Structural changes during toluene complete oxidation on supported EuFeO3 monitored by in situ 151Eu and 57Fe Mössbauer spectroscopy

Pure EuFeO3 and ceria were prepared via a sol–gel citrate route and were calcined at 700 °C. Separately, a 20 wt% EuFeO3/CeO2 was prepared via incipient wetness impregnation of calcined ceria with citrate precursors and calcined in the same conditions. SBET, XRD, toluene chemisorption, toluene–TPD and in situ 151Eu and 57Fe Mössbauer investigations were performed. All characterization data indicate the formation of a well-dispersed EuFeO3 at the surface of CeO2. During the oxidation of toluene 151Eu and 57Fe Mössbauer spectroscopy suggested a cooperative effect of the cations. The catalysts were tested in total oxidation of toluene. In terms of intrinsic activity for toluene combustion, supported catalysts were more active than bulk EuFeO3. All structural changes during operation time were reversible.