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

• Published in: Applied catalysis. B, Environmental Environmental, 2014-04, Vol.148-149, p.490-498
• Main Authors: Zhang, Chuanhui, Guo, Yanglong, Guo, Yun, Lu, Guanzhong, Boreave, Antoinette, Retailleau, Laurence, Baylet, Alexandre, Giroir-Fendler, Anne
• Format: Article
• Language: English
• Subjects: Catalysis; Chemical Sciences; Chemistry; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Environment and Society; Environmental Sciences; Exact sciences and technology; General and physical chemistry; Low-temperature reducibility; Perovskite; Sol–gel synthesis; Surface adsorbed oxygen; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Toluene oxidation
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2013.11.030

•LaMnO3 were synthesized by three different methods, citrate sol–gel, glycine combustion and co-precipitation.•LaMnO3 synthesized by citrate sol–gel exhibited the best catalytic performance for toluene oxidation.•No by-products were formed but only CO2 and H2O.•Specific surface area, reducibility and surface adsorbed oxygen were the main parameters.•Apparent activation energies of all samples correlated well with their catalytic activities. 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 60h. 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 76kJmol−1, respectively. The lowest apparent activation energy of sample LMO-SG was in good agreement with its better catalytic behavior for toluene oxidation.