Bimetallic Cu-Zn Catalysts for Electrochemical CO2 Reduction: Phase-Separated versus Core-Shell Distribution

Electrochemical CO2 reduction to fuels and chemicals is considered as one of the most important technologies to reach carbon neutrality. Bimetallic Cu-Zn materials have been proved as effective catalysts for electrochemical CO2 reduction. However, their structure-activity relation remains indistinct. Herein, we prepared two types of Cu-Zn bimetallic catalysts with core-shell and phase-separated structure distributions and studied their electrochemical CO2 reduction performance in detail. Interestingly, the phase-separated sample exhibited much higher activity and stability than the core-shell sample for reducing CO2 to CO, with a faradic efficiency up to 94% and stability beyond 15 h. The density functional theory calculation revealed that the phase-separated sample exhibited a lower energy barrier to form the *COOH intermediate and a more thermodynamically stable state than the core-shell sample. Our work paves an alternative way to design highly active and stable catalyst for electrochemical CO2 reduction by tuning the element spatial distribution.