Methanol synthesis from CO2 and H-2 on Cu/ZnO/Al2O3-ZrO2 catalysts. Catalytic activity and adsorption of reactants

Effect of preparation method and substitution of Al2O3 by ZrO2 on the adsor ption 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 i nvestigated. The catalytic activity increases in the series: Cu/ZnO/Al2O3 o btained by co-precipitation < Cu/ZnO/Al2O3 < Cu/ZnO/Al2O3 - ZrO2 obtained b y the amorphous precursor (citric acid) method < Cu/ZnO/ZrO2 obtained by th e amorphous precursor (citric acid) method. It has been found that catalyst s obtained by using citric acid as complexing agent show higher adsorption of methanol compared to water than the catalysts obtained by the coprecipit ation. A partial substitution of Al2O3 by ZrO2 evidently decreases the reve rsible adsorption of water and CO. A correlation between adsorptive and cat alytic properties has been established. With increasing ratio of reversible CO2/CO or CH3OH/H2O adsorption, an increase of the catalysts activity in t he synthesis of methanol from CO2 and H-2 is observed.