The efficient electrochemical conversion of CO₂ provides a route to fuels and feedstocks. Copper catalysts are well-known to be selective to multicarbon products, although the role played by the surface architecture and the presence of oxides is not fully understood. Here we report improved efficiency towards ethanol by tuning the morphology and oxidation state of the copper catalysts through pulsed CO₂ electrolysis. We establish a correlation between the enhanced production of C₂₊ products (76% ethylene, ethanol and n-propanol at −1.0 V versus the reversible hydrogen electrode) and the presence of (100) terraces, Cu₂O and defects on Cu(100). We monitored the evolution of the catalyst morphology by analysis of cyclic voltammetry curves and ex situ atomic force microscopy data, whereas the chemical state of the surface was examined via quasi in situ X-ray photoelectron spectroscopy. We show that the continuous regeneration of defects and Cu(i) species synergistically favours C–C coupling pathways.

CO ₂的有效电化学转化提供了通往燃料和原料的途径。众所周知，铜催化剂对多碳产物具有选择性，尽管尚未完全理解表面结构和氧化物的存在所起的作用。在这里，我们报告了通过脉冲CO ₂电解调节铜催化剂的形态和氧化态，从而提高了对乙醇的效率。我们建立了C ₂₊产品产量的增加（相对于可逆氢电极，在-1.0 V时76％的乙烯，乙醇和正丙醇的产量）与（100）台阶，Cu _{2的存在之间的相关性}O和Cu（100）上的缺陷。我们通过分析循环伏安曲线和非原位原子力显微镜数据来监测催化剂形态的演变，而表面的化学状态则通过准原位X射线光电子能谱进行了检查。我们表明，缺陷和Cu（i）物种的持续再生协同促进了CC耦合途径。