Doped ceria lattice parameter

Frolova-Borchert et al. fabricated nanocomposites comprised of fluo-rite-like Gd- or Pr-doped ceria and perovskite LaMnOa using Pechini route (Frolova-Borchert, et al., 2006). Interaction between components is reflected in the increase of doped ceria lattice parameters and disordering of Mn coordination sphere. Despite this interaction, nanocomposites possess a high conductiviy and a high lattice oxygen mobility and reactivity. 

It has been noted that the conductivity and activation energy can be correlated with the ionic radius of the dopant ions, with a minimum in activation energy occurring for those dopants whose radius most closely matches that of Ce4+. Kilner et al. [83] suggested that it would be more appropriate to evaluate the relative ion mismatch of dopant and host by comparing the cubic lattice parameter of the relevant rare-earth oxide. Kim [84] extended this approach by a systematic analysis of the effect of dopant ionic radius upon the relevant host lattice and gave the following empirical relation between the lattice constant of doped-ceria solid solutions and the ionic radius of the dopants. 

Lattice Parameters of Pure, Doped and Reduced Ceria 15.3. Electrical Conductivity ... 

Lattice parameters of pure, doped and reduced ceria... 

La-doped ceria. A correlation between synthesis process, nanodomain size, and total ionic conductivity was observed for Yb, Ho, and Dy -doped ceria. Furthermore, recent results question the established solubility limits of rare-earth cations in ceria. Although the lattice parameter of ceria increases with La doping up to 40 mol% LaOi the true solubility turns out to be below 20 mol% LaOj 5 as evidenced from the formation of C-LagOg after annealing Ceo.sLao.aOi g at 1000 °C for 7 days. Pronounced deviations from Vegard s law have been consistently observed for the lattice constant of Gd-doped ceria. These may be rationalized by the formation of C-GdgOg domains within the ceria fluorite lattice. ... 

Doped and undoped ceria exhibit ionic and electronic conduction at low oxygen partial pressures. Ce" " gets reduced to Ce ", which is the main cause for mechanical failure due to lattice expansion (for low oxygen partial pressure). The electrolyte/electrode interface may be delaminated due to the formation of cracks. When 40-50% of Ce" " ions are substituted with Gd " ions (Ceo.6Gdo.40i.8-CGO), then a balance between lattice parameters and conductivity with the YSZ electrolyte and an anchoring YSZ layer provides the ability to resist the thermal expansion mismatch. Uchida and co-workers obtained the electrocatalytic activities for the SDC and Yttria doped Ce02 (YDC) for the electrodes sintered at 1150 and 1250°C. The current density of 0.2-0.25 PJcvc is observed for SDC and YDC anodes,... 

In other cases, doping isovalent elements like and into the CeOj lattice strongly affects the redox properties of ceria by increasing both total and kinetic oxygen storage, in this system, bulk properties of the material play a key role in the extent of reduction rather than the surface. The excellent redox behavior of these materials is appears when the creation of structural defects by the variation of cell parameter takes place in a cubic system. Indeed, for ceria-zirconia, it has been reported that the optimum composition is around Ce,.,Zr 02 with 0.2 < x< and in this range bulk diffusion of 0 ion is approximately two... 

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