Surface properties of fumed silica (Cab-O-Sil) and Cab-O-Sil-supported Pt and Cu catalysts, studied by ir spectroscopy

János T. Kiss, István Pálinkó, Árpád Molnár

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Results of ir investigations are reported on some surface properties of a fumed silica (Cab-O-Sil) support, a Pt catalyst made by impregnation (Pt/CS-I) and two Cu catalysts made by precipitation (Cu/CS-P) or ion-exchange (Cu/CS-X). The support and the catalysts were studied in the OHOD exchange reaction of surface OH groups by consecutive treatment with H2 and D2 or H2 and D2O. The behaviour of the Cu and Pt catalysts was investigated in the isomerization of methylenecyclohexane. The effects of 1,1-dimethylcyclopropane on the catalysts and the support in the presence or absence of D2 were also examined. The major findings were as follows: (i) OHOD exchange with D2 is negligible for the support at room temperature, but the reaction is practically complete at 673 K, (ii) exchange is fast over Pt/CS-I, even at room temperature, but both Cu/CS catalysts are considerably less active, (iii) at ambient temperature, exchange with D2O proceeds almost to completion over the support and over each catalyst, (iv) isomerization of methylenecyclohexane occurs over Pt/CS-I, but not over the copper catalysts, (v) 1,1-dimethylcyclopropane adsorbs dissociatively over each catalyst without D2, (vi) in the presence of D2, however, it reacts through associatively adsorbed species over the copper catalysts, while a dissociative mechanism is observed together with the predominant associative ring opening over Pt/CS-I.

Original languageEnglish
Pages (from-to)273-278
Number of pages6
JournalJournal of Molecular Structure
Volume293
Issue numberC
DOIs
Publication statusPublished - Mar 1993

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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