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

Selective hydrogenation of CO 2 to methanol has attracted increasing attention. In this work, the Ga 2 O 3 /ZrO 2 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 ZrO 2 to Ga 2 O 3, improving the ability of Ga 2 O 3 to activate H 2 . The plasma decomposition also generates more interfacial Ga 2 O 3 /ZrO 2 _O v sites. This facilitates CO 2 activation on the catalyst surface in the form of HCO 3 *, which is favored for further conversion into HCOO* and CH 3 O* 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 g MeOH h –1 kg cat –1 at 5 MPa and 325 °C. This represents a 30.4% increase in the STY of methanol compared with the catalyst thermally decomposed.