Photochemical production of hydrogen peroxide by digging pro-superoxide radical carbon vacancies in porous carbon nitride

Artificial photosynthesis of H₂O₂, an environmentally friendly oxidant and a clean fuel, holds great promise. However, improving its efficiency and stability for industrial implementation remains highly challenging. Here, we report the visible-light H₂O₂ artificial photosynthesis by digging pro-superoxide radical carbon vacancies in three-dimensional hierarchical porous g-C₃N₄ through a simple hydrolysis-freeze-drying-thermal treatment. A significant electronic structure change is revealed upon the implantation of carbon vacancies, broadening visible-light absorption and facilitating the photogenerated charge separation. The strong electron affinity of the carbon vacancies promotes superoxide radical (^⋅O₂⁻) formation, significantly boosting the H₂O₂ photocatalytic production. The developed photocatalyst shows an H₂O₂ evolution rate of 6287.5 μM g⁻¹ h⁻¹ under visible-light irradiation with a long cycling stability being the best-performing photocatalyst among all reported g-C₃N₄-based systems. Our work provides fundamental insight into highly active and stable photocatalysts with great potential for safe industrial H₂O₂ production.