Facet‐Selective Deposition of Ultrathin Al<sub>2</sub>O<sub>3</sub> on Copper Nanocrystals for Highly Stable CO<sub>2</sub> Electroreduction to Ethylene
Hui Li, Peiping Yu, Renbo Lei, Feipeng Yang, Peng Wen, Xiao Ma, Guosong Zeng, Jinghua Guo, Francesca M. Toma, Yejun Qiu, Scott M. Geyer, Xinwei Wang, Tao Cheng, Walter S. Drisdell
Abstract
Abstract Catalysts based on Cu nanocrystals (NCs) for electrochemical CO 2 ‐to‐C 2+ conversion with high activity have been a subject of considerable interest, but poor stability and low selectivity for a single C 2+ product remain obstacles for realizing sustainable carbon‐neutral cycles. Here, we used the facet‐selective atomic layer deposition (FS‐ALD) technique to selectively cover the (111) surface of Cu NCs with ultrathin Al 2 O 3 to increase the exposed facet ratio of (100)/(111), resulting in a faradaic efficiency ratio of C 2 H 4 /CH 4 for overcoated Cu NCs 22 times higher than that for pure Cu NCs. Peak performance of the overcoated catalyst (Cu NCs/Al 2 O 3 ‐10C) reaches a C 2 H 4 faradaic efficiency of 60.4 % at a current density of 300 mA cm −2 in 5 M KOH electrolyte, when using a gas diffusion electrode flow cell. Moreover, the Al 2 O 3 overcoating effectively suppresses the dynamic mobility and the aggregation of Cu NCs, which explains the negligible activity loss and selectivity degradations of Cu NCs/Al 2 O 3 ‐10C shown in stability tests.