The electrosynthesis of C₂₊ hydrocarbons from CO₂ has attracted recent attention in light of the relatively high market price per unit energy input. Today’s low selectivities and stabilities towards C₂₊ products at high current densities curtail system energy efficiency, which limits their prospects for economic competitiveness. Here we present a materials processing strategy based on in situ electrodeposition of copper under CO₂ reduction conditions that preferentially expose and maintain Cu(100) facets, which favour the formation of C₂₊ products. We observe capping of facets during catalyst synthesis and achieve control over faceting to obtain a 70% increase in the ratio of Cu(100) facets to total facet area. We report a 90% Faradaic efficiency for C₂₊ products at a partial current density of 520 mA cm⁻² and a full-cell C₂₊ power conversion efficiency of 37%. We achieve nearly constant C₂H₄ selectivity over 65 h operation at 350 mA cm⁻² in a membrane electrode assembly electrolyser.

鉴于单位能量输入的相对较高的市场价格，由CO ₂电合成C ₂₊烃引起了近期的关注。当今，在高电流密度下对C ₂₊产品的低选择性和稳定性降低了系统的能效，从而限制了其经济竞争力的前景。在这里，我们提出了一种基于在CO ₂还原条件下原位电沉积铜的材料加工策略，该工艺优先暴露和维持Cu（100）面，这有利于C ₂₊的形成。产品。我们观察到催化剂合成过程中小平面的封盖，并实现了对小平面的控制，以使Cu（100）小平面与总小平面面积之比增加70％。我们报告了在520 mA cm ^-2的部分电流密度下C ₂₊产品的法拉第效率为90％，全电池C ₂₊功率转换效率为37％。在膜电极组件电解槽中，在350 mA cm ^{-2的条件下}，经过65小时的运行，我们在C ₂ H _4的选择性达到了几乎恒定。