Relation Between Dopant Concentration, Oxygen Mobility and Oxidation Activity in Doped Lanthanum Ferrite-Based Perovskite Oxides

Perovskite oxides show great promise as potential anode and cathode catalysts in Solid Oxide Fuel Cells. The structure-property relationships in these materials play a very important role in determining activity. The formation of oxygen vacancies and increased ionic mobility are very important factors determining the activity of these materials for both the anodic and cathodic processes as well as tolerance to poisons and stability. Previous work in our research group examined strontium- and cobalt-doped LaFeO₃. The oxygen mobility and vacancy generation was found to be a function of dopant composition. The present work explores the effect of substitution of Sr with Ba and additional doping with aliovalent transition metals and its effect on the oxygen vacancy generation and transfer capabilities. The work is aimed at understanding the structure-property relationships using techniques such as in-situ X-ray diffraction, Thermogravimetry, isotopically labeled oxygen exchange, X-ray photoelectron spectroscopy and methanol adsorption as a probe molecule. Also, a correlation between activity for the methane oxidation reaction and dopant concentration and oxygen vacancy generation will be discussed.