Complete oxidation of methane over perovskite oxides

Abstract

The complete oxidation of methane is of significant importance not only for exhaust emission treatment, but also for tunnel cleaniless. In the recent years, many interesting attempts have been focused on this topics. As well known, for the mentioned reaction perovskite oxides have also been suggested. One of the determining factors for this type of oxides to be used in this reaction is a stable bulk structure of the compounds, which is denoted as ABO 3. In addition, both A and B atoms in the oxides can be substituted either by metal atoms with valence same as that in the original compounds or by metal atoms with variable valences [1-31. In this paper, the authors report results of a study on a series of perovskite oxides formulated as Lal_xMexMnO > where Me denotes Ca, Sr, Ba atom, respectively. The catalytic properties for the total oxidation of methane were tested over this series of samples. XRD technique was used for determining the phase composition of the oxides. Mn4+/Mn ratio in each of the strontium substituted samples was measured by chemical analysis. For some of this series of samples magnetic susceptibility determination was performed as well.