Antireconstruction Cu Nanowire Catalysts Enabled by SiO2 Encapsulation for Durable Electrochemical CO2 Reduction

Abstract

Structural reconstruction─an uncontrollable process that compromises the stability of Cu-based catalysts in electrochemical CO₂ reduction (CO₂R)─presents a major scientific challenge that has yet to be overcome. In this work, we develop a well-controlled SiO₂ encapsulation approach to stabilize Cu-based CO₂R electrocatalysts against reconstruction. Using Cu nanowires (CuNWs) as a model platform, we demonstrate that SiO₂ encapsulation can significantly suppress Cu reconstruction while retaining ∼95% of the initial CO₂R performance over 24-h stability tests at −1.15 V vs reversible hydrogen electrode (V_RHE). In contrast, unencapsulated CuNWs exhibit severe structural deterioration with attenuated CO₂R activity under identical testing conditions. In situ Raman studies and density functional theory (DFT) calculations reveal that the antireconstruction effect results from the formation of a robust Cu–O–Si interface that can not only serve as a structural anchor but also contribute to strengthening the Cu–Cu bonding at the exposed Cu active sites during CO₂R operation. These results decipher the stabilizing mechanism of SiO₂ encapsulation, and provide key insights for designing durable Cu-based CO₂R electrocatalysts toward practical applications.