Research progress of heterogeneous photocatalyst for H2O2 production: A mini review

Abstract

H2O2 is an excellent green oxidant with important applications in many fields. The conventional anthraquinone process for synthesizing H2O2 is usually accompanied by high economic costs and stringent process requirements. The photocatalytic production of H2O2via heterojunction semiconductors has proven to overcome these limitations, which is a promising alternative to the conventional anthraquinone process. In this review, we provide a comprehensive summary of the semiconductor heterojunction materials that have been attempted to be used in the photocatalytic generation of H2O2 in recent years. Firstly, a brief description of the photoreaction mechanisms of different types of heterojunctions in the photocatalytic process is presented, focusing on the generation pathways and competing reactions for the photoproduction of H2O2. Then, the types of heterojunctions applied for photoproduction of H2O2 are comprehensively summarized. Among them, the four most widely used types of heterojunctions, including type-II heterojunctions, Z-scheme systems, S-scheme systems, and Schottky heterojunctions, and their current applications in the reaction of photoproduction of H2O2 are highlighted. By comparing the differences in the internal electric fields of different types of heterojunctions, different charge transfer pathways of various types of heterojunctions in the photoproduction of H2O2 are distinguished. Furthermore, the great potential of other types of heterojunctions, such as p-n heterojunctions, in photocatalysis is further outlined. Finally, the challenges as well as opportunities for the development of novel heterostructural photocatalysts for H2O2 production are outlined. We sincerely hope this minireview can attract more attention from scientific research workers in the field of photocatalytic H2O2 generation, making them valuable for environmental remediation and industrial applications in the future.