VOL 97, No. 11 (2024)

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.

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.

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.

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.

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.

The paper investigates the process of “soft” mechanochemical synthesis of the CuO/ZnO/Al2O3 composite using copper/zinc hydroxocarbonates and aluminum oxide as feedstock. Using the methods of X-ray phase and synchronous thermal analysis, the patterns occurring at the stage of mechanochemical activation and further heat treatment have been studied. The effect of the mill's energy stress on the textural properties of the composite is shown. By the method of low-temperature adsorption-desorption of nitrogen, it was found that in the process of mechanochemical synthesis, the total specific surface of the samples changes slightly, while the nature of processing has a significant effect on such textural characteristics as pore size distribution, active surface and dispersion of copper. Using the thermoprogrammable reduction method, the temperature ranges of activation of the composite for its use as a catalyst were obtained. The positive effect of mechanical activation on the formation of the composite structure, hich makes it possible to use it as the main component of the catalyst for the production of ammonia, hydrogen and methanol, is shown.

The physicochemical characteristics of the commercial bentonite S-4205-02 (Bentovin), as well as its structural parameters, are given. Clay agglomerates were mainly up to 10…20 ?m in size. X-ray spectral analysis showed rather high content of Fe2O3, Na2O, CaO, which corresponded to the ferruginous-aluminum variety of montmorillonite with a predominance of Na+ and Ca2+ ions in the interlayer space. The presence of potassium indicates the illite presence. According to the X-ray phase analysis, the main component of the product was montmorillonite (MM) with impurities of quartz/cristobalite, kaolinite, illite, hematite. Thermal analysis curves and the infrared spectrum of bentonite were analyzed. The specific surface area was 58 ± 6 m2/g (BET). On the basis of this bentonite and orthophosphoric acid (OPA), a geopolymer bentonite phosphate binder has been for the first time synthesized. Using X-ray and IR spectral analysis, it was shown that when reacting aluminosilicate powder with OPA, the MM structure was completely destroyed with the formation of aluminum and silicon phosphates.

The work is devoted to the synthesis of silicon oxycarbide composite modified with titanium oxide by joint mechanical treatment of white soot and activated carbon with TiO2 particles deposited on its surface. The deposition of titanium oxide was confirmed by elemental analysis data. Scanning electron microscopy showed that the size of the particles does not exceed 100 nm. The structure of the obtained materials was studied using such methods as X-ray diffraction and IR spectroscopy. It was found that the silicon oxycarbide composite is highly amorphous; the XRD patterns displayed peaks, which can be attributed to the plane reflections of anatase. The investigation of the IR spectra showed the presence of bands corresponding to vibrations of Ti–O–Ti and Ti–O–C bonds. The porosity of the synthesized samples was studied using nitrogen low-temperature adsorption/desorption. It was revealed that the composite has a fairly developed porous structure with a predominance of meso- and macropores. The material is suggested to be used as a photocatalyst for the destruction of organic compounds in purification processes.