Modulating Active Hydrogen Supply and O2 Adsorption: Sulfur Vacancy Matters for Boosting H2O2 Photosynthesis Performance

Photocatalytic two‐electron oxygen reduction reaction (2e– ORR) represents a promising approach for H2O2 production. However, the lack of photocatalysts with appropriate O2 adsorption and hydrogenation capabilities impedes the H2O2 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 H2O2 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) O2 adsorption configuration and a modest binding strength of O2 and OOH*, largely avoiding the O‐O bond cleavage. Besides, the formation of electron‐deficient S sites weakens the S‐Hads bond, facilitating the *Hads migration to adjacent Ni sites and accelerating the hydrogenation kinetics of O2 to OOH* intermediate. As a result, the elaborately designed Ni‐ZnS‐Sv photocatalyst exhibits a high H2O2 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 H2O2 photosynthesis systems.