LaMnO₃ perovskite oxides prepared by different methods for catalytic oxidation of toluene

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• 作者：Chuanhui Zhang ; Yanglong Guo ; Yun Guo ; Guanzhong Lu ; Antoinette Boreave ; Laurence Retailleau ; Alex ; re Baylet ; Anne Giroir-Fendler
• 关键词：Perovskite ; Sol&ndash ; gel synthesis ; Toluene oxidation ; Low-temperature reducibility ; Surface adsorbed oxygen
• 刊名：Applied Catalysis B: Environmental
• 出版年：27 April, 2014
• 年：2014
• 卷：148-149
• 期：Complete
• 页码：490-498
• 全文大小：1701 K

文摘

Perovskite-type oxides of LaMnO₃ (LMO) were synthesized by citrate sol-gel (SG), glycine combustion (GC) and co-precipitation (CP) methods, respectively. The physicochemical properties of these LaMnO₃ materials were characterized by XRD, N₂ sorption, H₂-TPR and O₂-TPD. Their catalytic performances were evaluated for the oxidation of toluene. It was shown that well-formed perovskite structures were obtained over samples LMO-SG and LMO-GC. Traces of La₂O₃ phase were detected over sample LMO-CP. The ranking in terms of specific surface area, low-temperature reducibility and concentration of surface adsorbed oxygen species from the highest to the lowest value was LMO-SG > LMO-CP > LMO-GC, which was in good agreement with the catalytic activity order. Sample LMO-SG exhibited the optimum catalytic activity and durability without any deactivation observed during the steady state of 60 h. Its superior catalytic performance could be greatly attributed to its higher specific surface area, better low-temperature reducibility and more available surface adsorbed oxygen species. The apparent activation energies of samples LMO-SG, LMO-GC and LMO-CP were 71, 84 and 76 kJ mol^鈭?, respectively. The lowest apparent activation energy of sample LMO-SG was in good agreement with its better catalytic behavior for toluene oxidation.