Carbon nitride in dark photocatalysis: Construction, reaction mechanism, and environmental application

Abstract

Dark photocatalysis can effectively overcome the dependence of traditional photocatalysis on continuous light by decoupling the light absorption and catalytic reaction process. By storing photogenerated charge carriers produced by light, this technology can continuously drive catalytic reactions under dark conditions, thus improving the efficiency of solar energy utilization. Research on dark photocatalysis is still in its initial stage, with current work mainly focusing on metal-based material systems. Due to its unique electronic structure and other advantages, carbon nitride (CN_X) offers new possibilities for the development of non-metallic dark photocatalysts. This paper reviews research progress of CN_X-based materials in the field of dark photocatalysts, focusing on methods for endowing them with dark photocatalytic ability through the construction of heterojunctions (such as composites with energy storage materials or long afterglow materials), and through molecular modification (introduction of functional groups, construction of conjugated structures and defect engineering). This paper also reviews the applications of CN_X-based dark photocatalysts in hydrogen production, hydrogen peroxide synthesis, and pollutant degradation. Finally, by analyzing the main challenges and opportunities of CN_X in the process of dark photocatalysis, this review presents strategies for developing more efficient CN_X-based dark photocatalysts and solving energy and environmental problems in the future.