Highly active Pt/In2O3-ZrO2 catalyst for CO2 hydrogenation to methanol with enhanced CO tolerance: The effects of ZrO2

The supported Pt catalyst is normally not active for CO2 hydrogenation to methanol at the presence of CO. Herein, ZrO2 is added into Pt/In2O3 for CO2 hydrogenation to methanol with CO as a co-feed gas. High activity with enhanced CO tolerance is achieved on Pt/In2O3-ZrO2. For example, the space-time yield of methanol reaches 0.569 g(methanol) g(cat)(-1) h(-1 )at 300 degrees C and 5 MPa under feed gas containing 4% CO of 21,000 cm(3).h(-1)g(cat)(-1). With the addition of ZrO2, a stronger electron transfer occurs between Pt and the In2O3-ZrO2 solid solution support. This leads to weaker CO adsorption, which suppresses over-reduction of In2O3 and enhances CO tolerance of the Pt catalyst. The oxygen vacancy of In2O3 modified by ZrO2 promotes CO2 activation. The synergy between Zrmodified oxygen vacancy (In-O-v-Zr) and Pt catalyst facilitates methanol synthesis from CO2 hydrogenation via formate route. This is different from Pt/In2O3, which takes CO hydrogenation route.