There is a need to develop sulfur tolerant materials that are appropriate for three-way catalysis. In light of this, a study on the effect of SO2 on the structural, morphological, and catalytic properties of metal free CeO2 and Ce0.75Zr0.25O2 oxides was carried out. Both CeO2 and Ce0.75Zr0.25O2 were susceptible to crystalline grain size growth and surface area loss when exposed to gaseous mixtures containing 20-40 ppm SO2 at 600°C. The CO disproportionation reaction occurred on CeO2 and Ce0.75Zr0.25O2, as well as on the Pd metal surface. This reaction led to the deposition of carbon on the surface of the materials and the formation of gaseous CO2. Surface superoxides were highly reactive toward gaseous ethylene, while adsorbed peroxides were spectator species. The chemical inertness of the surface peroxides in hydrocarbon oxidation reactions originated from its resistance toward O-O bond dissociation.
|Publication status||Published - Dec 1 2004|
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