Peerlings Matt L J, Vink-van Ittersum Maaike E T, de Rijk Jan Willem, de Jongh Petra E, Ngene Peter
Materials Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands.
ACS Catal. 2025 May 23;15(11):9695-9705. doi: 10.1021/acscatal.5c01614. eCollection 2025 Jun 6.
Copper is an attractive catalyst for the electrochemical reduction of CO to high value C products such as ethylene and ethanol. However, the activity, selectivity and stability of Cu-based catalysts must be improved for industrial applications. In this work, we investigate the effects of ionomers on the microenvironment and consequently the catalytic performance of CuO particles with a well-defined cubic shape. CuO particles without an ionomer coating were compared to those with a Nafion-based cation-exchange layer (CEL) and a Sustainion-based anion-exchange layer (AEL), as well as electrodes with two successive layers of Nafion and Sustainion in either order. Using these model electrodes, we found that the selectivity to C products is significantly improved with a Nafion coating, regardless of whether it is in direct contact with the copper surface or present as an overlayer on top of chloride-exchanged Sustainion. The selectivity improvement by Nafion is ascribed to the exclusion of proton-donating bicarbonate ions, which limits the competing hydrogen evolution reaction. Interestingly, introducing a second layer of Sustainion causes a selectivity shift from ethylene to ethanol. In addition, improved catalyst stability is observed for the Nafion-containing electrodes due to a mitigation of potassium bicarbonate precipitation and copper agglomeration. These results demonstrate that regulating the catalyst microenvironment via ionomer coatings is a promising approach to designing electrodes with superior and tunable catalytic performance.
铜是一种有吸引力的催化剂，可用于将CO电化学还原为高价值的碳产物，如乙烯和乙醇。然而，对于工业应用而言，铜基催化剂的活性、选择性和稳定性仍需提高。在这项工作中，我们研究了离聚物对微观环境的影响，进而研究了其对具有明确立方形状的CuO颗粒催化性能的影响。将未涂覆离聚物的CuO颗粒与涂覆了基于Nafion的阳离子交换层（CEL）和基于Sustainion的阴离子交换层（AEL）的颗粒进行比较，同时也与依次具有两层Nafion和Sustainion的电极进行比较。使用这些模型电极，我们发现，无论Nafion涂层是直接与铜表面接触还是作为氯化物交换的Sustainion顶部的覆盖层存在，Nafion涂层都能显著提高对碳产物的选择性。Nafion对选择性的提高归因于质子供体碳酸氢根离子的排除，这限制了竞争性析氢反应。有趣的是，引入第二层Sustainion会导致选择性从乙烯转向乙醇。此外，由于减轻了碳酸氢钾沉淀和铜团聚，含Nafion的电极的催化剂稳定性得到了提高。这些结果表明，通过离聚物涂层调节催化剂微观环境是设计具有优异且可调催化性能电极的一种有前景的方法。
