Photochemical production of hydrogen peroxide by digging pro-superoxide radical carbon vacancies in 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 (O-center dot(2)-) formation, significantly boosting the H2O2 photocatalytic production. The developed photocatalyst shows an H2O2 evolution rate of 6287.5 mM 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.

Automated summary

In this study, visible-light H2O2 artificial photosynthesis was achieved by introducing carbon vacancies in three-dimensional hierarchical porous g-C3N4. The implanted carbon vacancies resulted in a significant change in electronic structure, broadening visible-light absorption and facilitating photogenerated charge separation. The introduction of carbon vacancies promoted the formation of superoxide radicals, significantly boosting H2O2 photocatalytic production. The developed photocatalyst exhibited a high H2O2 evolution rate and long cycling stability, making it a promising candidate for safe industrial H2O2 production.