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

Abstract

Artificial photosynthesis of H 2 O 2 , 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 H 2 O 2 artificial photosynthesis by digging pro-superoxide radical carbon vacancies in three-dimensional hierarchical porous g-C 3 N 4 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 2 − ) formation, significantly boosting the H 2 O 2 photocatalytic production. The developed photocatalyst shows an H 2 O 2 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-C 3 N 4 -based systems. Our work provides fundamental insight into highly active and stable photocatalysts with great potential for safe industrial H 2 O 2 production. • Innovative hydrolysis-freeze-drying-thermal treatment (HFDT) method • 3D hierarchical porous carbon nitride (g-C 3 N 4 ) with carbon vacancies • H 2 O 2 evolution rate of 6287.5 μM g −1 h −1 with an outstanding long cycling stability • Modulating electronic structure and promoting H 2 O 2 evolution through carbon vacancies Ding et al. report an innovative hydrolysis-freeze-drying-thermal treatment method for fabricating a 3D hierarchical porous carbon nitride with carbon vacancies. Owing to the synergistic effects between the carbon vacancies and the unique 3D hierarchical porous structure, the highly efficient photocatalytic H 2 O 2 production is achieved.