Controlling the C 1 /C 2+ product selectivity of electrochemical CO 2 reduction upon tuning bimetallic CuIn electrocatalyst composition and operating conditions.

Electrochemical carbon dioxide (CO) reduction (eCOR) over Cu-based bimetallic catalysts is a promising technique for converting CO into value-added multi-carbon products, such as fuels, chemicals, and materials. For improving the process efficiency, electrocatalyst development for the eCOR must be integrated with tuning of operating conditions. For example, CuIn-based materials typically lead to preferential C product selectivity, which delivers the desired C products upon varying the In/Cu ratio and operating conditions (, in 0.1 M KHCO electrolytes using an H-type cell with a cation exchange membrane in 1 M KOH electrolytes using a flow cell with an anion exchange membrane). At lower Cu-loading (, InCuO material), the maximum faradaic efficiency of HCOOH (FE) of 70% was achieved at -1 V the reversible hydrogen electrode ( RHE) in an H-type cell. However, upon increasing the Cu loading, the preferential product selectivity could be altered: the InCuO material led to a high CO selectivity (maximum FE of 51%) in the H-type cell at -0.8 V RHE and delivered a current density of 100 mA cm with a FE of up to 37% at -0.8 V RHE in the flow cell configuration. Various characterization tools were also employed to probe the catalytic materials to rationalize the electrocatalytic performance.