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The morphology of nickel and cobalt oxides deposited on various substrates, namely ?-alumina and silica gel, is investigated. The main purpose of the work was to study the effect of synthesis methods, such as impregnation and mechanochemical synthesis, on the textural characteristics and surface morphology of the resulting composites.
The characteristics of the composites were determined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and the method of low-temperature nitrogen adsorption/desorption. The results showed that the choice of the synthesis method significantly affects the size and shape of the oxide particles, as well as the distribution of nickel and cobalt oxides on the substrate surface. The impregnation method ensures a uniform distribution of metal oxide particles, but at the same time, they have a great tendency to agglomeration, especially cobalt oxide.
The mechanochemical method makes it possible to increase the lability of the components and increase the degree of adhesion, which makes it possible to achieve greater dispersion of metal oxides. This is achieved by a controlled degree of encapsulation of the oxides in the substrate. The data obtained can be useful for the development of new composite materials with improved catalytic and structural properties.
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The effect of plasma chemical treatment on the structure of vermiculite promoted by zirconium oxychloride has been studied using scanning electron microscopy, X-ray phase analysis, IR spectroscopy and X-ray photoelectron spectroscopy. It has been established that plasma chemical treatment improves the catalytic activity and stability of the material while maintaining the chemical characteristics of the systems, due to the transition of metals to the oxide form, in particular zirconium.
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Composite materials based on K 25 hollow glass microspheres were obtained by modifying them with silver nanoparticles obtained by an environmentally friendly “green” method using an aqueous plant extract of Taraxacum root as a reducing agent, while simultaneously carrying out the process of synthesis of nanoparticles and their fixation on the surface and in the pores of the microspheres using ultrasonic exposure and subsequent heat treatment at 300…350 ?С. The developed composite materials based on K 25 hollow glass microspheres with silver nanoparticles deposited on their surface were studied using scanning electron microscopy, IR spectroscopy, and x-ray diffraction methods. Elemental analysis of the composites was obtained using energy-dispersive X-ray spectroscopy. The effectiveness of the method of applying silver nanoparticles to the surface of glass microspheres was shown.
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In this work, mesoporous TiO2-montmorillonite composites with hydrothermally activated impregnation (115 °C, 0.5…5.0 h) of a mechanically and thermally activated support with titanium polyhydroxocomplexes were obtained.
The materials were characterized by X-ray phase analysis, IR spectroscopy, low-temperature nitrogen adsorption/desorption, scanning electron microscopy, electrophoretic light scattering, and energy-dispersive spectroscopy. It has been established that the time of hydrothermal treatment significantly affects the size of titanium dioxide crystallites, the ratio of anatase and rutile phases, as well as the surface morphology and textural properties of the composites. Using the photometric method, the adsorption capacity and photocatalytic activity of the composites with respect to the model dye Rhodamine B were assessed. In general, hydrothermal treatment leads to a significant increase in the photoactivity of the composite. At the same time, increasing the processing time leads to a weakening of this effect. The resulting composites demonstrated a pronounced synergistic effect of adsorption and photocatalysis in the removal of Rhodamine B from a highly concentrated (40 mg/l) aqueous solution.
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In this work, a number of titanium oxide powders with different crystal structures and textural characteristics were synthesized. The initial raw materials were metallic titanium and rutile (rutile particle size 25 ?m, specific surface area 3 m2/g), from which titanium salts were synthesized with their subsequent decomposition. Titanium salts were obtained by interaction with mineral acids and ammonium carbonate. The resulting salts were thermally decomposed or hydrolyzed by adding ammonium hydroxide, which led to the precipitation of titanium oxide. The phase composition of the synthesized samples included rutile and anatase, as well as titanium fluoride impurities at low firing temperatures.
A relatively simple and economically feasible method for synthesizing titanium oxide with a specific surface area of up to 92 m2/g by simple chemical transformations is proposed, which involves thermal decomposition of synthesized titanium halides. The best of the synthesized anatase samples had the shape of irregular polyps, a specific surface area of 56…92 m2/g, and a particle size of 20…60 ?m.
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Cu-series green glaze was prepared using raw materials such as kaolin, feldspar, calcite, talc, limestone, quartz, and copper oxide. This study investigated the effects of formulation composition and preparation process on the glaze surface of the green glaze using both single-factor method and orthogonal experimental design. The single-factor method involved systematically varying one factor at a time, such as the proportions of raw materials, firing temperature, and firing time,
to observe their individual effects on the green glaze surface. On the other hand, the orthogonal experimental design considered multiple factors simultaneously and analyzed their relative importance on the glaze effect. By employing these methods, the study aimed to optimize the formulation composition and preparation process of the copper-based green glaze to achieve the desired glaze surface effect. To improve the efficiency and quality of glazes in industrial production applications.
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The structure of ZrO2–Sc2O3 powders in the composition range from 1 to 15 mol. % Sc2O3 with the addition of 0.1 mol. % Eu2O3 as a spectroscopic probe, obtained by the coprecipitation method and heat-treated at temperatures from 500 to 1200 °C, was studied. The crystal structure was identified by the X-ray diffraction method and Raman spectroscopy.
The local structure was estimated by the spectral and luminescent properties of the Eu3+ ion in the powder preparations.
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Phosphate glasses heavily doped with Nd3+ ions are critical components in developing efficient near-infrared laser systems. This study investigates the luminescence sensitization of Nd3+ ions in BaO-P2O5 glass using silver nanoaggregates.
The research demonstrates that thermally stimulated formation of Agmn+ molecular clusters multiplies the photoluminescence of Nd3+ ions in 15 folds, whereas the formation of plasmonic nanoparticles leads to a less increase. These findings open new avenues for manipulating the properties of phosphate glasses and enhancing the efficiency of laser systems.
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A method of analytical calculation of the thermal conductivity coefficient of glass is proposed, which allows, by taking into account the physical essence of the process of radiation-conductive heat transfer in translucent media, to increase the reliability of calculations for different thicknesses of products, taking into account their temperature, and simplify the analysis of temperature conditions during glass cooking and operation of products made from it.
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The paper presents the results of experimental modeling of glass-like carbon synthesis from high pressure supercritical fluid in the C–O–H system at temperature 800 °C and pressure 500…1000 atm. A full characterization of the carbon material is described on the basis numerous methods, such as CHNS-O analysis, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X-ray and electron diffraction, infrared and multiwave Raman spectroscopy. According to the features complex and comparison with industrial glassy carbon, the produced carbon material is classified as a glass-like substance. The results of the experimental synthesis demonstrate possible different formation mechanisms and, as a result, the polygenesis of glass-like state of carbon. The resulting material, due to a radically different method of synthesis (by polycondensation), can potentially have special surface and bulk properties.
