CO2 hydrogenation to methanol over CeO2-ZrO2-supported Cu-Ga catalysts: Influence of catalyst composition on catalytic performance

Abstract

To address the challenges posed by the greenhouse effect and climate change, and to achieve carbon neutrality, the hydrogenation of CO₂ into methanol (CH₃OH/MeOH) has gained significant attention due to its utility as a fuel and fuel additive. In this study, we synthesized bi-metallic catalysts based on Ga/Cu supported on ZrO₂- and CeO₂-based oxides using the wet impregnation method for the direct hydrogenation of CO₂ into methanol. The catalyst composition and metal-support interaction (MSI) were identified as critical factors influencing methanol production. Our findings revealed that the appropriate dispersion of metallic particles on the support significantly enhanced both CO₂ conversion and methanol selectivity. A synergistic effect was observed for Ga and Cu supported on a CeO₂/ZrO₂ composite (80:20), achieving highest CO₂ conversion of 15 % at reaction conditions of 300 °C and 410 psi. 1Cu1Ga/CZ (80:20) catalyst exhibits durability over 100 hours at 240° C possess 7.2 % conversion of CO₂ with 50 % of MeOH selectivity without significant decaying under the pressure of 410 psi and space velocity of 4500 mLh⁻¹g⁻¹. H₂-TPR and CO₂-TPD analyses indicate that the 1Cu1Ga/CZ (80:20) catalyst exhibits the highest redox activity and CO₂ adsorption capacity among all the catalysts tested. Additionally, the study emphasizes the importance of optimizing metal (promoter) loading and support composition to maximize catalytic performance and enhance methanol yield.