Effect of Ni content on Cu–Mn/ZrO2 catalysts for methanol synthesis from CO2 hydrogenation

Abstract

The synthesis of methanol via CO₂ hydrogenation is a promising route to a carbon-neutral economy. The key to the process is catalysts. In this research, a series of Cu–Mn–Ni/ZrO₂ catalysts with different Ni : Cu ratios (CMZ, CMNZ-0.01, CMNZ-0.05, CMNZ-0.1, and CMNZ-0.2) were synthesized by co-precipitation for the hydrogenation of CO₂ to methanol. It was found that an appropriate Ni content led to increased Cu dispersion and surface area. Consequently, more active Cu sites were exposed, leading to higher CO₂ conversion. Moreover, the addition of a small amount of Ni enhanced the basicity on the catalyst surface, effectively stabilizing intermediates such as *COOH and *OCH₃, which improved the methanol selectivity. At 240 °C and 5 MPa, the CMNZ-0.01 catalyst showed better performance with a methanol selectivity of 57.84% and CO₂ conversion of 14.57%, which were higher than those of the Cu–Mn/ZrO₂ catalyst.