Temperature-programmed reduction of metal-exchanged zeolite-A catalysts

M. Afzal, G. Yasmeen, M. Saleem, J. Afzal

Research output: Contribution to journalConference article

Abstract

The reduction of metal (Co, Ni, and Cu)-exchanged zeolite-A was studied by a temperature-programmed reduction (TPR) technique. The TPR profiles indicate that the metals are in a dispersed form. The hydrogen consumption in the reduction process demonstrates that the metals are present in monovalent and divalent forms. High-temperature reduction peaks are also observed in the cases of CoA and NiA. Nitrogen adsorption reveals that, on heating at high temperature, the pore capacity of zeolite-A increases when exchanged with transition metals because more space is occupied by water molecules. This is confirmed by thermal analysis. After dehydration, the cations are in changed positions; they are often located in hidden sites (hexagonal prism and sodalite cages). The activation energy for the reduction process is calculated.

Original languageEnglish (US)
Pages (from-to)277-284
Number of pages8
JournalJournal of Thermal Analysis and Calorimetry
Volume62
Issue number1
DOIs
StatePublished - 2000
Event1st Italian Russian Calorimetry WorkshopNew Trends in Calorimetry and its Applications - Barga, Italy
Duration: Oct 31 1999Nov 3 1999

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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