S-scheme ZnO/WO3 heterojunction photocatalyst for efficient H2O2 production

Designing highly efficient photocatalyst for hydrogen peroxide (H2O2) production is an ideal strategy to avoid the shortcomings of traditional H2O2 production and to realize the conversion of solar energy to chemical energy. In this work, a step-scheme (S-scheme) heterojunction photocatalyst composed of ZnO and WO3 is carefully prepared by hydrothermal and calcination method for efficient photocatalytic H2O2 production. The ZW30 composite photocatalysts exhibit enhanced activity with the highest H2O2-production rate of 6788 μmol L−1 h−1. The results show that the photocatalytic H2O2 production process is dominated by a direct two-electron O2 reduction pathway. The enhanced photocatalytic H2O2-production activity is attributed to the formation of interfacial internal electric field (IEF) in the S-scheme heterojunction, which boosts the spatial separation of charge carriers and enables electrons with the strongest reduction power to participate in H2O2 production. This work provides an in-depth insight of the great advantages of S-scheme heterojunction in photocatalytic H2O2 production.