reparation and methane combustion catalytic activity of nanometer perovskite-type complex oxides La_(1-x)Sr_xFeO_3 and LaFe_(1-y)Mn_yO_3

摘要

Perovskite-type complex oxides (ABO_3) have a well-defined structure and high thermostability, and the oxidation state of metal ions as well as oxygen vacancies can be changed through partial substitution of metal ions at A or B site, so they are suitable model compounds for the study of the relationship between the solid state chemistry and the catalytic properties. LaFeO_3 and its partially cation-substituted oxide system prepared by solid-state reaction have been applied to the complete oxidationof methane, carbon monoxide and propane, but their rather small specific surface areas (S_(BET)) limited the improvement of their catalytic activities. However, it is well known that nanometer oxides have larger S_(BET) and their physical and chemical properties are unique. Owing to this nature, they are expected to have lower reaction temperature of combustion of methane, and to improve the catalytic activity. In this study, two series of substituted nanometer oxide LaFeO_3 with Sr at A site or Mn at B site were first prepared, and their catalytic activity was investigated primarily.