Mechanisms of CO oxidation reaction and effect of chlorine ions on the CO oxidation reaction over Pt/CeO2 and Pt/CeO2/gamma-Al2O3 catalysts


Oran U., Uner D.

APPLIED CATALYSIS B-ENVIRONMENTAL, cilt.54, ss.183-191, 2004 (SCI İndekslerine Giren Dergi)

  • Cilt numarası: 54 Konu: 3
  • Basım Tarihi: 2004
  • Doi Numarası: 10.1016/j.apcatb.2004.06.011
  • Dergi Adı: APPLIED CATALYSIS B-ENVIRONMENTAL
  • Sayfa Sayısı: ss.183-191

Özet

The reaction orders and activation energies of CO oxidation reaction over Pt/gamma-Al2O3, Pt/CeO2 and Pt/CeO2/Y-Al2O3 were investigated for stoichiometric gas mixtures. The effect of residual chlorine originating from catalyst precursors on the CO oxidation activity of Pt/gamma-Al2O3, Pt/CeO2 and Pt/CeO2/gamma-Al2O3 was also studied. Indirect evidence was collected indicating that platinum was selectively deposited on alumina surface when Pt/CeO2/gamma-Al2O3 catalyst was prepared from the physical mixture of pure oxides. The reaction orders of CO and O-2 was found approximately as -2.0 and +1.0, respectively, over the Pt/gamma-Al2O3 catalyst, but as -1.0 and 0.0 over the Pt/CeO2 and Pt/CeO2/gamma-Al2O3 catalysts. The activation energy of CO oxidation reaction over Pt/gamma-Al2O3 catalyst under stoichiometric conditions was around 120.0 kJ/mol. On the other hand, over Pt/CeO2 catalysts activation energies were measured to be around 70 kJ/mol. Surface reaction mechanisms were postulated to explain the differences in the reaction orders and activation energies. (C) 2004 Elsevier B.V. All rights reserved.