| 초록 |
Especially catalytic dehydrogenation processes are of increasing importance because of growing demand for olefins such as propylene and isobutene. Isobutene is in particularly high demand as a feed stock for the production of oxygenated hydrocarbons required in reformulated gasoline, such as MTBE, ETBE and TBA. Supported Pt is a good dehydrogenation catalyst for the production of isobutene. Since the dehydrogenation of isobutane to isobutene is an endothermic, high temperatures are required to achieve high conversions. However, the rates of isomerization, hydrogenolysis, and cocking reactions become significant at these higher temperatures. Accordingly, the selectivity for dehydrogenation becomes low at the high temperatures required for favorable dehydrogenation thermodynamics. Catalyst systems that employ Pt/Sn on a neutral support have been reported to exhibit high dehydrogenation selectivity and catalyst stability for dehydrogenation of light paraffins at elevated temperatures[1-3]. In model studies on well-defined Pt(111) surfaces, the interaction of either Sn or K with hydrocarbons has been extensively studied. However, little fundamental information is available for the influence of both Sn and K on the Pt(111) for the hydrocarbon products of these reactions. Therefore, we reported here new studies of the influence of co-adsorbed Sn and K on Pt(111) for hydro-/dehydrogenation reactions using AES, LEED, CO TPD, and in-situ high pressure reactor equipped with GC.
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