Enhanced CO₂ Electrochemical Reduction Performance over Cu@AuCu Catalysts at High Noble Metal Utilization Efficiency

The electrochemical CO₂ reduction reaction (CO₂RR) represents a viable alternative to help close the anthropogenic carbon cycle and convert intermittent electricity from renewable energy sources to chemical energy in the form of value-added chemicals. The development of economic catalysts possessing high faradaic efficiency (FE) and mass activity (MA) toward CO₂RR is critical in accelerating CO₂ utilization technology. Herein, an elaborate Au-Cu catalyst where an alloyed AuCu shell caps on a Cu core (Cu@AuCu) is developed and evaluated for CO₂-to-CO electrochemical conversion. Specific roles of Cu and Au for CO₂RR are revealed in the alloyed core-shell structure, respectively, and a compositional-dependent volcano-plot is disclosed for the Cu@AuCu catalysts toward selective CO production. As a result, the Au₂-Cu₈ alloyed core-shell catalyst (only 17% Au content) achieves an FE_CO value as high as 94% and an MA_CO of 439 mA/mg_Au at -0.8 V (vs RHE), superior to the values for pure Au, reflecting its high noble metal utilization efficiency.