In Situ Growth of Copper Phenylacetylide Nanobelts on Copper Foil for Enhanced Electroreduction of CO2 to Multi-Carbon Products

Abstract

Copper-based metal–organic composites are promising catalysts for electrochemical CO₂ reduction reaction (eCO₂RR). However, it is difficult to prepare stable Cu⁺ active sites in a controllable way and maintain them in the catalytic reduction. In this work, a (CuPA-Ag)/Cu electrode was prepared by the ion sputtering of Ag NPs on the copper foil, followed by the in situ growth of Ag NP-grafted CuPA NBs on its surface. The electrode possessed a large amount of Cu⁺ active sites due to the strong σ-donation and π-backdonation interactions between the phenylacetylene ligand and Cu⁺, which significantly improved the catalytic performances. Using the optimized electrode and reaction conditions, the eCO₂RR achieved Faraday efficiencies of 44.5% for C₂H₄ and 56.5% for C₂₊ products in the H cell. With periodic supplementation of the CO₂ source, the eCO₂RR maintained an FE_C2H4 above 40% for 11 h. Its superior catalytic performance originated from the densely stacked nanobelt structures with a large electrochemical surface area and enhanced electron transfer, the synergistic effect between Ag and Cu⁺ to promote the CO₂ absorption and C–C coupling, and the hydrophobicity of CuPA to inhibit the hydrogen evolution reaction.