Ru/alumina and Ru$z.sbnd;Mo/alumina catalysts: An XPS study

RuAl2O3 and RuMoAl2O3 catalysts have been prepared by impregnating respectively γ-Al2O3 and calcined MoAl2O3 with aqueous solutions of ruthenium (III) acetate. XPS spectra of catalysts dried at 393 K, calcined in air at 873 K, and sulfided in H2H2S are reported. Ru and Mo species in the catalysts, according to the respective binding energies, were ruthenium dioxide and oxomolybdenum (VI) in catalysts calcined at 873 K and a ruthenium sulfide and MoS2 in the sulfided catalysts. Unusually low Ru binding energies were found for some catalysts. The properties of the catalysts in thiophene HDS are interpreted with the aid of the XPS results.