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Search results for: DOPED CERIA
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Electrical properties of nanocrystalline Sm-doped ceria ceramics
PublicationWłaściwości ceramiki z cerii zależa zwykle silnie od struktury ziaren. W pracy przedstawiono właściwości elektryczne ceramiki z cerii domieszkowanej samarem wykonanje w technologii 'net shape' posiadającej strukturę nanokrystaliczną.
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Nanocrystalline doped zirconia and ceria films for fuel cell application
PublicationW artykule przestawiono porównanie właścowości warstw nanokrystalicznych przygotowanych w technologii 'net-shape'. Materiały te mają zastosowanie w tlenkowychogniwach paliwowych.
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Nanocrystalline doped zirconia and ceria films for fuel cell application
PublicationW artykule przedstawiono i porównano właściwości nanokrystalicznych warstw ceramicznych przygotowanych na bazie tlenku ceru i tlenku cyrkonu.
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Gigantic electro-chemo-mechanical properties of nanostructured praseodymium doped ceria
PublicationSome oxygen defective fluorites are non-Newnham electrostrictors, i.e., the electromechanical response does not depend on their dielectric properties. Here, we show gigantic electrostriction in nanocrystalline 25 mol% praseodymium doped ceria (PCO) bulk ceramics. The material was fabricated with a fieldassisted spark plasma sintering (SPS) process from high-purity nanoscale PCO powders (<20 nm). The SPS process consolidates the...
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Spray pyrolysis of doped-ceria barrier layers for solid oxide fuel cells
PublicationGadolinium doped ceria (Ce0.8Gd0.2O2 − x-CGO) layer fabricated by spray pyrolysis is investigated as the diffusion barrier for solid oxide fuel cell. It is deposited between the La0.6Sr0.4FeO3 − δ cathode and the yttria stabilized zirconia electrolyte to mitigate harmful interdiffusion of elements. The parameters of the fabrication process are linked to the measured area specific resistances of the symmetrical cells and the efficiency...
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Electrical conductivity of nanostructured acceptor-doped ceria fabricated by spark plasma sintering (SPS)
PublicationHigh purity nanoscale powders (~10–15 nm size) of two different compositions of ceria, doped with Gd3+ and Ca2+, have been consolidated by spark plasma sintering (SPS) at different temperatures. Fully-dense samples were observed only at a sintering temperature of 980 °C. The as-sintered samples showed rather fast grain growth with an average grain size below 300 nm. The electrical properties of the samples were evaluated by impedance...
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Structural and catalytic properties of ceria layers doped with transition metals for SOFCs fueled by biogas
PublicationThe aim of this paper was to investigate an influence of the nanocrystalline Ce0.8A0.2O2-δ (A = Mn, Fe, Co, Ni, Cu) materials on the direct internal reforming of biogas in SOFC. Structural analysis of fabricated compounds has been done. An in-situ analysis of a composition of outlet gases from operating SOFC was performed using FTIR spectroscopy with simultaneous electrical tests. It was found out, that type of dopant strongly...
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Copper and cobalt co-doped ceria as an anode catalyst for DIR-SOFCs fueled by biogas
PublicationThe nanocrystalline compounds of Co and Cu co-doped ceria (with up to 20 mol.% of dopants) were fabricated by the reverse microemulsion synthesis method. They were deposited in a form of layers on the surface of SOFC anode in an aim to act as electrochemically active materials for biogas reforming process. Fourier Transformed Infrared Spectroscopy was used to analyze a composition of outlet gases simultaneously with the tests of...
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Analysis of the grain boundary conductivity for nanocrystalline doped ceria using the brick layer model.
PublicationW pracy przedstawiono wyniki badań elektrycznych i mikrostrukturalnych ceru domieszkowanego itrem. Gęste i nanokrystaliczne filmy przygotowane zostały z użyciem prekursorów polimerowych na szafirze. Konduktancja elektryczna była badana w funkcji temperatury syntezy, która jest skorelowana z wielkością ziaren. Otrzymano mniejszą konduktancję nanokrystalicznego filmu ceru w porównaniu z próbkami ceramicznymi.
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Evaluation of Praseodymium and Gadolinium Doped Ceria as a Possible Barrier Layer Material for Solid Oxide Cells
PublicationIn this work, nanocrystalline layers based on the Pr, Gd co-doped CeO2 were investigated. For the preparation of thin layers, lowtemperature spray pyrolysis technique was used. Different stoichiometries of the layers were produced for comparison on polished sapphire substrates. The microstructure of the prepared thin layers was studied by scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD)....
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Investigation of praseodymium and samarium co-doped ceria as an anode catalyst for DIR-SOFC fueled by biogas
PublicationThe Pr and Sm co-doped ceria (with up to 20 mol.% of dopants) compounds were examined as catalytic layers on the surface of SOFC anode directly fed by biogas to increase a lifetime and the efficiency of commercially available DIR-SOFC without the usage of an external reformer. The XRD, SEM and EDX methods were used to investigate the structural properties and the composition of fabricated materials. Furthermore, the electrical...
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Electro-chemo-mechanical properties in nanostructured Ca-doped ceria (CDC) by field assisted sintering
PublicationRecent investigations have shown that highly oxygen defective cerium oxides generate non-classical electrostriction that is superior to lead-based ferroelectrics. In this work, we report the effect of field-assisted spark plasma sintering (SPS) on electro-chemo-mechanical properties of calcium doped ceria (CDC). Nanometric powders of Ca.10 nm are rapidly consolidated to form polycrystalline nanostructures with a high degree of...
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Investigation of thin perovskite layers between cathode and doped ceria used as buffer layer in solid oxide fuel cells
PublicationIn this paper, thin perovskite layers between cathode material of solid oxide fuel cells and gadolinia-doped ceria buffer layer are investigated. Thin layers made of LaNi0.6Fe0.4O3-δ (LNF), La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), or SrTi0.65Fe0.35O3-δ (STF) were symmetrically deposited by spin coating method from metallo-organic polymer precursors on a Ce0.8Gd0.2O2-δ (CGO) substrate. Porous and about 40-μm-thick LNF cathodes were deposited...
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Nanocrystalline undoped ceria oxygen sensor.
PublicationW pracy przedstawiono wyniki badań struktury i elektrycznych właściwości nanokrystalicznego czujnika na bazie niedomieszkowanego tlenku ceru. Zbadano wpływ ciśnienia parcjalnego tlenu na rezystancję cienkowarstwowego tlenku ceru. Konduktancja tlenku ceru w zakresie stężeń tlenu od 10ppm do 100% ma charakter eksponecjalny z parametrem -0.25. Zbadano szybkość odpowiedzi oraz wpływ dwutlenku azotu oraz dwutlenku siarki na odpowiedź...
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Electrical properties of poros nanocrystalline undoped ceria oxygen sensor
PublicationW pracy zaprezentowano wykonanie czujnika z niedomieszkowanego tlenku ceru o nanometrowych ziarnach krystalicznych. Zastosowana metoda nanoszenia warstw zalicza się do metod niskotemperaturowych. Wytworzone warstwy przebadano za pomocą dyfrakcji rentgenowskiej, mikroskopii elektronowej oraz spektroskopii impedancyjnej. Wykonane czujniki charakteryzują się szybkim czasem odpowiedzi i stabilnym zachowaniem przy zmianach ciśnienia...
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Electrical properties of ceria films prepared by net shape technology
PublicationW pracy przedtswiono procedurę przygotowania gęstych warstw elektrolitu z wykorzystaniem technologii Net Shpe. Technologia ta na znaczne obniżenie temperatury przygotania tego typu warst. Okresloślono parametry elektryczne warst domieszkowanego ceru przygotowanych w tej technologii.
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Ceria Based Protective Coatings for Steel Interconnects Prepared by Spray Pyrolysis
PublicationStainless steels can be used in solid oxide fuel/electrolysis stacks as interconnects. For successful long term operation they require protective coatings, that lower the corrosion rate and block chemical reactions between the interconnect and adjacent layers of the oxygen or the hydrogen electrode. One of the promising coating materials for the hydrogen side is ceria. Using standard sintering techniques, ceria sinters at around...
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Nanocomposite nickel ceria cermet with low nickel content for anode-supported SOFCs
PublicationW pracy przedstawiono badania nanokompozytowego cermetu z zawartościa niklu 7.5, 11, 14% niklu w cermecie. Cermet przygotowno z wykorzystanim technologii net shape.
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Corrosion Study of Ceria Protective Layer Deposited by Spray Pyrolysis on Steel Interconnects
PublicationSingle fuel cells and electrolysis cells are assembled into stacks using interconnects in order to increase power and gas production capacity. The most common choice for the interconnect material is stainless steel. It has good electrical and mechanical properties and is also cost effective. One of the problems when using steel is the formation of a thermally grown oxide scale during use which has a lower electrical conductivity...
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La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ oxygen electrodes for solid oxide cells prepared by polymer precursor and nitrates solution infiltration into gadolinium doped ceria backbone
PublicationInfiltration is a method, which can be applied for the electrode preparation. In this paper oxygen electrode is prepared solely by the infiltration of La0.6Sr0.4Co0.2Fe0.8O3‐δ (LSCF) into Ce0.8Gd0.2O2-δ (CGO) backbone. The use a polymer precursor as an infiltrating medium, instead of an aqueous nitrate salts solution is presented. It is shown that the polymer forms the single-phase perovskite at 600 °C, contrary to the nitrates...
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Doped-TiO2 :a review
PublicationTlenek tytanu(IV) jest efektywnym fotokatalizatorem do oczyszczania wody i powietrza oraz w powierzchniach samoczyszczących. TiO2 wykazuje stosunkowo wysoką reaktywność i stabilność chemiczną pod wpływem promieniowania UV, którego energia jest większa od pasma wzbronionego (3,3 eV dla czystego anatazu). Opracowanie metody otrzymywania fotokatalizatora wykazującego wysoką reaktywność pod wpływem światła widzialnego pozwoli na wykorzystanie...
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Benchmarking parków technologicznych w Polsce. Wyniki badania. - [Seria Innowacje]
PublicationAutorzy na podstawie przeprowadzonych badań dokonują benchmarkingu parków technologicznych w Polsce, wskazując na najlepsze rozwiązania w funkcjonowaniu analizowanych organizacji.
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Nano - and microcrystals of doped niobates
PublicationPublikacja przedstawia wyniki analizy pomiarów wysokotemperaturowej rentgenografii strukturalnej niobanu lantanu domieszkowanego magnezem.
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Comparison of the paracetamol electrochemical determination using boron-doped diamond electrode and boron-doped carbon nanowalls
PublicationTwo different type of electrodes, boron-doped diamond electrode (BDD) and boron-doped carbon nanowalls (B:CNW) electrode, were used for the electrochemical determination of paracetamol using the cyclic voltammetry and the differential pulse voltammetry in phosphate buffered saline, pH = 7.0. The main advantage of these electrodes is their utilization without any additional modification of the electrode surface. The peak current...
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Fabrication of La-Doped Bi4Ti3O12 Ceramics
PublicationLa-modified Bi4Ti3O12 is a typical ferroelectric, piezoelectric and electro-optic material, having relatively low coercive field, low dielectric constant, high Curie temperature and high breakdown strength. Goal of the present research was to apply mixed oxide method for fabrication of BiTLax ceramics, study its chemical composition, crystalline structure and microstructure. The compound BiTLax for x=0, 0.25, 0.5, 0.75 ceramic...
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The upper critical field in doped MgCNi3
PublicationDyskutowany jest wpływ domieszkowania MgCNi3 na górne pole krytyczne (H_c2). H_c2 monotonicznie maleje wraz ze wzrostem koncentracji domieszki. Silniejszy wpływ widoczny w przypadku domieszkowania Fe może być tłumaczony poprzez efekt rozrywania nadprzewodzących par Coopera poprzez centra magnetyczne tworzone przez domieszki Fe.
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PROPERTIES OF DOPED ALKALINE-EARTH STANNATES
PublicationThe lanthanum doped barium stannate properties are investigated in this work. Including electrical and microstructural properties.
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Equation of state for Eu-doped SrSi2O2N2
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Luminescence of LiBaF3 and KMgF3 doped with Eu2+
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Superconductivity and ferromagnetism in Pd doped Y9Co7
PublicationThe ferromagnetic superconductor Y9Co7 was chemically doped to yield the solid solution Y9Co7-xPdx for 0 < x < 0.4. The lattice parameter a does not depend on x, whereas c increases with increasing Pd content up to x ¼ 0.2, the palladium solubility limit. The transition from ferromagnetism (TC ¼ 4.25 K) to superconductivity (Tsc ¼ 2.4 K) was observed only for the parent Y9Co7 compound. For the lowest tested Pd doping level (x ¼...
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Limited dissolution of transition metals in the nanocrystalline cerium (IV) oxide
PublicationNanocrystalline cerium (IV) oxides doped with transition metals have gained significant interest recently, mostly in the field of catalysis. Herein, we present the comprehensive studies on ceria doped with 10 mol.% of transition metals (Mn, Fe, Co, Ni or Cu) synthesized by the reverse microemulsion method. The aim of this work is to study the properties of those materials with the use of different complementary methods like XRD,...
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Cerium-doped orthophosphates: new promising scintillators
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Visible light photoactivity and structure of doped TiO2
PublicationOmówiono strukturą i właściwości TiO2 domieszkowanego siarką, węglem oraz borem. Aktywność fotokatalityczna zbadano w reakcji degradacji fenolu pod wpływem światła z zakresu widzialnego (l > 400 nm). Aktywność fotokatalizatorów odniesiono do ich właściwości takich jak powierzchnia właściwa, struktura krystaliczna oraz charakter chemiczny domieszki. Stwierdzono, że fotokatalizatory o najwyższej aktywności mają strukturę anatazu...
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Rare-earth doped materials for optical waveguides
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Luminescence properties of aluminosilicate glasses doped with neodymium
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High pressure spectroscopy of chromium doped LiTaO3crystals
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Spectroscopic properties of the Ce-doped borate glasses
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Heteropolyanions doped polyimine—Preparation and spectroscopic properties
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Production and characterization of MWBNNT and B-doped SWCNT
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Non-adiabatic superconductivity in the electron-doped graphene
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Raman Study on Doped Multiwalled Carbon Nanotubes
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Electrical and structural properties of Nb-doped SrTiO3
PublicationNiobium-doped strontium titanate synthesized via conventional solid-state reaction has been studied. Influence of niobium content on the lattice parameters and electrical conductivity has been reported. Various reduction conditions have been investigated. For samples reduced in hydrogen at 1400°C, a transition from thermally activated to metallic behavior has been observed. Maximum electrical conductivity (ca. 55 Scm−1 at 650°C)...
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Photocatalytic performance of alkali metal doped graphitic carbon nitrides and Pd-alkali metal doped graphitic carbon nitride composites
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Water uptake analysis of acceptor-doped lanthanum orthoniobates
PublicationIn this work, lanthanum orthoniobates doped with either antimony, calcium, or both have been synthesized and studied. The water uptake of the investigated materials has been analyzed by means of thermogravimetric studies. The results show the difference between the thermodynamics of hydration between the lanthanum orthoniobate system and other proton conducting ceramics. The relation between the water uptake and effective acceptor...
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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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Applying of Doped Graphene Oxide Coatings for Corrosion Prevention
PublicationINTRODUCTION Graphene is a carbonaceous material characterized by extraordinary properties (high electron mobility, high surface area, high mechanical strength of 1100 GPa, very dense network hindering the passage of even the smallest helium atoms) [1]. Therefore, it found many applications, also as an anti-corrosive layer [2]. Electrophoretic Deposition (EPD) is one of the methods to deposit coatings. However, due to slight solubility...
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DFT studies of the refractive index of boron-doped diamond
PublicationThe density functional theory is one of the optimal solutions in calculation of optical properties of materials on the quantum scale. In this paper, we have investigated the refractive index of a boron-doped diamond structure with the usage of Atomistic Toolkit software from Synopsys. During this study, various methods and pseudopotentials were checked to obtain an optimal performanceaccuracy method for calculation of such materials....
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Structural and electrical properties of titanium-doped yttrium niobate
PublicationIn this work, the influence of the substitution of niobium by titanium in Y3Nb1-xTixO7-δ on the structural and electrical properties is reported. Several experimental techniques, i.e. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS), were applied to investigate the system Y3Nb1-xTixO7-δ. Titanium in Y3Nb1-xTixO7-δ is an acceptor-type...
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Spectroscopic Properties of Yb3+/Tb3+Doped Germanate Glasses
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Spectroscopic properties of rare earth doped germanate glasses
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