IR-SPECTROSCOPIC STUDY OF THE STATE OF CU AND PT IN COPPER-PLATINUM-ALUMINA CATALYSTS FOR PARAFFIN DEHYDROGENATION SUBJECTED TO DIFFERENT REDUCTIVE AND OXIDATIVE TREATMENTS

The state of supported metals in copper-platinum-alumina catalysts (0. 15 at % Pt, 2 and 7.5 at % Cu), which differ in the preparation method and pretreatment conditions, is studied by diffuse-reflectance IR spe ctroscopy using CO adsorption. It is found that a major part of metall ic platinum in the samples reduced in an H-2 flow at 600 degrees C for ms Pt-Cu alloys. The activity of the catalysts in propane dehydrogenat ion is studied. The propylene yield is shown to depend on the concentr ation of Pt atoms at the surface of alloy particles. These Pt atoms ar e assumed to be responsible for the activity of the catalysts in the r eaction of propane dehydrogenation.