Cd/Cd(OH)2 Nanosheets Enhancing the Electrocatalytic Activity of CO2 Reduction to CO

Abstract Electric‐driven conversion of carbon dioxide (CO 2 ) to carbon monoxide (CO) under mild reaction conditions offers a promising approach to mitigate the greenhouse effect and the energy crisis. Surface engineering is believed to be one of the prospective methods for enhancing the electrocatalytic activity of CO 2 reduction. Herein, hydroxyl (OH) groups were successfully introduced to cadmium nanosheets to form cadmium and cadmium hydroxide nanocomposites ( i. e . Cd/Cd(OH) 2 nanosheets) via a facile two‐step method. The as‐prepared Cd/Cd(OH) 2 /CP (CP indicates carbon paper) electrode displays excellent electrocatalytic activity for CO 2 reduction to produce CO. The Faradaic efficiency of CO reaches 98.3 % and the current density achieves 23.8 mA cm −2 at −2.0 V vs. Ag/Ag + in a CO 2 ‐saturated 30 wt% 1‐butyl‐3‐methylimidazole hexafluorophosphate ([Bmim]PF 6 )‐65 wt% acetonitrile (CH 3 CN)‐5 wt% water (H 2 O) electrolyte. And the CO partial current density can reach up to 71.6 mA cm −2 with the CO Faradaic efficiency of more than 85 % at −2.3 V vs. Ag/Ag + , which stands out against Cd/CP, Cd(OH) 2 /CP, and Cd/CdO/CP electrodes. The excellent electrocatalytic performance of the Cd/Cd(OH) 2 /CP electrode can be attributed to its unique structural properties, suitable OH groups, perfect interaction with electrolyte, abundant active sites and fast electron transfer rate.