Regulating *COOH intermediate via amino alkylation engineering for exceptionally effective photocatalytic CO2 reduction

Photocatalytic reduction of CO2 into fuel represents a promising approach for achieving carbon neutrality, while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target products. Engineering the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes, yet it remains a significant challenge. In this study, amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides (PCN), which could efficiently drive the photocatalytic CO2 reduction. Experimental characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO2 reduction into *COOH intermediate, transforming the adsorption of *COOH intermediate from the endothermic to an exothermic process. Notably, the as-prepared materials demonstrated outstanding performance in photocatalytic CO2 reduction, yielding CO at a rate of 152.8 μmol h−1 with a high selectivity of 95.4% and a quantum efficiency of 6.6%.