Selective Conversion of Carbon Dioxide to Acetic Acid over Thermally Transformed Co and Co–Ni ZIF-67 Catalysts

Carbon dioxide utilization is essential for reducing our carbon footprint, and significant efforts are needed to use CO2 as a feedstock to generate value-added chemicals. Acetic acid, a vital bulk chemical used in several industries, is industrially produced through the methanol carbonylation process. While some progress has been made toward hydrocarboxylation of methanol to acetic acid, which utilizes methanol and CO2 as reactants, a direct pathway to convert CO2 without an additional carbon source remains a significant challenge. Here, we demonstrate that thermally transformed Co and Co–Ni ZIF-67 exhibit hydrogenation and C–C coupling activities, converting CO2 to acetic acid via a formate intermediate in aqueous media. Bimetallic Co–Ni ZIF-67 with Co:Ni = 1:2, thermally transformed at 280 °C, proved to be the best catalyst due to the presence of mixed oxidation state of Co2+ and Co0 sites, which provide the bifunctional activity of CO2 reduction and C–C coupling.