Methanol synthesis from CO2 and H2 on Cu/ZnO/Al2O3-ZrO2 catalysts.: Catalytic activity and adsorption of reactants

Effect of preparation method and substitution of Al2O3 by ZrO2 on the adsorption of CO, CO2, H2O and methanol on the Cu/ZnO/Al2O3 - ZrO2 catalysts as well as their activity in the synthesis of methanol from CO2 and H-2 were investigated. The catalytic activity increases in the series: Cu/ZnO/Al2O3 obtained by co-precipitation < Cu/ZnO/Al2O3 < Cu/ZnO/Al2O3 - ZrO2 obtained by the amorphous precursor (citric acid) method < Cu/ZnO/ZrO2 obtained by the amorphous precursor (citric acid) method. It has been found that catalysts obtained by using citric acid as complexing agent show higher adsorption of methanol compared to water than the catalysts obtained by the coprecipitation. A partial substitution of Al2O3 by ZrO2 evidently decreases the reversible adsorption of water and CO. A correlation between adsorptive and catalytic properties has been established. With increasing ratio of reversible CO2/CO or CH3OH/H2O adsorption, an increase of the catalysts activity in the synthesis of methanol from CO2 and H-2 is observed.