Electrocatalytic CO₂ reduction to higher-value hydrocarbons beyond C₁ products is desirable for applications in energy storage, transportation and the chemical industry. Cu catalysts have shown the potential to catalyse C–C coupling for C₂₊ products, but still suffer from low selectivity in water. Here, we use density functional theory to determine the energetics of the initial C–C coupling steps on different Cu facets in CO₂ reduction, and suggest that the Cu(100) and stepped (211) facets favour C₂₊ product formation over Cu(111). To demonstrate this, we report the tuning of facet exposure on Cu foil through the metal ion battery cycling method. Compared with the polished Cu foil, our 100-cycled Cu nanocube catalyst with exposed (100) facets presents a sixfold improvement in C₂₊ to C₁ product ratio, with a highest C₂₊ Faradaic efficiency of over 60% and H₂ below 20%, and a corresponding C₂₊ current of more than 40 mA cm^–2.

对于能量存储，运输和化学工业中的应用，需要电催化将CO ₂还原为C ₁产物以外的更高价值的烃类。铜催化剂已显示出催化C ₂₊产物进行C-C偶联的潜力，但在水中的选择性仍然很低。在这里，我们使用密度泛函理论来确定不同Cu面上CO ₂还原中初始C–C耦合步骤的能量，并建议Cu（100）和阶梯式（211）面有利于C ₂₊Cu（111）上形成产物。为了证明这一点，我们报告了通过金属离子电池循环方法在铜箔上刻面曝光的调整。与抛光的铜箔相比，我们的具有100个切面的100循环Cu纳米立方体催化剂在C ₂₊与C _1的产品比率上提高了六倍，最高的C ₂₊法拉第效率超过60％，H ₂低于20％，相应的C ₂₊电流大于40 mA cm ^–2。