Study of tungsten oxide and sulfate interactions on doubly-doped zirconia aerogels

A zirconia aerogel, prepared by a sol-gel route followed by supercritical drying, was doped with both tungstate and sulfate by sequential incipient wetness impregnations. The role of the dopants and activation temperature on the physical and chemical properties was studied. The materials were characterized by nitrogen adsorption, X-ray diffraction, n-butane isomerization, Raman and infrared spectroscopy. Tungstate and sulfate were catalytically active over non-overlapping ranges of activation temperature and thus offered no synergistic catalytic effects. The effects of the two dopants on each other appeared to be primarily physical.