Ethanol decomposition and steam reforming of ethanol over CeZrO₂ and Pt/CeZrO₂ catalyst: Reaction mechanism and deactivation

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• 作者：Sania M. de Lima ; Adriana M. Silva ; Uschi M. Graham ; Gary Jacobs ; Burtron H. Davis ; Lisiane V. Mattos ; Fá ; bio B. Noronha
• 关键词：Fuel cell ; Fuel processor ; Hydrogen production ; Steam reforming of ethanol ; Ethanol decomposition ; CeZrO₂ ; Pt/CeZrO₂ ; Deactivation
• 刊名：Applied Catalysis A: General
• 出版年：2009
• 出版时间：15 January 2009
• 年：2009
• 卷：352
• 期：1-2
• 页码：95-113
• 全文大小：3088 K

文摘

The catalyst performance and the deactivation profiles of CeZrO₂ and Pt/CeZrO₂ were evaluated for the ethanol decomposition and steam reforming of ethanol reactions at 773 K. Unpromoted CeZrO₂ was quite stable whereas Pt/CeZrO₂ catalyst deactivated for all feed compositions studied. A reaction mechanism was proposed based on diffuse reflectance infrared spectroscopy analyses carried out under reaction conditions. The decomposition of the dehydrogenated and the acetate species is facilitated by the presence of the metal and resulted in high selectivity to hydrogen, methane, CO and CO₂ over Pt/CeZrO₂. Diffuse reflectance infrared spectroscopy, transmission electron microscopy and temperature programmed oxidation and desorption analyses indicate that the loss of the Pt-support synergy leads to a buildup of carbonaceous residue, which is the likely reason of the deactivation of Pt/CeZrO₂. In addition, once the interfacial boundary is lost, the demethanation of acetate becomes hindered, resulting in an increase in acetaldehyde selectivity with time onstream.