Persulfate-Induced Three Coordinate Nitrogen (N3C) Vacancies in Defective Carbon Nitride for Enhanced Photocatalytic H2O2 Evolution

Abstract

In-situ photocatalytic H 2 O 2 production has been receiving increasing attention in recent years for sustainable H 2 O 2 synthesis. Graphitic carbon nitride (g-C 3 N 4 ) is regarded as one of the most promising semiconductor photocatalysts for H 2 O 2 evolution. Introducing N defects in g-C 3 N 4 has been proved to be an effective strategy to enhance photocatalytic activity. However, the photocatalytic mechanism of the N vacancies is ambiguous and different types of N vacancies in g-C 3 N 4 may exhibit different effects on photocatalytic activity. Herein, we develop a facile sodium persulfate eutectic polymerization method to prepare the g-C 3 N 4 with abundant three coordinate nitrogen (N3 C ) vacancies. This type of nitrogen vacancy has not been studied in g-C 3 N 4 for photocatalytic H 2 O 2 production. Our results showed that the introduction of N3 C vacancies in the g-C 3 N 4 successfully broadened the light absorption range, inhibited the photoexcited charge recombination with enhanced O 2 adsorption to promote oxygen activation. The photocatalytic H 2 O 2 evolution from the N3 C -rich g-C 3 N 4 is 4.5 times higher than that of the pristine g-C 3 N 4 . This study demonstrates a novel strategy to introduce N3 C vacancies in g-C 3 N 4 , which offers a new method to develop active catalysts for photocatalytic H 2 O 2 evolution.