Multi‐Shell Copper Catalysts for Selective Electroreduction of CO2 to Multicarbon Chemicals

Abstract Electrocatalytic CO 2 reduction (CO 2 R) coupled with renewable electricity has been considered as a promising route for the sustainability transition of energy and chemical industries. However, the unsatisfactory yield of desired products, particularly multicarbon (C 2+ ) products, has hindered the implementation of this technology. This work describes a strategy to enhance the yield of C 2+ product formation in CO 2 R by utilizing spatial confinement effects. The finite element simulation results suggest that increasing the number of shells in the catalyst wil lead to a high local concentration of *CO and promotes the formation of C 2+ products. Inspired by this, Cu nanoparticles are synthesized with desired hollow multi‐shell structures. The CO 2 reduction results confirm that as the number of shells increase, the hollow multi‐shell copper catalysts exhibit improved selectivity toward C 2+ products. Specifically, the Cu catalyst with 4.4‐shell achieved a high selectivity of over 80% toward C 2+ at a current density of 900 mA cm −2 . Evidence from in situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy unveils that the multi‐shell Cu catalyst exhibits an enhanced *CO atop coverage and the stronger interaction with *CO atop compared to commercial Cu, confirming the simulation results. Overall, the work promises an effective approach for boosting CO 2 R selectivity toward value‐added chemicals.