Modulating Active Hydrogen Supply and O ₂ Adsorption: Sulfur Vacancy Matters for Boosting H ₂ O ₂ Photosynthesis Performance

Abstract Photocatalytic two‐electron oxygen reduction reaction (2e − ORR) represents a promising approach for H 2 O 2 production. However, the lack of photocatalysts with appropriate O 2 adsorption and hydrogenation capabilities impedes the H 2 O 2 production performance. Herein, we report the synthesis of Ni‐doped ZnS hollow nanocubes with S vacancies (Ni‐ZnS‐Sv) as a dual‐site 2e − ORR photocatalyst for efficient H 2 O 2 production. Experimental results and density functional theory calculations reveal the vital roles of Sv in modulating the electronic structures of Ni and S dual sites toward enhanced 2e − ORR selectivity and activity. The atomically dispersed Ni sites with electron‐rich state enable a Pauling‐type (end‐on) O 2 adsorption configuration and a modest binding strength of O 2 and OOH*, largely avoiding the O─O bond cleavage. Besides, the formation of electron‐deficient S sites weakens the S─H ads bond, facilitating *H ads migration to adjacent Ni sites and accelerating the hydrogenation kinetics of O 2 to OOH* intermediate. As a result, the elaborately designed Ni‐ZnS‐Sv photocatalyst exhibits a high H 2 O 2 yield of 5649.49 µmol g −1 h −1 under UV–vis light irradiation in pure water. Our work offers new insights into the design principles of high‐performance photocatalysts for artificial H 2 O 2 photosynthesis systems.