V‐Doped Cu<sub>2</sub>Se Hierarchical Nanotubes Enabling Flow‐Cell CO<sub>2</sub> Electroreduction to Ethanol with High Efficiency and Selectivity
Weipei Sun, Peng Wang, Yawen Jiang, Zhiwei Jiang, Ran Long, Zheng Chen, Pin Song, Tian Sheng, Zhengcui Wu, Yujie Xiong
Abstract
Abstract CO 2 electrocatalytic reduction (CO 2 ER) to multicarbon (C 2+ ) products is heavily pursued because of their commercial values, and the efficiency and selectivity have both attracted tremendous attention. A flow‐cell is a device configuration that can greatly enhance the conversion efficiency but requires catalysts to possess high electrical conductivity and gas permeability; meanwhile, the catalysts should enable the reaction pathway to specific products. Herein, it is reported that V‐doped Cu 2 Se nanotubes with a hierarchical structure can be perfectly compatible with flow‐cells and fulfil such a task, achieving CO 2 electroreduction to ethanol with high efficiency and selectivity. As revealed by the experimental characterization and theoretical calculation, the substitutional vanadium doping alters the local charge distribution of Cu 2 Se and diversifies the active sites. The unique active sites promote the formation of bridge *CO B and its further hydrogenation to *COH, and, as such, the subsequent coupling of *COH and *CO L eventually generates ethanol. As a result, the optimal Cu 1.22 V 0.19 Se nanotubes can electrocatalyze CO 2 to ethanol with a Faradaic efficiency of 68.3% and a partial current density of −207.9 mA cm −2 for the single liquid product of ethanol at −0.8 V in a flow‐cell. This work provides insights into the materials design for steering the reaction pathway toward C 2+ products, and opens an avenue for flow‐cell CO 2 ER toward a single C 2+ liquid fuel.