Structure Characterization of Nanocrystalline Yttria- Stabilized Zirconia Powders Prepared via Microwave-Assisted Synthesis

The structure development of nanocrystalline yttria-stabilized zirconia (ZrO2-3.4 mol % Y2O3) synthesized by coprecipitation of hydroxides followed by microwave drying and calcination in the temperature range from 300 to 1000 degrees C was investigated. A complex series of methods was used for the structure characterization: X-ray diffraction (XRD) analysis, radial distribution function of electronic density (RDF), small-angle X-ray scattering (SAXS), and high-resolution transmission electron microscopy (HRTEM). The wide range of the used techniques allowed us to reveal the structure formation at all hierarchic levels of organization: atomic level, where features of the local atomic arrangement were discovered; crystallite level; and the level of secondary particles (aggregates), where grain boundaries are formed and nanostructuring takes place. The nanostructure features, the grain boundaries containing a lot of defects, were found to improve the catalytic performance of zirconia in CO oxidation. The results demonstrated that significant changes of zirconia properties can be expected when the material is transformed into the nanostructural state.