A series of catalysts constituted of mixed copper and zinc oxides supported on alumina were prepared by co-precipitation method. The cooper content was in the 10-90 wt.% range. Their catalytic behavior in the hydrogenation of carbon dioxide to methanol was investigated at high pressure (up to 75 bars). The catalysts were characterized by elemental analysis, N2-adsorption, N2O-chemisorptions, and X-ray diffraction (XRD). The catalysts showed a clear activity in the hydrogenation reaction that could be correlated to the surface area of the metallic copper and to the reaction pressure. The CuO/ZnO/Al2O3 catalyst with a Cu/Zn/Al weight ratio of 60/30/10, exhibits the highest carbon dioxide conversion and methanol selectivity. Finally, a mechanism pathway has been proposed on copper active sites of (Cu 0 /Cu I ) oxidation state.

In this study the influence of metal dispersion, spinel formation, and surface properties of binary and ternary catalysts (CuOeCeO 2 , ZnOeCeO 2 , CuOeZnOeCeO 2 , and CuOeZnOeAl 2 O 3 ) was evaluated. The catalysts prepared by polyol method using polyethylene glycol as a solvent have been tested in the CO 2 hydrogenation to methanol performed at atmospheric pressure. The catalysts prepared by polyol method presented improved properties in terms of metal oxide dispersion, morphology (i.e. sponge-like shape for the CeO 2 -containing catalysts), and a large variety of metal and metal oxide species on the surface. Moreover, the CuOeZnOeCeO 2 and CuOeZnOeAl 2 O 3 catalysts exhibited a higher activity and selectivity in the methanol synthesis by CO 2 hydrogenation than those displayed by catalysts prepared by more conventional methods.

No abstract

No abstract