Photocatalytic hydrogen peroxide evolution: What is the most effective strategy?

As an efficient eco-friendly oxidant and a new energy carrier in fuel cells, hydrogen peroxide (H2O2) is widely implemented in chemical synthesis, disinfection and other fields. Compared with the traditional anthraquinone process, the photocatalytic production of H2O2 has ignited a surge of interest in virtue of its safety, greenness and low-cost, while the low evolution efficiency has severely hindered its commercial viability. In recent years, researchers have been scrambling to achieve stable photocatalysts with decent solar conversion efficiency through a variety of modification strategies. For a specific photocatalytic material, the question of which modification strategy is the best one to expedite the photocatalytic H2O2 production comes into being. Therefore, a comprehensive and timely review is needed to deepen the insight into the mechanism of these tactics with different performance improvement levels. In this review, the evolution and optimization mechanisms of photocatalytic H2O2 evolution were first introduced. Second, the modification strategies for strengthening photocatalytic H2O2 production were systematically summarized, and the advantages and challenges of these approaches were discussed. Further, the accomplishments of semiconductor photocatalytic materials are carefully analyzed, and the most suitable strategies are concluded based on the characteristics of various photocatalysts. Eventually, the challenges and future prospects of photocatalytic H2O2 evolution are presented. This review is anticipated to provoke new insights into the rational design of high-performance photocatalysts towards H2O2 generation.