Single-atom Cu anchored phosphorus-doped graphitic carbon nitride for selective photocatalytic CO₂ reduction

Solar-driven CO₂ conversion into valuable chemicals offers an intriguing solution to ameliorate the global warming and energy crisis. Although graphitic carbon nitride (g-C₃N₄) demonstrates photocatalytic activity for CO₂ reduction, the practical application is hindered by sluggish reaction dynamics and rapid photogenerated charge recombination. Herein, we report Cu single atoms anchored on phosphorus-doped g-C₃N₄ nanosheets (Cu/PCN), fabricated through an in-situ icing assisted photodeposition method. Experimental results demonstrate that the phosphorus doping effectively enhances the reduction potential of photogenerated electrons and the engineering of Cu atoms can significantly accelerate the photogenerated charge separation. Further DFT calculations reveal that introducing Cu single atoms in the phosphorus-doped g-C₃N₄ effectively lower the energy barrier for the critical COOH∗ intermediates, thus promoting the CO evolution. As a result, the optimized Cu_0.8/PCN photocatalyst exhibits outstanding performance in visible-light-driven CO₂ photoreduction, achieving a remarkable CO generation rate of 6.01 μmol g^-1 h^-1. This work provides an atomic-level metal-nonmetal synergistic modulation strategy for promoting CO generation form CO₂ photoreduction kinetically.