Convoluted selectivity trends and a missing link between reaction product distribution and catalyst properties hinder practical applications of the electrochemical CO₂ reduction reaction (CO₂RR) for multicarbon product generation. Here we employ operando X-ray absorption and X-ray diffraction methods with subsecond time resolution to unveil the surprising complexity of catalysts exposed to dynamic reaction conditions. We show that by using a pulsed reaction protocol consisting of alternating working and oxidizing potential periods that dynamically perturb catalysts derived from Cu₂O nanocubes, one can decouple the effect of the ensemble of coexisting copper species on the product distribution. In particular, an optimized dynamic balance between oxidized and reduced copper surface species achieved within a narrow range of cathodic and anodic pulse durations resulted in a twofold increase in ethanol production compared with static CO₂RR conditions. This work thus prepares the ground for steering catalyst selectivity through dynamically controlled structural and chemical transformations.

复杂的选择性趋势以及反应产物分布和催化剂性能之间缺失的联系阻碍了电化学 CO ₂还原反应 (CO ₂ RR) 在多碳产物生成中的实际应用。在这里，我们采用亚秒级时间分辨率的操作 X 射线吸收和 X 射线衍射方法来揭示暴露于动态反应条件下的催化剂的惊人复杂性。我们表明，通过使用由交替工作和氧化电位周期组成的脉冲反应方案，动态扰乱源自 Cu _{2的催化剂}O 纳米立方体，可以解耦共存铜物种的集合对产物分布的影响。_{特别是，与静态 CO 2} RR 条件相比，在狭窄的阴极和阳极脉冲持续时间范围内实现的氧化和还原铜表面物质之间的优化动态平衡导致乙醇产量增加两倍。因此，这项工作为通过动态控制的结构和化学转变来控制催化剂的选择性奠定了基础。