Oxide-derived copper electrodes have displayed a boost in activity and selectivity toward valuable base chemicals in the electrochemical carbon dioxide reduction reaction (CO2RR), but the exact interplay between the dynamic restructuring of copper oxide electrodes and their activity and selectivity is not fully understood. In this work, we have utilized time-resolved surface-enhanced Raman spectroscopy (TR-SERS) to study the dynamic restructuring of the copper (oxide) electrode surface and the adsorption of reaction intermediates during cyclic voltammetry (CV) and pulsed electrolysis (PE). By coupling the electrochemical data to the spectral features in TR-SERS, we study the dynamic activation of and reactions on the electrode surface and find that CO₂ is already activated to carbon monoxide (CO) during PE (10% Faradaic efficiency, 1% under static applied potential) at low overpotentials (−0.35 V_RHE). PE at varying cathodic bias on different timescales revealed that stochastic CO is dominant directly after the cathodic bias onset, whereas no CO intermediates were observed after prolonged application of low overpotentials. An increase in cathodic bias (−0.55 V_RHE) resulted in the formation of static adsorbed CO intermediates, while the overall contribution of stochastic CO decreased. We attribute the low-overpotential CO₂-to-CO activation to a combination of selective Cu(111) facet exposure, partially oxidized surfaces during PE, and the formation of copper-carbonate-hydroxide complex intermediates during the anodic pulses. This work sheds light on the restructuring of oxide-derived copper electrodes and low-overpotential CO formation and highlights the power of the combination of electrochemistry and time-resolved vibrational spectroscopy to elucidate CO2RR mechanisms.

中文翻译：

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用时间分辨拉曼光谱探测铜电极上低过电位 CO2 到 CO 的活化动力学

氧化物衍生的铜电极在电化学二氧化碳还原反应 (CO2RR) 中对有价值的基础化学品的活性和选择性有所提高，但氧化铜电极的动态重组与其活性和选择性之间的确切相互作用尚不完全清楚。在这项工作中，我们利用时间分辨表面增强拉曼光谱 (TR-SERS) 研究了铜（氧化物）电极表面的动态重组以及循环伏安法 (CV) 和脉冲电解 (PE) 过程中反应中间体的吸附。 ）。通过将电化学数据与 TR-SERS 中的光谱特征相结合，我们研究了电极表面的动态活化和反应，发现 CO _{2在低过电势（-0.35 V RHE} ）下，PE（法拉第效率为 10%，静态施加电势下为 1%）期间已经被活化为一氧化碳 (CO )。在不同时间尺度上不同阴极偏压下的 PE 表明，在阴极偏压开始后，随机 CO 直接占主导地位，而在长时间施加低过电位后没有观察到 CO 中间体。阴极偏压（-0.55 V _RHE）的增加导致静态吸附 CO 中间体的形成，而随机 CO 的总体贡献减少。我们将低过电位 CO ₂选择性Cu(111)晶面暴露、PE过程中的部分氧化表面以及阳极脉冲过程中铜-碳酸盐-氢氧化物复合中间体的形成-to-CO活化。这项工作揭示了氧化物衍生铜电极的重组和低过电位 CO 的形成，并强调了电化学和时间分辨振动光谱相结合在阐明 CO2RR 机制方面的作用。