Several methods can be used to obtain, from powder diffraction patterns, crystallite size and lattice strain of polycrystalline samples. Some examples are the Scherrer equation, Williamson–Hall plots, Warren/Averbach Fourier decomposition, Whole Powder Pattern Modeling, and Debye function analysis. To apply some of these methods, it is necessary to remove the contribution of the instrument to the widths of the diffraction peaks. Nowadays, one of the main samples used for this purpose is the LaB6 SRM660b commercialized by the National Institute of Standard Technology; the width of the diffraction peak of this sample is caused only by the instrumental apparatus. However, this sample can be expensive for researchers in developing countries. In this work, the authors present a simple route to obtain micron-sized polycrystalline CeO2 that have a full width at half maximum comparable with the SRM660b and therefore it can be used to remove instrumental broadening.

X-ray diffraction (XRD) was used to determine the temperature at which the transformation of Ce2O(CO3)2·H2O to ceria (CeO2) occurs under both a flow of nitrogen and air as a function of temperature. The Ce2O(CO3)2·H2O synthesised from Ce(NO3)3·6H2O and urea was further investigated using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD results indicate that, under a flow of nitrogen, CeO2 is formed at temperatures greater than 500 °C and that this occurs via an as yet unidentified intermediate phase, which is present between 430 and 540 °C. Results obtained by the XRD correspond to those obtained using TGA, which show weight  losses commencing at 430 and at 465 °C. No further weight loss occurs above 540 °C, because of the formation of CeO2 as the stable product. The crystallite size was also determined and observed to increase with increasing temperature. Under a flow of air the transformation occurred at a lower temperature, as CeO2 was formed at 250 °C. SEM and TEM reveal the particles have a rod-shaped morphology which is retained after calcination. These results may be used to optimise synthesis methods to minimise crystallite size growth and reduce sintering that is undesirable in many applications, particularly catalysis.

This paper describes the spatial and temporal investigation of laser ablated plasma plume of cerium oxide target using Langmuir probe. Cerium oxide target was ablated using a KrF (λ ~ 248 nm) gas laser. Experimental studies confirmed that oxygen partial pressure of 2 × 10−2 mbar is sufficient enough to get good quality films of cerium oxide. At this pressure, plume was diagnosed for their spatial and temporal behavior. Spatial distribution was investigated at a distance of 15 mm, 30 mm, and up to a maximum distance of 45 mm from the target, whereas temporal behavior has been recorded in the range of 0 to 50 µS with an interval of 0.5 µS. The average electron densities are found to be maximum at 30 mm from the target position and the plasma current of the laser ablated ceria is found to be maximum at 22 µS.