The synergism of Co3O4 co-catalysis and Pt-doping boosting hematite photoanode for efficient solar H2O2 synthesis

Abstract

Photoelectrochemical (PEC) syntheses is a green approach for the production of H2O2, which depends on the semiconductor photoanode to initiate the two-electron oxidation of H2O into H2O2. At present, the development of cheap and efficient photoanodes for H2O2 production holds great promise, but remains challenging. Herein, a Co3O4@Pt-Fe2O3 photoanode was designed and investigated for H2O2 production, based on the assistance of Co3O4 co-catalysis and Pt-doping. The Co3O4@Pt-Fe2O3 photoanode demonstrated superior PEC performance towards H2O2 production, a H2O2 production Faraday efficiency of 77.38% and a H2O2 yield of 0.073 μmol cm−2 be achieved at 1.00 V vs. RHE under AM 1.5 G irradiation. The experimental investigations and theoretical calculations jointly revealed the synergistic effect of Co3O4 co-catalysis and Pt-doping on the Co3O4@Pt-Fe2O3 photoanode for H2O2 production. Specifically, Pt-doping introduces defect sites into Fe2O3 photoanode, which could improve the bulk carrier mobility and density. Meanwhile, Co3O4 co-catalysis is conducive to achieve two-electron water oxidation on Pt-Fe2O3 photoanode selectively, and weaken the decomposition of H2O2 product in cell. Furthermore, the internal electric field of Co3O4/Pt-Fe2O3 can promote the separation of surface carrier for H2O2 production. The present work presents an efficient Co3O4@Pt-Fe2O3 photoanode for H2O2 production, which could inspire the development of similar materials for H2O2 synthesis.