In-Plane Carbon Lattice-Defect Regulating Electrochemical Oxygen Reduction to Hydrogen Peroxide Production over Nitrogen-Doped Graphene

Abstract

Carbon-based materials are considered to be active for electrochemical oxygen reduction reaction (ORR) to hydrogen peroxide (H 2 O 2 ) production. Nevertheless, less attention is paid to the investigation of the influence of in-plane carbon lattice defect on the catalytic activity and selectivity toward ORR. In the present work, graphene precursors were prepared from oxo-functionalized graphene (oxo-G) and graphene oxide (GO) with H 2 O 2 hydrothermal treatment, respectively. Statistical Raman spectroscopy (SRS) analysis demonstrated the increased in-plane carbon lattice defect density in the order of oxo-G, oxo-G/H 2 O 2, GO, GO/H 2 O 2 . Furthermore, nitrogen-doped graphene materials were prepared through ammonium hydroxide hydrothermal treatment of those graphene precursors. Rotating ring-disk electrode (RRDE) results indicate that the nitrogen-doped graphene derived from oxo-G with lowest in-plane carbon lattice defects exhibited the highest H 2 O 2 selectivity of >82% in 0.1 M KOH. Moreover, a high H 2 O 2 production rate of 224.8 mmol g catalyst –1 h –1 could be achieved at 0.2 V RHE in H-cell with faradaic efficiency of >43.6%. Our work provides insights for the design and synthesis of carbon-based electrocatalysts for H 2 O 2 production.