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Oscillatory behaviour during the oxidation of methane over palladium metal catalysts

Oscillatory behaviour during the oxidation of methane over palladium metal catalysts
Oscillatory behaviour during the oxidation of methane over palladium metal catalysts
Oscillatory reactions over palladium foil and wire catalysts during the oxidation of methane have been investigated over a wide range of reaction temperatures and argon/methane/oxygen feed gas compositions. Characterisation of the catalyst has also been carried out using scanning electron microscopy (SEM) techniques, which revealed the presence of a porous surface. This suggested that the metal surface has undergone a change since the reaction commenced, and using X-ray powder diffraction (XRD) techniques the palladium phase was shown to be the dominant phase present. Hysteresis phenomena were observed in the activity of the reaction as the temperature was cycled up and down, showing that the metal surface was continually changing throughout the reaction. The activation energies of the reaction during the high reactivity mode, PdO, and low reactivity mode, Pd, were also calculated. Oscillation rates were observed to depend on the dominant surface. Oscillations were frequent when the high reactivity mode was dominant while the activation energy of this mode was found to be low. When the low reactivity mode was dominant, the oscillations were slower and the activation energy was three times larger. The results obtained imply that the behaviour of the palladium surface, switching back and forth from the reduced state to the oxidised state, is responsible for the oscillatory behaviour seen in this system.
oscillations, methane oxidation, palladium foil catalyst, palladium wire catalyst
0926-860X
183-197
Zhang, X.
d7cf1181-3276-4da1-9150-e212b333abb1
Lee, C.
774e8767-13f8-4725-bc9f-c1200ccd78ab
Mingos, D.M.P.
f9a82d7c-a540-40a8-96f0-e1a5040582cc
Hayward, D.O.
de16843b-f75c-4a7d-a001-fb862ce747e6
Zhang, X.
d7cf1181-3276-4da1-9150-e212b333abb1
Lee, C.
774e8767-13f8-4725-bc9f-c1200ccd78ab
Mingos, D.M.P.
f9a82d7c-a540-40a8-96f0-e1a5040582cc
Hayward, D.O.
de16843b-f75c-4a7d-a001-fb862ce747e6

Zhang, X., Lee, C., Mingos, D.M.P. and Hayward, D.O. (2003) Oscillatory behaviour during the oxidation of methane over palladium metal catalysts. Applied Catalysis A: General, 240 (1-2), 183-197. (doi:10.1016/S0926-860X(02)00422-2). (Submitted)

Record type: Article

Abstract

Oscillatory reactions over palladium foil and wire catalysts during the oxidation of methane have been investigated over a wide range of reaction temperatures and argon/methane/oxygen feed gas compositions. Characterisation of the catalyst has also been carried out using scanning electron microscopy (SEM) techniques, which revealed the presence of a porous surface. This suggested that the metal surface has undergone a change since the reaction commenced, and using X-ray powder diffraction (XRD) techniques the palladium phase was shown to be the dominant phase present. Hysteresis phenomena were observed in the activity of the reaction as the temperature was cycled up and down, showing that the metal surface was continually changing throughout the reaction. The activation energies of the reaction during the high reactivity mode, PdO, and low reactivity mode, Pd, were also calculated. Oscillation rates were observed to depend on the dominant surface. Oscillations were frequent when the high reactivity mode was dominant while the activation energy of this mode was found to be low. When the low reactivity mode was dominant, the oscillations were slower and the activation energy was three times larger. The results obtained imply that the behaviour of the palladium surface, switching back and forth from the reduced state to the oxidised state, is responsible for the oscillatory behaviour seen in this system.

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More information

Submitted date: 10 February 2003
Keywords: oscillations, methane oxidation, palladium foil catalyst, palladium wire catalyst

Identifiers

Local EPrints ID: 49123
URI: http://eprints.soton.ac.uk/id/eprint/49123
ISSN: 0926-860X
PURE UUID: aced97f8-1b1e-494d-b306-99f7fa98c754
ORCID for X. Zhang: ORCID iD orcid.org/0000-0002-4375-1571

Catalogue record

Date deposited: 24 Oct 2007
Last modified: 16 Mar 2024 03:55

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Contributors

Author: X. Zhang ORCID iD
Author: C. Lee
Author: D.M.P. Mingos
Author: D.O. Hayward

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