Controlling the C1/C2+ product selectivity of electrochemical CO2 reduction upon tuning bimetallic CuIn electrocatalyst composition and operating conditions

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 52; no. 43; pp. 15958 - 15967
• Main Authors: Gu, Lin, Abhishek Dutta Chowdhury
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 07.11.2023
• Subjects: Anion exchanging; Bimetals; Carbon dioxide; Cation exchanging; Electrocatalysts; Electrolytes; Membranes; Tuning
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/d3dt03044j

Electrochemical carbon dioxide (CO2) reduction (eCO2R) over Cu-based bimetallic catalysts is a promising technique for converting CO2 into value-added multi-carbon products, such as fuels, chemicals, and materials. For improving the process efficiency, electrocatalyst development for the eCO2R must be integrated with tuning of operating conditions. For example, CuIn-based materials typically lead to preferential C1 product selectivity, which delivers the desired C2+ products upon varying the In/Cu ratio and operating conditions (i.e., in 0.1 M KHCO3 electrolytes using an H-type cell with a cation exchange membrane vs. in 1 M KOH electrolytes using a flow cell with an anion exchange membrane). At lower Cu-loading (i.e., InCu5Ox material), the maximum faradaic efficiency of HCOOH (FEHCOOH) of 70% was achieved at −1 V versus the reversible hydrogen electrode (vs. RHE) in an H-type cell. However, upon increasing the Cu loading, the preferential product selectivity could be altered: the InCu73Ox material led to a high CO selectivity (maximum FE of 51%) in the H-type cell at −0.8 V vs. RHE and delivered a current density of 100 mA cm−2 with a FEC2+ of up to 37% at −0.8 V vs. RHE in the flow cell configuration. Various characterization tools were also employed to probe the catalytic materials to rationalize the electrocatalytic performance.