Selective CO₂ -to-Syngas Conversion Enabled by Bimetallic Gold/Zinc Sites in Partially Reduced Gold/Zinc Oxide Arrays

Electrocatalytic CO₂ -to-syngas (gaseous mixture of CO and H₂ ) is a promising way to curb excessive CO₂ emission and the greenhouse gas effect. Herein, we present a bimetallic AuZn@ZnO (AuZn/ZnO) catalyst with high efficiency and durability for the electrocatalytic reduction of CO₂ and H₂ O, which enables a high Faradaic efficiency of 66.4 % for CO and 26.5 % for H₂ and 3 h stability of CO₂ -to-syngas at -0.9 V vs. the reversible hydrogen electrode (RHE). The CO/H₂ ratios show a wide range from 0.25 to 2.50 over a narrow potential window (-0.7 V to -1.1 V vs. RHE). In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy combined with density functional theory calculations reveals that the bimetallic synergistic effect between Au and Zn sites lowers the activation energy barrier of CO₂ molecules and facilitates electronic transfer, further highlighting the potential to control CO/H₂ ratios for efficient syngas production using the coexisting Au sites and Zn sites.