Three-Dimensionally Ordered Macroporous La0.6Sr0.4MnO3 Supported Ag Nanoparticles for the Combustion of Methane

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• 作者：Hamidreza Arandiyan ; Hongxing Dai ; Jiguang Deng ; Yuan Wang ; Hongyu Sun ; Shaohua Xie ; Bingyang Bai ; Yuxi Liu ; Kemeng Ji ; Junhua Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 10, 2014
• 年：2014
• 卷：118
• 期：27
• 页码：14913-14928
• 全文大小：1171K
• ISSN：1932-7455

文摘

A series of Ag nanoparticles (NPs) supported on three-dimensionally ordered macroporous (3DOM) La_0.6Sr_0.4MnO₃ (yAg/3DOM La_0.6Sr_0.4MnO₃; y = 0, 1.57, 3.63, and 5.71 wt %) were successfully prepared with high surface areas (38.2鈥?2.7 m²/g) by a facile novel reduction method using poly methacrylate colloidal crystal as template in a dimethoxytetraethylene glycol (DMOTEG) solution. Physicochemical properties of these materials were characterized by means of numerous techniques, and their catalytic activities were evaluated for the combustion of methane. It is shown that the yAg/3DOM La_0.6Sr_0.4MnO₃ materials possessed unique nanovoid-like 3DOM architectures, and the Ag NPs were well dispersed on the inner walls of macropores. Among the La_1鈥?i>xSr_xMnO₃ (x = 0.2, 0.4, 0.6, 0.8) and yAg/3DOM La_0.6Sr_0.4MnO₃ (y = 0, 1.57, 3.63, and 5.71 wt %) samples, 3.63 wt % Ag/3DOM La_0.6Sr_0.4MnO₃ performed the best, giving T_10%, T_50%, and T_90% (temperatures corresponding to methane conversion =10, 50, and 90%) of 361, 454, and 524 掳C, respectively, and the highest turnover frequency (TOF_Ag) value of 1.86 脳 10^鈥? (mol/mol_Ag s) at 300 掳C. The apparent activation energies (39.1鈥?7.5 kJ/mol) of the yAg/3DOM La_0.6Sr_0.4MnO₃ samples were much lower than that (91.4 kJ/mol) of the bulk La_0.6Sr_0.4MnO₃ sample. The effects of water vapor and sulfur dioxide on the catalytic activity of the 3.63 wt % Ag/3DOM La_0.6Sr_0.4MnO₃ sample were also examined. It is concluded that its super catalytic activity was associated with its high oxygen adspecies concentration, good low-temperature reducibility, large surface area, and strong interaction between Ag and La_0.6Sr_0.4MnO₃ as well as the unique nanovoid-walled 3DOM structure.