Effect of grain size and microstructure on radiation stability of CeO₂: an extensive study

Abstract

To investigate the variation in the radiation stability of ceria with microstructure under the electronic excitation regime, ceria samples sintered under different conditions were irradiated with high energy 100 MeV Ag ions. The ceria nanopowders were synthesized and sintered at 800 °C (S800), 1000 °C (S1000) and 1300 °C (S1300), respectively. The samples with widely varying grain size, densities and microstructure were obtained. The pristine and irradiated samples were studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). None of the samples amorphized up to the highest fluence of 1 × 10(14) ions per cm(2) employed in this study. XRD and Raman studies showed that the sample with lowest grain size suffered maximum damage while the sample with largest grain size was most stable and showed little change in crystallinity. Raman spectroscopy indicated the enhanced formation of Ce(3+) and related defects in the sample with larger grain size after irradiation. The most intriguing result was the absence of Ce(3+)-related defects in the sample with lowest grain size which actually showed maximum damage upon irradiation. The XPS studies on S800 and S1300 provided concrete evidence for the presence of Ce(3+) and oxygen ion vacancies in S1300. The grain boundaries and grain size dependent stability have been discussed.

Effect of annealing temperature on oxygen vacancy concentrations of nanocrystalline CeO2 film

“…Some authors have attributed this peak to oxygen ions with unusual coordination in a defective CeO x (x<2) structure [34]. Recently, reports assigned this peak to oxygen vacancies in CeO 2 [35,36]. In this work, the presence of A c c e p t e d M a n u s c r i p t hydroxyl groups or carbonate is not found.…”

Graphene Supported Silver Nanocrystals Preparation for Efficient Oxygen Reduction in Alkaline Fuel Cells

“…Such kind of anomalies has attributed to the prevalence of point defects such as oxide formation. 11,58 The average nanocrystal size of each catalyst was calculated from Ag(111) peak using Scherrer formula. 11 The sizes were estimated as 8.8, and 8.1, nm for AgNCs/rGO_AA, and AgNCs/rGO_NaBH 4 , respectively, which are in good agreement with the predetermined particle sizes by HRTEM.…”

Phase‐dependent radiation‐resistant behavior of BaTiO3: An in situ X‐ray diffraction study

“…The modes observed at 307 cm −1 can be assigned to the in‐plane vibration of the Ti–O bonds in an off centric Ti‐displaced TiO 6 octahedra as in the ferroelectric phases of BaTiO 3. Similarly, the mode observed at 252 cm −1 can be assigned to the rotation of the TiO 3 units of the TiO 6 octahedra. These two modes are the characteristic frequencies observed only in tetragonal BaTiO 3.…”

“…investigated radiation (940 MeV Au at fluence of 1.5×10 13 ions/cm 2 ) induced amorphization of CaZrO 3 . The ion‐induced amorphization as a function of fluence has been monitored by in situ X‐ray diffraction (XRD) studies and the increasing lattice strain has been attributed to the amorphization process . From many reports, we found that the radiation tolerance of the different oxide materials has been improved by increasing the density of grain boundaries or making them nanocrystalline and also depends on stoichiometry or nonstoichiometry and structure type of the materials .…”

“…The ion-induced amorphization as a function of fluence has been monitored by in situ X-ray diffraction (XRD) studies and the increasing lattice strain has been attributed to the amorphization process. [14][15][16][17] From many reports, we found that the radiation tolerance of the different oxide materials has been improved by increasing the density of grain boundaries or making them nanocrystalline 16,18,19 and also depends on stoichiometry or nonstoichiometry and structure type of the materials. 17,[20][21][22] The stability of BaTiO 3 under extreme conditions is of relevance for several mentioned applications.…”