Magnesium-Promoted Catalytic Stability of the Cu/ZnO/ZrO₂/Al₂O₃-MgO Catalyst in CO₂ Hydrogenation to Methanol

A Mg-promoted Cu/ZnO/ZrO2/Al2O3 catalyst (CZZAM) was developed for methanol synthesis via CO2 hydrogenation. Incorporating magnesium into the catalyst precursor improved the durability, addressing stability issues in our previously reported Cu/ZnO/ZrO2/Al2O3 (CZZA) catalysts. Comparative evaluations showed that CZZAM outperforms commercial Cu/ZnO/Al2O3 (CZA) and CZZA catalysts, achieving a maximum methanol space–time yield of 0.99 gMeOH·gcat–1·h–1 with a methanol selectivity of 50.6% and a yield of 12.7% under 24,000 mL·gcat–1·h–1 at 260 °C and 5 MPa. In a 60 h test, CZZAM exhibited only a 2.8% decrease in methanol productivity compared to over 9 to 10% declines for CZA and CZZA. Characterizations revealed that Mg addition enhanced Cu nanoparticle dispersion and structural stability. These findings demonstrate that Mg incorporation effectively enhances activity and stability in Cu/ZnO/ZrO2/Al2O3 catalysts for CO2 hydrogenation to methanol.