Inspired by grain refinement in the traditional metal processing, we develop a top-down approach by facile multiple-redox treatment to obtain the downsized Cu crystals over the self-supported copper electrodes for the enhanced selective CO₂ electroreduction. Specifically, the treated copper meshes exhibit an increased activity and selectivity for CO production with high Faradaic efficiency of 78% and partial current density of 13.2 mA cm⁻² at the potential of −0.8 V (vs. RHE). This investigation intends to ascribe the enhanced properties to the surface downsized crystals of Cu electrode induced by the multiple-redox treatments. Moreover, the molecular reaction mechanism of the elementary reaction of CO₂ conversion to CO is also discussed. This work offers a new top-down strategy to design and preparation of nanosized catalytic catalysts on a self-supported electrode and valuable insights in selective CO₂ conversion toward valuable fuels over Cu-based electrodes.

受传统金属加工中晶粒细化的启发，我们通过轻松的多氧化还原处理开发了一种自顶向下的方法，以在自支撑铜电极上获得尺寸减小的Cu晶体，从而增强了选择性CO _2的电还原。具体地，在-0.8V的电位下（相对于RHE），经处理的铜网以78％的高法拉第效率和13.2mA cm ^-2的分电流密度显示出用于CO生产的增加的活性和选择性。该研究旨在归因于通过多重氧化还原处理引起的Cu电极的表面减小的晶体的增强的性能。此外，CO ₂元素反应的分子反应机理还讨论了向CO的转化。这项工作提供了一种新的自上而下的策略，用于在自支撑电极上设计和制备纳米级催化催化剂，并提供了宝贵的见解，使人们可以选择性地将CO ₂转化为铜基电极上的有价值的燃料。