Lattice defects stabilized zirconia

Nanosized ceria-zirconia materials with improved thermal stability can be prepared by using the surfactant-assisted method. Structural refinements confirm that the nanocrystals contain structural microstrain and cationic lattice defects. Zirconium addition to ceria supresses the crystal sintering and imporves the thermal stability but leads to structure distortion. Both catalytic tests and CO-chemisorption show that Pd supported ceria-zirconia nanoparticles are active for CO oxidation. 

This observation suggests that the ionic transport can be related to the defect energy, which is defined by the interaction between the acceptors and oxygen sublattice. This interaction results in the barrier for ion hopping between equivalent positions in the lattice. Therefore, there has been considerable effort to optimize the ionic conductivity of stabilized zirconia by controlling the acceptors concentration and their size [1, 3]. 

The use of zirconia as a sohd electrolyte (and especially for oxygen-sensing devices) is facUitated by the fact that stabilized zirconia has a defect structure with a finite concentration of octahedral interstitial voids. The void space in the lattice is larger for the anions than for the Zr + cations, and the 0 anions are therefore the rate-... 

In this chapter, we present some latest analysis results of lanthanides (Lns Eu and Gd)-M6ssbauer structure and powder X-ray diffraction (XRD) lattice parameter (oq) data of defect-fluorite (DF) oxides with the new defect crystal chemistry (DCC) Oq model [ 1,2] as an upgrade of the former random oxygen coordination number (CN) Oq model [3,4]. This is, thus, the first report of our ongoing efforts to further elaborate the model and extend its applicability to more various systems, especially to pyrochlore (P)-type stabilized zirconias (SZs) and stabilized hafnias (SHs). 

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