Three-Dimensionally Ordered Macroporous La0.6Sr0.4MnO3 Supported Ag Nanoparticles for the Combustion of Methane
Three-Dimensionally Ordered Macroporous La0.6Sr0.4MnO3 Supported Ag Nanoparticles for the Combustion of Methane
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DOI：
10.1021/jp502256t
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发表时间：
2014-07-10
影响因子：
3.7
通讯作者：
Li, Junhua
中科院分区：
文献类型：
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作者：
Arandiyan, Hamidreza;Dai, Hongxing;Li, Junhua
通过一种简单的新型还原方法，使用聚苯乙烯，成功制备了一系列负载在三维有序大孔（3DOM）La0.6Sr0.4MnO3（yAg/3DOM La0.6Sr0.4MnO3；y = 0、1.57、3.63和5.71 wt%）上的银纳米颗粒（NP），其具有高表面积（38.2-42.7 m(2)/g）。在二甲氧基四乙二醇 (DMOTEG) 溶液中以甲基丙烯酸酯胶体晶体为模板。这些材料的物理化学性质通过多种技术进行了表征，并评估了它们对甲烷燃烧的催化活性。结果表明，yAg/3DOM La0.6Sr0.4MnO3材料具有独特的类纳米空隙3DOM结构，并且Ag纳米粒子很好地分散在大孔内壁上。在 La1-xSrxMnO3 (x = 0.2、0.4、0.6、0.8) 和 yAg/3DOM La0.6Sr0.4MnO3 (y = 0、1.57、3.63 和 5.71 wt%) 样品中，3.63 wt% Ag/3DOM La0.6Sr0.4MnO3 表现最好，给出T-10%、T-50%和T-90%（甲烷转化=10、50和90%对应的温度）分别为361、454和524℃，300℃时最高翻转频率（TOFAg）值为1.86 x 10(-5) (mol/mol(Ag) s)。表观活化能yAg/3DOM La0.6Sr0.4MnO3 样品的 (39.1-37.5 kJ/mol) 远低于块状 La0.6Sr0.4MnO3 样品的 (91.4 kJ/mol)。还检查了水蒸气和二氧化硫对 3.63 wt% Ag/3DOM La0.6Sr0.4MnO3 样品催化活性的影响。结果表明，其超强催化活性与其高氧种类浓度、良好的低温还原性、大比表面积、Ag与La0.6Sr0.4MnO3之间的强相互作用以及独特的纳米孔壁3DOM结构有关。
A series of Ag nanoparticles (NPs) supported on three-dimensionally ordered macroporous (3DOM) La0.6Sr0.4MnO3 (yAg/3DOM La0.6Sr0.4MnO3; y = 0, 1.57, 3.63, and 5.71 wt %) were successfully prepared with high surface areas (38.2-42.7 m(2)/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 La0.6Sr0.4MnO3 materials possessed unique nanovoid-like 3DOM architectures, and the Ag NPs were well dispersed on the inner walls of macropores. Among the La1-xSrxMnO3 (x = 0.2, 0.4, 0.6, 0.8) and yAg/3DOM La0.6Sr0.4MnO3 (y = 0, 1.57, 3.63, and 5.71 wt %) samples, 3.63 wt % Ag/3DOM La0.6Sr0.4MnO3 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 degrees C, respectively, and the highest turnover frequency (TOFAg) value of 1.86 x 10(-5) (mol/mol(Ag) s) at 300 degrees C. The apparent activation energies (39.1-37.5 kJ/mol) of the yAg/3DOM La0.6Sr0.4MnO3 samples were much lower than that (91.4 kJ/mol) of the bulk La0.6Sr0.4MnO3 sample. The effects of water vapor and sulfur dioxide on the catalytic activity of the 3.63 wt % Ag/3DOM La0.6Sr0.4MnO3 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 La0.6Sr0.4MnO3 as well as the unique nanovoid-walled 3DOM structure.