Search academic texts

Information × Registration Number 0218U002320, 0115U003277 , R & D reports Title New oxide systems with composite structures popup.stage_title Head Gladyshevskii Roman Evgenovych, Registration Date 14-02-2018 Organization Ivan Franko National University of Lviv popup.description2 The objects of the investigation are: inorganic compounds of the classes of oxides and chalcogenides; intermetallic compounds and their hydrides, subtle changes in the chemical composition, the conditions of synthesis and the crystal structures of which lead to the changes in a wide range of useful physical properties (e.g., systems based on PbO2 for electrochemical industry, superconducting cuprates with high critical parameters, manganates with high magnetoresistance, which are extremely sensitive to partial substitution of atoms); complex chalcogenides and chalcogen-halogenides with semiconducting, photoelectric, biomedical, catalytic properties, as well as hydrides of intermetallics with hydrogen sorption properties. The purpose of the work is the synthesis of new oxides, chalcogenides, chalcogen-halides, intermetallics and their hydrides; optimization of the synthesis conditions of simple and complex compounds and solid solutions; construction of phase diagrams; determination of crystal structure at different levels of organization of the structure of matter; electronic structure calculation; measurement of physical properties , as well as the recommendation for perspective compounds for creating materials with the desired properties. Methods of investigation were X-ray phase analysis, X-ray structural analysis, scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy, differential thermal analysis, electromotive force method, spectroscopy of light scattering combined with infrared spectroscopy, positron-annihilation lifetime spectroscopy, quantum-chemical calculations and obtaining quantitative characteristics of the chemical bond, crystal-chemical analysis, measurements of the optical, magnetic, electrical, solid-state, catalytic and hydrogen-sorption properties. The following items were investigated for the first time: phase equilibria in 20 oxide, chalcogen-halide and intermetallic systems; 17 cross-sections with respect to the formation of compounds; phase composition and microstructure parameters of PbO2-based materials during electrocrystallization in 6 PbO2-electrolyte systems; the influence of various complex agents on the properties of ZnS, HgS, HgSe, Hg3I2Se2 thin films; processes of complex formation in the Re-Se-Hal (Hal-Cl, Br) systems; impact of processing and substitution for a series of PbTe:Ag,Sb samples. The conditions for obtaining MMnO3 and M2MnM'O6 alkali-earth/rare-earth-containing manganates, a number of chalcogen-halogenides and intermetallic compounds have been optimized. The crystal structures of 76 compounds were determined, among them 7 compounds are representatives of new structure types of inorganic compounds. The structure of matter at the level of short-, medium- and long-range order organization for 9 chemically or technologically modified compounds or composites was determined. The electronic structure was calculated and quantitative characteristics of the chemical bond were obtained for 15 compounds. For lead-free and Pb-containing high-temperature superconductors, the Bi-2223 is characterized by a modulated structure, and a new type of disorder in a composite modulated structure is discovered, which is realized in the structure of the MnSi1.76 compound. Measurements of physical properties for 28 compounds and composites have been carried out. The following compounds and composites are the perspective candidates for practical application: Rh2Se9Cl6, Ir2Se9Cl6, Re3Se3S4Br13 and Re4Se4S4Br16 as components of catalytic systems (in particular in the process of dehydration of glycerin to acrolein, hydrogenation of m-nitrobenzoic acid to m-aminobenzoic acid, 2 patents of Ukraine were obtained), as well as semiconductors, chemical reagents and drugs; LiLaP4O12: Bi, Al2O3: Ce and {Zn, Hg}-{S, Se} films, Li2B4O7:Ag,Gd, La2CuSbS5, La2CuBiS5, TlHgBr3, AgGaSiSe4, Ag2Ga2SiS6 as semiconductor and optical materials (in particular for X-ray and gamma-radiation detection), optoelectronics, semiconductor technology, nano photonics); As4S4/Fe3O4, As4S4/PVP, BaZrO3-polystyrene, glauconite / polyaniline composites as solid-state and multifunctional materials (electro-optics, nanophotonics, sensory technologies, medicine); the Li1.5Cr0.5NiO3 compound as an electrochemical material (in accumulators), R2T2Al (R - rare earth metal, T - d element) compounds with W2CoB2 and Mo2FeB2 structure-types, as hydrogen sorption materials. Results of the scientific research carried out within the project have been published in 1 monograph, 2 textbooks, 46 articles (29 of them in the journals with impact factor), theses of 46 reports at scientific conferences (among them 16 abstracts at international conferences), and 2 security documents were received. The results are used to identify the phases in the development of new materials, to predict the phase diagrams of unexplored systems, the values of standard thermodynamic functions for some phases, calculated from the experimental data, can be used in the simulation of T-x diagrams of other systems by CALPHAD methods, quantitative parameters of physical properties and hydrogenation processes serve as a guide to the selection of potential candidate compounds in the objects for future research. Information on phase diagrams and crystal structures of compounds is included in the database for inorganic compounds and materials (Pearson's Crystal Data, Switzerland, Inorganic Crystal Structure Database, Germany, International Center for Diffraction Data, USA). The updated methodology of systematization of crystallographic characteristics of inorganic compounds allowed to systematize the crystal structures of 100,000 inorganic substances, which is the most complete database of such type at present time. Modernization of computer programs for the analysis of the structure of matter at different levels of its organization, chemical bonding has been carried out, and the composition-structure-property relationship has been established for the studied classes of compounds. Scientific results are also used as examples in courses of inorganic chemistry and crystal-chemistry for bachelors and masters of Lviv University. This work belongs to fundamental research, and its results are relevant to the chemical sciences, as well as related branches - physical, mathematical, geological, biological and engineering sciences. Product Description popup.authors Аксельруд Лев Гершович Гладишевський Роман Євгенович Горинь Андрій Маркіянович Демченко Павло Юрійович Заремба Оксана Іванівна Зелінський Анатолій Вікторович Зоренко Тетяна Євгеніївна Кужель Богдан Степанович Міліянчук Христина Юріївна Мельниченко Наталія Олексіївна Павлюк Володимир Васильович Сенчук Олександр Юрійович Шаповал Павло Йосифович popup.nrat_date 2020-04-02 Close