Determination of crystallite size distribution histogram in nanocrystalline anatase powders by XRD

TiO2 powders synthesized by pressurized fluid extraction and supercritical drying: Effect of water and methanol on structural properties and purity

“…The data were fitted using the computer program MSTRUCT [25], which is based on the FOX/ObjCryst [26] package. A model-based approach [27][28][29][30][31] was utilized rather than direct analysis of diffraction peaks breadth [32] in order to get a well-defined absolute measure of the particles 'size'. The approach has also the advantage that the instrumental broadening effects are already included in the procedure, suppressing one of the possible systematic errors.…”

“…In the analysis it was further assumed that the concentration of large structural defects is low [23] and peak broadening is caused solely by a finite size of diffracting particles. The microstructural model assumed spherical crystallites with diameter distributed according to the log-normal distribution which was found to be very appropriate for description of polydisperse nanoparticle systems [27,28,30]. The 'standard multiplicative deviation' [33] of the log-normal distribution was set to a constant value (s* = 1.35).…”

Refining bimodal microstructure of materials with MSTRUCT

“…The results of other approaches are summarized in Table II. The bimodal model gives almost as good solution as the refinement of the general size distribution histogram (Matěj et al , 2011) and significantly better fit than a standard model, assuming monodisperse particles. The agreement between determined size distribution parameters ( M , S ) with reference samples is quite good and even excellent when recalculated to area- and volume-averaged dimensions (〈 D 〉 A and 〈 D 〉 V ).…”

“…An application of the DoubleCompReflProf effect is illustrated here on the analysis of the artificial powder sample – the mixture of anatase crystallites of two different sizes (〈 D 1 〉 = 6.7 nm and 〈 D 2 〉 = 22.6 nm). The sample as well as the synthesis conditions were described in Matěj et al (2011, 2013). DoubleCompReflProf is a “virtual” effect.…”

“…As the MSTRUCT (Matěj and Kužel, 2009) belongs rather to the first group. The use of a specific broadening effect for the bimodal microstructure description is demonstrated here on a model case of the sample with anatase (TiO 2 ) crystallites with two different sizes (Matěj et al , 2011). On the contrary, in some cases the increased degrees of freedom of the second approach – using two phases with different microstructure and constrained parameters – is favourable.…”