Influence of oxychlorination treatments on the redox and oxygen storage and release properties of thermally aged Pd-Rh/CexZr1-xO2/Al2O3 model three-way catalysts

R A Daley, S Y Christou, A M Efstathiou, J A Anderson

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Model Pd-Rh/Al2O3 three-way catalysts with and without CexZr1-xO2 as oxygen storage component have been compared in their fresh, thermally aged and oxychlorinated treated surface states to determine the potential regenerating effects of the latter thermo-chemical treatments. Special attention has been made on the characterisation of the metal dispersion, redox properties and the oxygen storage and release properties of the catalyst following each of the treatment stages. It was found that thermal aging under the conditions employed leads to a loss of metal dispersion, but with negligible sintering of the ceria-zirconia mixed metal oxide. Loss of oxygen storage capacity is a consequence of the loss in metal area that results in a loss of interfacial contact with the storage component. Oxychlorination of the aged samples leads to even greater than 100% recovery of metal dispersion and a significant recovery of the oxygen storage capacity. As a consequence of these effects, catalytic activity for the CO/O-2 and NO/H-2/O-2 reactions was shown to improve significantly. The role of residual chloride following regenerating treatment is discussed in terms of ceria reducibility. (c) 2005 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)117-127
Number of pages11
JournalApplied Catalysis B: Environmental
Volume60
Issue number1-2
Early online date30 Mar 2005
DOIs
Publication statusPublished - 1 Sep 2005

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Metals
catalyst
Oxygen
oxygen
Catalysts
metal
Cerium compounds
Recovery
Thermal aging
Surface states
Carbon Monoxide
Zirconia
Oxides
Chlorides
Catalyst activity
Sintering
chloride
Oxidation-Reduction
loss
effect

Keywords

  • three-way catalysts
  • aging
  • regeneration
  • OSC
  • oxychlorination
  • PdRh
  • ceria-zirconia
  • automotive exhaust catalysts
  • PT-SN/AL2O3 catalysts
  • reforming catalysts
  • electron-microscopy
  • PD/AL2O3 catalysts
  • PD
  • behavior
  • surface
  • RH

Cite this

Influence of oxychlorination treatments on the redox and oxygen storage and release properties of thermally aged Pd-Rh/CexZr1-xO2/Al2O3 model three-way catalysts. / Daley, R A ; Christou, S Y ; Efstathiou, A M ; Anderson, J A .

In: Applied Catalysis B: Environmental, Vol. 60, No. 1-2, 01.09.2005, p. 117-127.

Research output: Contribution to journalArticle

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abstract = "Model Pd-Rh/Al2O3 three-way catalysts with and without CexZr1-xO2 as oxygen storage component have been compared in their fresh, thermally aged and oxychlorinated treated surface states to determine the potential regenerating effects of the latter thermo-chemical treatments. Special attention has been made on the characterisation of the metal dispersion, redox properties and the oxygen storage and release properties of the catalyst following each of the treatment stages. It was found that thermal aging under the conditions employed leads to a loss of metal dispersion, but with negligible sintering of the ceria-zirconia mixed metal oxide. Loss of oxygen storage capacity is a consequence of the loss in metal area that results in a loss of interfacial contact with the storage component. Oxychlorination of the aged samples leads to even greater than 100{\%} recovery of metal dispersion and a significant recovery of the oxygen storage capacity. As a consequence of these effects, catalytic activity for the CO/O-2 and NO/H-2/O-2 reactions was shown to improve significantly. The role of residual chloride following regenerating treatment is discussed in terms of ceria reducibility. (c) 2005 Elsevier B.V. All rights reserved.",
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AB - Model Pd-Rh/Al2O3 three-way catalysts with and without CexZr1-xO2 as oxygen storage component have been compared in their fresh, thermally aged and oxychlorinated treated surface states to determine the potential regenerating effects of the latter thermo-chemical treatments. Special attention has been made on the characterisation of the metal dispersion, redox properties and the oxygen storage and release properties of the catalyst following each of the treatment stages. It was found that thermal aging under the conditions employed leads to a loss of metal dispersion, but with negligible sintering of the ceria-zirconia mixed metal oxide. Loss of oxygen storage capacity is a consequence of the loss in metal area that results in a loss of interfacial contact with the storage component. Oxychlorination of the aged samples leads to even greater than 100% recovery of metal dispersion and a significant recovery of the oxygen storage capacity. As a consequence of these effects, catalytic activity for the CO/O-2 and NO/H-2/O-2 reactions was shown to improve significantly. The role of residual chloride following regenerating treatment is discussed in terms of ceria reducibility. (c) 2005 Elsevier B.V. All rights reserved.

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