Mesoporous manganese-cobalt oxide spinel catalysts for CO2 hydrogenation to methanol

The conversion of CO2 to methanol is seen as a potential environmental benign alternative source of fuel and chemicals. Manganese-cobalt catalyst shows promise for CO2 hydrogenation to methanol, but its selectivity towards hydrocarbons and other oxygenates needs to be suppressed. In this work, we report the activity of mesoporous manganese-cobalt spinel oxides with different Co/Mn ratios for CO2 hydrogenation to methanol. The catalysts were thoroughly characterized by N2 adsorption-desorption, XRD, XPS, TEM, ICP-OES, H2-TPR, and CO2-TPD. A significant improvement in methanol selectivity was observed over the manganese doped catalysts compared to the monometallic catalysts. The highest methanol selectivity of 29.8% (reaction conditions: 250 °C, 10 bar, 44, 400 h−1) was obtained with 20 wt.% manganese with a CO2 conversion of 49.1%, resulting in a methanol formation rate of 2280 mg/(gcat h). The enhanced methanol selectivity was attributed to a synergistic effect between cobalt and manganese as well as an increase in surface basicity.