LAUSR

Photocatalytic CO2 reduction to high value‐added C2 products (e.g., C2H4) is of considerable interest but challenging. The C2H4 product selectivity strongly hinges on the intermediate energy levels in the CO2 reduction pathway. Herein, Cu–N4 sites anchored phosphorus‐modulated carbon nitride (CuACs/PCN) is designed as a photocatalyst to tailor the intermediate energy levels in the the C2H4 formation reaction pathway for realizing its high production with tunable selectivity. Theoretical calculations combined with experimental data demonstrate that the formation of the C−C coupling intermediates can be realized on Cu–N4 sites and the surrounding doped P facilitates the production of C2H4. Thus, CuACs/PCN exhibits a high C2H4 selectivity of 53.2% with a yielding rate of 30.51 µmol g−1. The findings reveal the significant role of the coordination environment and surrounding microenvironment of Cu single atoms in C2H4 formation and offer an effective approach for highly selective CO2 photoreduction to produce C2H4.