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For the first time catalytic systems based on HZSM-5 zeolites (Si/Al=12, 25, 40) with nanosized anatase (NA) were obtained in situ by a modified hydrothermal method and a sol-gel method. Initial HZSM-5 and NA/HZSM-5 were characterized (XRPD, XAS, FT-IR, DSC, BET, XPS, SEM, TPD) and analyzed in the reactions of propane (liquefied petroleum gas) conversion (РС; temperature range 200–870 °С) with the formation of the main products propylene (C3H6, PP) and ethylene (C2H4, ETH) and liquid ethanol conversion (EC; temperature range 150–360 °C) with the formation of diethyl ether ((C2H5)2O, DEE) and ETH. In the PC reaction the maximum selectivity (SETH = 75%) and conversion (αP = 65%) were obtained on HZSM-5(40) (650 °С). With an increase in the NA content in NA/HZSM-5 SETH value increases up to 85%. In the EC reaction SDEE/ETH~98–99% was reached on HZSM-5(25) (200 °C) and HZSM-5(40) (300 °C); the αE to ETH is comparable (94%) for all HZSM-5 (300 °C). Modification of HZSM-5 with NA leads to a shift in the EC reaction temperature to lower temperature region (αE to ETH ~98% at 280 °C) with SDEE/ETH~94–100% for NA/HZSM-5(25) and NA/HZSM-5(12) obtained by a modified hydrothermal method. It was established the relationship between HZSM-5 and NA/HZSM-5 catalytic activity and their characteristics: Si/Al, NA content and Ti coordination number (NA/HZSM-5), the content of "zeolite water" with OH groups, specific surface area, meso- and micropores volume and spherical particles size (HZSM-5), surface energy of adsorption centers (HZSM-5 and NA/HZSM-5), and hence the content of acid sites, the strength of which is also determined by the temperature of the catalytic reaction. The reaction mechanisms have been presented. The obtained NA/HZSM-5 catalysts have a higher or comparable catalytic activity to commercial ones, but low cost, ease of preparation, and versatility.

The local environment of manganese and cobalt in diffusion doped Ca3(VO4)2 crystals was experimentally evidenced: tetrahedral coordination and the coordination intermediate between tetrahedral and octahedral was revealed for Mn(2+δ)+ and Co2+ ions.

The antimicrobial property against different bacteria with cerium oxide formation mainly depends on the content of Ce3+ ions.

New NT:M/zeolite composites with functional nanoparticles of titanium(IV) oxides NT (η-phase and anatase) have been prepared by introducing nitrates with dopant metals (M = Ag, Ni, and V) and zeolites (H-Beta and H-ZSM-5) within the process of NT synthesis during the hydrolysis of TiOSO4·nH2O. The prepared composites have been characterized by X-ray diffraction, XAS-method, XPS-spectroscopy, UV-Vis diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller and chemoluminescence methods. The greatest photodegradation rate constants (visible light radiation) were achieved in the reaction of thiamethoxam pesticide and difenoconazole fungicide oxidation in the presence of NE:Ni/H-Beta (NE – η-phase with composition TiO2−x·nH2O), i.e. k = 0.0270 min−1 and k = 0.0147 min−1 respectively, that is 2.5 times higher than the k value obtained for the commercial anatase Hombifine N (UV-irradiation). A relationship between the photocatalytic activity (PCA) and the NT:zeolite ratio, the type and concentration of M, the type of NT and zeolite, the content of OH groups and the reactive oxygen species (radical anions ˙OH, ˙O2− and H2O2) on the surface, and the composition and structure of the decomposed pollutant has been found. The decisive role of the composition of the volume and surface of nanocomposites in the realization of PCA has been noted. The adsorption (removal of P(V), As(V), Se(VI) ions from aqueous solutions) and antimicrobial activities (against bacteria Staphylococcus epidermidis, Bacillus antracoides, Escherichia coli) of the NT:M/zeolite composites, in the absence of light emission, have been studied for the first time and their high performance has been demonstrated: the removal degrees of P(V), As(V), and Se(VI) ions from aqueous solutions in the presence of all composites were more than 99% and the inhibition growth zone of composites NA:Ag/zeolite was >13 mm. New composites could be recommended for preparing wound dressings, antiseptic ointments for external use and water filters.

The bactericidal and bacteriostatic properties (in darkness) of salts RE(NO3)3 · xH2O (RE = La, Ce, Gd, Yb, Y) and composite hydrogels with poly(N-vinylpyrrolidone) against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Proteus mirabilis, and Klebsiella pneumonia bacteria and Candida albicans fungi have been analyzed. A correlation between the regions of delayed growth of microorganisms and the object characteristics is proposed. The mechanisms of interaction of Yb3+ ions of Yb(NO3)3 · xH2O salt, which exhibit high antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans with bacterial cell walls are demonstrated on ordered phospholipid monolayers (a model of biological membranes).

The local environment of Mo6+ ions in the structures of scheelite-type crystals (space group I41/a) with the initial compositions (Na1/2Gd1/2)MoO4 (NGM 1:1) and (Na2/7Gd4/7□1/7)MoO4 (NGM 1:2; □ - vacancies) was determined by X-ray absorption spectroscopy (XAS) for the first time. Different coordination environments of Na1+ and Gd3+ ions caused primarily by the difference in their formal charges have been established based on the comparison of Mo–Gd and Mo–Na interatomic distances. According to resent results and structural data known for the (Na1-хREx)MO4 crystals (RE3+ = rare-earth cations), the character of distribution of different Na1+ and RE3+ polyhedra over NGM crystal structures is influenced by the sizes and electronegativities of Na1+, RE3+, and М6+ (M6+ = Mo, W) ions, the Na1+:RE3+ ratio, and vacancies in the M site. Disordered distribution of Na1+ and RE3+ polyhedra in NGM occurs without changing the symmetry of crystals (space group I41/a) and ordered one is accompanied by reduction of crystal symmetry.

Nanocomposites prepared by mechanical mixing with grinding and mechanical activation of a mixture of Hombifine N with nanosized anatase (NA) and poly(N-vinylcaprolactam) (PVCL) polymer (PVCL25 and PVCL40 polymers were obtained by drying a PVC aqueous solution at 25 and 40°C, respectively) in different weight ratios have been studied by wide-angle X-ray scattering (WAXS) and (for the first time) small-angle X-ray scattering (SAXS). Amorphization of anatase (decrease in the average size of the coherent-scattering region), selection of X-ray amorphous hydrated titanium dioxide from the amorphous shell of anatase nanoparticles, destruction of PVCL, and disordering of its heterocycles in NA/PVCL (NA : PVCL = 1 : 1) nanocomposites upon mechanical activation have been revealed. The interaction (with water molecule exchange) between anatase, anatase, and PVCL nanoparticles during formation of NA/PVCL25 (NA : PVCL = 1 : 2) upon mechanical mixing with grinding is found to lead to segregation of anatase nanoparticles into two groups: particles with reduced and enhanced (formation of texture) degree of crystallinity (average sizes of coherent-scattering regions) in comparison with the initial anatase. SAXS made it possible to reveal structural inhomogeneities of different sizes in PVCL25 and PVCL40, which change differently upon mechanical activation, retaining the tendency to smaller sizes in PVCL25 (a coil) in comparison with PVCL40 (a globule). It is shown that the effects of mechanical activation and mechanical mixing with grinding on the components of NA–PVCL system differ, and that anatase nanoparticles play a decisive role in NA/PVCL nanocomposites, facilitating averaging of the inhomogeneity sizes upon mechanical activation. The results of studying the photocatalytic activity in the reaction of methyl orange decomposition (UV irradiation) in the presence of NA–PVCL samples indicate that it depends on the average sizes of coherent-scattering regions and is independent of the inhomogeneity sizes.

The detail investigation of the samples with nanodimensional anatase, formed by hydrolysis of TiOSO4 × xH2O without or in the presence of polymer poly(N-vinyl caprolactam), physical precipitation of the polymer followed by the capture of commercial Hombifine N are performed by X-ray powder diffraction using laboratory and synchrotron radiation sources, transmission electron microscopy with the diffraction, and elemental analysis. The two «core»-«shell» models with nanoparticles and their associates as a core can be applied to samples produced. The synchrotron and electron radiation change the degree of crystallinity and the imperfection of anatase, isolate of TiO2−x(OH)2x × yH2O from the nanoparticle shell with a decrease in its thickness, lead to the anatase – rutile phase transition. The double diffraction effect on the appearance of kinematically forbidden reflections caused by the dynamic character of the electron diffraction. The photoactivity depends on microstructural characteristics (specific surface, nanoobjects sizes). The structure and elemental composition of nanoparticles (associates) affect antimicrobial activity against Staphylococcus aureus and Escherichia coli.

Composite nanoparticles with a core consisting of associated anatase crystallites and a polymeric shell consisting of poly(N-vinylpyrrolidone) or poly(N-vinylcaprolactam) were synthesized and found to have antimicrobial activity against Escherichia coli and Staphylococcus aureus as well as photocatalytic activity in decomposition of methyl orange and methylene blue dyes. The highest antibacterial activity of the particles with poly(N-vinylpyrrolidone) shell is due to the larger amount of S O 4 2 − groups and water adsorbed on the surface, while their photocatalytic activity is comparable with that of commercial nanoanatase samples.

Bismuth germanate Bi4Ge3O12 single crystals doped with 0.1 and 1.0 wt% Dy2O3 have been successfully grown by the Czochralski method. The actual compositions of the Dy3+-doped Bi4Ge3O12 crystals have been refined for the first time using single-crystal and synchrotron powder X-ray diffraction. Different local structural behavior of the Dy3+ and Bi3+ ions in the Bi4Ge3O12 crystal matrix depending on the initial Dy3+ content has been revealed by X-ray absorption spectroscopy. In the crystal with the refined composition (Bi3.996(11)Dy0.004)Ge3O12 (0.1 wt% Dy2O3), the octahedron Dy3+O7 with a split vertex and vacancy octahedron Bi3+O5 are formed in adjacent octahedra. In the crystal with the refined composition (Bi3.952(47)Dy0.048)Ge3O12 (1.0 wt% Dy2O3), the semi-octahedron Dy3+O5 and distorted octahedron Bi3+O6 are realized. A character of distribution of the residual electron density showed a probable decrease in the symmetry of Dy3+-doped Bi4Ge3O12 crystals that limits the possible maximum Dy3+ content in the Bi4Ge3O12 crystal matrix. Noticeable fluctuations were not revealed in the absorption and luminescence spectra of Dy3+-doped Bi4Ge3O12 crystals.

Nanocomposites based on poly(N-vinylcaprolactam) containing functional nano-anatase particles were produced by mixing and mechanical grinding of mixtures of poly(N-vinylcaprolactam) and Hombifine N (nano-anatase) powders in a porcelain mortar (method 1) and by mechanical milling of the same powders using a high-energy planetary ball mill (method 2). Differences in the diffraction patterns of nanocomposites prepared by method 1 (partial crystallization and an amorphization of nano-anatase particles in the nano-anatase/poly(N-vinylcaprolactam) composite) and method 2 (amorphization of nano-anatase particles) were found. An increase in the X-ray intensity was found to cause physical degradation of the polymer in nano-anatase/poly(N-vinylcaprolactam) composites depending on its prehistory. The preparation of nanocomposites by method 2 was shown to increase photocatalytic activity in the degradation of the dye methyl orange under ultraviolet light irradiation.

Hydrolysis of TiOSO4 · xH2SO4 · yH2O and TiOSO4 · xH2O, performed in the presence of poly-N-vinylcaprolactam (PVCL) or poly-N-vinylpyrrolidone (PVP) and in an aqueous medium, has provided for the first time samples containing nanophases of, respectively, η-modification of TiO2 – x · nH2O ( intercalates TiO2 – x · (nH2O, PVCL) or TiO2 – x · (nH2O, PVP)) and with anatase structure (TiO2). The samples have been characterized by X-ray diffraction and X-ray photoelectron spectroscopy. They are found to have different antimicrobial activities. A relationship is established between the antimicrobial activity and the structural features of titanium(IV) oxide; concentration of hydrated titanium dioxide in the samples; and the content of free water and hydroxyl and $${\text{SO}}_{4}^{{2 - }}$$ groups on the surface of anatase and η-phase nanoparticles, respectively. The choice of polymer does not affect the antimicrobial activity.

Introduction The aim of postoperative examination, treatment and follow-up of patients with urinary stone disease is a prevention of recurrence. A choice of method of prevention is based on the results of postoperative examination with consideration of etiological factors of urinary stone disease. An analysis of influence of osteoporosis and its causative factors on the recurrence of urinary stone disease is presented in the article. Aim to clarify the influence of osteoporosis and its causative factors on excretion of calcium, uric acid and recurrence of urinary stone disease. Materials and methods A total of 86 patients after surgical treatment of urinary stone disease were included in the study. A physicochemical analysis of stones and their fragments, excretion of calcium and uric acid were done postoperatively. The risk factors for osteoporosis were identified using specific questionnaire. Bone mineral density (BMD) was assessed by X-ray densitometry. After X-ray phasic analysis of the stones and studying of the daily excretion of calcium and uric acid, 10 and 7 patients were prescribed to thiazide diuretics and allopurinol, respectively. In 69 patients (80.2%) there were no indications to the treatment and all of them were included in control surveillance group. Results Calcium oxalate stones were predominated in patients who were under surveillance (=0,0254). A prevalence of risk factors for osteoporosis was similar in all groups (=0,2156), as well as rate of decrease in BMD (=0,64). In patients taking thiazide diuretics, a significant decrease in daily calcium excretion was found (=0,0054) without significant changes in excretion of uric acid and diuresis volume. Among patients receiving allopurinol there was a significant decrease in daily uric acid excretion (=0,021), without significant changes in excretion of calcium and diuresis volume. There were no significant changes of these values in the control group. A recurrence of urinary stone disease in treatment group was detected in 4 patients with a decrease of BMD after 381+/-61 days, while in control group there were 5 recurrences in patients with decreased BMD and I recurrence in patient with normal BMD after 836+/-64 days. Conclusion Treatment aimed at prevention of recurrence of urinary stone disease allows to correct detected metabolic disturbances. However, such factor as the decrease in BMD can influence on the rate and frequency of recurrence of urinary stone disease. A clarifying of risk factors for osteoporosis and diagnosis of osteoporosis allow to give reliable recommendations for its treatment and to decrease risk of recurrence of urinary stone disease.

Promising luminescent CsCdX3 (X = Cl, Br) single crystals, both nominally-pure and doped with bismuth, have been studied comprehensively by X-ray diffraction, X-ray synchrotron radiation, and X-ray absorption spectroscopy. Crystal structure refinement shows vacancies in the Cs crystallographic site and partial substitution of Cd2+ ions by Bi3+ ones in both CsCdCl3 and CsCdBr3 (point defects BiCd•), which is consistent with the results of X-ray absorption spectroscopy. The assumed presence of Bi1+ ions in the Cs1+ sites of doped CsCdX3 (X = Cl, Br) crystals is not confirmed. In the photoluminescence spectra of Bi-doped CsCdCl3 and CsCdBr3 crystals, a single band in the near-IR spectral range with a maximum around 1000 nm is caused by point defects BiCd•. Photoluminescence spectra and decay kinetics of Bi-doped CsCdX3 (X = Cl, Br) indicate their promising use as luminescent materials.

The anatase nanoparticles are stabilized with titanium tetraisopropoxide Ti[OCH(CH3)2]4 and isopropyl alcohol without surfactants suitable for biological studies. We showed that the hydrodynamic radii in suspensions depend on temperature and the duration of hydrolysis, whereas the composition (a mixture of anatase with brookite, anatase, brookite, and rutile) and the sizes of crystallites (X-ray), nanoparticles, and aggregates (SEM) in the dried state are mainly dependent on the pH of the environment. The nonphase of the samples stems from coherent intergrowth of unit cells of anatase and brookite via geometric and structural complementarity. We found that photocatalytic activity (PCA; Rhodamine 6G model dye under UV radiation) depends on OH/H2O ratio (adsorbed), whereas antimicrobial activity (AMA) in the dark depends on an amount of free water on the surface of nanoparticles according to X-ray photoelectron spectroscopy (XPS). We revealed that samples with the smallest sizes of nanoparticles of all levels possess the highest PCA and AMA relative to Staphylococcus aureus and Escherichia coli.

Anatase–mordenite nanocomposite was synthesized in situ and characterized by X-ray diffraction analysis, Brunauer–Emmett–Teller measurements, infrared (IR) spectroscopy, electron diffraction measurements, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy. It was found that X-ray-amorphous anatase located in the zeolite micropores resulted in a decrease in the specific surface of anatase–mordenite compared to the initial mordenite. Anatase-containing nanoparticles in anatase–mordenite showed round shape and formed nano-associates and conglomerates. The water content in the zeolite cavities in anatase–mordenite was lower compared to mordenite. Anatase–mordenite nanocomposite exhibited higher photocatalytic activity in the model decomposition reaction of methyl orange under ultraviolet (UV) radiation and higher adsorption capacity for extraction of P(V) and As(V) ions from aqueous environment in the dark compared to the initial mordenite or anatase due to an increase in the content of active OH-groups on the nanocomposite surface compared to mordenite and an increase in the specific surface compared to anatase.

Single-crystal sillenite-type Bi24(M2-xMn4+x)O40 (M = Al3+, Fe3+, Ge4+, Ti4+, Cr4+, V5+) solid solutions have been studied by a complex of methods: single crystal and powder X-ray diffraction; EXAFS/XANES, IR and Raman spectroscopies; scanning and transmission electron microscopies; electron probe X-ray microanalysis. Structures of Bi24(M2-xMnx)O40 (M = Al, Fe, V, Ge) solid solutions contain Mn ions with two formal charges, Mn4+ and Mn5+, as well as vacancies in the Bi (M = V) and O (M = Cr, Fe, Al, V) sites. For the Bi24(M2-xMnx)O40 (M = Fe, Cr, V), a partial occurrence of Bi atoms in the tetrahedral sites has been detected by X-ray diffraction, which was confirmed by IR and Raman spectroscopies. Two isostructural sillenite-type solid solutions based on the Bi24Mn2O40 and γ-Bi2O3 with the impurity phases Mn2O3 and Bi2Mn4O10 were found in the system with M = Cr. Limits for isomorphic substitutions in the Bi24(M2-xMnx)O40 (M = Al, Fe, Ge, Ti, Cr, V) systems were theoretically estimated and compared with the experimental results obtained. A potential of elaborated combination of methods aimed at determining the precise real composition of solid solutions not identical to that of the initial charge was demonstrated. Homogeneity regions for sillenite family phases were predicted.

Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions.

Titanium oxide(IV)/zeolite nanocomposites obtained through the introduction of Beta(25), ZSM-5(12), MOR(5), and Y(2) zeolites into the reaction mixture, during the hydrolysis of titanyl sulphate, exhibit greater photocatalytic activity in the photodegradation reactions of methyl orange under ultraviolet radiation and a higher adsorption capacity to extract P(V) and As(V) from model aqueous environments compared to zeolites and nanoscale anatase prepared in the same way. The increase in the functional properties of nanocomposites is due to a higher amount of OH groups (photocatalytic activity and adsorption capacity) and lower amount of H2O (photocatalytic activity) on their surface, which is revealed with X-ray photoelectron spectroscopy. Moreover, spherical shape of particles with smaller average sizes than those of zeolites, which are characterized by a more diverse morphology, increases the photocatalytic activity and adsorption capacity of the nanocomposites.

PVCL25 and PVCL40 films have been synthesized by poly(N-vinylcaprolactam) (PVCL) aqueous solution flow coating and complete desiccation below (∼32–34°С) and above (40°С) the coil–globule phase transition temperature (ТPT) and (Hombifine N/PVCL)25 and (Hombifine N/PVCL)40 nanocomposite films added with Hombifine N (nanoanatase) have been obtained. The films are studied by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray microanalysis. The differences between the compositions and structural characteristics of the PVCL25 and PVCL40 films and (Hombifine N/PVCL)25 and (Hombifine N/PVCL)40 nanocomposites are found. It is established that the (Hombifine N/PVCL)40 nanocomposite film desiccated at Т > ТPT contains PVCL globules, inside which nanoanatase associates with ОН groups are located on the nanoparticle surface. These assocoiates are bound with water molecules in PVCL by hydrogen bonds, which makes the (Hombifine N/PVCL)40 nanocomposite a unique material with physicochemical properties differing from those of (Hombifine N/PVCL)25 nanocomposite.

The literature data on the composition and structure of rare-earth borate compounds of the huntite family with the general composition LnM3(BO3)4, where Ln3+ = Y, La = Lu and M3+ = Al, Fe, Cr, Ga, Sc as well as a number of solid solutions with М3+ = Sc are systematized. The difference between the real compositions of crystals and the compositions of the initial mixture, the most characteristic of rare-earth scandium borates, is shown. The significant role of the composition in the manifestation of the compounds symmetry is established. The necessity of determining the crystals symmetry only on single-crystals with detailed analysis of diffraction reflections is proved. Morphotropic series were selected depending on changes in the ionic radii of Ln and M. Attention is paid to the peculiarity of the structural behavior of Cr3+ ions. It was revealed that the formation of solid solutions and internal solid solutions is most likely for rare-earth scandium borates. The implementation of polytypic modifications for LnM3(BO3)4, where M3+ = Al, Cr, and polymorphs for a number of Ln ions with M3+ = Fe, the existence of which is not excluded for M3+ = Sc, is demonstrated. Crystal-chemical effects observed for huntite-like crystals (morphotropy, isomorphism, polymorphism, polytypy; internal solid solutions; phase order-disorder phase transitions of different nature) with specific features of scandium borates are presented. The realization of polymorphism and polytypism for compounds of the huntite family confirms the crystal-chemical situation, according to which hightemperature polymorphic modifications should form more symmetrical compounds, but it is not typical of polytypic modifications.

Czochralski-grown colorless and pink Bi4Ge3O12 (BGO) single crystals have been characterized by the X-ray diffraction, X-ray absorption, and luminescence and optical spectroscopy. Additional high-temperature vacuum annealing of the as-grown colorless crystal at 900–950 °C using a special reducing agent leds to the appearance of pink coloration and modification of its properties. The refinement of actual compositions of both BGO crystals showed the distribution of the Bi3+ions over two, tetrahedral and octahedral, sites, the Bi content in the colorless crystal being greater and lower in the octahedral and tetrahedral sites, respectively, compared with the colored crystal. A small amount of Bi5+ions was revealed in the tetrahedral sites of the colorless crystal. Oxygen vacancies, as a part of the color center responsible for the crystal coloration, were found in the structure of pink sample. The pink BGO crystal is characterized by photoluminescence in the near infra-red spectral range.

The nonlinear optical (NLO) properties of native defect-rich ZnO single crystals were studied in details within the excitation of the continuous wave (CW) and pulsed laser radiation at 532 nm (2.33 eV). Analysis of the experimental data of optical elastic scattering, Fourier transform infrared (FTIR), near infrared–visible–ultraviolet (NIR–Vis–UV) spectra recorded in reflection and absorption modes, and data of photoluminescence (PL) spectroscopy confirmed the contribution of both intrinsic defects and their clusters, being determined before by neutron diffraction and XRD analysis. It was shown that the high sensitivity of the NLO diagnostics via self-action of a laser beam is due to the resonant excitation of the deep defects states at wavelength 532 nm. It was also demonstrated the correlation of the real and imaginary parts of the cubic NLO susceptibility with PL and FTIR spectroscopies data dealing with the defect bands manifestation, while the elastic optical scattering and Vis-NIR spectroscopy data – with the intrinsic defect content. High photoinduced polarizabilities of the excited states provide application of the refractive NLO response and the optical elastic scattering indicatrices analysis as an express nondestructive technique to reveal the deep defects content in the bulk ZnO.

Nanosized low-temperature modifications of titanium(iv) oxide with the anatase and η-phase (TiO2–x•mH2O) structures were prepared by the sulfate method (pH

PVCL-intercalated samples containing nano-dimensional phases with η-modification of the TiO2−x·nH2O composition are obtained by hydrolysis of TiOSO4·xH2SO4·yH2O or TiOSO4·xH2O in the presence of poly(N-vinylcaprolactam) (PVCL). The incorporation of PVCL with water molecules into the interlayer space of the structure of the η-phase—TiO2−x·(PVCL nH2O)—is established by the X-ray diffraction study while the presence of PVCL in the sample composition is confirmed by the X-ray photoelectron and IR spectroscopy CHNS analysis and X-ray spectral microanalysis. Intercalated samples manifest the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. It is shown that the sample composition (the content of hydrated titanium dioxide) the composition of the η-phase (the presence of PVCL and H2O or the water content in the interlayer space of the structure), and the surface composition (S in the form of SO42− groups O in the form of adsorbed water and OH groups) affect the antimicrobial activity in the dark.

Nanocomposites based on the poly(N-vinylcaprolactam) (PVCL) fabricated from PVCL solutions at different drying temperatures (PVCL25 at 25 °C, PVCL40 at 40 °C) and titanium oxides(IV) nanoparticles (TNPs) were produced for the first time by dry mixing and grinding and mechanical milling in a planetary ball mill using different PVCL:TNP ratios. New effects in initial PVCL (hydration) and TNP [decomposition of η-phase; appearance of hydrated titanium dioxide (HTD)] samples, as well as in PVCL [(de)hydration, disordering of the heterocycles] and TNP (amorphization, dehydration of η-phase, partial crystallization of Hombifine N with anatase), involved as components in PVCL/TNP nanocomposites, were found. The different role of each type of treatments and its conditions in the specific of the effects observed was shown. Only high-frequency mechanical milling leads to the appearance of HTD and the complete disappearance of the second peak of PVCL (disordering of the heterocycles) in PVCL/TNP nanocomposites.

Titania nanoparticles (anatase or anatase + rutile) with enhanced photocatalytic activity were successfully produced by treating titanyl sulfate with various peroxo compounds (hydrogen peroxide, ammonium persulfate, and urea hydrogen peroxide) with further annealing. Transformation of titanyl sulfate to titanium dioxide was investigated by X-ray diffraction, electron microscopy, X-ray microanalysis, IR, Raman, X-ray photoelectron, and UV/vis spectroscopy. The peroxo compound and annealing temperature play an important role in phase composition and properties of the samples. Correlations between phase composition, oxygen content, band gaps, and constant rates for methyl orange (MO) discoloration were found. The [TiOx(O2)2−x(H2O)m] phase, which forms on the first stage of the reaction, contains nanoparticles with small crystallites (1–2 nm) and promotes formation of titanium dioxide with the anatase structure. Thermal decomposition of the peroxo-containing phase results in formation of titanium dioxide. Oxygen excess prevents transformation of anatase to rutile, decreases band gap, and increases activity of titanium dioxide (anatase or anatase + rutile) in the model reaction of MO destruction.

Nanocomposites based on poly-N-vinylcaprolactam (PVC), characterized by different drying temperatures of aqueous PVC solution at 25°С (PVC25) and 40°С (PVC40), with titanium(IV) oxide nanoparticles (TONs) (η-phase (TP: TiO2 – x · mH2O) with a superstructure to the anatase structure and ordered solid solution with partial replacement of oxygen atoms in the η-phase with peroxo group O 2 2– (PP: TiO x (O2)2 – x · nH2O)) have been obtained for the first time and characterized by X-ray diffraction and IR spectroscopy. It is found that a common feature of TP/PVC and PP/PVC obtained by dry mixing and grinding is the decrease in the number of water molecules for TP and PP in the interlayer space of the structure and their attachment to the PVC amide groups; the differences are related to the specificity of PVC behavior in these systems: mechanodestruction of PVC in PP/PVC40 and different numbers of water molecules in PVC25 and PVC40.

The effect of some sensitizers (methylene blue, methyl red, chlorophylls, coproporphyrin I, and hydrogen peroxide) on the transformation of η-TiO2, which is an anatase precursor in titanyl sulfate hydrolysis, into anatase has been studied. A decrease in the average crystallite size and suppression of the transformation of η-TiO2 into anatase is observed in the presence of methylene blue and methyl red organic dyes, as well as Ti(IV) peroxocomplexes,. The sample synthesized in the presence of 1 M H2O2 is characterized by the smallest crystallite sizes (2−4 nm) and the highest photocatalytic activity.

An influence of the type of rare-earth (RE) cation and composition of initial charge on the symmetry, structural features, and real composition of the single-crystal huntite family rare-earth scandium borates RESc3(BO3)4 (RE = Ce, Pr, Nd), grown by the Czochralski method, has been studied by single crystal and powder X-ray diffraction. A crystallization of scandium borates in the space groups C2/c (RE = Ce) and P321 (RE = Pr, Nd) has been found. Disordering in the structures with the space group P321, which has been first determined for the huntite family compounds, is due to the RE and Sc redistribution over two trigonal-prismatic sites to maintain the stability of crystal structure. The crystals grown from the initial charges NdSc3(BO3)4 and Nd1.25Sc2.75(BO3)4 are characterized by the greatest disordering, and they are isotypic, rather than isostructural, to the crystals obtained from the charges Pr1.1Sc2.9(BO3)4 and Pr1.25Sc2.75(BO3)4. A change in the unit cell parameters and interatomic distances depe...

Zeolite Y and the NTD/Y nanocomposite, which were synthesized in situ (the addition of zeolite Y to the reaction mixture in the course of the synthesis of NTD by the sulfate method), were studied by a variety of methods. The decrease in the particle size (scanning electron microscopy) and the water content in pores (X-ray powder diffraction study, the full-profile Rietveld method, IR spectroscopy, differential scanning calorimetry), the increase in OH groups content and the decrease in the water content on the surface of zeolite (X-ray photoelectron spectroscopy) in the composition of NTD/Y compared to the initial zeolite Y were all established. A larger specific surface area of NTD/Y (Brunauer–Emmet–Teller method) compared to the initial zeolite Y is due to the fact that zeolite Y in the nanocomposite contains a smaller amount of water because of the synthesis conditions and the presence of nanocrystalline NTD on the surface of zeolite particles. It was found that NTD/Y nanocomposite exhibits a higher photocatalytic activity in the model decomposition reaction of methyl orange under UV and adsorption capacity for the extraction of P(V) and As(V) ions from aqueous media compared to the initial zeolite and pure NTD obtained under the same conditions, which differs from NTD/Y by the larger particle size, the smaller specific surface and the smaller content of OH groups and water on the surface. The role of Bronsted and Lewis centers in the realization of properties is discussed.

Samples containing vanadium-doped nanosized titanium(IV) oxides with anatase and η-phase structures were prepared by a modified sulfate process, and samples with vanadium-doped η-phase were prepared for the first time. The bulk and the surface of the samples were characterized by a lot of methods, including X-ray diffraction, diffuse reflectance spectroscopy, X-ray absorption spectroscopy (EXAFS/XANES), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The photocatalytic activity (PCA) of the samples was studied in the reaction of photodegradation of the cationic dye rhodamine 6G (in the visible region) and the systemic triazole fungicide difenoconazole (in the UV and visible regions). The PCA was found to be influenced by the phase composition of the samples, the composition of their surface, and nanosized titanium(IV) oxide modifications. Vanadium-doped samples with η-phase containing different ions (Ti3+, Ti4+, V4+, and V5+) and reactive OH groups on the nanoparticle surface exhibited the highest PCA. The samples were shown to have a higher adsorption capacity (AC) for the extraction of As(V) (the highest AC in the presence of vanadium-doped anatase and η-phase) and P(V) (the highest AC in the presence of undoped anatase and η-phase) anions from aqueous systems. The adsorption capacity correlates with the amount of reactive OH groups on the nanoparticle surface and does not depend on the modification of the adsorbent. Only vanadium-doped anatase containing the largest fraction of an amorphous component and the largest amount of SO42− groups on its nanoparticle surface exhibits antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Bacillus anthracoides. Vanadium doped anatase and η-phase can be used to purify aquatic environments of harmful organic pollutants and a wide range of anions.

This article presents the results of a study of three commercial titanosilicalites (TS-1, TS-1N, TS-1G) with general formula [(TixSi12-x)O24] × wH2O (MFI-type) using the X-ray study (XRPD), IR spectroscopy (FT-IR), X-ray absorption spectroscopy (EXAFS/XANES), differential scanning calorimetry (DSC), Brunauer–Emmett–Teller method (BET), UV-VIS spectroscopy. It was established that the samples contain amorphous oxygenous titanium-containing formations, which does not allow the use of quantitative elemental methods of analysis to determine the content of titanium ions in the framework. The full-profile Rietveld method was used to determine the silicate modules (Si/Ti = 53 for TS-1, Si/Ti~47 for TS-1N and TS-1G) and the coordination numbers of titanium: CNTi~5.0, CNTi = 4.5, CNTi>5.0, respectively in the structures of TS-1, TS-1N, TS-1G. The distribution of Ti4+ ions over the sites of the MFI-type structure with the orthorhombic symmetry (space group Pnma, z = 8) were found: T2, T6, T10 for TS-1, T8, T10, T5 (unlikely) for TS-1N (Т10 double positions in sinusoidal channels) and Т2, Т10, Т12, Т9 (unlikely) for TS-1G (Т10 and Т12 double positions in sinusoidal channels). The best indicators of the allyl chloride epoxidation in the epichlorohydrin process at 30 °C were achieved for TS-1N and TS-1G. A higher yield of acetaldehyde was found on the TS-1(75) sample (TS-1 sample annealed at 75 °C for 2 h) at 290 °C (non-oxidative ethanol conversion), and ethylene - on the TS-1G(500) sample (TS-1G annealed at 500 °C for 2 h) at 700 °C (propane conversion). The revealed correlations between the catalytic parameters and the characteristics of the samples studied were discussed.

A structural features, real compositions, and point defects of nominally pure and Cr- and Ni-doped Sr 0.61 Ba 0.39 Nb 2 O 6 (SBN) crystals, which structure contains four chemically-different and ten crystallochemically-different atoms, have been determined using neutron, X-ray single crystal, X-ray powder, and X-ray synchrotron diffraction techniques, and EXAFS/XANES spectroscopy. The location of transition metal ions has been identified based on the analysis of electron (nuclear) density and confirmed by the EXAFS/XANES together with the definition of formal charges of Ni atoms in Ni-doped SBN crystals. The scope and application possibilities of diffraction methods and EXAFS/XANES spectroscopy for the determination of structural features and defect formation in functional bulk nominally-pure and Cr- and Ni-doped Sr 0.61 Ba 0.39 Nb 2 O 6 single crystals is established.

Single-crystal (Bi,Sm) 24 V 2 O 40 solid solutions with sillenite structure, grown by the hydrothermal method for the first time, have been studied using single-crystal X-ray diffraction, synchrotron radiation, and infrared spectroscopy. The real composition has been refined. The presence of Sm 3+ and Bi 3+ ions in one crystallographic site was determined by single-crystal X-ray diffraction and confirmed by the analysis of infrared spectra and calculation of the degree of distortion of the real [BiO 5 ] polyhedron.

Single crystals of scandium-containing rare-earth garnets in system R-Sc-C-O (R3+=Y, Gd; C3+=Al, Ga) have been grown by the Czochralski technique. X-ray diffraction analysis has been used to refine crystal compositions. The fundamental difference between the melt compositions and compositions of grown crystals has been found (except for compositions of congruent-melting compounds, CMC). The specific features of garnet solid solution formation have been established and the ternary diagrams with real or hypothetical phases have been built. The dinamics of coordination polyhedra changes with the formation of substitutional solid solutions have been proposed based on the mathematical modeling and experimental data. Possible existence of CMC with garnet structure in different systems as well as limit content of Sc ions in dodecahedral and octahedral sites prior to their partial substitution of ions, located in other sites, have been evaluated. It was established that the redistribution of cations over crystallographic sites (antistructural point defects) due to system self-organization to maintain its stability may be accompanied by cation ordering and the symmetry change of individual polyhedrons and/or the whole crystal.

NT/zeolite nanocomposites (NT - nanosized titanium(IV) oxides: η-phase and Hombifine N with anatase; zeolite: Beta(25), ZSM-5 with different modules Si/Al, MOR, or Y) have been obtained by two methods: modified cold-impregnation method (method 1) and in situ method of introduction of zeolites into the reaction mixture during the synthesis of NT by hydrolysis of TiOSO 4 ×xH 2 SO 4 ×yH 2 O or TiOSO 4 ×2H 2 O aqueous solutions (method 2), performed for the first time. According to the X-ray data, the following differences in the NT:zeolite systems under investigation have been revealed: the mixture of zeolites and NT in nanocrystalline (Hombifine N/zeolite) or amorphous states (η-phase/zeolite, except for η-phase/MOR, where NT peaks are absent) (method 1), and the mixture of Y-zeolite and amorphous NT or only Y-zeolite without NT (method 2), which indicates the different levels of interaction between NT and zeolites in the systems studied. The best characteristics of properties (photocatalytic, adsorption, and antibacterial) have been revealed in the nanocomposites synthesized by the method 2. The correlation between the photoreaction rate constant (the k value) under UV irradiation in the presence of nanocomposites ( k max for NT/ZSM-5(12)) and the type of precursor, its pH, synthesis duration, NT:zeolite ratio, organic dye composition (methyl orange or Rhodamine G) has been established. The highest degree of extraction of P(V) ions from model aqueous systems has been observed in the presence of nanocomposites with the largest total surface area of all particles ( R max = 99.48% for NT/MOR). The correlation between the sorption degree of P(V) ions and the modulus of zeolite is possible. Antibacterial activity in the dark towards Escherichia coli has been found for Y and Beta(25) zeolites and nanocomposites on their basis (methods 1 and 2) with the maximum diameter of bacterial growth inhibition (18 mm) obtained for NT/Beta(25) (method 2) synthesized only from TiOSO 4 ×xH 2 SO 4 ×yH 2 O precursor.

A procedure has been proposed for the preparation of capsules with shells composed of titanium dioxide nanoparticles and polymers via the formation of Pickering emulsions (colloidosomes) followed by layer-by-layer deposition of polyelectrolytes. The feasibility of stabilizing oil droplets of emulsions by spontaneous adsorption of partly hydrophobized nanoparticles of anatase-form titanium dioxide at the oil/water interface has been studied. Conditions have been determined for the formation of stable colloidosomes and the subsequent layer-by-layer deposition of oppositely charged polyelectrolytes onto their surfaces. It has been shown that hydrophobic dyes may be encapsulated using the procedure developed for the preparation of the capsules. The photocatalytic activity of TiO2 particles occurring in the shell has been demonstrated by the example of degradation of Nile red which is incorporated in the oil core of a capsule.

The morphologies and dynamics of poly(N-vinyl caprolactam) (PVCL) based hydrogels with titania nanoparticles in different states (native, air-dried to a constant weight and swollen in H2O or D2O) are studied by a combination of complementary techniques: wide angle X-ray scattering, small angle neutron scattering, neutron spin echo spectroscopy, differential scanning calorimetry. The results suggest the presence of different structural types of water leading to different properties of the hydrogels. We propose a hierarchical structure of hydrogels spanning from the molecular to the microscopic scale consistent with both the static structure (polymer mesh size, association of the nodes of crosslinks and microchains of PVCL) and the dynamics (rate of relaxation of polymer chains, hydrodynamic polymer-polymer correlation length). The presence of nanoscale titania does not change the molecular structure and nanostructure due to its aggregation into meso-domains, but does affect the microstructure, changing the response rate to a temperature jump from 20 to 50 °C. Titania nanoparticles do not change the equilibrium swelling degree of hydrogels.

Calcium orthovanadate Ca3(VO4)2 (CVO) is an efficient media for laser applications. Czochralski-grown green CVO single crystals doped with over-stoichiometric 0.1 (CVO:0.1Mn) and 1.0 wt.%Mn (CVO:1.0Mn) were studied by X-ray diffraction and X-ray absorption spectroscopy for the first time. In the CVO:1.0Mn, an occurrence of Mn3+ in Ca3 (two-capped trigonal prism), Ca4 (distorted octahedron), and defective Ca5 and Ca5A (highly-distorted octahedron) sites and vacancies in V2 and V3 sites (distorted tetrahedra) were revealed. In the CVO:0.1Mn, a presence of Mn3+ in Ca3 and Ca5A sites and vacancies in V2 site were found. In the CVO, the Mn3+ form elongated octahedra (tetragonal bipyramid; coordination number, 4 + 2) typical for the Jahn-Teller ions. Models for the rearrangement of Ca3 and Ca4 polyhedra into a tetragonal bipyramid are proposed. Along with the Mn3+, the Mn2+ and Mn5+ ions were observed by optical spectroscopy in CVO:0.1Mn (predominantly Mn2+ ions) and CVO:1.0Mn (only Mn5+ ions).

Rare-earth doping of strontium molybdate, SrMoO4, allows the combination of laser generation of light and its SRS conversion. The RE3+ introduction into the Sr2+Mo6+O4 matrix must inevitably lead to the appearance of point defects that will affect the possibility of the effective use of the material. In this work, we report comprehensive structural research of SrMoO4 single crystals both nominally pure and doped with different Tm3+ and Ho3+ concentrations, undertaken for the first time, using X-ray single crystal and powder diffraction (crystal structure), EXAFS/XANES (local structure), and optical spectroscopy. The compositions of the grown crystals are established for the first time. Introduction of RE3+ ions in the form of RE3+Nb5+O4 leads to partial substitution of Mo6+ ions by Nb5+ along with the main location of Nb5+ ions in the interstitial sites near the defect Mo6+ sites with the formation of their own distorted tetrahedra. Dopant ions either replace partially the Sr2+ ions (Ho3+ ions) or are located in the interstitial sites near the defect Sr2+ sites (Tm3+ ions). The effective distribution coefficients of the dopants are determined.