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.