Product selectivity differences between the electroreduction of CO₂ and CO under practical current densities are a widely encountered phenomenon that is rarely emphasized or investigated in the field. In this Perspective we have systematically gathered and structured data pertaining to CO₂ and CO electroreduction to underscore the disparities in multi-carbon product formation. In addition, we propose that contributions of the microenvironment and a change in the local pH caused by the formation of carbonate/bicarbonate ions are among the most viable reasons behind such differences in electrochemical performance. Investigating the in situ microenvironment during the electrolysis of CO₂ compared with CO will deepen the mechanistic understanding of different reaction pathways and reveal fundamental insights that may facilitate catalyst design and device-engineering strategies.

实际电流密度下 CO 电还原₂ 和 CO 之间的产物选择性差异是一种广泛遇到的现象，但很少被强调或研究场。在本视角中，我们系统地收集和结构化了与 CO₂ 和 CO 电还原相关的数据，以强调多碳产物形成的差异。此外，我们认为微环境的贡献和碳酸根/碳酸氢根离子的形成引起的局部pH值的变化是电化学性能差异背后最可能的原因之一。与 CO 相比，研究 CO 电解过程中的原位微环境₂将加深对不同反应途径的机理理解，并揭示可能有助于催化剂设计的基本见解和设备工程策略。