Abstract
•ZnO/WO3 step-scheme (S-scheme) H2O2-production photocatalyst prepared.•The ZnO/WO3 samples with high photocatalytic H2O2-production activity.•In-situ irradiated XPS measurements investigation on S-scheme mechanism.•Advantages of S-scheme heterojunction in H2O2-production discussed.
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.
Benefiting from the formation of the S-scheme heterojunction of ZnO and WO3, the useful electrons on the conduction band of ZnO and holes on the valence band of WO3 can be efficiently spatially separated, leading to high photocatalytic production of H2O2. The S-scheme heterojunction presents great advantages for efficient H2O2 production.
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