Distinct reconstruction of aluminum-doped oxide-derived copper enhances the selectivity of C2+ products in CO2 electroreduction

Abstract

The electrochemical carbon dioxide reduction reaction (eCO2RR) has great potential in addressing environmental and renewable energy storage issues simultaneously. However, highly valuable C2+ products are usually obtained at high overpotentials with low Faradaic efficiencies owing to the sluggish kinetics of C-C coupling of the reaction intermediates, especially in neutral electrolytes. Recently, oxide-derived copper (OD-Cu) has attracted significant attention for its high selectivity toward C2+ products in the eCO2RR. While various CuOx precursors have been reported to influence the reconstruction of CuOx and product selectivity, CuOx precursors with new dopants are required to understand the influence of metal dopants. Here, we synthesized Al-doped CuO (CuO_Al) using a metal-organic framework to examine the effect of Al dopants on the catalytic activity of OD-Cu. Interestingly, Al induces reconstruction of CuO_Al, forming nanoflakes, which exhibit a high Faradaic efficiency of 68.4% and a large partial current density of 478.7 mA cm−2 toward C2+ products at −1.08 V versus a reversible hydrogen electrode in a neutral 1 M KHCO3 electrolyte. Contact angle measurements and lead underpotential deposition revealed that the reconstruction provides CuO_Al with high hydrophobicity and high electrochemically active surface area, respectively. Our findings suggest that the dopant-mediated reconstruction of CuO into OD-Cu can effectively promote activity and selectivity toward C2+ products with enhanced structural properties by using small amounts of dopants. © 2023 The Royal Society of Chemistry