A total scattering Debye function analysis study of faulted Pt nanocrystals embedded in a porous matrix

Abstract

Faulted face-centred cubic platinum nanocrystals, grown within a nanoporous silica matrix, have been extensively characterized by the Debye function analysis method applied to wide-angle synchrotron X-ray total scattering data. A method for building databases of sampled interatomic distances of weakly faulted materials is proposed, maintaining statistical significance and allowing complete populations of differently sized and shaped nanocrystals to be used within the DEBUSSY approach. This study suggests that anisotropic Pt nanoclusters are formed in the presence of a shape-directing (templating) agent, and tentatively describes the effects of post-synthetic temperature treatments on fault probability, size, shape and dispersion of the nanocrystal populations. Surface relaxation effects are also observed in the smallest particles.

Combining X‐Ray Whole Powder Pattern Modeling, Rietveld and Pair Distribution Function Analyses as a Novel Bulk Approach to Study Interfaces in Heteronanostructures: Oxidation Front in FeO/Fe3O4 Core/Shell Nanoparticles as a Case Study

“…WPPM is particularly suited to deal with small crystallites when these parameters need to be taken into account. Note that although real‐space methods, like Debye function analysis, are being increasingly applied for the analysis of microstructural parameters, they are far from ideal for large particles like ours since calculating the Debye scattering equation, especially when defects are present, can be extremely time consuming …”

“…Note that although realspace methods, like Debye function analysis, are being increasingly applied for the analysis of microstructural parameters, [43] they are far from ideal for large particles like ours since calculating the Debye scattering equation, especially when defects are present, can be extremely time consuming. [44] For the modeling, first a NIST SRM Si 640d reference sample was refined to obtain a parametric description of the instrumental profile (IP), which corrects the main aberrations affecting XRD powder profiles. Note that this is important to guarantee that only the contribution related to the sample (size, shape, and strain) is being analyzed.…”

Ligand-induced symmetry breaking, size and morphology in colloidal lead sulfide QDs: from classic to thiourea precursors

“…The DSE method benefits from the description of nanocrystals at an atomistic level, which allows a number of relevant model parameters to be collectively considered within a unified model [26]. Such model includes the atomic arrangement, structural distortion and vacancies, nanoparticle size, morphology and surface relaxation [27][28][29][30]; the model is overall transferred into the pattern simulation in reciprocal space and can be optimized against the experimental WAXTS signal. As per the diffraction techniques, those parameters describe the ensemble of QDs in terms of distribution properties with high statistical significance, in contrast to microscopic techniques that probe local features on individual particles [31].…”

When Crystals Go Nano – The Role of Advanced X‐ray Total Scattering Methods in Nanotechnology

“…To model the morphology and the defectiveness of these materials appropriately, we developed an original method, with affordable CPU times according to the DebUsSy strategy:…”