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 FECO value as high as 94% and an MACO of 439 mA/mgAu at −0.8 V (vs RHE), superior to the values for pure Au, reflecting its high noble metal utilization efficiency.