Highly Active and Stable Cu-Cd Bimetallic Oxides for Enhanced Electrochemical CO Reduction.

Electrochemical reduction of carbon dioxide (CO) can produce value-added chemicals such as carbon monoxide (CO) and multicarbon (C). However, the complex reaction pathways of CO electro-reduction reaction (CORR) greatly limit the product selectivity and conversion efficiency. Herein, the Cu-Cd bimetallic oxides catalyst was designed and applied for the CORR. The optimized 4.73 %Cd-CuO exhibits remarkable electrocatalytic CORR activity for selective CO production in H-cell using 0.5 M 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF)/MeCN as electrolyte. The Faradaic efficiency of CO (FE(CO)) can be maintained above 90 % over a wide potential range of -2.0 to -2.4 V vs. Ag/Ag. Particularly, the catalyst achieves an impressive FE(CO) of 96.3 % with a current density of 60.7 mA cm at -2.2 V vs. Ag/Ag. Furthermore, scaling up the 4.73 %Cd-CuO catalyst into a flow cell can reach 56.64 % FE of C products (ethylene, ethanol and n-propanol) with a current density as high as 600 mA cm steadily. The excellent CORR performance of the as-synthesized 4.73 %Cd-CuO can be mainly attributed to the introduction of CdO to improve the ability of CuO to activate CO, the electronic interactions between Cu and Cd can boost the activation and conversion the key intermediates of CORR and ensure the continuous stability of the 4.73 %Cd-CuO in electrolysis process.