mA cm À2 ), CoSe 2 aerogel (173 mV@ 10 mA cm À2 ), and Ni-Co aerogel (94 mV@10 mA cm À2 ), indicating the synergic enhancement of the bimetallic selenide heterostructure.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The NiSe2-CoSe2 aerogel delivered a Tafel slope of 57.54 mV dec−1, lower than NiSe2 (95.36), CoSe2 (115.68), and Ni-Co (75.68) aerogels.

    “In Fig. 4(b), the NiSe 2 -CoSe 2 aerogel delivered a Tafel slope of 57.54 mV dec À1 , lower than those of NiSe 2 (95.36 mV dec À1 ), CoSe 2 (115.68 mV dec À1 ), and Ni-Co (75.68 mV dec À1 ) aerogels.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    NiSe2-CoSe2-2:1 had a HER overpotential of 84 mV at 10 mA cm−2, and NiSe2-CoSe2-1:2 had 92 mV.

    “In order to determine the best ratio of Ni and Co, we also tested the HER performance of NiSe 2 -CoSe 2 -2 : 1 (84 mV@10 mA cm À2 ) and NiSe 2 -CoSe 2 -1 : 2 aerogels (92 mV@ 10 mA cm À2 ) (Fig. S8(a) (ESI †), and the curves before IR-correction are shown in Fig. S8(b), ESI †).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    NiSe2-CoSe2-300 had a HER overpotential of 95 mV at 10 mA cm−2, and NiSe2-CoSe2-500 had 133 mV.

    “To optimize the selenization temperature, we tested the HER performance of NiSe 2 -CoSe 2 -300 (95 mV@10 mA cm À2 ) and NiSe 2 -CoSe 2 -500 (133 mV@ 10 mA cm À2 ) as well (Fig. S8(c), ESI, † and the curves before IR-correction are shown in Fig. S8(d), ESI †).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In the NiSe2-CoSe2 structure, the Ni site had a free energy of hydrogen adsorption (ΔGH*) of −0.26 eV, stronger than the Co site (−0.18 eV).

    “In the NiSe 2 -CoSe 2 structure, the Ni site exhibited stronger free energy of hydrogen adsorption (DG H Ã , À0.26 eV) than that of the Co site (À0.18 eV), indicating that electrons transferred from CoSe 2 to NiSe 2 at the heterointerface.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The simplified DFT model focusing on the bimetallic selenide heterostructure captures the relevant interactions of the complex aerogel with surface oxidation and metals without selenide.

  • May combine two claims.

    Interpretationreasoning

    The NiSe2-CoSe2 heterostructure was prepared with aerogel morphology, giving a high specific surface area with many exposed active sites.

    “(2) The NiSe 2 -CoSe 2 heterostructure with higher intrinsic activity was successfully prepared with an aerogel morphology, providing a high specific surface area with lots of exposed active sites.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    HER and OER polarization curves were corrected for 90% of the ohmic resistance, with solution resistance obtained from EIS at open-circuit potential.

    “All the polarization curves of the HER and OER were adjusted with 90% IR-correction according to the ohmic resistance of the solution (R s ), and the values of R s was obtained from the electrochemical impedance spectroscopy (EIS) results under the open circuit potential.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Selenium's metal-like properties give transition-metal selenides high electrical conductivity, enabling favorable charge transfer, kinetics, and energy conversion.

    “Besides, the unique metal-like properties of selenium allow excellent electrical conductivity of TMSes, which leads to desirable charge transfer, reaction kinetics, and energy conversion efficiency.17,18”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [17] 17. Y. Sun, K. Xu, Z. Wei, H. Li, T. Zhang, X. Li, W. Cai, J. Ma, H. J. Fan and Y. Li, Strong Electronic Interaction in Dual- Cation-Incorporated NiSe2 Nanosheets with Lattice Distor- tion for Highly Efficient Overall Water Splitting, Adv. Mater., 2018, 30, 1-7.

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

    • cites [18] 18. Y. Chen, J. Zhang, P. Guo, H. Liu, Z. Wang, M. Liu, T. Zhang, S. Wang, Y. Zhou, X. Lu and J. Zhang, Coupled Heterostructure of Mo-Fe Selenide Nanosheets Supported on Carbon Paper as an Integrated Electrocatalyst for Efficient Hydrogen Evolution, ACS Appl. Mater. Interfaces, 2018, 10, 27787-27794. source

  • May combine two claims.

    Interpretationreasoning

    The optimized NiSe2-CoSe2 has the best OER performance because of its balanced NiSe2/CoSe2 ratio and favorable morphology.

    “All of the above results indicated that the optimized NiSe 2 -CoSe 2 had the best OER performance due to its balanced ratio of NiSe 2 /CoSe 2 and favorable morphology.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Interpretationown data

    The OER performance change after cycling is mainly caused by catalyst loss from oxygen bubble overflow.

    “Such a change in performance mainly came from the sample falling out caused by oxygen bubble overflow.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The high performance is attributed to the aerogel's porous morphology with abundant active sites and the bimetallic selenide heterostructure with high intrinsic activity.

    “The exceptional performance was attributed to the unique porous morphology of the aerogel with abundant active sites and the bimetallic selenide heterostructure with excellent intrinsic activity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Metal aerogels have carrier-free three-dimensional interconnected networks that provide high specific area, many active sites, and abundant mass-transfer pathways.

    “Compared with other powder materials, metal aerogels have three-dimensional interconnected network structures without carriers, which not only present a high specific area with plenty of active sites, but also provide abundant pathways for mass transfer.27,28”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [27] 27. Y. Li, S. Guo, T. Jin, Y. Wang, F. Cheng and L. Jiao, Promoted synergy in core-branch CoP@NiFe-OH nanohybrids for efficient electrochemical-/photovoltage-driven overall water splitting, Nano Energy, 2019, 63, 103821. source
    • cites [28] 28. H. Wang, Q. Fang, W. Gu, D. Du, Y. Lin and C. Zhu, Noble Metal Aerogels, ACS Appl. Mater. Interfaces, 2020, 12, 52234-52250. source

  • May combine two claims.

    Interpretationown data

    The aerogel skeleton provides plenty of active sites and abundant mass transfer pathways.

    “Besides, the optimized NiSe 2 -CoSe 2 aerogel exhibited a C dl value superior to some reported selenides or heterostructure electrocatalysts with other nanostructures (Table S2, ESI †), proving plenty of active sites and abundant mass transfer pathways provided by the aerogel skeleton.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    The porous aerogel structure provides many active sites and mass-transfer pathways.

    “Such a shaggy and porous structure provided abundant active sites and mass transfer pathways.32,33”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [32] 32. L. Liu, L. X. Chen, A. J. Wang, J. Yuan, L. Shen and J. J. Feng, Hydrogen bubbles template-directed synthesis of self- supported AuPt nanowire networks for improved ethanol oxidation and oxygen reduction reactions, Int. J. Hydrogen Energy, 2016, 41, 8871-8880. source
    • cites [33] 33. A. A. Dubale, Y. Zheng, H. Wang, R. Hu ¨bner, Y. Li, J. Yang, J. Zhang, N. K. Sethi, L. He, Z. Zheng and W. Liu, High- Performance Bismuth-Doped Nickel Aerogel Electrocatalyst for the Methanol Oxidation Reaction, Angew. Chem., Int. Ed., 2020, 59, 13891-13899. source

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Overall water splitting LSV was measured in a two-carbon-cloth-electrode cell from 1.0 to 2.0 V without IR correction.

    “Besides, electrocatalytic performance of overall water splitting were tested by LSV on an electrolytic cell consisting of two carbon cloth electrodes with the optimized sample under the operating voltage from 1.0 to 2.0 V (without IR-correction).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Sufficient construction of the heterostructure under optimal preparation conditions could fully activate catalytic sites and provide a large electrochemical surface area.

    “the NiSe 2 -CoSe 2 aerogel exhibited a higher C dl value than other aerogels, suggesting that the sufficient construction of the heterostructure based on the optimal preparation conditions could fully activate catalytic sites and provide a large electrochemical surface area.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The superior performances were attributed to the large effective surface area of the aerogel with a three-dimensional interconnected network structure, as well as the high intrinsic activity of the heterostructure formed by NiSe2 and CoSe2.

    “Systematic characterization, electrochemical testing and DFT calculations illustrated that the superior performances were attributed to the large effective surface area of the aerogel with a three-dimensional interconnected network structure, as well as the high intrinsic activity of the heterostructure formed by NiSe 2 and CoSe 2 .”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The bifunctional NiSe2-CoSe2 aerogel showed good HER, OER, and overall water splitting capabilities with low potentials and favorable stabilities.

    “The bifunctional NiSe 2 -CoSe 2 aerogel showed splendid HER, OER and overall water splitting capabilities with low potentials and favorable stabilities.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The Co site in NiSe2-CoSe2 has favorable adsorption properties and high activity toward the HER.

    “In contrast, the Co site had the DG H Ã closer to zero (ideal state), demonstrating the favorable adsorption properties and high activity toward the HER.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The simplified DFT model focusing on the bimetallic selenide heterostructure captures the relevant interactions of the complex aerogel with surface oxidation and metals without selenide.
34 of 34

  • The paper relies on this without support.

    Non-noble materials that show HER or OER activity comparable to precious-metal catalysts have not been sufficiently studied or applied in overall water splitting.

    “Although some of the materials demonstrate electrocatalytic hydrogen or oxygen evolution reaction (HER or OER) activities comparable to those of precious metal catalysts, the research and applications of those materials in overall water splitting are insufficient.”

  • The paper relies on this without support.

    Few prior reports combine transition-metal selenides or their heterostructures with aerogel morphology for overall water splitting.

    “Nevertheless, there are few reports dedicated to combining the TMSes or TMSe-based heterostructures and the unique aerogel morphology for efficient overall water splitting.”

  • The paper relies on this without support.

    The electrochemical active surface area and mass-transfer pathways of ultrathin nanosheets or nickel-foam-based nanoarrays still need improvement.

    “However, the electrochemical active surface area and the amount of mass transfer paths of these structures still remain to be improved.”

  • The authors state this as an assumption.

    The simplified DFT model focusing on the bimetallic selenide heterostructure captures the relevant interactions of the complex aerogel with surface oxidation and metals without selenide.

    “Considering the complexity of the aerogel with surface oxidation and metals without selenide, we simplified the model and focused on the interactions within the bimetallic selenide heterostructure.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The Ir7Co3 aerogel's HER performance is superior to those of recently reported high-level HER electrocatalysts.

    “its performance is also superior to those of recently reported high-level HER electrocatalysts (Table S1, ESI†).”

    From Co@Ir core–shell nanochain aerogels for the hydrogen evolution reaction and the oxygen evolution reaction in alkaline media (2024) · cites this paper as [32]

    The ‘Electrocatalytic activity toward the HER’ section reports results for a NiSe₂–CoSe₂ aerogel, not Ir7Co3. A search for Ir7Co3 and the claimed comparison with recently reported HER electrocatalysts found neither in our copy; its Table S1 is cited for sample composition instead. No page number is available for these passages. (LLM, conf=0.78)

    Experimental — accuracy not yet measured

Cites

Flagged first, then by citations

Research works printed but not linked: 6

  1. Concina, 2017, Adv. Energy Mater., 7, 1
  2. Sun, 2018, Adv. Mater., 30, 1
  3. Liu, 2020, Appl. Catal., B, 262, 1
  4. Wang, 2019, Adv. Mater., 31, 1
  5. Cai, 2019, Adv. Mater., 31, 1
  6. Liu, 2020, Appl. Catal., B, 262, 1

Cited by

Sorted by citations

Related

Authors
Liu, H., Yang, F., Chen, F., Che, S., Chen, N., Xu, C., Wu, N., Wei, W., & Li, Y.
Affiliations
China University of Petroleum, Beijing (CN)
Corresponding author
  • Yang, Fan
  • Li, Yongfeng
ORCID
Venue
Materials Chemistry Frontiers
Publisher
Royal Society of Chemistry (RSC)
Published
2023
Volume
7
Issue
7
Pages
1365-1373
ISSN
2052-1537 (ISSN-L)
DOI
10.1039/d2qm01082h
OpenAlex
W4317932360
Cited by
40
References
40
Citations by year
2026: 7 · 2025: 14 · 2024: 10 · 2023: 9
FWCI
1.91
Type
journal article
Language
en
Open access
Licence
rsc.li/journals-terms-of-use (am, 389 d)
Locations
Materials Chemistry Frontiers (publishedVersion)
Funders
  • Science Foundation of China University of Petroleum, Beijing (2462020YXZZ033)
  • National Natural Science Foundation of China (21776302, 22278431)
Topics
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Electrocatalysts for Energy Conversion
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Advanced Photocatalysis Techniques
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › CO2 Reduction Techniques and Catalysts
Keywords
bimetallic selenides, aerogels, overall water splitting, hydrogen evolution reaction, oxygen evolution reaction, gelation, electrocatalysis

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 under definition version 3 (extract-v3) on 2026-09-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-09-28.

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.

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