Lattice parameter, defect concentration and oxygen diffusion in ceria solid solutions

Abstract

The results of x-ray diffraction, the size of lattice parameter, and the values of oxygen diffusion coefficient in YO 1.5 -CeO 2 , GdO 1.5 -CeO 2 , and NdO 1.5 -CeO 2 systems were reviewed.In YO 1.5 -CeO 2 system, the lattice parameter decreases as the concentration of YO 1.5 increases. In GdO 1.5 -CeO 2 system, the lattice parameter does not change very much. And in NdO 1.5 -CeO 2 system, it increases as the concentration of NdO 1.5 increases.When the oxygen diffusion coefficient was plotted as a function of lattice parameter, there was no correlation between them. However, when the oxygen diffusion coefficient was plotted as a function of the concentration of trivalent cation additives, there was very good correlation between them. Consequently, the diffusion coefficient does not depend on the size of crystal lattice in ceria solid solutions, but it depends on the concentration of trivalent cation additives.

Effect Synthesis Time of CeO2 Nanoparticles by Microwave-Assisted Hydrothermal as a Sensing Device on CO Gas Sensitivity

“…Table 1 reports the experimental data of Rietveld refinement. Data show that the lattice parameters and unit cell volumes are close to the values published in the literature [35][36][37] and a Joint Committee on Powder Diffraction Standards (JCPDS) card nº 34-0394 for CeO 2 powder where the theoretical lattice parameter was 5.411 Å 38 . An increase in the lattice parameter and unit cell volume is observed, which is normally associated with the synthesis time that influences the particle growth mechanism and, consequently, changes in morphology, crystallinity and deformation of the compound 7 .…”

Structure and radiation response of anion excess bixbyite Gd2Ce2O7

“…The family of oxygen deficient fluorite compounds has gained significant interest as systems for minor actinides disposal and understanding spent fuel chemistry, though they can be interesting systems also for their magnetic properties, their low thermal conductivity, and as ionic conductors [1][2][3][4][5][6]. Apart from these technological interests, these oxides provide a fascinating playground to explore the order mechanisms arising from flexible aliovalent doping and non-stoichiometry [7][8][9][10][11][12][13][14][15]. In most of these compounds, the preferred mechanism of charge compensation of the aliovalent doping is the creation of O vacancies.…”

Morphological Mapping of Hydrothermally Synthesised Nanoceria at High Ce Concentrations

“…Pure stoichiometric CeO 2 and oxygen hypostoichiometric CeO 2-x have the cubic fluorite structure, with space group Fm 3 À m, and lattice parameter 0.5409 nm. [14,21] Nanoscale CeO 2-x of different morphologies and exposed crystallographic planes has been synthesised by numerous methods, including precipitation, [22,23] hydrothermal and solvothermal syntheses, [24,25] sol-gel, [26] electrodeposition, [27,28] and microemulsion. [29] Of these, hydrothermal synthesis is considered to be one of the most advantageous owing to its economy, speed, and flexibility in terms of generating different CeO 2-x morphologies.…”