Photocatalytic synthesis of hydrogen peroxide has gradually become a promising method for in -situ production of hydrogen peroxide, which relies on sustainable solar energy. However, the commonly used photocatalyst, i.e ., carbon nitride (CN), still suffers from the drawbacks of narrow light absorption range and fast charge recombination. Here, we report a facile method to introduce nitrogen defects into carbon nitride together with sodium ion. By adjusting the ratio of sodium dicyandiamide, the band gap of carbon nitride can be controlled, while the carrier separation and transfer ability of carbon nitride is improved. The modified CN with sodium doping and nitrogen defect (SD-CN) demonstrates outstanding H 2 O 2 production performance (H 2 O 2 yield rate of 297.2 mu mol L -1 h -1 ) under visible light irradiation, which is approximately 9.8 times higher than that of pristine CN. This work deepens the understanding of the coordinated effect of structural defect and element doping of carbon nitride on the photocatalytic H 2 O 2 production performance, and provides new insight into the design of photocatalytic system for efficient production of H 2 O 2 . (c) 2024 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.