Isolated Ni Atoms for Enhanced Photocatalytic H<sub>2</sub>O<sub>2</sub> Performance with 1.05% Solar-to-Chemical Conversion Efficiency in Pure Water.

Jin, Cheng; Shen, Hao; Li, Jinhe; Guo, Xinge; Rao, Shaosheng; Yang, Wenqiang; Liu, Qinqin; Sun, Zhongti et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Photocatalytic hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production encounters a major impediment in its low solar-to-chemical conversion (SCC) efficiency due to undesired H<sub>2</sub>O<sub>2</sub> product decomposition. Herein, an isolated nickel (Ni) atom modification strategy is developed to adjust the thermodynamic process of H<sub>2</sub>O<sub>2</sub> production to address the challenge. Sacrificial experiments and in situ characterization reveal that H<sub>2</sub>O<sub>2</sub> generation occurs via a highly selective indirect two-electron oxygen reduction reaction. The optimized photocatalyst exhibits a remarkable H<sub>2</sub>O<sub>2</sub> production rate of 338.9 μmol g<sub>cat</sub><sup>-1</sup> h<sup>-1</sup> in pure water, representing a 48-fold enhancement. Notably, it attains an impressive SCC efficiency of 1.05%, surpassing that of current state-of-the-art catalysts. Theoretical insights reveal the downshifted d-band center facilitates moderate O<sub>2</sub> adsorption and barrier-free *OOH conversion, favoring H<sub>2</sub>O<sub>2</sub> release and preventing *H<sub>2</sub>O<sub>2</sub> decomposition. This work showcases efficient H<sub>2</sub>O<sub>2</sub> photosynthesis via d-band manipulation, presenting a fresh perspective for advancing high-efficiency SCC systems.