Photoinduced Lattice Compression of Cu for Enhanced Production of Ethylene from CO2

While engineering lattice strain has been proven effective in enhancing the electrochemical CO₂ reduction performance of a catalyst, the correlation between strain effect and the intrinsic catalytic mechanism has remained elusive. Herein, a photolithography-inspired method is proposed to regulate Cu(111) lattice strain. By irradiating the photosensitive Cu(Acac) sol–gel, Acac chelate bond undergoes π→π^* electronic transition, and the ring-closed Cu(Acac) decompose into the stabilized Cu(Acac) mesh which presents as nanospots embedded onto the surface of the Cu cluster. The photoinduced nanospots serve to exert compressive strain to the Cu(111) lattice in which the lattice distance is reduced by 5.7–11.4%. Herein, the catalyst with 11.4% lattice compression exhibits enhanced C₂H₄ production capabilities, reaching a maximal Faradaic efficiency of 57.00%, and a high partial current density of 456.01 mA cm⁻². Theoretical calculations reveal that the compressed Cu(111) lattice exhibits reduced surface energies, leading to a significant drop in the C─C coupling reaction free energy from 1.16 eV over the pristine lattice, to 0.57 eV over the 10% compressed lattice. Additionally, the 10% compressed lattice facilitates spontaneous *O splitting immediately after OC─CHO coupling which leads to the generation of C₂H₄-favoring *CCH intermediate.