Oxygen-ionic conductors based on substituted bismuth molybdates with column-type structural fragments

The possibility of synthesizing oxygen-ionic conductors from substituted bismuth molybdates containing [Bi12O14] n 8n+ columns, MoO4 tetrahedra, and isolated Bi ions in their structure was studied. The specifics of their structure and electric conductivity were investigated. The general formula of the solid solutions can be recorded as Bi13Mo5 - x Me x O 34 - δ, where Me is the fouror five-valent d metal (Ti, Zr, V, Nb). The electric conductivity of doped bismuth molybdates considerably increased compared with that of the matrix compound. The electric conductivity reached 5.5 × 10-3 S cm-1 at 700 C and 1.8 × 10-4 S cm-1 at 350 C for the zirconium-doped compound with x = 0.4. The porosity of the ceramics was less than 5%; the thermal expansion coefficient was of the order of 14 × 10-6 K-1. Based on the set of their characteristics, these compounds are recommended as materials for membranes of electrochemical devices. © 2013 Pleiades Publishing, Ltd

Crystal structure and conductivity of bismuth-containing complex oxides

In the paper, a comprehensive systematic study of different classes of bismuth containing oxide compounds was carried out. The relationship between composition, temperature and concentration regions of existence of stable, specific structure and properties of solid solutions on the basis of vanadates, molybdates, niobates and bismuth was found. The general regularities of synthesis of solid solutions with different variants of solid-phase and soluble methods were determined. On this basis, the optimal conditions for obtaining single-phase materials were formulated. For the first time the temperature and concentration boundaries of the regions of homogeneity and areas of stable existence of polymorphic modifications of solid solutions were defined and/or refined. The structural parameters of the synthesized phases were determined. By the method of electrochemical impedance spectroscopy the nature and features of impedance spectra, the temperature and concentration dependences of electrical conductivity of ceramic materials based on bismuth containing complex oxides were identified

Structure and electrical conductivity of cobalt-doped Bi 26Mo10O69

The existence boundaries, structures, and transport parameters of Bi 1 - x Co x [Bi12O14]Mo 5O20 ± δ and Bi[Bi12O 14]Mo5 - y Co y O20 ± δ solid solutions, which have a unique columnar structure, were studied. Electrical conductivity in these solid solutions was studied by impedance spectroscopy. © 2013 Pleiades Publishing, Ltd

BISMUTH-DOPED CALCIUM MOLYBDATE: CRYSTAL STRUCTURE AND CONDUCTIVITY

A series of bismuth-doped calcium molybdates Ca1−1.5хBixMoO4±δ (x=0–0.4) were synthesized by solid-state reaction with Bi2O3 (99.9%), MoO3 (99.5%) and CaCO3 (99.5%) and investigated using X-ray powder diffraction and impedance spectroscopy. The solid solutions exist up to x=0.222 have tetragonal unit cell (Sp.gr. I41/a)

Замещенные молибдаты висмута на основе Bi13Mo5O34±δ: получение и свойства

The present work is devoted to the investigation of the methods of a synthesis and properties of the one of the most interesting one-dimensional oxygen –ion conductors, the Bi13Mo5O34±δ –based complex oxides. The general compositions of these bismuth molybdates are Bi13Mo5-хMeхO34-δ, and Bi13-yMeyMo5O34-δ, with Me = Mg, Ca, Sr, Ba (IIA group) and Co, Fe, Ni (Fe triade). The samples have been synthesized using conventional ceramic technology. The powders and pellets of the bismuth molybdates were studied by X-Ray diffraction, scanning electron microscopy, laser dispersion, dilatometry, atom absorption and inductively-coupled plasma atomic emission spectrometry. Electrical conductivity has been studied using impedance spectroscopy method.Работа посвящена исследованию возможности получения, установлению специфики структуры и электропроводящих характеристик замещенных молибдатов висмута Bi13Mo5O34±δ, содержащих в структуре уникальные для твердых оксидов колонки [Bi12O14]n8n+ и проявляющих одномерную кислород-ионную проводимость. В качестве допантов были выбраны металлы IIA подгруппы (Mg, Ca, Sr, Ba) и металлы триады железа (Co, Fe, Ni). Для аттестации продуктов синтеза применялись методы рентгенофазового анализа и электронной микроскопии, проводились высокотемпературные исследования порошков и керамики сложных оксидов. Электропроводящие свойства были исследованы методом импедансной спектроскопии

PROPERTIES OF COMPLEX BISMUTH-DOPED OXIDES BASED ON CаMоO4

A series of bismuth-doped calcium molybdates Ca1-xBixMoO4+x / 2 , Ca1-3xBi2xΦxMoO4 , Ca1-3xBi1.6xΦ1.4xMoO4 were synthesized by conventional solid state technology and investigated using X-ray powder diffraction. For these complex oxides, structural features, energy gap values, and photocatalytic activity were determined

SYNTHESIS AND OPTICAL PROPERTIES OF SCHEELITE-LIKE MATERIALS BASED ON DOPED SrMoO4

The present work is devoted to the study of processes of synthesis and determi-nation of the ranges of solid solutions based on SrMoO4 , substituted with bismuth and vanadium.The obtained samples were subjected to XRD analysis. Reflection spectra were obtained for sin-gle-phase samples.Работа выполнена в рамках темы АААА-А19-119071090011-6 госзадания ИГГ УрО РАН

Adsorption dynamics of hydrophobically modified polymers at an air-water interface

The adsorption dynamics of a series of hydrophobically modified polymers, PAAαCn, at the air-water interface is studied by measuring the dynamic surface tension. The PAAαCn are composed of a poly(acrylic acid) backbone grafted with a percentage α of C8 or C12 alkyl moieties, at pH conditions where the PAA backbone is not charged. The observed adsorption dynamics is very slow and follows a logarithmic behavior at long times indicating the building of an energy barrier which grows over time. After comparison of our experimental results to models from the literature, a new model which accounts for both the deformation of the incoming polymer coils as well as the deformation of the adsorbed pseudo-brush is described. This model enables to fit very well the experimental data. The two fitting parameters give expected values for the monomer size and for the area per adsorbed polymer chain.This article is uploaded in "arXiv.org" https://arxiv.org/abs/1706.0710