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PdO x /Pd at Work in a Model Three-Way Catalyst for Methane Abatement Monitored by Operando XANES

Matam, Santhosh ; Chiarello, Gian ; Lu, Ye ; Weidenkaff, Anke ; Ferri, Davide

In: Topics in Catalysis, 2013, vol. 56, no. 1-8, p. 239-242

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    Title
    • PdO x /Pd at Work in a Model Three-Way Catalyst for Methane Abatement Monitored by Operando XANES
    Author
    • Matam, Santhosh. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Chiarello, Gian. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Lu, Ye. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Weidenkaff, Anke. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    • Ferri, Davide. Laboratory for Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600, Dübendorf, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Topics in Catalysis, 2013, vol. 56, no. 1-8, p. 239-242. Springer US; http://www.springer-ny.com
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:309664
    Summary
    The oxidation state of palladium in a model Pd/ACZ three-way catalyst was monitored by synchronous XANES and mass spectrometry during two consecutive heating (to 850°C) and cooling (to 100°C) cycles under stoichiometric conditions simulating exhaust after treatment of a natural gas engine. During heating in the first cycle, PdO reduction occurred around 500°C and the initial fully oxidized state of Pd was never recovered upon heating and cooling cycles. A mixed Pd2+/Pd oxidation state was at work in the second cycle. Hence, the operando XANES study reveals that the PdO x /Pd pair exists in a working catalyst but is less active than the catalyst in its initial state of fully oxidized palladium. It is also evident from XANES spectra that ceria-zirconia promotes re-oxidation of metallic Pd, thus reasonably sustaining catalytic activity after exposure to high temperatures