The electrochemical CO₂ reduction reaction (CO₂RR) can couple carbon-capture storage with renewable energy to convert CO₂ into chemical feedstocks. For this process, copper is the only metal known to catalyze the CO₂RR to hydrocarbons with adequate efficiency, but it suffers from poor selectivity. Copper bimetallic materials have recently shown an improvement in CO₂RR selectivity compared with that of copper, such that the secondary metal is likely to play an important role in altering inherent adsorption energetics. This review explores the fundamental role of the secondary metal with a focus on how oxygen (O) and hydrogen (H) affinity affect selectivity in bimetallic electrocatalysts. Here, we identify four metal groups categorized by O and H affinities to determine their CO₂RR selectivity trends. By considering experimental and computational studies, we link the effects of extrinsic chemical composition and physical structure to intrinsic intermediate adsorption and reaction pathway selection. After this, we summarize some general trends and propose design strategies for future electrocatalysts.

电化学的CO ₂还原反应（CO ₂ RR）可以将碳捕获存储与可再生能源耦合，以将CO ₂转化为化学原料。对于该方法，铜是已知的唯一能以足够的效率将CO ₂ RR催化成烃的金属，但铜的选择性差。铜双金属材料最近显示出CO ₂的改善与铜相比，RR的选择性高，因此辅助金属可能在改变固有的吸附能方面起着重要的作用。这篇综述探讨了仲金属的基本作用，重点是氧（O）和氢（H）的亲和力如何影响双金属电催化剂的选择性。在这里，我们确定了按O和H亲和力分类的四个金属基团，以确定它们的CO ₂ RR选择性趋势。通过考虑实验和计算研究，我们将外部化学成分和物理结构的影响与固有的中间吸附和反应路径选择联系起来。之后，我们总结了一些总体趋势，并提出了未来电催化剂的设计策略。