Nature and morphology of fumed oxides and features of interfacial phenomena

Gun’ko, Vladimir M.; Zarko, V.I.; Goncharuk, E.V.; Remez, O.S.; Skubiszewska–Zięba, J.; Wójcik, Grzegorz; Walusiak, B.; Blitz, Jonathan P.

doi:10.1016/j.apsusc.2016.01.062

Cited by 16 publications

(6 citation statements)

References 67 publications

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“…Complex binary (SA, ST) and ternary (AST) fumed oxides (Table) include crystalline alumina and titania, but silica is always amorphous (Fig. 1) [23,24,31]. For ST samples, titania (both anatase and rutile phases) crystallites are typically embedded into silica shells ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Several individual, binary, and ternary FMO (Table) including crystalline phases of titania (both anatase and rutile) and alumina (several phases) and completely amorphous silica (Pilot plant of Chuiko Institute of Surface Chemistry, Kalush, Ukraine) were used here and described in detail elsewhere [23][24][25]. Nanocomposites CeO 2 -ZrO 2 /SiO 2 (10 : 10 : 80 wt.…”

Section: Methodsmentioning

confidence: 99%

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Particulate morphology of nanostructured materials

Gun’ko¹,

Oranska²,

Paientko³

et al. 2020

Him. Fiz. Tehnol. Poverhni

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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.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Particulate morphology of nanostructured materials

Gun’ko¹,

Oranska²,

Paientko³

et al. 2020

Him. Fiz. Tehnol. Poverhni

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“…structural changes in water upon freezing with increasing sizes of ice crystallites causing huge disjoining pressure up to 2000 atm). This ice pressure can lead to destroying of core-shell nanoparticles (50-200 nm) of complex FMO, but smaller silica NPNP keep integrity under high pressure by ice crystallites in thick-wall stainless steel cryoreactors [19,22]. .…”

Section: Adsorptionmentioning

confidence: 99%

“…); (iii) nonuniform distribution of components in complex systems; (iv) medium effects (e.g. swelling); and (v) incorrect or inadequate models and methods used in the analyses of the experimental data [1][2][3][4][17][18][19][20][21][22][23][24][25][26][27][28]. As a whole, it is of importance to analyze the differences in the characteristics determined using different indirect methods taking into account the measurement conditions.…”

Section: Introductionmentioning

confidence: 99%

Nano/meso/macroporous materials characterization affected by experimental conditions and features of the used methods

Gun’ko¹

2020

Him. Fiz. Tehnol. Poverhni

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The aim of this study was to analyze a set of methods: adsorption, X-ray, microscopic, cryoporometry, relaxometry, and thermoporometry used to investigate the morphological and textural characteristics of materials being in vacuum, or gaseous or liquid dispersion media, as well the interfacial phenomena basic for the used approaches. Techniques used in the studies should be divided into eight groups: (i) adsorption-desorption of lowmolecular weight probe compounds (N 2 , Ar, etc.); (ii) adsorption or confinement of low-or high-molecular weight compounds in pores (voids) of solid particles being in liquid media; (iii) small angle X-ray scattering (SAXS) or small angle neutron scattering (SANS); (iv) quantitative analysis of images recorded using microscopic methods (TEM, SEM, AFM), etc.; (v) thermoporometry based on differential scanning calorimetry (DSC) with decreasing-increasing temperature utilizing melting thermograms; (vi) cryoporometry based on low-temperature 1 H NMR spectroscopy giving the dependence of signal intensity on temperature; (vii) relaxometry based on NMR spectroscopy dealing with transverse relaxation time vs. temperature; and (viii) relaxometry based on thermally stimulated depolarization current (TSDC) measurements related to dipolar and dc relaxations. Each method could be characterized by systematic errors caused by many factors. However, the use of a set of the aforementioned methods in parallel can allow one to elucidate the reasons and level of these systematic errors that is of importance for correct characterization of the materials studied. Thus, the larger the number of methods used in parallel, the more comprehensive the morphological and textural characterization of the adsorbents.

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“…HRTEM images of individual fumed oxides (a) A-300[7] and model for primary particle built of fullerene-like species Si 60 O 120 (OH) 60 (b).Fullerene-like molecules Si n O 1,5n (OH) n are structural analogues of carbon fullerenes where carbon atoms are substituted by tetrahedra SiO 3 (OH). InFig.…”

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confidence: 99%

A quantum chemical analysis of dependence of the protolytic properties of silica primary particles on their composition and spatial structure

et al. 2017

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High disperse silica is used as a sorbent and carrier of medical preparations in various branches of medicine, biotechnology etc. due to its physico-chemical properties, in particular, rather developed surface, chemical inertness, considerable adsorption capacity. The protolytic equilibrium of silica surface is to be examined, because the structure of its hydroxylic layer determines its properties. When silicic acid is polymerized, an increase in the molecular mass of the particles formed and the acidic properties of oligomers are changed.

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Nature and morphology of fumed oxides and features of interfacial phenomena

Cited by 16 publications

References 67 publications

Particulate morphology of nanostructured materials

Particulate morphology of nanostructured materials

Nano/meso/macroporous materials characterization affected by experimental conditions and features of the used methods

A quantum chemical analysis of dependence of the protolytic properties of silica primary particles on their composition and spatial structure

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