Understanding the role of CeO2 and MgO in Cu-based catalysts for CO2 hydrogenation to methanol

The catalytic hydrogenation of captured carbon dioxide (CO₂) to methanol (CH₃OH) is a promising strategy for reducing CO₂ emissions while producing sustainable fuel. This study investigates the performance of a trimetallic Cu/CeO₂/MgO (CuCeMg) catalyst for CO₂ hydrogenation to methanol and compares it Cu-CeO 2 (CuCe) and Cu-MgO (CuMg) formulations, as well as Cu-ZnOAl 2 O 3 (CuZnAl) reference catalyst. The synergistic interactions between Cu, CeO₂, and MgO were analyzed using X-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and temperature programmed reduction (TPR). The CuCeMg catalyst exhibited a balanced combination of medium and strong basic sites and moderate reducibility, resulting in competitive methanol space time yield of 138 g CH₃OH kg cat ⁻¹ h⁻¹ at 230 °C and 3 MPa under moderate reaction conditions. Although CuZnAl achieved the highest overall activity, CuCeMg demonstrated favorable selectivity at low temperature and effective CO₂ activation. These findings provide insight into how multifunctional supports based on CeO₂ and MgO can be tailored to enhance CO₂ hydrogenation performance and offer a platform for further catalyst optimization toward sustainable methanol production.