Influence of support composition on the structure and reactivity of strontium base catalysts

Strontium was supported on a variety of carriers, including silica, alumina, titania and carbon, by impregnation and decomposition of an acetate precursor at 773 K. These supported samples were characterized by surface area measurements, stepwise temperature-programmed desorption of carbon dioxide and activity for the catalytic decomposition of 2-propanol. In some cases, infrared and X-ray absorption spectroscopy were used to identify surface species. Results from these techniques suggested that strontium supported on silica forms a weakly basic surface silicate phase that had low activity for 2-propanol dehydrogenation. On alumina and titania, strontium acetate decomposed to form supported basic carbonates that were moderately active for 2-propanol dehydrogenation. When rates are normalized by the base site density determined from CO2 desorption, strontium supported on carbon was the most active sample for dehydrogenation of 2-propanol. These results suggest that the nature of supported alkaline earth catalysts is strongly dependent on the composition of the carrier.