Progress in the thermo-catalytic hydrogenation of CO₂ to ethanol

The chemical conversion of CO₂ is considered as one of the effective measures to reduce carbon emission, where breakthroughs have been made in the thermo-catalytic hydrogenation of CO₂ to ethanol in recent years. However, the synthesis of ethanol from CO₂ still suffers from some problems such as low ethanol yield and abundant by-products. In this paper, the research progress made in the thermo-catalytic hydrogenation of CO₂ to ethanol was reviewed. The performance of various catalysts with zeolites, metal oxides, perovskites, silica, organic frameworks and carbon-based materials as the support was evaluated and the synergistic effect of different metals on the CO₂ conversion and the intervention of various active species on the reaction were analyzed. Accordingly, the catalyst systems that can effectively promote the adsorption and activation of CO₂ and the coupling of C–C bond were summarized. Finally, the appropriate conditions as well as possible reaction mechanism for the CO₂ hydrogenation to ethanol were proposed. The insight shown in this paper should be beneficial to designing efficient catalysts, optimizing the reaction conditions and understanding the mechanism of CO₂ hydrogenation to ethanol in the future.