Au/Ce0.6Zr0.3Y0.1O2 Nanorods: Highly Active Catalysts for the Oxidation of Carbon Monoxide and Toluene

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• 作者：Wei Tan ; Guangsheng Guo ; Jiguang Deng ; Shaohua Xie ; Huanggen Yang ; Yang Jiang ; Hongxing Dai
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：December 3, 2014
• 年：2014
• 卷：53
• 期：48
• 页码：18452-18461
• 全文大小：619K
• ISSN：1520-5045

文摘

The Ce_0.6Zr_0.3Y_0.1O₂ (CZY) nanorods and its supported nanosized gold (xAu/CZY, Au loading (x) = 0.4鈥?.7 wt %) were prepared using the cetyltrimethylammonium bromide-assisted hydrothermal and polyvinylpyrrolidone-protected reduction methods, respectively. Physicochemical properties of the samples were characterized by means of numerous analytical techniques, and their catalytic activities were evaluated for the oxidation of CO and toluene. It is shown that the CZY in xAu/CZY was cubic in crystal structure, surface areas of CZY and xAu/CZY were in the range of 68鈥?9 m²/g, and the Au nanoparticles (NPs) with a size of 3.1鈥?.9 nm were well dispersed on the surface of CZY nanorods. Among the xAu/CZY samples, the 4.7Au/CZY sample possessed the highest adsorbed oxygen concentration and the best low-temperature reducibility, and showed the highest catalytic activity at a space velocity of 20鈥?00 mL/(g h): the T_50% and T_90% (temperatures required for achieving reactant conversions of 50 and 90%) were 32 and 60 掳C for CO oxidation and 218 and 265 掳C for toluene oxidation, respectively. Deactivation of water vapor addition was reversible, a result due to the competitive adsorption of H₂O and toluene as well as oxygen on the sample surface. The apparent activation energies (27鈥?7 and 39鈥?3 kJ/mol) obtained over xAu/CZY were lower than those (42 and 88 kJ/mol) obtained over CZY for CO and toluene oxidation, respectively. On the basis of the characterization results and activity data, we conclude that the excellent catalytic performance of 4.7Au/CZY was associated with its higher oxygen adspecies concentration, better low-temperature reducibility, and stronger interaction between Au NPs and CZY nanorods as well as better Au NPs dispersion.