Convergence of Tandem Catalysis and Nanoconfinement Promotes Electroreduction of CO2 to C2 Products

An efficient electrocatalytic conversion of CO 2 into valuable multicarbon (C 2+ ) products requires enhanced C–C coupling of C1 intermediates. Herein, we combine a tandem effect with a confinement strategy to construct a hollow Cu 2 O@Ag nanoshell electrocatalyst with a well-defined porous structure to improve the *CO intermediate coverage on the catalyst surface. In CO 2 electroreduction, in situ Raman spectroscopy shows that the introduction of Ag can not only promote the CO intermediate production but also improve the stability of Cu + to capture the *CO intermediate due to a CO-tandem effect, and the fine-tuned hollowness degree and pore size of Cu 2 O@Ag create a spatially confined microenvironment for trapping CO 2 as well as the enrichment of CO, which greatly facilitate subsequent C–C coupling for C 2+ product. The optimized Cu 2 O@Ag-45 with a specific nanoconfinement exhibits an enhanced ethylene (C 2 H 4 ) production under the wide potential range from −0.4 to −1.2 V (vs RHE), and a Faradaic efficiency of 55.4% for C 2+ products could be achieved at −1.2 V (vs RHE). This study highlights a promising strategy for the electrochemical reduction of CO 2 to C 2+ products on efficient C–C coupling catalysts.