Electron energy loss studies of propylene interactions in US-Y faujasites

Abstract

There has been considerable interest in the interactions of hydrocarbons in the Y faujasites and the nature of the formation of coke. From the literature there is a question as to which site (Al or Si) is active in the formation of the residual carbonaceous material left in the molecular sieve after reaction with a hydrocarbon. In order to address this question, the authors have undertaken a study of the interaction of a simple probe molecule (propylene) with two series of ultrastable Y faujasite as a function of reaction temperature from 40-500C. The techniques involved in the study are core electron energy loss spectroscopy (CEELS), X-ray photoelectron spectroscopy (XPS), and {sup 13}C nuclear magnetic resonance (NMR) using cross-polarization magic-angle spinning (CPMAS). In this note they will focus on the CEELS results and the new insight that it provides into this interaction in light of the information from the NMR and XPS data for this system.