In the recent years, significant progress has been made toward designing active and selective catalysts for electrochemical CO₂ reduction, with particular interest focused on the two major C2 products—ethylene and ethanol. Numerous efforts have been made to enhance the understanding of the heterogeneous copper-based CO₂ reduction mechanisms by computational studies. Here we provide a critical assessment of various proposed scenarios of the initial and post C–C coupling steps that result in either ethylene or ethanol. In silico rationalization of the parameters controlling the product selectivity, such as the catalyst structure and composition (Cu facets, the presence of defective sites and/or subsurface oxygen atoms, or the interplay with a second metal) and the reaction conditions (pH, applied potential, and electrolyte), is provided. A comprehensive scheme combining the proposed pathways is derived, and the issues that are still under debate and require further investigations are highlighted.

中文翻译：

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异质铜基催化剂对多碳产物的CO ₂还原反应（CO2RR）的机理理解

近年来，在设计用于电化学还原CO _2的活性和选择性催化剂方面已经取得了重大进展，特别关注的是两种主要的C 2产品-乙烯和乙醇。为了提高对异质铜基CO ₂的理解，已经做出了许多努力。通过计算研究来减少机制。在这里，我们对初始和后继CC-C偶联步骤（导致乙烯或乙醇）的各种拟议方案进行了重要评估。在计算机上合理化控制产物选择性的参数，例如催化剂的结构和组成（铜小平面，缺陷位点和/或次表面氧原子的存在，或与第二种金属的相互作用）和反应条件（pH值）电位和电解质）。得出了一个综合了提议路径的综合方案，并着重指出了仍在争论中且需要进一步研究的问题。