Directing the Selectivity of CO Electrolysis to Acetate by Constructing Metal-Organic Interfaces

Electrochemically converting CO2 to valuable chemicals holds great promise for closing the anthropogenic carbon cycle. Owing to complex reaction pathways and shared rate-determining steps, directing the selectivity of CO2/CO electrolysis to a specific multicarbon product is very challenging. We report here a strategy for highly selective production of acetate from CO electrolysis by constructing metal-organic interfaces. We demonstrate that the Cu-organic interfaces constructed by in situ reconstruction of Cu complexes show very impressive acetate selectivity, with a high Faradaic efficiency of 84.2 % and a carbon selectivity of 92.1 % for acetate production, in an alkaline membrane electrode assembly electrolyzer. The maximum acetate partial current density and acetate yield reach as high as 605 mA cm-2 and 63.4 %, respectively. Thorough structural characterizations, control experiments, operando Raman spectroscopy measurements, and density functional theory calculation results indicate that the Cu-organic interface creates a favorable reaction microenvironment that enhances *CO adsorption, lowers the energy barrier for C-C coupling, and facilitates the formation of CH3COOH over other multicarbon products, thus rationalizing the selective acetate production. A Cu-organic interface constructed by in situ reconstruction of Cu phthalocyanine can direct the selectivity of CO electrolysis to a specific multicarbon product, with an acetate Faradaic efficiency (FE) as high as 84.2 %, a record acetate partial current density of 605 mA cm-2, and an acetate yield up to 63.4 %. The impressive acetate selectivity is ascribed to the favorable reaction microenvironment created by the Cu-organic interface.+image

Automated summary

This study presents a strategy for highly selective production of acetate from CO electrolysis by constructing metal-organic interfaces. The Cu-organic interfaces constructed by in situ reconstruction of Cu complexes demonstrate impressive acetate selectivity, with high Faradaic efficiency and carbon selectivity. The study provides insights into the mechanism of selective acetate production.