Behaviour of oxygen species adsorbed on Al2O3-supported cerium oxide catalysts for methane oxidation
- 1 January 1995
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 91 (24) , 4459-4465
- https://doi.org/10.1039/ft9959104459
Abstract
The properties and catalytic behaviour of adsorbed oxygen species on alumina-supported cerium oxides (CeO2, CeAlO3 and CeO2 –x) for methane oxidation have been investigated by means of EPR, FTIR, temperature-programmed desorption (TPD) and 18O tracer techniques. The adsorbed oxygen on the cerium oxide catalysts was found to be the side-on type O2 – ion by EPR and FTIR measurements. The adsorption site of the O2 – ion on CeO2 –x/Al2O3 was assumed to be the site formed by the ensemble effect between oxygen vacancies and surface cations, while on the other catalysts the sites were cerium ions on the surface. The oxygen species desorbed after 18O2 adsorption at 773 K were 16O2 and 16O 18O in all catalysts, and the major products for methane oxidation were C16O2 and C16O 18O. These suggest that the adsorbed oxygen is activated through the lattice in cerium oxides. The activities of methane oxidation were influenced by the oxygen diffusion processes on the cerium oxides.Keywords
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