Spatial confinement of copper single atoms into covalent triazinebased frameworks for highly efficient and selective photocatalytic CO_(2)reduction

Converting CO_(2)into carbonaceous fuels via photocatalysis represents an appealing strategy to simultaneously alleviate the energy crisis and associated environmental problems,yet designing with high photoreduction activity catalysts remains a compelling challenge.Here,combining the merits of highly porous structure and maximum atomic efficiency,we rationally constructed covalent triazine-based frameworks(CTFs)anchoring copper single atoms(Cu-SA/CTF)photocatalysts for efficient CO_(2)conversion.The Cu single atoms were visualized by high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)images and coordination structure of Cu-N-C2 sites was revealed by extended X-ray absorption fine structure(EXAFS)analyses.The as-prepared Cu-SA/CTF photocatalysts exhibited superior photocatalytic CO_(2)conversion to CH4 performance associated with a high selectivity of 98.31%.Significantly,the introduction of Cu single atoms endowed the CuSA/CTF catalysts with increased CO_(2)adsorption capacity,strengthened visible light responsive ability,and improved the photogenerated carriers separation efficiency,thus enhancing the photocatalytic activity.This work provides useful guidelines for designing robust visible light responsive photoreduction CO_(2)catalysts on the atomic scale.