Atomic perspective in polymeric carbon nitride for sustainable photocatalysis

The isolation of graphene monolayer has ignited a surge of exploration into two-dimensional materials, unveiling unprecedented opportunities to control matter at atomic precision. Among these emerging families, polymeric carbon nitride (CxNy) stands out by bridging molecular tunability with semiconductor functionality. The nitrogen-rich framework further stabilizes metal atoms as atomically dispersed catalytic centers, transforming CxNy from a passive support into an electronically interactive participant in catalytic reactions. This perspective highlights recent advances in atomic-site engineering within CxNy frameworks, emphasizing how the interplay between coordination chemistry, electronic structure, and charge dynamics governs photocatalytic activity and selectivity. Finally, we discuss emerging principles of metal-support interactions and outline future directions toward programmable single-atom catalysts that unify structural, electronic, and functional precision within the CxNy structures. Polymeric carbon nitride (CxNy) stands out in the realm of two-dimensional materials for its tunable structure and electronic properties, making it a promising candidate for photocatalysis. This study explores how atomic-site modulation, particularly through metal-site engineering, enhances the photocatalytic efficiency of CxNy. They highlight that metal atoms anchored within the nitrogen-rich framework of CxNy improve light absorption and charge separation, leading to enhanced photocatalytic activity. Notably, single-atom catalysts within CxNy show superior performance in hydrogen evolution and other reactions due to precise control over electronic states and catalytic sites. This work highlights the potential of CxNy as a versatile platform for sustainable photocatalysis and suggests future directions.“This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.” Polymeric carbon nitride serves as a programmable platform for sustainable photocatalysis. Its nitrogen-rich framework stabilizes atomically dispersed metal centers, transforming it from a passive support into an electronically interactive participant. This Perspective highlights recent advances in atomic-site engineering within carbon nitride frameworks, emphasizing how atomic-scale regulation of the spatial microenvironment allows for precise control over electronic structure and charge dynamics. Finally, we discuss emerging principles of metal-support interactions and outline future directions toward programmable single-atom catalysts that offer a pathway toward efficient, durable, and selective solar-driven reactions.