Abstract
The aim of this study was to develop a technique to analyze the crystalline and particulate morphology of highly disperse complex metal and metalloid oxides, which include both crystalline and amorphous phases, using X-ray diffraction (XRD) data to compute crystallite size distributions (CSD) compared to the particles size distribution functions estimated from high-resolution transmission electron microscopy (TEM) images treated with specific software. Two versions of the XRD treatment methods were used: (i) full profile analysis (FPA) of whole XRD patterns with a self-consistent regularization (SCR) procedure using models for spherical and lamellar crystallites that allows us to estimate relative contributions of crystallites of different shapes; and (ii) analysis of main pure XRD lines with consideration of corrections on an instrumental line profile and background using a regularization procedure with models of spherical or lamellar crystallites. The XRD and TEM based approaches were tested to analyze the crystalline and particulate morphology of various disperse materials: complex (binary and ternary) fumed oxides with silica/alumina, silica/titania, and alumina/silica/titania including crystalline alumina and titania and amorphous silica; nanocomposites CeO 2 –ZrO 2 /SiO 2 (10 : 10 : 80 wt.%) and TiO 2 –ZrO 2 /SiO 2 (10 : 10 : 80 wt.%) including crystalline and amorphous phases and synthesized using a liquid-phase method and fumed silica A–300 as a substrate; and natural clays of complex composition including several crystalline phases. Obtained results show that the developed approaches to analyze the XRD patterns could be effectively used to compute the CSD in parallel with TEM image treatments, using specific software, for a deeper insight into crystalline and particulate morphology of various disperse materials.
Highlights
The particulate morphology (PM) plays an important role on applications of disperse materials such as adsorbents, fillers, catalysts, thickeners, carriers, etc. [1,2,3,4,5]
The aim of this study is to analyze the X-ray diffraction (XRD) data for various metal or metalloid oxides (MO) such as fumed MO (FMO) (Figs. 1–4, Table), oxides deposited onto fumed silica (Figs. 5 and 6), and natural clays (Figs. 7–9), to obtain the crystallite size distributions (CSD) functions compared to the PaSD functions computed using transmission electron microscopy (TEM) images treated with ImageJ [22]
A method based on X-ray diffraction data and TEM images was developed to analyze the particulate and crystalline morphology of various metal and metalloid oxides comparing the CSD (XRD) and PaSD
Summary
The particulate morphology (PM) plays an important role on applications of disperse materials such as adsorbents, fillers, catalysts, thickeners, carriers, etc. [1,2,3,4,5]. There are various methods giving indirect information on the PM such as small angle X-ray (or neutron) scattering (SAXS) [8,9,10], X-ray diffraction (XRD) [11,12,13], dynamic and static light scattering [14, 15], adsorption (for nonporous nanoparticles of fumed oxides) [16, 17] and other methods. Some of these methods give information on amorphous and crystalline particles, but others describe only crystalline phases. In the case of complex particles including several crystalline and amorphous phases, to obtain more accurate information, several methods from two mentioned groups
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