Selective Electrosynthesis of Ethanol via Asymmetric C–C Coupling in Tandem CO<sub>2</sub> Reduction
Peng Luan, Xue Dong, Linqi Liu, Jianping Xiao, Pengfei Zhang, Jie Zhang, Haibo Chi, Qingnan Wang, Chunmei Ding, Rengui Li, Can Li
Abstract
Selective electroreduction of CO 2 to ethanol has economic value and environmental significance. However, the activity and selectivity of CO 2 reduction toward ethanol are still low due to the sluggish kinetics of C–C coupling and the intense competition of hydrocarbon production. Herein, we report a layered tandem catalyst consisting of Cu nanosheets with a Cu(111)-oriented surface and Ag nanoparticles, which can effectively shift the selectivity from hydrocarbons to ethanol. The Faradaic efficiency of ethanol was improved from less than 30% on bare Cu(111) to 56.5 ± 2.6% on the layered Cu/Ag tandem catalysts, with a partial current density of 356.7 ± 9.5 mA cm –2 . In situ Raman spectroscopy results and density functional theory calculations suggest that the high selectivity toward ethanol can be attributed to the asymmetric *CH 2 –CO coupling mechanism, which is facilitated by the selective generation of *CH 2 species on (111)-facet-exposed Cu nanosheets and the high local CO concentration supplied by the Ag catalyst.