Recent Advances in Carbon Nitride Supported Single‐Atom Catalysts: Synthesis, Characterization, and Applications for CO2 Photoreduction

Abstract Photoreduction of CO 2 into value‐added chemicals and fuels is a promising green technology for solar‐to‐chemical conversion. Owing to the atomic utilization, unique metal‐support interaction, and unsaturated coordination active sites, single‐atom catalysts (SACs) have been attracting great attention in achieving high activity and selectivity of CO 2 photoreduction reactions. On the other hand, carbon nitride (C 3 N 4 ) with abundant periodically unsaturated coordination of nitrogen atoms can serve as an excellent support for anchoring metal single atoms. In this context, extensive research efforts have been paid in C 3 N 4 ‐based SACs for CO 2 photoreduction in recent years. In this review, we report the recent advances in C 3 N 4 supported SACs for CO 2 photoreduction. We start from the introduction of synthetic strategies of various C 3 N 4 supported metal SACs. Secondly, the main advanced characterization techniques and calculation methods for identifying the single‐atoms and their coordination environments of C 3 N 4 ‐based SACs are summarized. Thirdly, some state‐of‐the‐art works on the rational design of C 3 N 4 ‐based SACs and their applications in CO 2 photoreduction are introduced. Lastly, we briefly summarize the main challenges and propose important perspectives of C 3 N 4 ‐based SACs in CO 2 photoreduction. This review is expected to provide some useful guidelines for the development of efficient and stable C 3 N 4 ‐based SACs for CO 2 photoreduction.