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.