Effect of Mg and Mn oxide additions on structural and adsorptive properties of Cu/ZnO/ZrO2 catalysts for the methanol synthesis from CO2

Effect of addition of the Mg and Mn promoters on the activity of the Cu/ZnO/ZrO2 catalysts in the reaction of the synthesis of methanol from CO2 and H-2, and the steam reforming of methanol, as well as on the catalysts' adsorptive properties with respect to reactants (CO, CO2, H2O, methanol) was studied. Using the X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) techniques as well as investigating the reactive N2O adsorption, it was revealed that addition of the promoters leads to an increase of the copper dispersion in the reduced catalysts. The surface layers are depleted of copper and enriched in zinc and zirconium. The promoters introduced are accumulated preferentially on the catalysts' surface. Correlation between the adsorptive properties and the catalytic activity was established. The overall factor combining the adsorptive properties favoring the synthesis of methanol (RAF) and the catalytic activity increase in the series CuZnZr < CuZnZrMg < CuZnZrMn. (C) 2003 Elsevier Science B.V All rights reserved.