Catalytic behavior of platinum ion-exchanged zinc-aluminosilicates in n-pentane aromatization

Abstract

Abstract The n-pentane aromatization over platinum ion-exchanged zinc-aluminosilicate was investigated. The deactivation of the catalyst decreased with increasing density of strong acid sites of the zeolites. X- ray photoelectron spectrometry studies and platinum dispersion measurements revealed that platinum atoms became more cationic and were located inside the zeolite pores when platinum was loaded onto zeolites with a higher strong acid site density. Platinum atoms were less cationic and tended to migrate to the external surface where they aggregated when platinum was loaded onto zeolites that had a lower strong acid site density. The migration and aggregation of platinum were assumed to cause a rapid decline in catalyst activity.