Co0 − Coδ+ active pairs tailored by Ga-Al-O spinel for CO2-to-ethanol synthesis

Direct hydrogenation of CO2 into ethanol has been considered as an up-and-coming way to achieve CO2 utilization. Ethanol can be generated by reverse water gas shift as well as CO hydrogenation over Co-based catalysts, where the regulation of Co0 − Coδ+ is critical. Herein, we designed a supported Co-based catalyst doped with gallium, which was derived from Co-Al-O spinel precursor to facilitate synergistic catalyzing for CO2-to-ethanol transformation. The selectivity of ethanol reached 20.1 % in a continuous flow fixed micro-reactor over reduced CoGa1.0Al1.0O4/SiO2 catalyst at 270 °C and 3.0 MPa. Results of characterization show that the existence of the strong interaction between Ga oxide and cobalt induced the configuration of Co0 − Coδ+ active pairs, which promotes the process of ethanol synthesis by coupling the dissociation (CHx*)/non-dissociation (CO*) of the intermediates. The strategy by tuning the interaction between cobalt and gallium and/or aluminum oxide brings an avenue to tailor Co0 − Coδ+ active pairs for the hydrogenation of CO and CO2.