Customizing Oxygen Reduction Reaction Pathways for High‐Efficiency H 2 O 2 Photosynthesis by Anionic Intermediate‐Generating Polymer Photocatalysts

Abstract Artificial photosynthesis of hydrogen peroxide (H 2 O 2 ) is of great importance, yet faces the challenge of diversified oxygen reduction pathways, resulting in low‐efficiency H 2 O 2 production. Herein, a novel strategy is proposed to customize the direct one‐step two‐electron O 2 reduction pathway for H 2 O 2 synthesis by modulating the electron transport kinetics of anionic intermediate‐generating organic polymer photocatalysts. Combined experimental and characterization results revealed the relationship between the electron transfer kinetics of anionic intermediates and ORR pathways under thermodynamically favorable conditions. Specifically, anionic intermediates with optimized electron transfer kinetics effectively mediate oxygen reduction to H 2 O 2 via a direct one‐step two‐electron pathway. In contrast, sluggish electron transfer leads to an indirect two‐step two‐electron pathway for slow H 2 O 2 production, whereas rapid electron transfer induces side reactions for undesired H 2 O formation. The naphthalene diimide anionic intermediate (NTEA −• ) with moderated electron transfer speed exhibited an outstanding H 2 O 2 generation rate of 6372 µ mol g −1 h −1 and a remarkable solar‐to‐H 2 O 2 conversion efficiency of 1.02 %. Notably, the engineered NTEA membrane photocatalyst demonstrated an impressive H 2 O 2 concentration of up to 1150 µ mol L −1 in continuous‐flow reactor over 80 h. This work highlights that regulating the surface photoreaction pathways from the perspective of reaction kinetics is key to improving solar‐to‐chemical energy conversion efficiency.