| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 90 === The thesis is devoted to study catalytic oxidation of 1000-4000 ppmv methanol, ethanol, isopropanol using Pt/BN catalyst, compared with both Pt/Al2O3 and commercial PtPd/Al2O3/CeO2 catalyst. Pt/BN and Pt/Al2O3 were prepared by incipient wetness method and the composition of Pt was about 0.37%.
After reaction tests, it was shown that up to 60% methanol could be oxidized to carbon dioxide under room temperature, showing better activity compared with Pt/Al2O3 and PtPd/Al2O3/CeO2 catalyst. That’s due to the Pt-O bond on Pt active sites.
Using power law,
the reaction order of alcohol is equal or greater than 1, which indicates the rate of alcohol molecules adsorbed on Pt active sites is slow. Besides, the reaction order of oxygen is increased from negative to zero followed by increasing temperature. Oxygen atoms have priority to adsorb on Pt active sites and the tendency decreases as temperature increases.
As the number of carbon of an alcohol increases, the oxidative temperature difference of the three kinds of catalysts decreases. However, Pt/BN catalyst can still oxidize alcohol at lower temperature than that of Pt/Al2O3 catalyst. When the oxidative temperature is over 100℃, Pt/BN catalyst shows poor activity than that of PtPd/Al2O3/CeO2 catalyst resulting from the reactivity of lattice oxygen of CeO2.
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