Constraint of Reaction Intermediates in Ag@Cu 2 O Porous Core–Shell Nanospheres Toward Boosted CO 2 Electroreduction to C 2 H 4

At present, Cu‐based catalysts have problems such as low current density and low selectivity of products during the electrochemical reduction of CO 2 . Herein, a porous core–shell structure Ag@Cu 2 O catalyst is constructed by an in situ growth method, where a layer of Cu 2 O is encapsulated outside Ag. The catalyst is promoted to generate CO by Ag with a lower energy barrier, and the porous Cu 2 O shell accelerates the diffusion of CO 2 molecules and electrolyte through its continuous pores, while the physical confinement effect prolongs the residence time of CO intermediates on the surface of Cu 2 O, promoting CC coupling. Ag@2Cu 2 O demonstrates a 63% C 2 H 4 Faradaic efficiency at an electrode potential of −1 V vs reversible hydrogen electrode. Moreover, the mechanical flexibility and stress buffering capacity of the porous structure enable the catalyst to maintain structural integrity during continuous operation for up to 12 h.