Vol 70, No 4 (2025)

The phase formation, morphology, and optical properties of aluminum oxynitride (Al₅O₆N) doped with vanadium ions were studied in the concentration range of 0.01–5.0 at. % (relative to aluminum). All samples were obtained by calcining mixtures of Al₂O₃, AlN, and V₂O₅ at a temperature of 1750°C in a nitrogen flow. The resulting materials were predominantly single-phase γ-AlON with minor impurities of aluminum nitride, as well as VC, VN, VO, or their solid solutions, for vanadium concentrations of ≥0.1 at. %. In AlON:V, the band gap (E_g) ranges from 5.82 to 5.94 eV, depending on the vanadium concentration. The luminescence of AlON:V is attributed to intrinsic defects and impurity luminescence centers. The presence of vanadium in AlON results in an increase in the optical absorption and a decrease in the intensity of intrinsic luminescence, which is caused by the formation of vanadium-containing impurity phases.

The process of synthesizing nano-sized SNO₂ by direct chemical precipitation using tin(II) chloride and hydrogen peroxide has been investigated. The thermal behavior of the obtained powders was studied using simultaneous thermal analysis (TGA/DSC). The impact of H₂O₂ concentration in the reaction system on the set of functional groups in the materials was demonstrated using infrared spectroscopy, while X-ray diffraction analysis (XRD) was utilized to examine the crystalline structure of the powders, including the thermal transformation of tin(II) oxyhydroxide. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to show the effect of the reaction system composition on the size of primary particles and the agglomerates formed. In particular, it was established that with an increase of H₂O₂ concentration, both the size of the primary particles and the agglomerates decrease. The roughness of the films formed from the obtained nanopowders was studied using atomic force microscopy (AFM). Kelvin probe force microscopy (KPFM) was used to construct surface potential distribution maps for the obtained materials and to evaluate the electron work function from their surface.

The article is devoted to the synthesis, determination of structural features, electrical conductivity and pigment characteristics of cation-deficient scheelite-type Ca_1−1.5x–yBi_x+yФ_0.5xMo_1–yV_yO₄ solid solutions. Complex oxides were studied with X-ray diffraction and Raman spectroscopy. The concentration ranges of existence of different types and distortion of structure were discussed via the element ordering in A sublattice. The total electrical conductivity of the compounds was studied by impedance spectroscopy in the temperature range of 400–650°C. Arrhenius plots of electrical conductivity on the inverse temperature were constructed and analyzed. According to the diffuse light scattering data of powders, functions of color coordinates of the solid solutions were calculated.

It was established that during the interaction of bismuth hexamethylenedithiocarbamate (HmDtc) with a H[AuCl₄]/2M HCl solution, the individual forms of gold(III) binding in the solid phase are double complexes of [Au(S₂CNHm)₂][Bi(S₂CNHm)₂Cl₂] (I) and [Au(S₂CNHm)₂]₂[Bi₂(S₂CNHm)₂Cl₆] (II). The structures of the obtained compounds include centrosymmetric/non-centrosymmetric (in I/II) complex cations of Au(III), as well as heteroleptic bismuth anions: both the mononuclear and binuclear, whose the ratio Bi : Dtc : Cl = = 1:2:2/2:2:6 (I/II). The secondary S∙∙∙S and S∙∙∙Cl interactions that arise between these ionic structural units lead to the formation of three-dimensional supramolecular architectures. In the IR spectra of the compounds, the absorption bands of N–C(S)S bonds were assigned to HmDtc ligands in the inner sphere of Au(III) complex cations and Bi(III) anions. Thermal behavior of I and II was studied using the STA technique. The residual substance obtained after thermolysis of the samples is represented by metallic particles of a solid solution of bismuth in gold, coated with a layer of Bi₂O₃. For complex I, a high level of anti-mycobacterial activity in vitro was revealed against the non-pathogenic strain Mycolicibacterium smegmatis.

The synthesis of multicomponent single-phase rare earth zirconates LaGdZr₂O₇, (LaSmGd)_2/3Zr₂O₇, (LaSmGdY)_1/2Zr₂O₇, (LaNdSmGdY)_2/5Zr₂O₇ of the pyrochlore structure was performed. The isobaric heat capacity at 300–1800 K, thermal diffusivity were measured and the thermal conductivity of non-porous samples in the range of 300–1300 K was calculated.

Thermodynamic modeling of the film synthesis process from the gas phase in the Si–O–C–H–He and Si–O–C–H–N–He systems during the decomposition of hexamethyldisiloxane was performed. The modeling used the method for calculating chemical equilibria based on minimizing the Gibbs energy of the system, implemented using the Data Bank on the properties of electronic materials. It was shown that various phase complexes containing silicon oxide, carbide, and nitride can be obtained in CVD processes of such systems. The results of the thermodynamic modeling can be useful for developing methods for the synthesis of film coatings based on such phase complexes.

By the method of alkalimetric titration of aqueous solutions with pH-potentiometric indication at I = 0.1 mol/dm³ (KCl/KNO₃) and t = 25 ± 1°C the acid dissociation constants of functional groups in the composition of a new reagent N-(2-hydroxyethyl)iminodipropionic acid pKa₀ = 2.87 ± 0.02, pKa₁ = 4.00 ± 0.02 and pKa₂ = 9.25 ± 0.01. The complexation of the reagent with transition metal ions was studied. It is shown that N-functionalization of iminodipropionic acid by introduction of 2-hydroxyethyl substituent leads to a significant decrease in stability of complexes with copper(II) and nickel(II) ions, with cobalt(II), zinc(II) and cadmium(II) ions the stability of complexes does not significantly increase. Relatively high stability is characterized by complexes with silver(I) ions. Based on the obtained data, assumptions about the structure of the studied complexes were made.

Magnetic copper ferrite (II) nanoparticles are promising materials for biomedical, electronic and photocatalytic applications. In this work, homogeneous spherical CuFe₂O₄ nanoparticles with a size of 18.3 ± 0.4 nm and a band gap width of 2.37 eV were obtained by anion-exchange resin precipitation using AV-17-8 in OH form in the presence of dextran-40. The photocatalytic activity of the obtained material was studied on the example of photodegradation of a widely used anionic dye – indigo carmine in the presence of sacrificial reagents: sodium citrate, carbonate and hydrocarbonate, hydrogen peroxide. The effectiveness of the joint application of electron donors - sodium hydrocarbonate and citrate – in reducing the probability of recombination of photogenerated holes and electrons has been demonstrated. The kinetic parameters of the process were determined (pseudo-zero order, k_app. = 3.6 × 10^–7 mol/(l × min), T_1/2 = 75.8 ± 2.3 min) and its mechanism was elucidated. The intermediates of the photocatalytic oxidation of indigocarmine were determined by NMR.

Using aerosol-assisted vapor deposition (AACVD), bilayer ZnO/Cr₂O₃ thin-film nanocomposites were prepared and validated using various physicochemical analysis techniques. The thermal behavior of precursors: zinc and chromium acetylacetonates was studied using TGA/DSC. The chemical composition of the obtained coatings was confirmed by EDX method, and the physical composition was confirmed by X-ray diffraction and Raman spectroscopy. The microstructural features were studied by SEM method. It was found that by varying the precursor concentration it is possible to change the morphology of the obtained coatings from an island structure to a continuous film. It is shown that ZnO/Cr₂O₃ bilayer films demonstrate a noticeable chemoresistive response in acetone detection.