Synergistic Redox Dual-Site Strategy to Boost Photosynthesis of Hydrogen Peroxide

Graphitized carbon nitride (C3N4)-based photocatalysts provide a prospective approach for producing hydrogen peroxide (H2O2) in artificial photosynthesis. However, their activity is constrained by the sluggish water oxidation reaction (WOR) process, which hampers the supply of protons and electrons necessary for the oxygen reduction reaction. Here, this work demonstrates a synergistic redox dual-site strategy via co-modified with 3,4,9,10-perylenetetracarboxylic acid diimide (PDI) and Pt single atoms in C3N4 support, which achieves an exceptional H2O2 yield of 802 mu mol g-1 h-1 and a selectivity of 91.8% without sacrificial agents. Mechanistic studies reveal that Pt single atoms act as photogenerated electron-rich sites to effectively activate O2 to form superoxide radicals, and PDI promotes WOR driving force to provide abundant protons. The optimized reduction and oxidation half-reactions improve the proton-coupled electron transfer process, thereby enhancing the selective photosynthesis of H2O2. This work underscores the importance of finely controlling half-reactions in photocatalytic processes to promote efficient and synergistic overall reactions.