Investigation of the behaviour of a Pd/γ-Al2O3 catalyst during methane combustion reaction using in situ DRIFT spectroscopy
Investigation of the behaviour of a Pd/γ-Al2O3 catalyst during methane combustion reaction using in situ DRIFT spectroscopy
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DOI：
10.1016/j.apcata.2005.08.008
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发表时间：
2005-10-13
影响因子：
5.5
通讯作者：
Ruiz, P
中科院分区：
文献类型：
--
作者：
Demoulin, O;Navez, M;Ruiz, P
原位和/或操作 DRIFT 光谱用于研究用于甲烷燃烧的 Pd (2 wt.%)/gamma-Al2O3 催化剂在各种条件下的行为。在传统的富含 O-2 的反应条件下，可以观察到旁观物质（碳酸盐和/或甲酸盐），但没有表面中间物质。在反应条件下，没有观察到随钯初始氧化态变化的差异。甲酸盐/碳酸盐物种在低温（< 400 摄氏度）下被识别，并在二氧化碳生产开始时消失。它们不参与甲烷氧化的整个反应途径，因此被认为是观察物种。它们的生产需要连续的 CO 源，并且来自 CO 与 γ-氧化铝载体的 OH 基团的相互作用。在贫 O-2 (O-2/CH4 = 2) 条件下，在高温 (> 400 摄氏度) 下观察到 CO 桥接在金属钯 (Pd-x(0)-CO) 上，这证明了甲烷的不完全氧化。基于之前的操作拉曼研究，提出了一种机械方案，该方案考虑了观察到的各种表面现象。 (c) 2005 Elsevier B.V. 保留所有权利。
In situ and/or operando DRIFT spectroscopy was applied to the study of the behaviour of a Pd (2 wt.%)/gamma-Al2O3 catalyst, used in methane combustion, under various conditions. Under conventional O-2-rich reaction conditions, spectator species (carbonates and/or formates) could be observed, but no surface intermediate species. No differences were observed under reaction conditions in function of the initial oxidation state of palladium. Formates/carbonates species were identified at low temperature (< 400 degrees C) and disappeared when CO, production started. They are not involved in the overall reaction pathway of methane oxidation and are thus suggested to be spectator species. Their production requires a continuous source of CO and would come from the interaction of CO with OH-groups of the gamma-alumina support. Under O-2-lean (O-2/ CH4 = 2) conditions, CO bridging on metallic palladium (Pd-x(0)-CO) is observed at high temperature (> 400 degrees C), evidencing incomplete oxidation of methane. Based on previous operando Raman studies, a mechanistic scheme is proposed, which takes into account the various surface phenomena observed. (c) 2005 Elsevier B.V. All rights reserved.