Electrocatalytic CO₂ reduction has been developed as a promising and attractive strategy to achieve carbon neutrality for sustainable chemical production. Among various reduction products, multi-carbon (C₂₊) compounds with higher energy density are desirable value-added products. Herein, we review and discuss the recent progress and challenges in preparing C₂₊ products. We start with the elaboration of the most recent advancement of carbon–carbon coupling results and the newly proposed mechanisms, which are much more complicated than that of single-carbon products. The complex scenarios involved in the initial CO₂ activation process, the catalyst micro/nanostructure design, and mass transfer conditions optimization have been thoroughly discussed. In addition, we also propose the synergistic realization of high C₂₊ product selectivity through the rational design of the catalyst and elaborate on the influence of electrolytes (anion/cation/pH/ionic liquid) using theoretical calculation analysis and machine learning prediction. Several in situ/operando techniques have been elaborated for tracking the structural evolution and recording the reaction intermediates during electrocatalysis. Additional insights into the triphasic interfacial reaction systems with improved C₂₊ selectivity are also provided. By presenting these advances and future challenges with potential solutions related to the integral development of electrochemical reduction of carbon dioxide to C₂₊ products, we hope to shed some light on the forthcoming research on electrochemical carbon dioxide recycling.

中文翻译：

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二氧化碳电化学还原为多碳 (C2+) 产品：挑战和前景

电催化CO ₂还原已被开发为一种有前途且有吸引力的策略，以实现可持续化学生产的碳中和。在各种还原产品中，具有较高能量密度的多碳(C ₂₊ )化合物是理想的增值产品。_{在此，我们回顾并讨论了制备C 2+}产品的最新进展和挑战。我们首先阐述碳-碳耦合结果的最新进展和新提出的机制，它们比单碳产品复杂得多。初始CO _{2涉及的复杂场景} 对活化过程、催化剂微/纳米结构设计和传质条件优化进行了深入讨论。此外，我们还提出通过催化剂的合理设计协同实现高C _{2+产物选择性，并利用理论计算分析和机器学习预测详细阐述了电解质（阴离子/阳离子/pH/离子液体）的影响。}已经详细阐述了几种原位/操作技术，用于跟踪电催化过程中的结构演化和记录反应中间体。_{对具有改进的 C 2+}的三相界面反应系统的更多见解还提供了选择性。通过介绍这些进展和未来的挑战以及与二氧化碳电化学还原成C ₂₊产品的整体开发相关的潜在解决方案，我们希望为即将开展的电化学二氧化碳回收研究提供一些启示。