Performance of palladium and platinum supported on alumina pillared clays in the catalytic combustion of propene

Abstract

The effect that the metal content of various pillared-clay-supported catalysts may have on the oxidation of propene was studied in this work. For this purpose, an alumina pillared montmorillonite (Al-PILC) was used as a support for palladium and platinum. The catalysts, with metal loadings of between 0 and 2 wt%, were characterized by chemical analysis, nitrogen physisorption at −196 °C, carbon dioxide physisorption at 0 °C, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), CO and H₂ chemisorption at 35 °C, NH₃ chemisorption at 70 °C and temperature-programmed reduction (TPR). Bulk PdO, Pd, and palladium–alumina structures were detected for the palladium catalysts. Likewise, bulk PtO₂ and small PtO₂ particles, which partially interact with the support, were observed for the Pt/Al-PILC catalysts. The results obtained suggest that the propene oxidation over Pd/Al-PILC and Pt/Al-PILC is a structure sensitive reaction as the turnover frequencies are affected by metal dispersion and the structure of the surface catalysts.