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

Electric-driven conversion of carbon dioxide (CO₂ ) 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 CO₂ 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 CO₂ 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 CO₂ -saturated 30 wt% 1-butyl-3-methylimidazole hexafluorophosphate ([Bmim]PF₆ )-65 wt% acetonitrile (CH₃ CN)-5 wt% water (H₂ 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.