Extended Conjugation Tuning Carbon Nitride for Non‐sacrificial H <sub>2</sub> O <sub>2</sub> Photosynthesis and Hypoxic Tumor Therapy**
Jin Ma, Xiaoxiao Peng, Zhixin Zhou, Hong Yang, Kaiqing Wu, Zhengzou Fang, Dan Han, Yanfeng Fang, Songqin Liu, Yanfei Shen, Yuanjian Zhang
Abstract
Abstract Artificial photocatalysis offers a clean approach for producing H 2 O 2 . However, the poor selectivity and activity of H 2 O 2 production hamper traditional industrial applications and emerging photodynamic therapy (PDT)/chemodynamic therapy (CDT). Herein, we report a C 5 N 2 photocatalyst with a conjugated C=N linkage for selective and efficient non‐sacrificial H 2 O 2 production in both normoxic and hypoxic systems. The strengthened delocalization of π‐electrons by linkers in C 5 N 2 downshifted the band position, thermodynamically eliminating side H 2 evolution reaction and kinetically promoting water oxidation. As a result, C 5 N 2 had a competitive solar‐to‐chemical conversion efficiency of 0.55 % in overall H 2 O 2 production and exhibited by far the highest activity under hypoxic conditions (698 μM h −1 ). C 5 N 2 was further applied to hypoxic PDT/CDT with outstanding performance in apparent cancer cell death and synchronous bioimaging. The study sheds light on the photosynthesis of H 2 O 2 by carbon nitrides for health applications.