Ionic redox behaviour of La(Sr)MnO{sub 3} catalyst during transient CO oxidation

Journal Article · Fri Dec 01 04:00:00 EST 1995 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1995.1318· OSTI ID:224023

Petrolekas, P D; Metcalfe, I S ^[1]

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1. Imperial College of Science, London (United Kingdom)

The technique of solid electrolyte potentiometry (SEP) was employed to monitor in situ the oxygen activity (the oxidation state) of La(Sr)MnO{sub 3} catalyst during CO oxidation under steady-state and transient conditions. The reaction at 550{degrees}C was found to proceed through an ionic redox mechanism; the reoxidation and the reduction reactions occur at different sites on the catalyst surface and oxygen diffuses through the oxide lattice from the ox-sites, where it is adsorbed, to the r-sites, where it reacts with CO. Under reaction conditions it cannot be assumed that oxygen adsorbed at the r-sites is in equilibrium with oxygen adsorbed at the ox-sites. The rate was accordingly found to be a function of the catalyst oxygen activity and the gas-phase oxygen (reoxidation determined reaction) or carbon monoxide (reduction-determined reaction) partial pressure. Transient data can also be interpreted within the framework of the ionic redox model. 10 refs., 5 figs.

• OSTI ID: 224023
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 157; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CARBON MONOXIDE
CATALYSTS
CATALYTIC EFFECTS
LANTHANUM COMPOUNDS
MANGANATES
OXIDATION
POTENTIOMETRY
REDUCTION
STRONTIUM COMPOUNDS
VALENCE