The results of a study of the influence of the thickness of porous glass (PG) plates modified with zinc oxide on its photocatalytic properties and ability to photogenerate oxygen in aqueous media are presented.

In present work Mn2+-doped MgO-Al2O3-ZrO2-SiO2 materials were synthesized. Their structure, morphology, chemical composition and luminescent properties were studied using X-Ray diffraction, scanning electron microscopy, EDX analysis and luminecent spectroscopy. It was shown that the application of sol-gel method provides the high-volume homogeneity of chemical composition of synthesized materials. Introduction of Mn into the composition of sol-gel materials accelerates significantly the crystalization processes during the thermal treatment. In the luminescence spectra several groups of emission bands are observed. These bands are situated in blue and yellow-red part of spectrum. this phenomenon is related with incorporation of Mn2+ into the structure of different crystals formed during the thermal treatment of gels. Obtained materials can be perspective for application as luminophores in the lighting for plant production.

The electrical properties of glasses composed of 8Na2O–(22 – x)B2O3–70SiO2–xCr2O3, where x varies from 0.3 to 6 mol

A methodology is developed and ZnO nanoparticles are synthesized in porous glasses. The synthesis is carried out by impregnating silicate porous glasses in an aqueous solution of zinc nitrate and its subsequent thermolysis. The spectral and luminescent properties of the synthesized composites are studied. The ability of ZnO nanoparticles formed in porous glass to produce reactive oxygen species under UV irradiation is studied.

Mn2+-doped MgO–Al2O3–ZrO2–SiO2 materials have been synthesized by the sol–gel method, and their structure, morphology, chemical composition, and luminescent properties have been studied using X-ray diffraction, scanning electron microscopy, EDX analysis, and luminescence spectroscopy. The sol–gel method has been shown to ensure high homogeneity of the chemical composition over the volume of the synthesized materials. The introduction of Mn into the composition of sol–gel materials significantly accelerates crystallization processes in them during heat treatment. The luminescence spectra of the materials display several groups of emission bands in the blue and yellow-red parts of the visible spectral range. The resulting materials are promising for use as phosphors in the lighting for plant production.

Porous glass (PG) obtained by leaching of sodium borosilicate glass (NBS) is actively used in sorption and separation technologies. Modifying the NBS system with additives can drastically affect the resulting PG. Here, we report on the effect that Cr2O3 had on the leaching behavior of phase-separated glasses in the Na2O-B2O3-SiO2-Cr2O3 system in 3 M HCl solution. The structure of these glasses was investigated by means of XRPD, EPR, and SEM. All chromium ions exist in the Cr3+ state and are octahedrally coordinated. Most Cr2O3 crystallized as eskolaite in the silica-rich phase. The leaching process is limited by the interdiffusion in the leached porous layer. Cr2O3 did not get extracted from the glass into a leaching solution. PGs containing a significant amount of eskolaite were obtained. The component extraction rate for Cr-doped glasses was higher than for Fe-containing glasses with similar compositions, which was explained by the difference in their structural roles.

Разработана методика, и синтезированы наночастицы ZnO в пористых стеклах. Синтез проведен путем пропитки силикатных пористых стекол в водном растворе нитрата цинка и его последующего термолиза. Исследованы спектрально-люминесцентные свойства синтезированных композитов. Изучена способность наночастиц ZnO, сформированных в пористом стекле, к выработке активных форм кислорода при УФ-облучении.

Composite sol-gel materials of the MgO–Al 2 O 3 –ZrO 2 –SiO 2 system were synthesized and the processes of their thermal evolution and crystallization were studied. Application of sol-gel compositions of the MgO–Al 2 O 3 –ZrO 2 –SiO 2 system to the surface of quartz ceramics leads to a significant increase in the mechanical strength of the material. The processes of thermal evolution of the sol-gel composition were studied using IR spectroscopy, X-ray diffraction, electron microscopy, and energy dispersive analysis. It was shown that the formation of the oxide composite structure of materials begins at the stage of wet gels. Treatment of quartz ceramics with composite sols followed by drying and heat treatment up to 1200°C results in modification of the surface layers of the material, which makes it possible to increase the mechanical strength of the material by more than 20%. Sol-gel modifying compositions, upon drying and subsequent heat treatment, form polycrystalline structures bonded to quartz ceramic particles and consisting of various oxide crystals.

Glass composition of 6Na2O 22B2O3·70SiO2·2Cr2O3 is studied by scanning electron microscopy, X‑ray powder diffractometry (XRPD), and differential thermal analysis, depending on the duration of heat treatment at a temperature of 550°C. It is established that during heat treatment for 24–96 h, a phase separation structure with interpenetrating phases is formed in the studied glass, and a crystalline phase of eskolaite—Cr2O3 is also formed. With the maximum heat treatment duration of 96 h, cristobalite is formed in the bulk of the glass, which is accompanied by a decrease in the glass transition temperature of the low-viscosity phase. In this case, the intensity of eskolaite peaks decreases. Cr2O3 and SiO2 crystallize apparently due to the substance of the low-viscosity phase.

A methodology for the formation of molecular clusters of silver in silicate nanoporous glasses has been developed. Composite materials containing molecular clusters of silver, silver nanoparticles and zinc oxide have been synthesized. The synthesis was carried out by impregnation of porous glasses in aqueous solutions of silver and zinc nitrates stabilized with high-molecular polyvinylpyrrolidone, followed by heat treatment of samples for decomposition of metal nitrates and polymer. Spectral-luminescent properties of composites have been investigated. Keywords: porous glass, zinc oxide, silver molecular clusters, silver nanoparticles, spectral-luminescent properties.

In the work, the MgO–Al 2 O 3 –ZrO 2 –SiO 2 coatings on the surface of quartz ceramics were prepared by sol-gel method. The synthesized materials were examined by X-ray phase and electron microscopic analyses. It is shown that composite gels retain an amorphous structure after thermal treatment at 600°C, and the formation and subsequent transformation of various oxide crystal phases is observed after calcination at temperatures above 900°C. The behavior of the thermal evolution of the structure of the obtained gels is generally similar to the course of structural changes occurring during glasses crystallization.

Glass composition of 6Na2O 22B2O3·70SiO2·2Cr2O3 is studied by scanning electron microscopy, X‑ray powder diffractometry (XRPD), and differential thermal analysis, depending on the duration of heat treatment at a temperature of 550°C. It is established that during heat treatment for 24–96 h, a phase separation structure with interpenetrating phases is formed in the studied glass, and a crystalline phase of eskolaite—Cr2O3 is also formed. With the maximum heat treatment duration of 96 h, cristobalite is formed in the bulk of the glass, which is accompanied by a decrease in the glass transition temperature of the low-viscosity phase. In this case, the intensity of eskolaite peaks decreases. Cr2O3 and SiO2 crystallize apparently due to the substance of the low-viscosity phase.

A methodology for the formation of molecular clusters of silver in silicate nanoporous glasses has been developed. Composite materials containing molecular clusters of silver, silver nanoparticles and zinc oxide have been synthesized. The synthesis was carried out by impregnation of porous glasses in aqueous solutions of silver and zinc nitrates stabilized with high-molecular polyvinylpyrrolidone, followed by heat treatment of samples for decomposition of metal nitrates and polymer. Spectral-luminescent properties of composites have been investigated.

ZnO–SnO2–Ag(AgCl) nanocomposites consisting of hexagonal ZnO, tetragonal SnO2, metallic Ag and AgCl nanocrystals were prepared by wet polymer-salt synthesis. The materials were studied using optical and luminescent spectroscopy, SEM, EDS and XRD analysis. The ability to generate chemically active singlet oxygen and antibacterial activity of prepared materials against both gram-positive and gram-negative bacteria were tested. It was showed that Ag structural transformation starts in initial composite solutions and proceeds at all stages including drying and thermal treatment of ZnO–SnO2–Ag(AgCl) synthesis. During this transformation, Ag exists in different forms (ions, molecular clusters, metallic and salt (AgCl) nanoparticles) and structural states (free Ag+ ions and Ag-PVP complexes in the solutions; Ag+ ions embedded into oxides crystal matrices; molecular clusters in the solutions and in PVP-salt composites; nanoparticles). Synthesized ZnO–SnO2–Ag(AgCl) powders consist of small (about 50 nm) nanoparticles—“nanogenerators” of chemically active singlet oxygen. This provides high antibacterial activity of these materials against both gram-positive and gram-negative bacteria.

This paper describes the low-temperature polymer-salt synthesis of ZnO–Ag nanopowders and presents the results of studying their structure, morphology, and properties. The methods of X-ray phase analysis and electron microscopy are used to study the structure and morphology of materials. It is found that the resulting nanopowders consist of nanoparticles of about 30 nm. The experiments show that the resulting nanopowders have antibacterial activity against both gram-positive and gram-negative bacteria.

This article presents the results of a study of the effect on the adsorption properties of microporous glass of its modification with ZnO–Ag nanocrystals. The adsorption processes from solutions of the Chicago Blue Sky organic dye are studied by spectrophotometric methods. It is found that the introduction of ZnO–Ag nanocrystals into glass pores increases the adsorption capacity of the material. It is shown that in concentrated (>10–6 M) Chicago Blue Sky dye solutions adsorption processes compete with the aggregation of dye molecules in solutions.

In this study, composite Ag/AgBr/Zn(NO3)2/PVP coatings are synthesized from solutions and their structure and luminescent properties are studied. It is shown that the luminescent properties of aqueous solutions and Ag/AgBr/Zn(NO3)2/PVP composite coatings formed from them are largely determined by the presence in the structure of materials of various small Agn (n < 5) molecular clusters. The formation of AgBr particles is accompanied by a change in the shape of the luminescence spectra, which indicates the evolution of the sizes and concentrations of various Agn molecular clusters when introducing bromide anions into the composition of materials.