LaCoO3 nanopowders by XPS

Mixed oxide materials belonging to the perovskite family (ABO3 , LaCoO3) have come underintense scrutiny for their possible applications in different scientific and technological fields, suchas heterogeneous catalysis, oxygen sensors, solid oxide fuel cells and magnetic media. The growinginterest in such mixed oxide systems relies on a detailed investigation of structure-propertiesrelationships that can lead to the optimization of their performances with respect to differentapplications, e.g., catalysis, sensors, etc. Similar solid state devices would require high surface areathin films in order to optimize the full potential of these oxide materials; specifically, nanostructuredsystems with a high defect content (oxygen vacancies and local lattice disorder) are expected toshow superior properties with respect to the conventional ones. The possibility to tailor thesefeatures as a function of the surface area and grain size appears thus as a powerful tool in order tooptimize the material properties for functional applications. In particular the present investigation isfocused on x-ray photoelectron spectroscopy (XPS) and x-ray excited Auger electron spectroscopy(XE-AES) analysis of the main core levels (O 1s, Co 2p, Co LMM, La 3d, and La 4d) of LaCoO3nanophasic powders obtained by combustion synthesis. The formation of LaCoO3 was ascertainedby the position and shape of La 3d and Co 2p photopeaks.