Effect of the metal nature on the reaction mechanism of the partial oxidation of ethanol over CeOb>2b>-supported Pt and Rh catalysts

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• 作者：A.M. Silva ; L.O.O. Costa ; A.P.M.G. Bar ; as ; L.E.P. Borges ; L.V. Mattos ; F.B. Noronha
• 关键词：Fuel cell ; Partial oxidation of ethanol ; Hydrogen production ; Pt/CeOb>2b> catalyst ; RhCeOb>2b> catalyst
• 刊名：Catalysis Today
• 出版年：2008
• 期刊代码：13_09205861
• 类别：ce
• 出版时间：April-June 2008
• 卷：133-135
• 期：Complete
• 页码：755-761
• 文件大小：621 K

摘要

In this work, the effect of the metal nature on the reaction mechanism of the partial oxidation of ethanol on Pt/CeOb>2b> and Rh/CeOb>2b> catalysts was studied by using diffuse reflectance infrared spectroscopy (DRIFTS) analyses. The results showed that the nature of the metal affected the reaction mechanism. On Pt/CeOb>2b> catalyst, adsorption of ethanol gives rise to ethoxy species, which can be decomposed, producing CHb>4b>, Hb>2b> and CO, and dehydrogenated, forming acetaldehyde. The acetaldehyde species are dehydrogenated to acetyl species or may desorb. The acetyl species can be oxidized to acetate species or can be decomposed, forming CHb>4b>, Hb>2b> and CO. Furthermore, the acetate species previously formed can be decomposed to CHb>4b>, CO and/or oxidized to COb>2b> via carbonate species. On the other hand, for Rh-based catalyst, the ethoxy species can be also dehydrogenated to a cyclic compound (oxametallacycle). This intermediate is dissociated to CO, CHb>xb> and Cb>xb>, which are oxidized to COb>2b>. Furthermore, it was observed that the oxidation of acetyl species to acetate species and the formation of COb>2b> are favored depending on the presence of the Ob>2b> in the feed on Pt/CeOb>2b> and Rh/CeOb>2b> catalysts, respectively.