CHARACTERIZATION OF SILICA-SUPPORTED PALLADIUM-COPPER ALLOYS

A variety of techniques: chemisorptions of hydrogen and carbon monoxide, temperature-programmed reduction, X-ray diffraction and neopentane conversion as a catalytic probe, were employed for characterization of silica-supported palladium-copper alloys. Pd-Cu/SiO2 catalysts prepared by coimpregnation from aqueous solutions of respective metal chlorides and reduction at 380-degrees-C for 15 hours exhibit good alloy dispersion (metal particle size of 2-4 nm) and homogeneity. The selectivity for neopentane isomerization increases with the copper content, achieving the maximum at 50 at % Cu. On the other hand, the increase of the Cu content causes a gradual decline of the overall activity and increase of activation energy.