Solvent effects on the preparation of CuO-ZnO-ZrO2-Al2O3 catalyst by citrate complexing method for CO2 hydrogenation to methanol

CO₂ hydrogenation to methanol is one of the effective ways to achieve carbon neutrality, and copper-based catalysts are excellent catalysts for this reaction. However, the solvent effect is often overlooked when developing highly active and stable copper-based catalysts. In this study, the solvent effect of CuO-ZnO-ZrO₂-Al₂O₃ (CZZA) catalysts prepared by a citrate complexing method was investigated. It was found that ethanol as a solvent could significantly improve the catalytic performance of CZZA catalyst. The study highlights the role of ethanol in improving the dispersion of the active component Cu⁰ and promoting the formation of oxygen vacancies, thereby improving the overall catalytic efficiency. The results of in-situ DRIFTS showed that the CZZA catalyst achieved CO₂ hydrogenation through the formate pathway and demonstrated that hydrogen overflow is crucial. The simple improvement method proposed in this work can effectively improve the dispersion of metal oxides and enhance the interaction between the active species Cu and metal oxides, providing a basis for the design of efficient catalysts for CO₂ hydrogenation to methanol.