Construction of Zinc-Bismuth Composite Oxide Interface Helps Electrochemical Reduction of CO2 to Produce Formic Acid Efficiently and Stably

Electro-reduction of CO 2 (CO 2 RR) to formic acid is one of the most efficient and promising technologies for the utilization of CO 2 , however, designing catalysts with high reactivity and selectivity to achieve the conversion of CO 2 to formic acid is still a great challenge. Therefore, in this study, Bi 2 O 3 -ZnO/ZnAl 2 O 4 composite oxide catalysts were constructed using layered double hydroxides as precursors to enhance the interfacial stability and utilize the synergistic effect of zinc-bismuth dual active sites for the efficient electrocatalytic reduction of CO 2 to formate. The product formate bias current density reached up to 25.8 mA·cm − 2 at -1.3 V (vs. RHE) in an H-type electrolytic cell and the Faraday efficiency of formate was maintained at about 93% under stability tests up to 14 h, which was superior to most other reported catalysts. In the formation of the Bi 2 O 3 -ZnO/ZnAl 2 O 4 interface, zinc promotes the electroreduction of CO 2 to produce *CO 2 − intermediates, while bismuth reduces CO production and improves formic acid selectivity by providing more reactive sites. In addition, the interface between zinc and bismuth optimizes electron and proton flow, helping to maintain a lower energy threshold during the reaction and thus improving catalytic efficiency. This interface engineering approach utilizes zinc-bismuth dual active sites to achieve high selectivity and stability of CO 2 electrocatalytic reduction, providing insights for the development of large-scale efficient CO 2 RR catalysts in the future. Graphical