Study by EXAFS and TEM of the Effect of the Reduction-Oxidation Cycles over Pt/Al2O3–K and PtSn/Al2O3–K Catalysts

Abstract

TEM and X-Ray absorption spectroscopy at the Pt L_III edge have been used to study the effect of several consecutive reduction-oxidation cycles on the state of platinum for two Pt/Al₂O₃-K and PtSn/Al₂O₃-K catalysts used industrially for the selective dehydrogenation of high molecular weight paraffins. The results indicate that, whereas the size of the platinum oxide particles in the Pt/Al₂O₃-K monometallic catalyst increase after the different reduction-oxidation cycles, the presence of tin induces that platinum binds more strongly to the alumina surface, avoiding the sintering of platinum during the different reduction-oxidation cycles.