Cerium Dioxide-Induced Abundant Cu/Cu Sites for Electrocatalytic Reduction of Carbon Dioxide to C Products.

In recent years, the electrochemical reduction of carbon dioxide (CORR) has made many advances in C production. Cu/Cu site is beneficial for C-C coupling process, but the oxidation state of copper cannot be well maintained during the reaction process, resulting in a decrease in catalyst activity. Based on this consideration, in this work, transition metal oxide CeO with a hollow cube structure and oxygen vacancies was introduced to stabilize and increase Cu/Cu active sites (CeCu). The catalyst exhibits excellent CORR performance, with FE achieving 73.52 % and j >280 mA/cm at 1.26 V (vs. RHE). Ethanol is the main C product and FE reaches 39 % at 1.26 V. The experimental results indicate that the presence of CeO provides a large number of oxygen vacancies and forming Cu-O-Ce structure by the strong interaction of CeO and Cu NPs. The structure of Cu-O-Ce and abundant oxygen vacancies lay a good foundation for the CO adsorption. Moreover, it increases the content of Cu/Cu sites, effectively inhibiting hydrogen evolution reaction, promoting the C-C coupling interaction, thereby facilitating the generation of C products. The DFT theoretical calculation further demonstrates that CeCu is more inclined towards the ethanol pathway, confirming its high selectivity for ethanol.