Spectroscopic characterization of gold supported on tungstated zirconia
Spectroscopic characterization of gold supported on tungstated zirconia
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DOI：
10.1016/j.cattod.2012.02.027
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发表时间：
2012-06-30
期刊：
影响因子：
5.3
通讯作者：
Mametsheripov, S.
中科院分区：
文献类型：
--
作者：
Kantcheva, M.;Milanova, M.;Mametsheripov, S.
用阳离子吸附法从[Au(En)(2)]Cl3-水溶液中制备了以氧化钨为载体的负载金催化剂。用X射线衍射仪对材料进行了表征。DR-UV-Vis光谱和XPS。用吸附CO的FT-IR光谱研究了沉积的金物种的性质。结果表明，金颗粒优先占据无WOX表面，金的分散程度取决于配位不饱和(CuS)Zr4+离子的量。用钨对氧化锆进行改性，提高了金的吸收率，但同时也降低了(CuS)Zr4+离子的浓度，从而降低了金团簇的分散度。根据原位红外光谱的结果，Au/WOx-ZrO2催化剂在低温范围内(最高150℃)表现出比不含WOx的Au/ZrO2催化剂更高的CO氧化活性。含W催化剂的低温活性可能与载体氧离子的碱性降低，从而减少了稳定碳酸盐物种的积累有关。(C)2012爱思唯尔B.V.保留所有权利。
Gold catalysts supported on tungstated zirconia (containing 5-20 wt% WO3) are prepared by cationic adsorption from aqueous solution of [Au(en)(2)]Cl-3 complex. The materials are characterized by XRD. DR-UV-vis spectroscopy and XPS. The nature of the deposited gold species is studied by FT-IR spectroscopy of adsorbed CO. It is concluded that the gold particles occupy preferentially the WOx-free zirconia surface and the dispersion of gold depends on the amount of coodinatively unsaturated (cus) Zr4+ ions. Modification of zirconia by tungsten increases the gold uptake but at the same time causes decrease in the concentration of (cus) Zr4+ ions thus lowering the dispersion of gold clusters. According to the results of in situ FT-IR spectroscopy, the Au/WOx-ZrO2 catalysts display higher activity in the CO oxidation in the low-temperature range (up to 150 degrees C) than the WOx-free Au/ZrO2 sample. The low-temperature activity of the W-containing catalysts could be associated with decreased basicity of the support oxide ions resulting in reduced accumulation of stable carbonate species. (C) 2012 Elsevier B.V. All rights reserved.