Dual-Scale Integration Design of Sn–ZnO Catalyst toward Efficient and Stable CO₂ Electroreduction

Electrochemical CO₂ reduction to CO is a potential sustainable strategy for alleviating CO₂ emission and producing valuable fuels. In the quest to resolve its current problems of low-energy efficiency and insufficient durability, a dual-scale design strategy is proposed by implanting a non-noble active Sn–ZnO heterointerface inside the nanopores of high-surface-area carbon nanospheres (Sn–ZnO@HC). The metal d-bandwidth tuning of Sn and ZnO alters the extent of substrate–molecule orbital mixing, facilitating the breaking of the *COOH intermediate and the yield of CO. Furthermore, the confinement effect of tailored nanopores results in a beneficial pH distribution in the local environment around the Sn–ZnO nanoparticles and protects them against leaching and aggregating. Through integrating electronic and nanopore-scale control, Sn–ZnO@HC achieves a quite low potential of −0.53 V vs reversible hydrogen electrode (RHE) with 91% Faradaic efficiency for CO and an ultralong stability of 240 h. This work provides proof of concept for the multiscale design of electrocatalysts.