In Situ Fabrication of Cd Layer on Zn Foil Through Replacement Reaction for Electrochemical CO₂ Reduction to CO.

Transforming carbon dioxide (CO2) into valuable chemical products or carbonaceous fuels is a crucial strategy for addressing the impact of global climate change and energy challenges. Electrochemical CO2 reduction reaction (eCO2RR) shows promise in this regard, but challenges remain in the eCO2RR, such as poor electrocatalytic activity and low selectivity of the target product. In this study, we report a one‐step method of replacement reaction for synthesizing a cadmium layer on the zinc foil surface (named as the Cd/Zn electrode) for efficient eCO2RR to CO. The thicknesses of Cd layers could be easily adjusted by varying the molar concentration of Cd2+. The Cd/Zn electrode with an approximately 2.0 μm thick Cd layer exhibited superior electrocatalytic performance of the eCO2RR to CO in the ionic liquid‐containing electrolytes. The highest Faradaic efficiency of CO reached up to 99.0 % at −1.9 V vs. Ag/Ag+, and the maximum CO partial current density achieved 34.8 mA cm−2 at −2.3 V vs. Ag/Ag+. The 3D fluffy Cd layer with a suitable thickness on the Zn foil surface provided abundant active sites, fast charge transfer rate, and strong adsorption ability of CO2⋅− intermediates, which contributed to the enhancement of the electrocatalytic performance of the eCO2RR to CO. [ABSTRACT FROM AUTHOR]