Preparation of Ga ₂ O ₃ /ZrO ₂ Catalysts with Low Gallium Loading for CO ₂ Hydrogenation to Methanol

Selective hydrogenation of CO2 to methanol has attracted increasing attention. In this work, the Ga2O3/ZrO2 catalysts of low gallium loadings were prepared with thermal decomposition and low-temperature plasma decomposition of the gallium precursor. The plasma decomposition leads to enhanced electron transfer from ZrO2 to Ga2O3, improving the ability of Ga2O3 to activate H2. The plasma decomposition also generates more interfacial Ga2O3/ZrO2_Ov sites. This facilitates CO2 activation on the catalyst surface in the form of HCO3*, which is favored for further conversion into HCOO* and CH3O* for methanol formation. All of these cause a higher activity of the plasma-decomposed catalyst. For example, the space-time yield (STY) of methanol over the plasma-decomposed catalyst of 0.7 wt % gallium loading reaches 176 gMeOH h–1 kgcat–1 at 5 MPa and 325 °C. This represents a 30.4% increase in the STY of methanol compared with the catalyst thermally decomposed.