Artificial photosynthesis of H₂O₂ from H₂O and O₂ has gained significant attention. However, most photocatalysts are deactivated by salt, limiting their applications. This study introduces a metal-free photocatalyst, synthesized using a phenolic condensation approach, composed of carbon dots, procyanidins, and 4-methoxybenzaldehyde. This catalyst shows exceptional H₂O₂ production (1776 µmol g⁻¹h⁻¹ in real seawater), exceeding that of a pure polymer by 4.8 times. Photoelectrochemical and transient photovoltage analyses clarify the active site and catalytic mechanism in seawater, opening new avenues for efficient and practical H₂O₂ photoproduction.

Qingyao Wu, Jingjing Cao, Xiao Wang, Yan Liu, Yajie Zhao, Hui Wang, Yang Liu, Hui Huang, Fan Liao, Mingwang Shao, Zhenghui Kang