Electroreduction of CO₂ to high value-added products such as hydrocarbons provides a promising way to create a carbon neutral circular economy. Copper (Cu) is the most effective metal catalyst with selectivity towards hydrocarbons but Cu catalyst alone generally produces hydrocarbons at low selectivity and yield. Operando surface enhanced infrared absorption spectroscopic (SEIRAS) analysis reveals that the low hydrocarbon yield is attributed to the poor ability of Cu to produce carbon monoxide (CO), which is a crucial intermediate for hydrocarbon formation. In the current study, an Ag-Cu dual-cathode CO₂RR device is developed, which allows separate control of electrode potential. This dual-cathode cell shows increased hydrocarbon yield (83 % for methane and 106 % for ethylene) and a 200 mV lower onset potential for C₂H₄, compared to electrolysis with a single Cu cathode. The CO produced by the Ag cathode transfers to Cu and increase its CO coverage, facilitating methane formation as well as promoting CC coupling to form ethylene. This study also reveals a mismatch of optimum electrode potential between Ag and Cu, which results in compromised performance of the two components in an Ag-Cu bimetallic electrocatalyst, but poses no challenge in the dual-cathode cell. To optimize the performance of the dual-cathode cell, we propose the use of a single-pass dual-gas-diffusion-cathode reactor with enhanced mass transfer for maximum hydrocarbon production. This work verifies that splitting the complex CO₂RR process into two separate steps is a feasible method to improve the overall efficiency and rate of advanced products while reducing the energy input.

将CO ₂电还原为高附加值的产品（例如碳氢化合物）提供了一种创造碳中和循环经济的有前途的方法。铜（Cu）是对烃具有选择性的最有效的金属催化剂，但仅铜催化剂通常会以较低的选择性和收率生产烃。Operando表面增强红外吸收光谱（SEIRAS）分析表明，低碳氢化合物收率归因于Cu产生一氧化碳（CO）的能力差，而一氧化碳是形成碳氢化合物的关键中间体。在当前的研究中，Ag-Cu双阴极CO ₂开发了RR设备，它允许单独控制电极电位。与使用单个Cu阴极进行电解相比，该双阴极电池显示出更高的烃产率（甲烷为83％，乙烯为106％），C ₂ H _4的起始电位降低了200 mV 。由银阴极产生的一氧化碳会转移到铜上并增加其一氧化碳的覆盖率，促进甲烷的形成并促进碳的转化。C偶联形成乙烯。这项研究还表明，Ag和Cu之间的最佳电极电势不匹配，这会导致Ag-Cu双金属电催化剂中两种组分的性能下降，但对双阴极电池没有挑战。为了优化双阴极电池的性能，我们建议使用单程双气体扩散阴极反应器，该反应器具有增强的传质能力，可最大程度地生产碳氢化合物。这项工作验证了将复杂的CO ₂ RR工艺分为两个单独的步骤是一种可行的方法，可以在降低能耗的同时提高先进产品的整体效率和生产率。