Bi13-xMexMo5-yMe’yO34±δ –based, Me, Me’ = IIA group and an iron triad metals, new electrolytic materials: synthesis, structure, properties

Объектами исследования настоящей НИР являются уникальные по своему строению доированные молибдаты висмута, отвечающие формулам Bi13-xMexMo5-yMe’yO34±δ, Me,Me’= металлы IIA группы и триады железа: синтез, структура, свойства.. Цель настоящего исследования – разработка методов получения висмут - содержащих оксидных материалов в системе Bi-Mo-O установление механизма формирования электролитических свойств материалов, аттестация их электропроводящих и каталитических свойств. Использованы различные методы получения порошков и керамики: твердофазный синтез в различных вариантах - брикетирование и отжиг порошков, синтез через жидкие прекурсоры. Методы исследования и аттестации: рентгеноструктурный анализ, лазерная дифракция, электронная микроскопия, термогравиметрический анализ. Методы изучения физикохимических свойств материалов: импедансная спектроскопия и измерение каталитической активности в проточном реакторе. По результатам работы были синтезирован и аттестованы ряд молибдатов висмута, изучена их кристаллическая структура и её особенности, исследована температурная устойчивость, аттестованы электропроводящие и каталитические свойства заявленных молибдатов висмута.This research is devoted to the synthesis, structure, properties of substituted bismuth molybdates which have formulas Bi13-xMexMo5-yMe’yO34±δ, Me,Me’== IIA metals of IIA group and an iron triad and show unique structure. The purposes of this research are development of methods of synthesis BiO-based complex oxides materials in Bi-Mo – O system, understanding the mechanism of formation of electrolytic properties of materials, and testing their electroconductive and catalytic properties. Various methods of synthesis of powders and ceramics are used, they are conventional solid-state synthesis in various options (making pellets and annealing of powders) and synthesis using liquid precursors. Research and certification methods are X-ray diffraction analysis, laser diffraction, electronic microscopy, thermogravimetric analysis. Methods of studying of physicochemical properties of materials are impedance spectroscopy and measurement of catalytic activity in the flowing reactor. As a result of work the number of substituted bismuth molybdates was synthesized and examined, their crystal structure and its features was studied, temperature stability and electroconductive and catalytic properties were investigated.Программа развития УрФУ на 2013 год (п.1.2.2.3

Bismuth Molybdate-based Oxygen Ion Conductors: Synthesis and Properties

The present research is devoted to the synthesis and investigation of properties and structure of Ba-, Mn-, S-, and P- substituted Bi26Mo10O69. The complex oxides have been synthesized using conventional method. The samples were examined using XRPD, IR FT spectroscopy, Rietveld full profile structure refinement, SEM, laser diffraction, and densitometry. Photocatalytic properties were investigated at RhB oxidation under UV irradiation. Electrical conductivity was studied with impedance spectroscopy. As a result, the best samples of Ba-, Mn-, S-, and P- substituted Bi26Mo10O69 can be recommended as high ionic conductive materials. Keywords: oxygen ion conductors, bismuth molybdat

Preparation and characterization of Bi26–2xMn2xMo10O69-d and Bi26.4Mn0.6Mo10–2yMe2yO69-d(Me = V, Fe) solid solutions

Received: 06.06.2017; accepted: 23.06.2017; published: 14.07.2017.Single phase samples of bismuth molybdate, Bi26Mo10O69, doped with Mn on the bismuth sublattice and V, Fe on the molybdenum sublattice were found to crystallize in the triclinic Bi26Mo10O69 structure at low doping levels and in the monoclinic Bi26Mo10O69 structure - at higher dopant concentration. The assumption that all Mn ions have an oxidation state of +2 was confirmed by means of magnetic measurement results analysis using Curie-Weiss law. Conductivity was investigated using impedance spectroscopy. The conductivity of Bi26.4Mn0.6Mo9.6Fe0.4O69-d was 1.2*10-2 S*cm-1 at 973 K and 2.2*10-4 S*cm-1 at 623 K, and the conductivity of Bi26.4Mn0.6Mo9.2V0.8O69-d was 2.2*10-3 S*cm-1 at 973 K and 2.2*10-5 S*cm-1 at 623 K

ABO4 type scheelite phases in (Ca/Sr)MoO4 - BiVO4 - Bi2Mo3O12 systems: synthesis, structure and optical properties

Received: 25.03.2021. Revised: 12.04.2021. Accepted: 28.04.2021. Available online: 29.04.2021.The cation deficient complex oxides of (Ca/Sr)MoO4 - BiVO4 - Bi2Mo3O12 triple system are promising photocatalysts and pigments. Compounds with general formula of Ca1−1.5x-yBix+yФxMo1-yVyO4 and Sr1−1.5x-yBix+yФxMo1-yVyO4 were synthesized by convention solid state technique in the range of 550-720 °C. Two wide regions of the solid solutions (ordinary and superstructured scheelite-type phases respectively) were found for each system. The diffuse scatering of homogeneous samples was investigated in the range of 190-1100 nm. Energy gaps calculated with linear approximation of Kubelka-Munk function decreases with bismuth and vanadium content.The XPRD data were obtained in Ural-M center of Institute for Metallurgy, Ural Br. of RAS This work is supported by grant of RSF, project № 20-73-10048

Sheelite-related strontium molybdates: synthesis and characterization

Received: 25.10.2018. Accepted: 17.12.2018. Published: 31.12.2018.The present research is devoted to the cationic-deficient SrMoO4‑based sheelite-related complex oxides. The doping with bismuth to A sublattice and codoping with bismuth and vanadium (to A and B sublattices, respectively) were discussed. The X-Ray powder diffraction and infrared spectroscopy were used to investigate structural characteristics of the complex oxides. In Sr1–1.5xBixMoO4, a superstructural ordering was observed. Conductivity and dielectric loss of ceramic samples are measured using alternating current.This work was financially supported by grant of Russian Foundation for Basic Research, project № 16‑33‑60026

Optical properties and energy band parameters of luminescent CaMoO 4 :Bi ceramics

We studied the role of intrinsic defects of matrix and Bi dopant in the formation of optical properties and energy structure of CaMoO 4 :Bi ceramic. Non-elementary luminescence was detected in a pure CaMoO 4 matrix due to radiative transitions in intrinsic vacancy-type defects, which are associated with non-stoichiometry in calcium. The experiment showed that Bi ions act as quenchers of luminescence. © Published under licence by IOP Publishing Ltd.The work has been funded by the Ministry of (Governmenttask№3.1485.2017/4.6)

IN SITU TEMPERATURE-DEPENDENT RAMAN SPECTROSCOPY AND LATTICE DYNAMICS OF SCHEELITE AND SCHEELITE-LIKE COMPOUNDS

Here we present the results from an in situ Raman thermal spectroscopy study on specific features of the lattice dynamics of scheelite-type compounds (natural and synthetic scheelite, synthetic CaMoO4 and SrMoO4) in the temperature range of 83–873 K. Spectroscopic data processing has been carried out based on both classical "peak fitting" and statistical approaches. It has been suggested that an increase in temperature causes nonuniformity of MoO4 and WO4 tetrahedra transformation. It has been assumed that dynamics in thermal expansion of unit cells of Ca-containing compounds is slower than that in thermal expansion of WO4 (MoO4) polyhedral. This diffence is mainly due to the fact that thermal expansion is mainly defined by the expansion of CaO8 (SrO8) polyhedra

Ab Initio Calculation of the Electronic Structure of a Solid Solution of Strontium-Bismuth Molybdat

Scheelite-like compounds based on SrMoO4 have been studied. Based on X–ray structural data, models of Sr1-3xBi2xMoO4 structures (x=0.2125) are constructed, at x≥0.175, a superstructural ordering is observed associated with the location of cationic vacancies. From the first principles, calculations of the density of states in the vicinity of the forbidden zone are performed. The calculated values of the band gap width were compared with the values obtained from the reflection spectra. © 2021 Institute of Physics Publishing. All rights reserved.The work was carried out using the equipment of the Centre for Collective Use of the North Caucasus Federal University with the financial support of the Ministry of Education and Science of Russia, the unique identifier of the project RF-2296.61321X0043 (agreement No. 075-15-2021-672). The synthesis, certification and experimental determination of the functional characteristics of the materials was carried out with the support of the grant of the Russian Research Foundation 20-73-10048

SYNTHESIS, STRUCTURE AND PROPERTIES OF LOW-SYMMETRY MOLYBDATES OF BISMUTH Bi13-xAxMo5-yByO34±δ (A – Ba, Mn; B-Fe)

The paper discusses the research of the availability and property measurement of oxygenic ionic conductors based on bismuth molibdates with a double substitution (A: Ba, Mn and B: Fe).The formulas of substitutional solid solutions look like Bi13-xAxMo5-yByO34±δ. The samples were synthesized by the standard ceramic technology in two stages, the phase composition was controlled by the method ofx-ray analysis. The electrical conductivity of complex oxides studied using impedance spectroscopy. The ignificant increase in conductivity compared to the matrix compound.Работа выполнена при финансовой поддержке гранта Президента МК-7979.2016.3

SYNTHESIS, STRUCTURE, SIZE AND CONDUCTIVE PROPERTIES OF LOW-SYMMETRY MOLYBDATES OF BISMUTH Bi13-XAXMo5-YBYO34±δ (A - Ba; B-V, CO)

Substitution in Bi13Mo5O34±δ is possible in the position of molybdenum and isolated bismuth atoms. The formulas of substitutional solid solutions look like Bi13-XAXMo5-YBYO34±δ . The paper discusses the research of the availability and property measurement of oxygenic ionic conductors based on bismuth molibdates with a double substitution (A: Ba and B: V, Co).The samples were synthesized by the standard ceramic technology in two stages, the phase composition was controlled by the method of x-ray analysis. The electrical conductivity of complex oxides studied using impedance spectroscopy. The significant increase in conductivity compared to the matrix compound.Работа выполнена при финансовой поддержке гранта Президента МК-7979.2016.3