Two types of cooperative nitrogen vacancies in polymeric carbon nitride for efficient solar-driven H2O2 evolution

Hydrogen peroxide generation based on photocatalysis is a sustainable and clean process compared with the current industrial way but suffers from low efficiency due to the rapid recombination of carriers and the lack of suitable active sites. To enhance the efficiency in hydrogen peroxide generation, herein, we introduce two types of cooperative N vacancies, i.e., NHx and N2C vacancy, into the framework of polymeric carbon nitride. It is found that the optimized sample delivers a 15 times enhancement in solar-driven H2O2 production as well as excellent stability. And the apparent quantum efficiency reached to 26.78% and 11.86% at 340 nm and 420 nm, respectively. A series of comparative experiments and density functional theory calculations both reveal that NHx and N2C vacancies can accelerate photoexcited charge separation and assist in activating oxygen in the two-electron pathway, respectively. The strategy of targeted introducing two types of cooperative N vacancies provides a novel and promising solution to design and develop efficient catalyst in various photocatalytic reactions. This work will motivate future work in defect chemistry towards various photocatalytic reactions.