Highly Selective Conversion of Carbon Dioxide to Methanol through a Cu−ZnO−Al₂O₃−ZrO₂/Cu−MOR Tandem Catalyst

Methanol formation from CO₂ hydrogenation attracts great attention in view of utilization of carbon resources. However, CO₂ transformation to methanol is challenging because of the thermodynamic equilibrium restriction and water-caused catalyst deactivation. It is desired, therefore, to develop highly active, selective and stable catalysts for CO₂ hydrogenation to methanol. Herein, we propose a novel tandem catalyst composed of Cu−ZnO−Al₂O₃−ZrO₂ (CZAZ) and Cu−MOR for highly selective conversion of CO₂ to methanol. During CO₂ hydrogenation by the CZAZ catalyst, the by-product methane is continuously transformed to methanol through reaction with water via the Cu−MOR catalyst, thus enhancing CO₂ conversion and methanol selectivity. Under mild reaction conditions (200 °C and 3.0 MPa), high CO₂ conversion (40.7 %) and methanol selectivity (97.6 %) are achieved, outperforming state-of-the-art CO₂ hydrogenation catalysts. Further, water-caused deactivation of the catalyst through aggregation and densification is suppressed owing to water consumption via methane oxidation to methanol, validating a high CZAZ/Cu−MOR tandem catalyst stability.