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

Abstract

• ZnO/WO 3 step-scheme (S-scheme) H 2 O 2 -production photocatalyst prepared. • The ZnO/WO 3 samples with high photocatalytic H 2 O 2 -production activity. • In-situ irradiated XPS measurements investigation on S-scheme mechanism. • Advantages of S-scheme heterojunction in H 2 O 2 -production discussed. Designing highly efficient photocatalyst for hydrogen peroxide (H 2 O 2 ) production is an ideal strategy to avoid the shortcomings of traditional H 2 O 2 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 WO 3 is carefully prepared by hydrothermal and calcination method for efficient photocatalytic H 2 O 2 production. The ZW30 composite photocatalysts exhibit enhanced activity with the highest H 2 O 2 -production rate of 6788 μmol L −1 h −1 . The results show that the photocatalytic H 2 O 2 production process is dominated by a direct two-electron O 2 reduction pathway. The enhanced photocatalytic H 2 O 2 -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 H 2 O 2 production. This work provides an in-depth insight of the great advantages of S-scheme heterojunction in photocatalytic H 2 O 2 production. Benefiting from the formation of the S-scheme heterojunction of ZnO and WO 3 , the useful electrons on the conduction band of ZnO and holes on the valence band of WO 3 can be efficiently spatially separated, leading to high photocatalytic production of H 2 O 2 . The S-scheme heterojunction presents great advantages for efficient H 2 O 2 production.