Selective production of ethylene from CO2 over CuAg tandem electrocatalysts

The electrochemical reduction reaction of CO2 (CO2RR) is desirable for decreasing CO2 concentration in the atmosphere and producing value-added chemicals. The development of advanced catalysts is a key challenge for the practical application of CO2RR. Recently, the bimetallic catalysts with two or more reaction sites acting synergistically are one of the most interesting catalysts. Herein, CuAg bimetallic catalysts with various Cu/Ag ratios are synthesized by the ultrasonic spray pyrolysis (USP) method for the selective production of ethylene (C2H4) via CO2RR. The electrocatalytic performances of the CuAg catalysts with different compositions are evaluated in a full flow single cell and the Cu90Ag10 exhibits 1.5 times the higher C2H4 Faradaic efficiency and the C2H4 current density at a cell voltage of 2.2 V than the bare Cu. Ag in the bimetallic catalysts provides additional CO via desorption-re-adsorption and diffusion process for CC coupling on the Cu surface to synthesize C2H4. In addition, the improved performance of the Cu90Ag10 is attributed to not only the synergistic effect between Cu and Ag but also the appropriate Cu/Ag ratio.