Recent advances in photocatalytic H2O2 production: modification strategies of 2D materials and in situ application of H2O2.

Environmental pollution and the energy crisis are two major problems that threaten human health and restrict industrial development. Hydrogen peroxide (H₂O₂) is a green oxidant and clean energy widely used in sterilization, degradation of pollutants and as an energy carrier, which is one of the important strategies to solve these two major problems. In recent years, solar-driven photocatalytic production of H₂O₂ has gained significant attention and been extensively studied. Two dimensional (2D) material photocatalysts offer promising prospects and distinct advantages for H₂O₂ production. However, their performance is hindered by challenges such as rapid electron-hole recombination, wide bandgaps, and slow reaction kinetics. Additionally, the high solubility of H₂O₂ in water and its tendency to decompose easily make it difficult to recover from solutions containing sacrificial agents, thereby restricting its practical applications. To the best of our knowledge, there are few reviews focused on the photocatalytic production of H₂O₂ using 2D material composite catalysts and its in situ applications. This review provides a detailed discussion of various strategies, including introducing vacancy defects, elemental doping, heterojunction engineering, functionalization and multi-strategy coupling, to improve the photocatalytic performance of 2D material composite photocatalysts. Furthermore, this review highlights the in situ applications of H₂O₂ produced through photocatalysis in diverse fields, including water purification, sterilization, and pharmaceutical intermediate synthesis. It concludes by outlining the key challenges in the photocatalytic production of H₂O₂ and proposing practical solutions.