The Role of Chlorine in Induction Periods During the Oxidation of Methane over Pd/SiO 21

Abstract

The effect of chlorine elimination from Pt-Sn catalyst on the behavior of hydrocarbon reconstruction in propane dehydrogenation was investigated. The results showed that the chlorine elimination significantly affects multiple characteristics of the catalysts, the type of Pt active phases, and the behavior of hydrocarbon reconstruction. There was no apparent change in catalyst structure. In contrast, the acidity of the catalyst, its specific surface area, and pore volume remarkably decreased whereas its mean pore diameter increased under the same conditions. The degree of Pt sintering, which is disadvantageous to the reaction, was also aggravated. The chlorine elimination also influenced the behavior of hydrocarbon reconstruction in propane dehydrogenation and demonstrated a crucial function in determining selectivity as evidenced by coking experiments. In this work, a strong correlation was established to demonstrate the relation between the structure of Pt active phase and the behavior of hydrocarbon reconstruction in propane dehydrogenation. It is an optimum progress that the chlorine elimination conditions of the Pt active phases centered on the Pt(100) surfaces and the PtSnK/Al2O3 exhibited the best catalytic performance and a low coking rate. Finally, a new model was established to describe the influence of chlorine elimination on the interactions between Pt and SnOx.