Electronic perturbation of Cu nanowire surfaces with functionalized graphdiyne for enhanced CO₂ reduction reaction

Electronic perturbation of the surfaces of Cu catalysts is crucial for optimizing electrochemical CO₂ reduction activity, yet still poses great challenges. Herein, nanostructured Cu nanowires (NW) with fine-tuned surface electronic structure are achieved via surface encapsulation with electron-withdrawing (-F) and -donating (-Me) group-functionalized graphdiynes (R-GDY, R = -F and -Me) and the resulting catalysts, denoted as R-GDY/Cu NW, display distinct CO₂ reduction performances. In situ electrochemical spectroscopy revealed that the *CO (a key intermediate of the CO₂ reduction reaction) binding affinity and consequent *CO coverage positively correlate with the Cu surface oxidation state, leading to favorable C-C coupling on F-GDY/Cu NW over Me-GDY/Cu NW. Electrochemical measurements corroborate the favorable C₂H₄ production with an optimum C₂₊ selectivity of 73.15% ± 2.5% observed for F-GDY/Cu NW, while the predominant CH₄ production is favored by Me-GDY/Cu NW. Furthermore, by leveraging the *Cu-hydroxyl (OH)/*CO ratio as a descriptor, mechanistic investigation reveals that the protonation of distinct adsorbed *CO facilitated by *Cu-OH is crucial for the selective generation of C₂H₄ and CH₄ on F-GDY/Cu NW and Me-GDY/Cu NW, respectively.