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Search results for: V2O5
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Ac and dc conductivities in v2o5-p2o5 glasses containing alkaline ions
PublicationWe investigated the ac and dc conductivity in 50V2O5-(50 − x)P2O5-xA2O (A = Li, Na, K) glasses as a function of temperature. The measurements were carried out in the frequency range from 10−4 to 107 Hz. For all compositions, the dc conductivity decreased with the increasing alkali ion content. The decrease in conductivity was more pronounced for larger alkali ions. The ac conductivity exhibited a universal dynamic response: σac...
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Warunki krystalizacji cienkich warstw V2O5 i V2O3 wytwarzanych metodą zol-żel
PublicationPraca ta przedstawia wyniki badań struktury cienkich warstw tlenku wanadu otrzymanych metodą zol - żel. Cienkie warstwy osadzano metodą spin - coating na podłożach wykonanych ze szkła kwarcowego oraz krzemowych. Tak przygotowane próbki wygrzewano w zakresie temperatur od 200 °C do 1200 °C. Zakres temperatur dobrano w taki sposób, aby można było zarówno określić optymalną temperaturę krystalizacji nanoprętów V2O5 jak i otrzymać...
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Evolution of the surface species of the V2O5–WO3 catalysts
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Effects of V2O5 Additive on Structure and Dielectric Properties of BiNbO4 Ceramics
PublicationGoal of the present research was to investigate the influence of V2O5 additive on the structure and dielectric properties of BiNbO4 ceramics. To fabricate BiNbO4 ceramics with V2O5 added the solid state reaction route and pressureless sintering was utilized. Thus obtained ceramics was characterized in terms of its microstructure (SEM), chemical composition (EDS), phase composition and crystalline structure (X-ray phase and structural...
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The influence of thermal conditions on V2O5 nanostructures prepared by sol-gel method
PublicationThis work presents the result of structure investigations ofV 2O5 nanorods grown from thin films and powders prepared by sol-gel method. To examine the best temperature of nanorods crystallization, thin films deposited by spin-coating method on quartz glass or silicon substrates and bulk xerogel powders were annealed at various temperatures ranging from 100∘C to 600∘C. The structure of the samples was characterized by X-ray diffraction...
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STUDY OF CuO AND V2O5 EFFECT ON IR SPECTRA OF POLYCRYSTALLINE BISMUTH NIOBATE
PublicationBismuth niobate (BiNbO4) ceramics were fabricated by mixed oxide method and sintered by presureless sintering method. BiNbO4 ceramics doped with V2O5 additive in amount 0.125 wt%, 0.250 wt% and 1 wt% of was sintered at T = 910°C whereas BiNbO4 ceramics doped with 2 wt% of CuO additive was sintered at T = 890°C and T = 910°C. It was found that V2O5 additive improved morphology of the ceramic samples. However, the chemical composition...
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Electrical conductivity and relaxation processes in V2O5 nanorods prepared by sol–gel method
PublicationProperties of high purity V2O5 nanorods prepared by a sol – gel method are presented. The studied materials were characterized by: X-ray diffractometry (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The electrical impedance was measured as a function of temperature and frequency. The obtained results show that the electrical conductivity increases with increasing temperature. The d.c. conductivity...
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Synteza i badanie struktury nanoprętów V2O5 wytworzonych metodą zol-żel
PublicationPraca ta przedstawia wyniki badań struktury cienkich warstw tlenku wanadu otrzymanych metodą zol - żel. Cienkie warstwy osadzano metodą spin - coating na podłożach ze szkła kwarcowego oraz krzemowych a następnie wygrzewano w różnych temperaturach w zakresie od 400 °C do 600 °C w celu określenia optymalnej temperatury krystalizacji nanoprętów. Otrzymane próbki przebadano metodą dyfraktometrii rentgenowskiej, skaningowym mikroskopem...
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Increasing the conductivity of V2O5 -TeO2 glass by crystallization: structure and charge transfer studies
PublicationIn the present paper, V2O5-TeO2 glass...
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Enhancing electrical properties through in-situ controlled nanocrystallization of V2O5–TeO2 glass
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Increasing the conductivity of V2O5-TeO2 glass by crystallization: structure and charge transfer studies
PublicationIn the present paper, V 2 O 5 -TeO 2 glass was prepared by the melt-quenching technique. Crystallization of glass with a vanadium content higher than 35%mol results in an increase in electrical conductivity by a few orders of magnitude and a decrease in activation energy from ~0.40 to ~0.12 eV. In this work, a critical review of existing charge transfer models was presented on the example of V 2 O 5 -TeO 2 glass and glass–ceramics....
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The influence of nanostructures size on V2O5 electrochemical properties as cathode materials for lithium ion battery
PublicationIn this paper, V2O5 nanostructures with a size depending on the annealing temperature are successfully synthesized by a sol-gel method. The crystal structure and morphology of samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected area electron diffraction (SEAD) and scanning electron microscopy (SEM), respectively. Electrochemical testing such...
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Physical and sealing properties of BaO–Al2O3–SiO2–CaO–V2O5 glasses for solid oxide fuel cell applications
PublicationIn this study, the properties of BaO–Al2O3–SiO2 (SAB) glasses incorporated with CaO and V2O5 as the network modifier and additive, respectively, are evaluated. The electrical resistivities of the glasses decrease upon the addition of CaO but increase upon increasing their V2O5 content because the V5+ species lower the ionic mobility of the glasses. The addition of V2O5 improves the wettability of the glasses on the Crofer 22 APU...
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Electronic conductivity in Na2O-FeO-P2O5 glasses. oz.
PublicationZbadano przewodnictwo stałe i zmiennoprądowe w szkłach: 50P2O5-(50-x)FeO-xNa2O i 50P2O5-(50-x)FeO-xCaO, gdzie x zmieniano od 7 do 20mol%. Wykazano,że zamiana CaO na Na2O w małym stopniu zmienia przewodnictwo elektryczne szkieł, co sugeruje, że przewodnictwo w szkłach zawierających Na2O ma charakter elektronowy. Do badania procesów migracji elektronów i jonów zastosowano metodę tarcia wewnętrznego. W widmie tarcia wewnętrznego...
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Oxygen vacancy-enriched V2O5·nH2O nanofibers ink for universal substrates-tolerant and multi means-integratable NH3 sensing
PublicationUniversal substrates-tolerant and multi means-integratable ammonia (NH3) sensing is highly desired in future Internet of Things in environmental monitoring, food security and early diagnosis of human diseases, however, is still less than satisfactory. Here, an oxygen vacancy-governed NH3 sensing has been developed with V2O5·nH2O nanofibers (NFs) ink, via combined thermal decomposition of ammonium metavanadate and dilution. As-obtained...
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Enhanced Photoelectrocatalytical Performance of Inorganic-Inorganic Hybrid Consisting BiVO4, V2O5, and Cobalt Hexacyanocobaltate as a Perspective Photoanode for Water Splitting
PublicationThin layers of BiVO4/V2O5 were prepared on FTO substrates using pulsed laser deposition technique. The method of cobalt hexacyanocobaltate (Cohcc) synthesis on the BiVO4/V2O5 photoanodes consists of cobalt deposition followed by electrochemical oxidation of metallic Co in K3[Co(CN)6] aqueous electrolyte. The modified electrodes were tested as photoanodes for water oxidation under simulated sunlight irradiation. Deposited films...
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Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4
PublicationSodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz–1 MHz) and wide temperature range (153–473 K). At 36.6 °C, DC conductivities of all glasses vary between 1.1 ∗ 10−12 and 8.9 ∗ 10−12 S cm−1 and have similar activation energies (between...
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Nonlinear optical birefringence in Li2SO4-MgO-P2O5 amorphous system -influence of Cu ions
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DC and AC Conductivity, Biosolubility and Thermal Properties of Mg-Doped Na2O–CaO–P2O5 Glasses
PublicationBioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy...
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Effect of Nb and Al on in vitro dissolution behavior and structure of Na2O-MgO CaO-P2O5 glasses
PublicationIn vitro dissolution, structure, and thermal properties of the glass series Na2O-MgOsingle bondCaOsingle bondNb2O5 -Al2O3-P2O5 were studied. The dissolution behavior in phosphate-buffered saline (PBS) confirmed the potential bioactive properties of tested glasses. The dissolution process was found to depend on the Al, Nb, and Mg contents. Al, respectively, suppresses the Nb and accelerates the Mg release process from the glasses....
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Effect of crystallinity on structural, thermal, and in vitro dissolution properties of Na2O-CaO-Nb2O5/MgO-P2O5 glass-ceramics
PublicationThe impact of the crystallinity on structural, thermal, and in vitro dissolution properties were examined for Na2O- CaO-Nb2O5/MgO-P2O5 glasses/glass-ceramics. Glass-ceramics were synthesized via a spontaneous crystallization process. The Nb content in the materials increased with melting temperature, furthermore, the crystallinity is proportional to the Nb content. The presence of crystalline niobates and phosphates is confirmed...
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Struktury nanokrystaliczne w układzie V O: wytwarzanie i właściwości
PublicationTlenki wanadu charakteryzują się ogromną różnorodnością właściwości fizycznych i chemicznych, dzięki czemu w ciągu ostatnich kilkudziesięciu lat były intensywnie badane. Właściwości te wynikają bezpośrednio z możliwych struktur jakie mogą przyjmować tlenki wanadu. W układzie V–O można otrzymać wiele różnych związków, przy czym do głównych tlenków wanadu zalicza się V2O5, VO2, V2O3 oraz VO, w których wanad znajduje się odpowiednio...
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Photoluminescence of partially reduced Eu2+/Eu3+ active centers in a NaF–Al2O3–P2O5 glassy matrix with tunable smooth spectra
PublicationIn this work, a series of photoluminescent materials have been synthesized based on optically transparent and chemically stable glasses of the nominal composition Na3Al2(PO4)2F3 (NaF–Al2O3–P2O5 system) doped with 1 wt% of europium. It has been shown that the synthesis conditions (mainly the temperature and duration of the melting stage under reducing conditions) strongly affected the photoluminescence spectra of the material. This...
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Investigations on the influence CuO doping on elastic properties of Li2SO4–MgO–P2O5 glass system by means of acoustic wave propagation
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Influence of NiO doping on elastic properties of Li2SO4-MgO-P2O5 glass system-Investigation by means of acoustic wave propagation
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Third harmonic generation studies of 1.06 μm Nd:YAG laser beam in Li2SO4–MgO–P2O5 glass system-influence of CuO
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Influence of Ni ion site occupancy on laser induced third harmonic generation (THG) studies in Li2SO4–MgO–P2O5 amorphous system
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Microstructure and Dielectric Properties of Barium-vanadate Glasses
PublicationThe ac and dc conductivity in barium-vanadate glasses was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The XRD results show that all samples are amorphous but microscopy investigation reveals that glasses with greater amount of V2O5...
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Intense and stable room-temperature photoluminescence from nanoporous vanadium oxide formed by in-ambient degradation of VI3 crystals
PublicationVanadium oxides have attracted research interest because their optoelectronic properties make them optically active with room-temperature photoluminescence (PL) emission, which, however, is not sufficiently intense for real applications. For this reason, many nanostructured vanadium oxides are currently fabricated through several precursors and different treatments to improve the PL efficiency and enhance the PL intensity. Herein,...
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Pulsed Laser Deposition of Bismuth Vanadate Thin Films—The Effect of Oxygen Pressure on the Morphology, Composition, and Photoelectrochemical Performance
PublicationThin layers of bismuth vanadate were deposited using the pulsed laser deposition technique on commercially available FTO (fluorine-doped tin oxide) substrates. Films were sputtered from a sintered, monoclinic BiVO4 pellet, acting as the target, under various oxygen pressures (from 0.1 to 2 mbar), while the laser beam was perpendicular to the target surface and parallel to the FTO substrate. The oxygen pressure strongly affects...
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Superconducting properties of vn-sio 2 sol-gel derived thin films
Publicationin this work studies of structure and superconducting properties of vnsio2 films are reported. the films were obtained through thermal nitridation (ammonolysis) of solgel derived v2o3sio2 coatings (in a proper v2o3/sio2 ratio) at 1200 ◦c. this process leads to the formation of disordered structure with vn metallic grains dispersed in the insulating sio2 matrix. the structural transformations occurring in the lms as a result...
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Tailoring the Size and Shape—New Path for Ammonium Metavanadate Synthesis
PublicationAmmonium metavanadate, NH4VO3, plays an important role in the preparation of vanadium oxides and other ammonium compounds, such as NH4V3O8, (NH4)2V3O8, and NH4V4O10, which were found to possess interesting electrochemical properties. In this work, a new route for the synthesis of NH4VO3 is proposed by mixing an organic ammonium salt and V2O5 in a suitable solvent. The one-step procedure is carried out at room temperature. Additionally,...
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STRUKTURA SZKŁO-CERAMIKI ZAWIERAJĄCEJ FERROELEKTRYCZNĄ FAZĘ BiV
PublicationLiteratura opiusuje próby wytworzenia nanokompozytów, w których skład wchodzą matryca szkła i rozproszone w niej nanokrystality fazy ferroelektrycznej. Najczęstsza metoda wykorzystywana do otrzymywania takiej szkło - ceramiki polega na wytopie szkła, a następnie jego krystalizacji. W literaturze można znaleźć dużo przykładów wytwarzania tego typu materiałów dwu lub więcej składnikowych. Najwięcej badań dotyczy ferroelektrycznych...
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Transition Metal Oxides influence on phosphate and borate glasses structure
PublicationBorate and phosphate glasses possess many potential luminescence and optical applications. With their low melting point, they are one of the most often studied amorphous materials. In recent years these glasses, doped with transition metal oxides (TMO), gained much attention due to their tunable structural and thermal properties. Review of systems containing TMOs was presented. Additionally synthesis of binary MnO-P2O5 and MnO-B2O3...
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Nonlinear impedance in oxide glasses containing single and mixed alkali ions
PublicationThe aim of the present was to find more clues on the nonlinearities in impedance of oxide glasses. The first family of researched glasses has a composition of FeO-P2O5-Na2O. Oxide glasses containing iron and alkali are well known for a very low alkali ion mobility and may be considered purely polaron conducting. These glasses show no detectable nonlinearities in the impedance spectra. The second was a family of ionic conducting...
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Mixed conductivity in tungstenite-phosphate glasses containing alkali metal ions
PublicationThe conductivity of glasses in the 50WO3-(50-x)P2O5-xA2O (A = Na, K, Cs) system has been investigated as a function of composition. It is shown that in tungstenite-phosphate glasses containing different alkali metal ions the conductivity decreases with an increase in the alkali metal ion content. A decrease in conductivity is larger for heavier ions and reaches more than seven orders of magnitude in the case of glass containing...
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Właściwości strukturalne i elektryczne szkieł tlenkowych z grupy Pb-P-O
PublicationPrzeprowadzono wytop szkieł ołowiowo-fosforanowych xPbO-(100-x)P2O5 (gdzie x=10,20,30,40,50,60). Stwierdzono, że na skutek parowania następuje zubożenie szkieł w ołów względem początkowej stechiometrii. Zbadano właściwości strukturalne oraz przeanalizowano doniesienia literaturowe w zakresie właściwości elektrycznych tych szkieł. Zaobserwowano, że w zależności od udziału tlenku ołowiu w strukturze szkła następuję wyraźna zmiana...
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Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
PublicationNew phosphate glasses and glass-ceramics P2O5–Bi2O3–K2O–Nb2O5-SrF2 doped with Eu were synthesized and studied in this work. The influence of the SrF2 content (0–15 mol%) and the parameters of the heat treatment on their structural and optical properties were investigated. For the above purpose, the structural characterization by FTIR spectroscopy and XRD measurements was carried out, which showed a significant effect of SrF2 on...
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Niobate in silicate and phosphate glasses: Effect of glass basicity on crucible dissolution
PublicationUsing niobium crucibles for melting phosphate and silicate glasses of various modifier oxide contents, and therefore varying optical basicity (Λ), was found to result in varying dissolution rates of niobate during melting. Because of their high electronic polarizability, even small concentrations of niobates are detectable in the Raman spectra of glasses. Even less than 1 mol% Nb2O5 can be identified, as independently confirmed...
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Możliwość wykorzystania popiołów z osadów ściekowych w betonie
PublicationIlość popiołów lotnych ze spalania osadów ściekowych rośnie na całym świecie. Ich unieszkodliwianie jest poważnym problemem ekologicznym. W pracy przedstawiono ocenę możliwości wykorzystania popiołów lotnych z osadów ściekowych w betonie. Wykonano dwie serie badawcze dla dwóch współczynników (w/s) równych 0,49 oraz 0,55 z udziałem 10% i 20% popiołu lotnego (SSA), jako zamiennika cementu. Skład chemiczny wykazał, że popiół (SSA)...
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Structural investigations of niobium-doped bioactive calcium-phosphate glass-ceramics by means of spectroscopic studies
PublicationSynthetic calcium-phosphate based glasses and glass-ceramics play a crucial role in the development of tissue engineering. These materials have a high biocompatibility with biological analogues, excellent ability to undergo varying degrees of resorbability and due to their non-toxicity and relatively high bioactivity they are commonly used as bone and dental implants. A substantial research effort is devoted to improve synthetic...
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Influence of Cement Replacement with Sewage Sludge Ash (SSA) on the Heat of Hydration of Cement Mortar
PublicationThe amount of fly ash from the incineration of sewage sludge is increasing all over the world, and its utilization is becoming a serious environmental problem. In the study, a type of sewage sludge ash (SSA) collected directly from the municipal sewage treatment plant was used. Five levels of cement replacement (2.5%, 5%, 7.5%, 10% and 20%) and unchanged water-to-binder (w/b) ratio (0.55) were used. The purpose of the study was...
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SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NIOBIUM-DOPED HYDROXYAPATITE CERAMICS
PublicationHydroxyapatite (HAp) ceramic materials are considered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important...
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Nickel phase deposition on V2CTx/V2AlC as catalyst precursors for a dry methane reforming: The effect of the deposition method on the morphology and catalytic activity
PublicationDry reforming of methane (DRM) is a promising alternative technology for the production of syngas with simultaneous utilization of two main greenhouse gases (CH4, CO2). However, DRM technology is still an industrially immature process due to the lack of stable and active catalyst. Therefore, the search for new catalytic materials is of great research interest. Recently, MAX and MXenes materials are increasingly being tested as...