N vacancies modulated Zn single atoms for efficient H2O2 photosynthesis

Abstract

Solar-powered photosynthesis though two-electron oxygen reduction presents an eco-friendly and energy-efficient approach for producing high-value H₂O₂. However, achieving highly efficient photosynthesis for H₂O₂ generation is challenging due to limited photogenerated charge transfer efficiency and the sluggish kinetic process. Herein, we use a defect engineering approach that involves creating N vacancies around Zn–N₄ to modify the electron density of Zn single atoms for efficient H₂O₂ production. The presence of adjacent N vacancies increases the electron density of Zn–N₄ sites and makes the *H₂O₂ desorption step that generates H₂O₂ (*H₂O₂ → H₂O₂) thermodynamically more favorable. The separation and migration of photogenerated electron–hole pairs is also greatly promoted. Under simulated sunlight, the H₂O₂ yield for Zn–N₄ sites with adjacent N vacancies reaches 1363.4 μmol g⁻¹ h⁻¹, 3.2 times higher than that of CN, and the apparent quantum yield is 24.6% (λ = 350 nm).