Highly efficient photocatalytic H2O2 production with cyano and SnO2 co-modified g-C3N4

Light-driven molecular oxygen reduction to H2O2 from water is an emerging environmentally friendly approach that can convert solar energy into green chemical. In this work, the photocatalytic properties of g-C3N4 for H2O2 production was enhanced by co-modification with cyano group and SnO2 nanocrystal through a facile one-step thermal polymerization method. The cyano group and SnO2 nanocrystal broaden the photo-absorption range of g-C3N4, enhance the electron generation and transfer ability, and provide more active sites for O2 and H+ adsorption. Significantly, this structure modification strategy leads to excellent H2O2 production performance, and the H2O2 yield rate reaches 703.4 μM g-1h−1 under visible light illumination, which is superior among g-C3N4-based photocatalysts. Moreover, the reaction mechanism study indicates that the photocatalytic H2O2 production proceeds through a two-step single-electron reaction and the catalyst shows good cyclability for long-term use. This work demonstrates a novel and feasible modification approach to improve the photocatalytic activity of g-C3N4, and will promote the development of advanced semiconducting catalysts for photocatalytic H2O2 evolution.