BaSnO3 is one of the materials prospective for high-temperature proton-conducting membranes. For that purpose, it is subjected to acceptor doping-BaSn1-xMxO3-delta (M = M3+ metal). This provides appearance of oxygen vacancies in the crystal structure allowing for further hydration and, consequently, proton conductivity. Such doping, oxygen vacancies formation, and hydration influence materials electronic properties in the vicinity of the band gap. However, for BaSnO3, as a proton conducting oxide, such effects have not been considered before. This work aims to experimentally and theoretically reveal changes in the band gap parameters of BaSn1-xScxO3-delta depending on the dopant concentration x and hydration. The results obtained indicate on strong concentration dependence of the band gap parameters, showing three distinct ranges: x <= 0.10, 0.15 <= x <= 0.20, and x >= 0.25. This effect arises mainly from redistribution of the Sn 5s-and Sc 3d-states in the conduction band. In general, Sc doping gradually increases the band gap of the BaSnO3 from 3.04 eV at x = 0 to 3.63 eV at x = 0.37. Effect of hydration is even more complex, with no changes of the band gap at x <= 0.10, and with transformation of the absorption edge shape and the band gap increase at x >= 0.15. Besides, absorption spectra of BaSnO3 show no typical for acceptor-doped oxides oxygen vacancy peak near the absorption edge. Thus, such behavior of BaSnO3 differs significantly from that for other similar proton-conducting perovskites, making it intriguing material for further deeper studies.

Barium stannate BaSnO3 is a semiconducting oxide with cubic perovskite structure. It is capable for different types of doping, both in Ba and Sn sites, both by acceptor and donor dopants, allowing efficiently tuning its properties. Thus, BaSnO3 finds numerous applications, and its usage as a proton conducting ceramic electrolytes is one of them. Recently, it was reported that In-doped BaSn1-xInxO3-delta shows outstanding properties, like ability to form wide range of solid solutions up to x = 0.65, good chemical stability and high proton conductivity. However, this material lacks data on its band gap parameters, but given the semiconducting nature of barium stannate these data is crucial for comprehensive understanding of its functional properties. Therefore, this work is aimed at elucidating changes in the band gap parameters of BaSn1-xInxO3-delta promoted by doping and proton incorporation by hydration and hydrogenation. The results obtained indicate on systematic decrease of the band gap E-g with In concentration, from 3.04 eV at x = 0 to 2.76 eV at x = 0.6, which is suggested to be due to replacement of the Sn 5s states by In 5s. Besides, there is transformation of the absorption edge shape at x > 0.4 arising from substantial oxygen non-stoichiometry. Hydration leads to increase of E-g, and the higher the x, the greater the E-g change. However, that nature of this effect is not yet clear. Simultaneously, as oxygen sublattice becomes complete, the absorption edge shape restores to initial state. Effect of hydrogenation is more complex, leading to strong local tetragonal/orthorhombic distortions at x <= 0.2 and even phase decomposition at x >= 0.4. All this behavior of In-doped BaSnO3 diverges from typical trends observed in classical wide-gap proton conductors, such as doped LaScO3, BaZrO3, SrTiO3, and SrZrO3, thus, requiring a special attention.

Machine learning interatomic potential for LiGe2(PO4)3 in a form of a set of neural networks (DeePMD-model) was trained on DFT data. DFT simulations in GGA PBE approximation were performed for ordered and disordered LiGe2(PO4)3 supercell with 432 atoms which allowed the developed potential to describe crystalline, molten and glassy states. The developed DeePMD-potential was verified using literature and our experimental data demonstrating good agreement with it. Neural network molecular dynamic simulations indicate that P atoms have tetrahedral oxygen environment in both crystalline and glassy state. Coordination environment of Ge atoms is more complex. They have octahedral oxygen environment in crystalline state and mixed environment in glassy state: 4-, 5- and 6-coordinated Ge atoms were found. It was shown by calculation of orientational order parameters that in glassy LiGe2(PO4)3 4-coordinated Ge atoms have tetrahedral oxygen environment, while 6-coordinated Ge atoms have octahedral oxygen environment. Analysis of O-Ge-O angle distribution for 5-coordinated Ge atoms in glassy LiGe2(PO4)3 demonstrates that the environment of Ge atoms in this case is represented by various structures: square pyramids, trigonal bipyramids and transitional structures from 5-coordinated Ge atoms to tetrahedrons.

Currently, the properties of molten lithium, sodium and potassium fluoride eutectic mixtures with different additions are immensely important for the development of molten salt nuclear reactors. In the present work, the density of molten FLiNaK mixtures with additions of neodymium fluoride was studied by the Archimedean method. The neodymium fluoride addition increased the density of the 46.5 mol

Li7La3Zr2O12 is one the most promising materials for Li-conducting solid electrolytes. The incorporation of Ta5+ and Nb5+ into the Zr4+ sites stabilizes its cubic structure and significantly enhances Li-conductivity, due to the formation of Li vacancies. In this research, we have studied the band gap features of Ta and Nd-doped Li7La3Zr2O12. Our findings indicate that Nb ions are present not only in the +5 valence state, but also in the +4 state, leading to the formation of oxygen vacancies. In the case of the Ta-doping, such an effect was not observed. This could be the reason for the approximately one order of magnitude higher lithium conductivity observed in the case of the Ta doping, in comparison to the Nb doping.

The solid solution Ba5In2-xYxAl2ZrO13 (0 <& khcy;<0.50)with hexagonal structure (space group P 6 3 / mmc ) was prepared by the solid-state reaction method. The effects of isovalent Y3+-substitution on the structure, hydration, bandgap and transport properties have been investigated. The introduction of yttrium was accompanied by lattice expansion, which led to an increase in the concentration of protons during hydration. The doping did not lead to a significant increase in oxygen-ion conductivity since there was no change in oxygen stoichiometry. At the same time, doping led to an increase in ionic transport numbers due to a decrease in hole conductivity. Proton conductivity contribution and the values of proton conductivity increase with the increase in yttrium concentration. The phases with yttrium content x > 0.2 were predominant proton conductors at the temperature below 600 degrees & Scy; degrees & Scy; under wet air.

This paper presents a review of data on the solubility of rare earth oxides in halide melts of alkali and alkaline earth metals. The highest solubility of rare earth oxides is observed in fluoride melts, the lowest – in chloride melts. There are very few works devoted to the study of the solubility of rare earth oxides in mixed chloride-fluoride melts. The solubility of rare earth oxides decreases in the series La-Ce-Pr-Nd-Gd. The greatest number of works are devoted to the study of the solubility of neodymium, lanthanum and cerium oxides. There are practically no data on the solubility of “heavy” rare earth oxides (from Tb to Lu) in halide melts.

Hydrogen energy is one of the ways to ensure environmentally friendly and sustainable development of human society. Solid oxide fuel cells are designed to produce energy using hydrogen as fuel. One of the most important components of solid oxide fuel cells is the electrolyte. New promising electrolyte materials are compositions with Ruddlesden-Popper structure, in particular BaLa2In2O7. However, the mechanism of ionic transport has not been studied. In this paper, the electronic structure and chemical bonding were examined using a combination of experimental methods and theoretical calculations. This article is the first step towards understanding the nature of the ion transport mechanism in the composition BaLa2In2O7 with Ruddlesden-Popper structure.

The glass with a 12.5Li2O–50GeO2–37.5P2O5 composition was synthesized by melt quenching. Thermal annealing was used to obtain a single-phase LiGe2(PO4)3 composition, which is promising as a solid electrolyte for all-solid-state lithium-ion power sources. By using full x-ray scattering with analysis of the pair distribution function, and diffuse reflectance spectroscopy in the UV-Vis range, the local structure and optical properties of initial (amorphous) glass and crystallized glass were studied. An assessment of the influence of glass crystallization on these properties was carried out. It was shown that structuring in the glass is observed only at the level of the first-second coordination sphere of Ge and P atoms. The presence of F+ centers in the glass was revealed in the optical absorption spectra of the initial glass; their concentration decreases as a result of glass crystallization. The estimated value of the band gap for the crystallized glass, i.e., for the LiGe2(PO4)3 phase, is 6.15 eV for the case of direct allowed transitions, which exceeds the calculated value known from the literature by approximately 2 times.

In this work, materials with a fluorite structure of the Ce0.8Sm0.2O1.9-(3x)/2F3x series are obtained and studied for the first time. The synthesis method has been developed based on the solid-phase interaction of SmF3 with a highly dispersed precursor obtained in reactions of solution combustion synthesis (SCS) of cerium and samarium nitrates with a mixture of glycine and citric acid. The materials in the range of 0.01 = x <= 0.1 possess a cubic structure (Fm-3m space group), the unit cell parameter decreases according to the size factor. The Raman spectra study shows that for Ce0.8Sm0.2O1.9 the main Raman peak is described by the sum of two components with maxima at 460.5 cm(-1), FWHM = 28.1 cm(-1) and at 484.5 cm(-1), FWHM = 18.3 cm(-1). After the introduction of fluorine, the third component appears at similar to 461.2 cm(-1) with a much smaller FWHM equal to12.1 cm(-1). Thus, the Raman spectra analysis allows the presence of fluorine in the fluorite-like materials including sintered ceramics to be identified. The conductivity maximum (3.7 mS cm(-1) at 600 degrees C, E-a = 0.95 eV) and the maximal electrolyte domain boundary value (1.58 x 10(-22) atm) is reached at x = 0.10 of fluorine content, which generally determines the prospects for the fluorine-doped material application in the SOFC technology. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Neodymium nickelates Nd2Ni1-xO4+delta with Ni non-stoichiometry, varied in a wide x range of 0.0-0.08, are synthesized for the first time, and their properties are studied depending on the Ni content. The limit of Ni deficiency is found to reach 6%. According to the XRD data, the materials of the Nd2Ni1-O-x(4+delta) series are single-phase in the range of x from 0.0 to 0.06 and exhibit an orthorhombic structure with a Fmmm space group. Results of the TGA-DSC studies shows that the temperature of the Fmmm - I4/mmm phase transition changes insignif-icantly (up to similar to 5 degrees C), thus does not depend on Ni non-stoichiometry. The Raman scattering studies reveal that at low Ni deficiency the Raman spectra are typical for the Ni-stoichimetric oxidized (delta approximate to 0.2) Nd2NiO4+(delta). While at the limiting value of x equal to 0.06, the lattice disorder and [NiO6] octahedral distortions reach a maximum feasibility with Ni-O1 vibrations getting involved into Raman scattering. The highest total conductivity (101 S/ cm at the maximum) is observed for the sample with x = 0.02, which shows a more pronounced second-order overtone at 800-930 cm(-1) in Raman scattering. This material can be recommended for further studies and possible electrochemical applications as the most prospective in the series due to its superior electrical properties.

Published data are examined, and the choice of possible imitators for studying the electrochemical partitioning of americium and curium in molten salts is substantiated. Since the direct study of americium and curium is difficult because of their high radioactivity, the corresponding lanthanides (europium and gadolinium) are proposed for the use as imitators. The structures of their external electron shells are very similar, and the oxidation levels are also similar. The electrochemical partitioning in molten salts is concluded to be most promising, since similar media make it possible to conduct the process at elevated temperatures and they are more resistant to radiation than aqueous and organic solvents. The calculation results show that AmCl 3 is easily reduced to AmCl 2 at elevated temperatures in chloride melts. The conventional standard potentials of Am 2+ /Am and Cm 3+ /Cm in the molten LiCl–KCl eutectic according to the data of independent authors are presented. In the melts based on the LiCl–KCl eutectic, the electrode potentials of americium and curium are found to nearly coincide; hence, the direct electrochemical partitioning of these elements is theoretically impossible. The electroreduction potentials of the Eu/Gd couple are additionally estimated more precisely. The data obtained show that the conventional standard potentials of Eu 2+ /Eu significantly differ from those of Gd 3+ /Gd, unlike the pair of Am 2+ /Am and Cm 3+ /Cm, because of which europium and gadolinium cannot serve as imitators for studying the partitioning of americium and curium. In addition, the Eu 2+ /Eu couple cannot be used in the LiCl–KCl melt, because the reduction potential of europium is more negative than the reduction potential of lithium. The conventional electroreduction potentials of Mg, Sc, Sr, Ba, Pr, and Nd in the LiCl–KCl melt at different temperatures are examined. The data obtained show that, among the chosen elements, the potentials of magnesium are closest to the potentials of americium and the scandium potentials are close to those of curium, which makes them more preferable for studying americium and curium partitioning in the LiCl–KCl melt.

Glasses in the yP(2)O(5)-xLa(2)O(3)-(100-y-x)V2O5 system have been obtained in the composition ranges of y = 5, 10, and 15 mol% and x =1, 2, 3, 4, and 5 mol% using the melt quenching method. The concentration dependences of characteristic temperatures and density are found to pass through the maximum and minimum, respectively. In all studied composition ranges, the introduction of 1 mol% La2O3 leads to a slight increase in conductivity; after that, the conductivity gradually decreases. Such behavior is explained by the results of non-constant field molecular dynamics simulation in terms of the mean coordination number of the V...V pair. The conductivity value at a temperature of 50 ?& nbsp;reaches 3.2.10(-4) S.cm(-1) for the composition x = 1 and y = 5.

Eu-doped bismuth-based Bi1.5M0.4Mg0.5Nb1.5O7-δ (M = Li and Na) pyrochlores were synthesized by the organic-inorganic precursor combustion technique. The study examined the effect of rare earth element Eu3+ doping on the structural, dielectric, optical, and luminescence properties of synthesized materials. The analysis showed that the substitution of Bi3+ cations with Eu3+ leads to dielectric permittivity decreasing due to the structural distortion for the Eu-concentrated compositions and low polarizability of Eu3+. The band gap values predicted by electronic band structure calculation using DFT-HSE03 are in line with the experimental ones and tended to increase with the decrease in the unit cell parameters with Eu concentration changing. By the optical and luminescence measurements, the specific roles of Li- and Na-containing host types, additional phases, and dopant concentration in bismuth niobate pyrochlores are shown concerning the dielectric, structural, and Eu3+ emission properties. All Eu-doped bismuth-based pyrochlore ceramics behave as high-frequency dielectrics up to 200 °C and have mixed conductivity (electronic, proton, and oxygen) at T > 200 °C. The obtained dielectric parameters make them suitable for high-frequency ceramic capacitors.

Solid electrolytes with high values of lithium-ion conductivity are required for the creation of high-energy lithium and lithium-ion power sources, and compounds with a garnet structure based on Li7La3Zr2O12 (LLZO) are one of the candidate materials for this purpose. In the present work, solid electrolytes of the Li7-xLa3Zr2-xTaxO12 system with x = 0.0-2.0 were synthesized using the sol-gel method. According to X-ray diffraction analysis, all of the compounds with x >= 0.1 have the same cubic modification with the space group Ia (3) over bard. However, an increase in Ta concentration affects the short-range order crystal structure of these materials, resulting in higher local distortions, which was shown by pair distribution function (PDF) analysis. Particularly, the PDF data indicate an increase in the probability of Li ions to locally occupy not only two typical positions, Li1-96 h and Li2-24 d, but also a third one, Li3-48 g. The maximum value of lithium-ion conductivity in the studied system was observed for the Li6.4La3Zr1.4Ta0.6O12 compound (i.e., x = 0.6) and had the value of 1.4 x 10(-4) S cm(-1) at 25 degrees C. This is consistent with the results of density functional theory (DFT) modeling, which confirmed that a moderate Ta-doping (up to x < 1.0) is most suitable for enhancing Li diffusion in LLZO materials. A combination of DFT modeling, structural characterization of the short and average structures, and conductivity measurements in this work allowed getting insight into this important class of Li-conducting oxides and ideas on improving their properties.

Amorphous glasses of the composition xMgO–yP2O5– (100 – x – y)V2O5 with x = 1–5 and y = 5, 10, and 15 mol % are obtained by the melt quenching technique. The amorphous state of samples is confirmed by XRD analysis. The density of glasses is determined by pycnometry. The introduction of 1 mol % magnesium oxide into the glass composition sharply decreases its density, the further increase in the magnesia concentration is accompanied by the graduate increase in density. The conductivity of glasses is measured by two methods: on direct current and by impedance spectroscopy. Comparing these results makes it possible to infer the electronic nature of conduction. The temperature dependence of glass conductivity is linear in the Arrhenius coordinates. For the compositions with y = 10 and 15, the dependence of conductivity on the magnesia content (x) passes through maximum x = 1 mol %. The glass model is build by the self-assembly procedure with the use of the non-constant force field molecular dynamics method. The analysis of configurations reveals that the concentration of 4-cooordinated environment of vanadium passes through a small maximum when 1 mol % MgO is present in the section xMgO–10P2O5–(90 – x)V2O5, which can be considered as an explanation of the conductivity maximum.

El presente estudio pretende aportar nuevas metodologías para la

The single crystal and polycrystalline specimens of La0.84Sr0.16CoO3-δ oxide were synthesized and characterized by X-ray powder diffraction analysis, energy dispersive X-ray microanalysis, the electron backscatter diffraction technique, and X-ray photoelectron spectroscopy. A thin slab was prepared from the grown single crystal with its surface corresponding to the (110) plane. The kinetics of the oxygen exchange between the gas phase and a single crystal and a polycrystalline specimen was studied by means of 16O/18O oxygen isotope exchange at T = 750-850 °C and PO2 = 5.3 × 10-3-2.2 × 10-2 atm. Temperature dependencies of the oxygen heterogeneous exchange rate, the oxygen dissociative adsorption and incorporation rates, and oxygen diffusion coefficients were obtained. The relationship between the crystallographic orientation of oxides and the kinetic parameters of oxides has been established. Correlations between the surface state and the rates of individual stages of oxygen exchange as well as oxygen diffusion pathways in the single crystal compared with those in the polycrystalline specimen are considered.

The La2Mo2O9 and La2(MoO4)3 powders were synthesized using a solid-state reaction method and used to prepare dense ceramics. X-ray photoelectron spectroscopy was used to study the chemical composition and charge numbers of the elements in the subsurface area of dense ceramics of lanthanum molybdates. The spectra were measured under an ultra-high vacuum of 7 × 10-11 atm at 30 °C and 600 °C, and under an oxygen atmosphere at 2 × 10-3 atm at 600 °C and 825 °C. High resolution spectra for La 3d, Mo 3d and O 1s states were obtained and analyzed. The kinetics of oxygen exchange were considered in the framework of a two-step model including the consecutive steps of dissociative adsorption and the incorporation of oxygen. The oxygen adsorption (ra) and incorporation (ri) rates were calculated. Correlations between the oxide surface defect chemistry and the rates of individual oxygen-exchange steps were discussed.

Improving wear resistance of drill pipe sub thread is a vital task, and finding effective solution for it would much assist oil and gas companies to enhance well construction process. The report presents the results of comparative wear resistance tests for P147/147 and P133/133 subs of the top drive manufactured by OOO «NIGMASH» in Bashkortostan. The tests were performed by OOO «Tatburneft» holding company, a division of PAO «TATNEFT». Both, series and test subs were made from 40X2H4A steel. This report shows the results of metallographic studies and tests for improvement of the parts wear resistance, including the method of final electromechanical hardening (EMH) of the box and pin threads as compared with the conventional method of bulk heat treatment. The researches has developed the equipment, tools and technology for hardening of tool joint thread of drill pipe subs. The performed tests and studies aimed at enhancing efficiency of oil and gas well drilling. Their results are of much interest for oilfield operators, drilling and service contractors, as well as drilling subs manufacturers and repair companies.