Hydrothermal Fabrication and Catalytic Properties of La1-xSrxM1-yFeyO3 (M = Mn, Co) That Are Highly Active for the Re

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• 作者：Jiguang Deng ; Hongxing Dai ; Haiyan Jiang ; Lei Zhang ; Guozhi Wang ; Hong He ; Chak Tong Au
• 刊名：Environmental Science & Technology
• 出版年：2010
• 出版时间：April 1, 2010
• 年：2010
• 卷：44
• 期：7
• 页码：2618-2623
• 全文大小：199K
• 年卷期：v.44,no.7(April 1, 2010)
• ISSN：1520-5851

文摘

A series of La_1-xSr_xM_1-yFe_yO₃ (M = Mn, Co; x = 0, 0.4; y = 0.1, 1.0) perovskite-type oxide catalysts have been fabricated via a strategy of citric acid complexation coupled with hydrothermal treatment. The materials are characterized by a number of analytical techniques. The oxidation of toluene is used as a probe reaction for the evaluation of catalytic performance. It is found that both La_0.6Sr_0.4FeO₃ and LaFeO₃ exhibit high activities. The partial substitution of manganese and cobalt with iron can significantly improve the catalytic performance of La_0.6Sr_0.4MnO₃ and La_0.6Sr_0.4CoO₃. At toluene/O₂ molar ratio = 1/200 and space velocity = 20 000 h⁻¹, the catalytic activity decreases in the sequence of La_0.6Sr_0.4Co_0.9Fe_0.1O₃ > La_0.6Sr_0.4FeO₃ > La_0.6Sr_0.4Mn_0.9Fe_0.1O₃ > LaFeO₃ > La_0.6Sr_0.4CoO₃ > La_0.6Sr_0.4MnO₃. Compared to the Fe-free counterparts, the La_0.6Sr_0.4Mn_0.9Fe_0.1O₃ and La_0.6Sr_0.4Co_0.9Fe_0.1O₃ catalysts are, respectively, 50 and 85 °C lower with regard to the temperature required for complete toluene oxidation. Toluene can be completely oxidized at 245 °C over La_0.6Sr_0.4Co_0.9Fe_0.1O₃. The excellent catalytic performance of La_0.6Sr_0.4Co_0.9Fe_0.1O₃ can be attributed to the presence of (i) Fe³⁺−O−Fe⁴⁺ couples, (ii) a transition of electronic structure, and (iii) a trace amount of Co₃O₄.