FTIR study of the interaction of NO, and propene with Pt/BaCl2/SiO2

The interactions between NO2 and BaCl2/SiO2 and Pt/BaCl2/SiO2 and the subse quent reaction of propene with the NO2 derived surface and bulk complexes h ave been studied using FTIR. Barium nitrate species are generated in both c ases along with surface nitrosyl species on Pt. Heating in vacuum increased the degree of crystallinity of the nitrate in the absence of Pt or in case s where Pt-Ba interactions were absent but led to partial decomposition for samples where Pt was in intimate contact with Ba. Heat treatment in the pr esence of propene accelerated the rate of nitrate decomposition for Pt/BaCl 2/SiO2 and this could be further enhanced using a prereduced sample. Propan e does not appear to interact directly with the nitrate but acts by removin g oxygen from the metal surface. No evidence was obtained to indicate a rol e of organo-nitro species in the process. (C) 1999 Elsevier Science B.V. Al l rights reserved.