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

Abstract

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 µmol 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.