The simultaneous oxidation of hydrocarbon (HC) and sulfur dioxide (SO₂) on the Fe-impregnated calcined sepiolite-supported Pt (Pt/Fe-CSp) catalysts was studied in comparison with that on the calcined sepiolite-supported Pt (Pt/Csp) catalysts. The HC oxidation activity on the Pt/FeCSp catalysts was higher than that on the Pt/CSp catalysts. Nevertheless, the SO₂ oxidation activity on the Pt/FeCSp catalysts was more suppressed than that on the Pt/CSp catalysts. The selectivity of the reaction to the oxidation of HC and SO₂ depended upon the amount of supported Fe, which depended upon the calcination temperature. The maximum amount of the supported Fe was about 4.8wt%. Also, XRD and NMR showed that the amount of supported Fe depended upon the distortness of the local structure of calcined sepiolite (CSp).

Mossbauer spectroscopy showed that most of Fe on the Pt/Fe-CSp catalysts was Fe³⁺. Pulse chemisorption analysis of the redox reaction indicated that Fe on CSp had a high oxygen storage capacity. The addition of Fe to Pt/CSp catalysts was thought to be responsible for this redox reaction and the high selectivity of reaction to the oxidation of HC and SO₂.

The Pt/Fe-CSp catalysts are expected to be useful for catalysts in purifying the exhaust gas from a boiler or a combustion engine using the fuel such as light oil containing sulfur.

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