Use este identificador para citar ou linkar para este item: http://www.repositorio.cdtn.br:8080/jspui/handle/123456789/412
Título: Investigation of the solid state reaction of LaMnO3 with Fe and its effect on the catalytic reactions with H2O2
Título do periódico: Journal of the Brazilian Chemical Society Campinas
Autor(es): Moura, Flávia C.C.
Araújo, Maria H.
Ardisson, José Domingos
Macedo, Waldemar Augusto de Almeida
Albuquerque, Adriana Silva de
Lago, Rochel M.
Afiliação: Universidade Federal de Minas Gerais/UFMG, Belo Horizonte, MG, Brasil
Universidade Federal de Minas Gerais/UFMG, Belo Horizonte, MG, Brasil
Centro de Desenvolvimento da Tecnologia Nuclear/CDTN, Belo Horizonte, MG, Brasil
Centro de Desenvolvimento da Tecnologia Nuclear/CDTN, Belo Horizonte, MG, Brasil
Centro de Desenvolvimento da Tecnologia Nuclear/CDTN, Belo Horizonte, MG, Brasil
Centro de Desenvolvimento da Tecnologia Nuclear/CDTN, Belo Horizonte, MG, Brasil
Data do documento: 2007
Palavras-chave: Perovskites;iron oxides;Moessbauer effect
Resumo: In this work, the reaction of the perovskite LaMnO3.15 with Fe has been promoted by thermal treatment of the mixture Fe/LaMnO3.15 at 200, 400 and 600 §C. Mössbauer spectroscopy, X-ray diffraction (XRD), temperature programmed reduction (TPR) and temperature programmed desorption (O2-TPD) analyses suggested that at 400 and 600 §C oxygen from perovskite is transferred to Fe§ to produce an oxygen deficient perovskite, LaMnO3-d, and highly dispersed iron oxides, mainly Fe3O4 and FeO. XRD lattice parameters and crystallite size showed that LaMnO3 suffers a strong lattice distortion after reaction but no collapse of the perovskite structure. Reactivity studies pointed to a special interface effect of Fe/LaMO3 towards two reactions with H2O2, the decomposition to O2 and the oxidation of the model molecule, the methylene blue dye. As the treatment temperature of the Fe/LaMnO3.15 increased, the activity for H2O2 decomposition decreased, whereas the activity for the dye oxidation increased. These results are discussed in terms of a decrease in the concentration of Mn4+surf and Mn3+surf species, active for the H2O2 decomposition, with the formation of Mn2+surf and Fe2+surf species, active for the Fenton reaction.
Acesso: L
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