Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, M5S 3G4, Canada.
Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, 100084, Beijing, China.
Nat Commun. 2023 Apr 25;14(1):2387. doi: 10.1038/s41467-023-37898-8.
Performing CO reduction in acidic conditions enables high single-pass CO conversion efficiency. However, a faster kinetics of the hydrogen evolution reaction compared to CO reduction limits the selectivity toward multicarbon products. Prior studies have shown that adsorbed hydroxide on the Cu surface promotes CO reduction in neutral and alkaline conditions. We posited that limited adsorbed hydroxide species in acidic CO reduction could contribute to a low selectivity to multicarbon products. Here we report an electrodeposited Cu catalyst that suppresses hydrogen formation and promotes selective CO reduction in acidic conditions. Using in situ time-resolved Raman spectroscopy, we show that a high concentration of CO and OH on the catalyst surface promotes C-C coupling, a finding that we correlate with evidence of increased CO residence time. The optimized electrodeposited Cu catalyst achieves a 60% faradaic efficiency for ethylene and 90% for multicarbon products. When deployed in a slim flow cell, the catalyst attains a 20% energy efficiency to ethylene, and 30% to multicarbon products.
在酸性条件下进行 CO 还原能够实现高的单次 CO 转化率效率。然而，与 CO 还原相比，析氢反应具有更快的动力学，这限制了多碳产物的选择性。先前的研究表明，Cu 表面吸附的氢氧根离子在中性和碱性条件下促进 CO 还原。我们假设在酸性 CO 还原中，有限的吸附氢氧根物种可能导致多碳产物的选择性较低。在这里，我们报告了一种电沉积的 Cu 催化剂，它能够抑制氢气的形成，并在酸性条件下促进 CO 的选择性还原。通过原位时间分辨拉曼光谱，我们表明催化剂表面高浓度的 CO 和 OH 促进了 C-C 偶联，这一发现与 CO 停留时间增加的证据相关。优化后的电沉积 Cu 催化剂对乙烯的法拉第效率达到 60%，对多碳产物的法拉第效率达到 90%。当在一个超薄的流动池中使用时，该催化剂对乙烯的能量效率达到 20%，对多碳产物的能量效率达到 30%。
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