THE INFLUENCE OF SULFUR-DIOXIDE ON PROPANE OXIDATION ACTIVITY OVER SUPPORTED PLATINUM AND PALLADIUM

Earlier studies have shown that sulfur dioxide and metal-support inter action can strongly influence propane oxidation over platinum. In part icular, oxidation activity is enhanced when platinum is supported on s ulfated gamma-alumina or zirconia compared to gamma-alumina. Therefore , it is of interest to compare the performance of palladium under the same experimental conditions. Four model catalysts were examined: Pt/g amma-alumina, Pt/zirconia, Pd/gamma-alumina and Pd/zirconia. The metal loading was kept at or below 0.05 wt% to emphasize changes in activit y attributable to metal-support interaction. Reaction rates were measu red with and without sulfur dioxide. Surface sulfation was analyzed by measuring acid strength and evaluating spectra obtained by Fourier-tr ansform infrared spectroscopy. In contrast to platinum, sulfation does not promote propane oxidation on Pd/gamma-alumina, and Pd/zirconia is less active than Pd/gamma-alumina.