ABSTRACT

Electrochemical CO₂ reduction reaction (CO₂RR) is an appealing strategy to alleviate the energy and environment issues caused by CO₂ emission, and Cu-based electrodes show great potential in CO₂ conversion. The wide product distribution makes Cu fail to be a high-efficiency catalyst for a specific product, and the competition with hydrogen evolution reaction is another critical issue. Various intermediates are involved in the CO₂RR processes and some of them act as selective-dependent species, resulting in different products. Identifying the favorable pathways among those furcated from the key intermediates is crucial to target specific products. Herein, the key intermediates and competitive pathways furcated from them are discussed in detail. The *COOH and *OCHO can be formed upon CO₂ activation, leading, respectively, to CO and HCOO⁻ production. The *CO intermediate can competitively undergo hydrogenation and C-C coupling to, respectively, form *CHO/*COH and *OCCO. Aldehydes can lead to the formation of alcohols or hydrocarbons. The approaches to modulate the reaction tendency of these key intermediates are reviewed based on the characteristics of each possible pathway. The challenges and perspectives for the mechanism understanding are also discussed.

摘要

电化学CO ₂还原反应(CO _{2 RR)是缓解CO 2}排放引起的能源和环境问题的一种有吸引力的策略，而铜基电极在CO ₂转化方面显示出巨大的潜力。广泛的产物分布使得Cu无法成为特定产物的高效催化剂，与析氢反应的竞争是另一个关键问题。_{CO 2}涉及各种中间体RR 过程和其中一些过程充当选择性依赖物种，产生不同的产品。确定从关键中间体分叉出来的有利途径对于靶向特定产品至关重要。在此，详细讨论了关键中间体和从它们衍生的竞争途径。_{*COOH 和 *OCHO 可以在 CO 2}活化时形成，分别产生 CO 和 HCOO ^-生产。*CO 中间体可以竞争性地进行氢化和 CC 偶联，分别形成 *CHO/*COH 和 *OCCO。醛可导致醇或碳氢化合物的形成。根据每种可能途径的特点，对调节这些关键中间体的反应趋势的方法进行了综述。还讨论了机制理解的挑战和前景。