The interaction of alumina with HCl: An infrared spectroscopy, temperature-programmed desorption and inelastic neutron scattering study
The interaction of alumina with HCl: An infrared spectroscopy, temperature-programmed desorption and inelastic neutron scattering study
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DOI：
10.1016/j.cattod.2006.02.041
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发表时间：
2006-05-30
期刊：
影响因子：
5.3
通讯作者：
Lennon, David
中科院分区：
文献类型：
--
作者：
McInroy, Alastair R.;Lundie, David T.;Lennon, David
本文用漫反射红外光谱、温度-时间曲线、红外光谱等方法研究了HCl与η-氧化铝催化剂的相互作用。冲压解吸和非弹性中子散射（INS）光谱。红外光谱提供的证据解离吸附的HCl和一个过程中，羟基末端结合到铝被氯取代。程序升温脱附实验表明，HCl在350-> 970 K的温度范围内脱附，表明解离HCl吸附发生在宽范围的活性位点上。INS实验表明，残留的氧化铝羟基在约100 ℃时表现出平面外变形特征γ（OH）。200 cm（-1）。而面内变形模式δ（OH）在约100 °处出现。1000 cm（-1）。通过氯化氢的吸附形成新的表面羟基，产生8（OH）的功能，可以分为两个带在990和1050 cm（-1）。氧化铝/HCl系统内的氢键负责在红外光谱中观察到埃文斯透射窗口，其通过（i）氢键合的羟基基团和化学吸附的水的v（OH）模式与（ii）表面羟基基团的8（OH）模式的泛音之间的费米共振相互作用发生。INS技术是能够区分不同的羟基键合的几何形状的基础上的局部对称性的活性位点。(c)2006 Elsevier B. V.保留所有权利。
The interaction of HCl with an eta-alumina catalyst has been investigated by a combination of diffuse reflectance infrared spectroscopy, temperature-pro.-rammed desorption and inelastic neutron scattering (INS) spectroscopy. Infrared spectra provide evidence for dissociative adsorption of HCl and for a process in which hydroxyl groups terminally bound to Al are replaced by chlorine. Temperature-programmed desorption experiments show HCl to desorb over the temperature range 350-> 970 K, indicating dissociative HCl adsorption to occur on a wide range of active sites. INS experiments show the residual alumina hydroxyl groups to exhibit an out-of-plane deformation feature, gamma(OH), at ca. 200 cm(-1). while the in-plane deformation mode, 8(OH), is seen at ca. 1000 cm(-1). The formation of new surface hydroxyl groups via the adsorption of hydrogen chloride yields a 8(OH) feature that can be resolved into two bands at 990 and 1050 cm(-1). Hydrogen bonding within the alumina/HCl system is responsible for the observation of an Evans transmission window in the infrared spectrum, that occurs via a Fermi resonance interaction between (i) the v(OH) mode of hydrogen bonded hydroxyl groups and chemisorbed water with (ii) the overtone of the 8(OH) mode of surface hydroxyl groups. The INS technique is able to discriminate among different hydroxyl group bonding geometries on the basis of the local symmetry of the active sites. (c) 2006 Elsevier B.V. All rights reserved.