Dissertations / Theses on the topic 'Oxygen conductor'
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Al-Musa, Abdullah Abdulaziz. "Partial oxidation of propene using solid electrolyte membrane reactors." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/6915.
Full textZhang, Yaoqing. "Exploring novel functionalities in oxide ion conductors with excess oxygen." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2576.
Full textCorallini, Serena. "Structure and dynamics of a new Brownmillerite compound Sr₂₋ₓBaₓScGaO₅ in view of possible application as oxygen ion electrolite at moderate temperature." Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S172.
Full textOxygen ion conductors operating at low temperature, below 300 ° C, are materials of major interest for several applications in the area of solid state ionicsas solid fuel cells, batteries, electrodes, sensors, catalysts, etc. However till now, the solid oxygen ion conductor works reasonably only at high temperatures above 800 ° C, which limits their application. In the search for improved oxygen ion conductors Brownmillerite structures ( ABO2.5 eq. A2B2O5 ) has always played an important role, especially in the low temperature regime where the dynamics of the tetrahedral chain induced mobility of oxygen. In this context, we have synthesized a new phase Sr1-xBaxScGaO5 with x = 0 (SSGO) and x = 0.1 (SBSGO) containing diamagnetic 3d0 ions to have a pure ion conductor. Depending on the synthesis route, the compound has two polymorphs, orthorhombic and cubic, which are both important for the oxygen conductivity. The reaction in the solid state leads to an orthorhombic Brownmillerite-type structure, while tmeling synthesis (using the Travelling Floating Zone method FTZ ) gives an oxygen-deficient Perovskite structure. The structures of both polymorphs were analyzed using the neutron powder diffraction as function of the temperature (D2B@ILL). A detailed analysis of SSGO Brownmillerite type shows that the Sc occupies octahedral sites, while the Ga occupies exclusively the tetrahedral ones. This cation ordering is unusual for the Brownmillerite structures. Moreover Sr2-xBaxScGaO5 undergoes a phase transition from an ordered configuration of the tetrahedral chains (GaO4) characteristic of I2mb space-group at room temperature, toward a disordered one characteristic of Imma space group (500 ° C). This important result confirms that the disorder of the tetrahedral chains is dynamic and it is the key to have oxygen ion conductor at moderate temperatures. Synthesis at elevated temperatures (up to melting point) gives a cubic structure Pm ̅m, stable up to 1000 ° C. The Perovskite -type structure is highly oxygen deficient. The mobility of the oxygen of these new compounds was studied by thermogravimetry analysis (TGA) coupled with mass spectrometry (MS) after the isotope exchange 18O-16O, by Raman and NMR spectroscopy coupled with theoretical ab-initio calculations (WIEN2k), by inelastic neutron scattering (IN6@ILL) coupled with calculations of ab-initio molecular dynamics (VASP ) . The results obtained from the structural and the lattice dynamics studies show that activation of the ion mobility is related to the transition to a disordered structure Imma, which implies an important dynamics of the chains GaO4 and the diffusion along the one-dimensional vacancy channel. These results have been reproduced by molecular dynamics calculations, in which the diffusion pathway is due only to the oxygen in the tetrahedral planes
Guironnet, Laure. "Compréhension de l'influence des paramètres micro et nano structuraux sur les performances électrochimiques de conducteurs mixtes." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0077.
Full textThe technology of ceramic membranes for oxygen separation knows a great interest due to high energetic efficiency in comparison with the cryogenic distillation process. However, for now, the oxygen fluxes produced by the membrane technology are not high enough for industrial applications. It is therefore necessary to improve the performances of the membranes. The results obtained in this work, using an original device, allowed us to a better understanding of the influence of architectural parameters on the oxygen flux and on the mechanisms limiting the transport of oxygen through the membrane. As a result, it is possible to investigate new architectures of membrane of which the oxygen flux could be close to industrial targets
Akin, Figen Tulin. "Ionic Conducting Ceramic Membrane Reactor for Partial Oxidation of Light Hydrocarbons." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1021991903.
Full textMiyazaki, Kazunari. "Studies on proton-conducting ceramic fuel cells for hydrogen-carrier utilization." Kyoto University, 2020. http://hdl.handle.net/2433/254526.
Full textAlves, Fortunato Maíra. "La zircone yttriée : un nouveau support pour la catalyse environnementale." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10175.
Full textThe aim of this work is to investigate the interactions between Pt nanoparticles and Yttria-Stabilized Zirconia (YSZ), an ionically conducting support. The idea was to overcome the effects of electrochemical promotion of catalysis (EPOC) observed on Pt/YSZ electrochemical catalysts which present low metal dispersion to conventional catalytic systems based on metallic nanoparticles finely dispersed on YSZ powered support. In that configuration, the migration of the oxygen ions from YSZ toward the Pt surface is not electrically controlled but thermally induced without any polarisation. First, we have established a new procedure to measure the Pt dispersion over YSZ. The metal support interactions between Pt and YSZ were characterized by Temperature Programmed Reduction and Infrared Spectroscopy. The importance of the YSZ oxygen vacancies on the chemisorptive behaviours of Pt as well as its catalytic for the propane oxidation was clearly demonstrated. The thermal migration of oxygen ions was validated by using the Isotopic Exchange procedure 18O/16O. The impact of these vacancies was evaluated and a mechanism of the propane deep oxidation on Pt/YSZ was proposed including the important role of bulk YSZ oxygen species in opposition with conventional supports such as silica and non-substituted zirconia. Finally, the key parameters that can influence the Pt/YSZ interactions such as the YSZ specific surface area, the yttria content, the YSZ preparation route as well as the loading and size of Pt nanoparticles were investigated. Our results point out that the thermal migration of oxygen ions from YSZ toward Pt surface occurs from 100 °C. In addition, the exchange between oxygen species from YSZ bulk and those from the gas phase is extremely fast starting from 100 °C. The Pt catalytic activity for the propane deep oxidation seems to be promoted by the mobility of the bulk YSZ oxygen species
Bu, Junfu. "Advanced BaZrO3-BaCeO3 Based Proton Conductors Used for Intermediate Temperature Solid Oxide Fuel Cells (ITSOFCs)." Doctoral thesis, KTH, Tillämpad processmetallurgi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165073.
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Martin, Manfred. "Oxygen and cation diffusion processes in oxygen ion conductors." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193656.
Full textMartin, Manfred. "Oxygen and cation diffusion processes in oxygen ion conductors." Diffusion fundamentals 6 (2007) 39, S. 1-16, 2007. https://ul.qucosa.de/id/qucosa%3A14216.
Full textSchmidt, Marek Wojciech, and Marek Schmidt@rl ac uk. "Phase formation and structural transformation of strontium ferrite SrFeOx." The Australian National University. Research School of Physical Sciences and Engineering, 2001. http://thesis.anu.edu.au./public/adt-ANU20020708.190055.
Full textBenahmed-Gasmi, Amina. "Nouveaux précurseurs de matériaux organiques conducteurs : des donneurs-pi aux polymères conjugués." Angers, 1996. http://www.theses.fr/1996ANGE0020.
Full textKay), Thomas Julie K. (Julie. "Oxygen ion conduction in layered intergrowth structures with intrinsic oxygen vacancies." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/17392.
Full textDeronzier, Eva. "Etude et optimisation des propriétés de transport de l’oxygène à travers des matériaux conducteurs mixtes pour la production d’énergie décarbonée." Thesis, Limoges, 2020. http://www.theses.fr/2020LIMO0056.
Full textMixed ionic and electronic conductors (MIEC) are used in numerous areas, such as cathode materials for the solid oxide fuel cells (SOFC) or as membrane materials for the oxygen gas separation. However, currently, oxygen semi-permeation fluxes produced by ceramic membranes are too low for potential industrial applications. Our study focuses on the better understanding of the oxygen transport mechanisms through the ceramic membranes in order to improve the oxygen semi-permeation fluxes through the membrane. The oxygen transport properties of lanthanum-based or barium-based perovskite materials are characterized and studied by a new and original setup. Then, new architectures of membranes are developed and their electrochemical performances are characterized
Zhen, Y. S. "Oxygen ion conduction in doped rare earth oxides." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383333.
Full textFrydenlund, Madelen Mørk. "Development of a new class of oxygen ion mixed conductors." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemisk prosessteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26129.
Full textNamjoshi, Shantanu A. "Interfacial properties of mixed conductors based on bismuth oxide for oxygen separation." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/20205.
Full textVibhu, Vaibhav. "Stabilité et vieillissement des études de nickelates base praséodyme comme cathodes pour oxyde solide piles à combustible." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0017/document.
Full textThis PhD work is dedicated to stability and ageing studies of Praseodymium based nickelates ascathodes for Solid Oxide Fuel Cells (SOFCs). With this respect Ln2NiO4+δ (Ln=La, Pr or Nd)compounds with the K2NiF4 type structure act as alternative cathode materials for IT-SOFC due totheir mixed ionic and electronic conductivity (i.e. MIEC properties). Pr2NiO4+δ shows excellentelectrochemical properties at intermediate temperature (i.e. low polarization resistance Rp value, Rp= 0.03 Ω.cm² at 700 °C), while La2NiO4+δ exhibits higher chemical stability. So, the properties ofLa2-xPrxNiO4+δ nickelates were investigated with the aim to find best compromise between chemicalstability and electrochemical performances. After synthesis, the physical and chemical properties aswell as their transport and electrochemical properties have been determined. Measurements of thepolarization resistance of symmetrical half-cells have been carried out by impedance spectroscopy.Then, the chemical stability and the electrochemical performance of the materials have been studiedfor duration up to one month. As an interesting point, even after complete dissociation of Pr2NiO4+δinto PrNiO3-δ,Pr4Ni3O10+δ and Pr6O11, the polarization resistance does not show significant change.So finally, two new materials PrNiO3-δ and Pr4Ni3O10+δ were investigated as SOFCs cathodeshowing very promising results for Pr4Ni3O10+δ in symmetrical cell (Rp (Pr4Ni3O10+δ) = Rp(Pr2NiO4+δ) = 0.15 Ω.cm² à 600 ° C) and complete cell (1.6 W.cm-2 at 800 °C)
Ledru, Romuald. "Mesure par spectroscopie d'admittance de jonctions Métal/Oxyde/Semi-Conducteur Organique : Analyse de la réponse diélectrique du pentacène." Thesis, Reims, 2012. http://www.theses.fr/2012REIMS035/document.
Full textOrganic transistors are vital in many applications of organic electronics but the electrical performance and time stability are technological limitation in order to make this technology reliable. Moreover, in these devices, the charge transport phenomenon has not to be clearly understood even if different models are commonly used to explain the field effect in organic transistors. In this context, this thesis talks about the admittance spectroscopy characterization of metal / oxide / organic semiconductor / metal junctions and analysis the organic semiconductor electrostatic behavior.The admittance spectroscopy measurements were performed on a wide frequency range (0.1Hz to 1MHz) in which the measured dielectric loss may be associated with the orientation phenomenon (as oscillation) of dipoles present in the structure.The frequency responses show three dynamic behaviors. At low frequencies (<10Hz), we observed an ionic diffusion, which is related to the ions movement of H+ through the structure. At high frequencies, (>10kHz) the response is due to defects into the oxide. Finally, at intermediate frequencies, the organic semiconductor response is identified and assigned to the permanent dipoles into the bulk. From these responses, an analytical model is developed and used to describe the dynamic responses. The semi-conductor behavior is described by the sum of a Debye and Cole-Cole function type. The analysis of the model parameters has highlighted the influence of permanent dipoles on the organic semiconductor permittivity. Finally, this model has been agreed on different samples based on pentacene and was applied to the Poly-3-hexylthiophene
Armstrong, Tad John. "Oxygen permeation properties of perovskite-related intergrowth oxides exhibiting mixed ionic-electronic conduction /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
Full textKilo, Martin, Marcela Andrea Taylor, Günter Borchardt, Ines Kaiser-Bischoff, Hans Boysen, Christoph Rödel, and Martin Lerch. "Fast anion-conduction in oxynitrides: oxygen and nitrogen transport in (Y, Zr)-(O, N)." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192927.
Full textKilo, Martin, Marcela Andrea Taylor, Günter Borchardt, Ines Kaiser-Bischoff, Hans Boysen, Christoph Rödel, and Martin Lerch. "Fast anion-conduction in oxynitrides: oxygen and nitrogen transport in (Y, Zr)-(O, N)." Diffusion fundamentals 8 (2008) 8, S. 1-7, 2008. https://ul.qucosa.de/id/qucosa%3A14154.
Full textBergerot, Laurent. "Etude de l'élaboration d'oxyde transparent conducteur de type-p en couches minces pour des applications à l'électronique transparente ou au photovoltaïque." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENI003/document.
Full textTransparent electronic is currently limited by the lack of a really performant p-type transparent conducting oxide (TCO), which makes the elaboration of a transparent p-n junction challenging. Cuprous oxide Cu2O is a promising p-type TCO, but its optical transmittance in the visible spectrum is limited by its relatively low band gap (2.1 eV). In this thesis, we aim at increasing this value. To achieve that, we explore MOCVD as the growth method for strontium and calcium doping of cuprous oxide. According to ab-initio calculations performed at Tyndall Institute in Cork, doping with these elements is supposed to increase the band gap of Cu2O. In chapter I, we introduce the context of this thesis. After explaining the required conditions that a material must fulfil to be a p-type TCO, we present the state of the art of Cu2O. In chapter II, we present all the techniques used in this work, from the elaboration (MOCVD, thermal annealing) to characterization (SEM, TEM, AFM, XRD, FTIR, Raman spectroscopy, XPS, UV-vis-NIR spectroscopy, 4 point probe and Hall effect measurement). In chapter III, our objective is to synthesize pure, undoped Cu2O thin films. We explore the influence of the MOCVD parameters on the films composition and morphology. We get homogenous films on Si/SiO2 substrates, while we get heterogeneous films with un-deposited parts on silicon substrate. In addition, we show the risk to get the metallic copper phase when precursor concentration is high, oxygen partial pressure is low, and/or temperature is high. This enables us to determine the optimal deposition conditions. Starting from those optimal conditions, we study the influence of strontium doping on the functional properties of the films (resistivity, band gap and visible light transmittance) in chapter IV. A decrease of resistivity was observed with strontium doping. While undoped films show resistivity values of 103 Ω.cm or more, films doped from 6 to 15% strontium show resistivity values of about 10 Ω.cm. P-type conductivity was confirmed through Hall effect measurements, with a mobility close to 10 cm2.V-1.s-1 and a charge carrier density of about 1016 cm-3. The large difference between this carrier density and the Sr concentration can be linked with the presence of a strontium carbonate and fluoride contamination that was detected by FTIR and XPS. The exact influence of those impurities is not well known. In addition, no significant variation of optical properties was observed, the band gap remained close to 2.4 eV and average transmittance in the 500-1000 nm range was about 55%. Similar tendencies were observed for calcium doping, addressed in chapter V. Calcium doping showed the particularity of leading to the presence of cavities localized at the substrate/Cu2O interface, for a high dopant concentration and under UV assistance. Eventually, we performed thermal annealing on some samples, doped and undoped, in chapter VI. For undoped samples, it allowed to decrease resistivity in the 10-100 Ω.cm range. For doped samples, it allows samples showing initial resistivity of about 10 Ω.cm to decrease it to 1 Ω.cm. No impact of thermal annealing on sample morphology or composition was observed. In this thesis, we successfully established the effects of Sr or Ca doping, which lead to a significant decrease of the resistivity without impact on the optical properties, unlike what was predicted by the ab initio calculations. We were thus able to improve the p-type transparent Cu2O thin films properties
Graia, Thameur. "Conducteurs par ions oxygène : propriétés structurales et électriques d'oxydes mixtes de bismuth, de cadium et de plomb." Lille 1, 1987. http://www.theses.fr/1987LIL10006.
Full textKoussi-Daoud, Sana. "Préparation électrochimique et caractérisation de couches nanostructurées de semi-conducteurs de type p pour cellules photovoltaïques hybrides." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066505/document.
Full textThe objective of this thesis was the electrochemical deposition (ECD) of p-type semiconductors forthe fabrication of p-Dye Sensitized Solar Cells (p-DSSCs). The electrodeposition method remained unexploredfor the p-DSSC applications. The best conditions for ECD of nickel oxide layers with a controlled thickness havebeen defined. Nickel oxide has been deposited in water medium, in ethanol, in dimethyl sulfoxide (DMSO)medium and in a mixture of DMSO/water solvent. The layers have been characterized by XRD, Ramanspectroscopy, SEM, optical measurements… then have been tested as a photocathode in p-DSSCs. The cuprousoxide (Cu2O) electrodeposition in an aqueous bath has also been investigated. The photovoltaic efficiency of thevarious prepared layers has been evaluated in p-DSSCs. We have also prepared inverse opal organized structureswith a perfectly defined macropore organization and size using a macrosphere polystyrene template. Finally, wehave explored the ECD of a copper delafossite CuFeO2 in DMSO medium
Grimaud, Alexis. "Propriétés de conduction mixte O2- / H+ / e- dans quelques phases dérivées de la perovskite : application aux cathodes de piles à combustible H+-SOFC." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00695911.
Full textVannier, Rose-Noëlle. "Nouvelles phases d'Aurivillius, conductrices bidimensionnelles par ions oxydes." Lille 1, 1992. http://www.theses.fr/1992LIL10002.
Full textGauquelin, Nicolas. "Impact of the structural anisotropy of La2NiO4+δ on high temperature surface modification and diffusion of oxygen." Rennes 1, 2010. http://www.theses.fr/2010REN1S216.
Full textLa2NiO4+δ a d'abord été étudiée en raison de ses similitudes structurales avec le supraconducteurs à haute température La2CuO4+δ et plus récemment comme matériau prometteur pour cathodes dans les piles à combustible à oxyde solide ainsi qu’en tant que membrane d'échange d'oxygène. Il cristallise dans le type structural en couches K2NiF4 et contient des oxygène en site interstitiel très mobiles dans son état fondamental et est ainsi surstoichiométrique. Au cours de cette thèse, la croissance de pures monocristaux de La2NiO4+δ à l’aide de la méthode du four à image, ils ont été caractérisés par diffraction de neutrons et la méthode de Laue en retour et des morceaux orientés de monocristal dans les directions cristallographiques [100] et [001] ont été préparés. La morphologie de la surface à haute température a été étudiée à l’aide de recuits dans des atmosphères différentes en utilisant différentes techniques de microscopie, la stabilité à haute température étant un paramètre nécessaire en vue d'applications et une modification structurelle vers des phases riches en nickel à T> 1273K fut découverte. La sensibilité de la non-stœchiométrie au refroidissement a été étudiée un nouvel appareil d’échange isotopique 18O-16O permettant la trempe des échantillons avec de l'azote liquide fut développé. Grâce à cet appareil, l'autodiffusion d’oxygène par SIMS dans la gamme 673-873K dans les deux directions cristallographiques a été réalisée. Les effets de la désorientation de la surface de l'échantillon sur la détermination du plus petit coefficient de diffusion ont été reportes et ont révélé la très forte anisotropie (> 5 ordres de grandeur de différence) entre les différents chemins de diffusion. Enfin utilisant HTXRD et des expériences de libération d'oxygène, démonstration fut faite que la diffusion de l'oxygène interstitiel commence à être pertinente à 550-600K et un changement de comportement est observé autour de 700K, où le mécanisme de diffusion peut changer d'interstitiel à interstitialcy
Goux, Aurélie. "Electrodépôt en présence d'additifs d'un oxyde semi-conducteur : le ZnO." Paris 6, 2004. http://www.theses.fr/2004PA066141.
Full textHadjar, Abdelkader. "Catalyseurs électrochimiques pour le stockage et la réduction des oxydes d'azote (NOx)." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10111.
Full textThe main objective of this study was to demonstrate the coupling between NOx storage/reduction process on barium, with an electrochemical reduction of NOx (micro fuel cell effect) on the same catalyst. The micro fuel cell effect is ensured by a an electromotive force (potential) which is created between catalytic nanoparticules (Pt and Rh) in contact with an ionic conductor (YSZ) and an electronic conductor (doped SiC). The micro fuel cell effect was observed, during the regeneration phase of the catalysts (rich period), on a Pt/Ba/doped α-SiC-YSZ/Rh monolithic system under lean-burn gasoline conditions at 400°C with an enhancement of about 10 % of the NOx conversion over a complete cycle lean/rich. This electrochemical effect was characterized by the electrochemical oxidation of CO (produced by steam reforming) into CO2 by using O2- ions coming from YSZ. Under Diesel conditions, the micro fuel cell system was found to work at low temperature especially at 300°C. In the second part of the work, a new generation of NOx Storage and reduction catalyst was developed consisting only of noble metals (Pt and/or Rh) deposited on YSZ support (Ba free catalyst). The catalytic measurements revealed that YSZ can be used as a NOx storage material in lean burn conditions (Gasoline and Diesel) especially when it was previously reduced under hydrogen. The storage mechanism would take place on the oxygen vacancies created by the removal of O-2 ions from the YSZ structure
Noirault, Samuel. "Nouvelles phases oxydes céramiques conductrices anionique et protonique pour pile à combustible." Nantes, 2008. http://www.theses.fr/2008NANT2053.
Full textIn the course of a prospective study devoted to electrolytes for SOFC and PCFC, the oxyborates Ln26O27(BO3)8 (Ln=La, Nd) and derivatives of Ba2In2O5 obtained by cationic substitution, have been characterized. Their reaction with water vapor on heating was analyzed and its effects on the structure and ionic conductivity were studied. The structure of Ln26O27(BO3)8 and Ln26O26(OH)2(BO3)8 (Ln=La, Nd) phases have been determined from single crystal data. These oxyborates are unusual examples of oxygen-deficient materials, with a structure of low symmetry, exhibiting fast proton conduction in wet air. A thermodynamic analysis of the hydration process of (Ba1-xLax)2In2O5+x-n1-x-n(OH)2n (0≤x<0. 6) phases shows that their stability increases when x decreases. Under wet air a protonic contribution to the total conductivity is evidenced for all compositions. Ba2(In1-xMx)2O5 and Ba2(In1-xMx)2O4(OH)2 (M=Sc, Y) phases were prepared up to x=0. 5 (M=Sc) and x=0. 35 (M=Y). A complete miscibility of Ba2In2O5 and BaMO3 (M = Ce, Ti et Zr) phases was observed and Ba2(In1-xMx)2O4+2x(OH)2(1-x) phases were obtained for all x values. The anhydrous phases are good oxygen ion conductors (σ>10-2 S. Cm-1 at 700°C for Ba2(In1-xScx)2O5 phases) and a high level of proton conduction was measured at T<400°C under wet air. On account of equivalent or even better performances compared to standard materials a possible use of such phases as an electrolyte for fuel cells operated under natural was evaluated by measuring their reactivity with CO2
Tedjar, Farouk. "Contribution à l'étude physico-chimique de [gamma]MnO2 : conduction mixte électronique-protonique." Grenoble INPG, 1988. http://www.theses.fr/1988INPG0103.
Full textPinter, Zoltan. "Caractérisation de couches épaisses de semi-conducteur WO3 et WO3 / TiO2 pour la réalisation de capteurs à NO2." Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0007/these.pdf.
Full textCurrently, the development of the chemical sensors applied in particular in the automobile industry to control the combustion process, becomes more and more important for economic reasons and to abate the atmospheric pollution. Several sensors are applied to detect different gas molecules produced or consumed during the oxidation of the combustibles materials like: O2, CO, CO2, H2O, SO2, SO3, Nox, CHx, etc. In order to realise the sensors controlling the volume of NO2 of the exhaust fumes in the exhaust pipe, we decided to study and characterise the basic materials used for this purpose, namely: WO3 and WO3/TiO2 thick layers with a thickness of 100-200 micrometers. The morphology, composition and the size of the sensor, from the viewpoint of its application, vary with different parameters, particularly with the variation of the elaboration conditions of the gas sensitive layer. The correlation between the experimental results allows us to understand the general behaviour of the WO3 and WO3/TiO2 thick layers from the aspect of the interaction of the two material types (WO3 and TiO2) on the one hand, and on other hand the sensing behaviour of these sensors in the presence of NO2. The spectroscopic and thermal studies allow us to recognise the importance of the TiO2 addition for the sensitivity of WO3 to NO2 and its stabilisation effect for the structure of the tungsten trioxide. On the basis of these results, we propose a microstructure for these mixed layers. Indeed, the layers are composed of polycristallin grains of WO3 interacting with the TiO2 grains forming chemical bonds at the domain of the interface. In this case, the addition of TiO2 leads to the structural stabilisation of the WO3 and increases the sensitivity of the layer for NO2
Hammouche, Abderrezak. "Contribution à l'étude de La(1-x)Sr(x)MnO3 comme matériau d'électrode à oxygène à haute température." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0075.
Full textChen, Xiyong. "Thermo-mechanical/structural properties and oxygen permeation behavior of mixed ionic electronic conductors La(1-x)Sr(x)CoO(3-delta) /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/9893.
Full textDarricarrere, Gwenaël. "Contribution à l'étude des phénomènes de conductivité et de polarisation dans quelques verres oxydes ioniques." Montpellier 2, 2006. http://www.theses.fr/2006MON20103.
Full textBettahar, Noureddine. "Oxydes mixtes de platine et de bismuth et/ou de plomb : synthèse, étude structurale et conductivité électrique." Lille 1, 1987. http://www.theses.fr/1987LIL10039.
Full textBrisse, Romain. "Synthèse de composés push-pull pour la photosensibilisation d'oxydes semi-conducteur de type p." Palaiseau, Ecole polytechnique, 2015. http://www.theses.fr/2015EPXX0116.
Full textBenjelloun, Driss. "Conduction électrique dans Fe₂O₃α et Cr₂O₃ oxydes de structure corindon déformée." Bordeaux 1, 1985. http://www.theses.fr/1985BOR10571.
Full textChmielowski, Radoslaw. "Bicouche oxyde ferroélectrique / oxyde conducteur Bi3. 25La0. 75Ti3O12 / Sr4Ru2O9 : élaboration par ablation laser, caractérisations structurales et propriétés électrique." Toulon, 2007. http://www.theses.fr/2007TOUL0007.
Full textBilayers ferroelectric oxide / conductive oxide, Bi3. 25La0. 75Ti3O12 (BLT) / Sr4Ru2O9 / Si[100] were elaborated by pulsed laser deposition. Structural characterizations were done by electron microscopy and X-ray diffraction; electrical properties were measured by impedance spectroscopy and Van der Pauw’s method. It is the first time that Sr4Ru2O9 is elaborated as thin films. We have shown that Sr4Ru2O9 is a conductive oxide at high temperature and has a semiconductor behavior at low temperature. The BLT thin films have polarization out of the substrate plane. Thick films of the BLT have polarization in the plane, which corresponds to a preferential orientation (00l). An intermediate layer, based on SrTiO3, between the substrate oxide Sr4Ru2O9 and the layer of BLT, was highlighted by electron microscopy. This phase grows at the cost of the ferroelectric material
Magrez, Arnaud. "Nouveaux oxydes électrolytes solides : relation entre microstructure et conductivité ionique." Nantes, 2002. http://www.theses.fr/2002NANT2025.
Full textChesnaud, Anthony. "Oxy-gallates et oxy-germanates de terres rares conducteurs par ions oxygène." Nantes, 2005. http://www.theses.fr/2005NANT2047.
Full textWahyudi, Olivia. "Exploring oxygen mobility in (Pr/Nd)2NiO4+δ : single crystal growth, isotopic exchange depth profiling and structural characterization by X-ray, neutron and electron diffraction." Rennes 1, 2011. http://www.theses.fr/2011REN1S166.
Full textCette étude vise à mieux comprendre la mobilité à température modérée de l’ion oxygène, dans les nickelates de néodyme et de praséodyme à structure de type Ruddlesden-Popper. Parmi les applications visées figurent Les piles à combustible tout solide et les membranes pour la séparation de l’oxygène. Des monocristaux de haute qualité ont été synthétisés et caractérisés par diffraction des rayons X, des neutrons et des électrons. La microscopie électronique à transmission a révélé des superstructures complexes, et les réflexions satellites ont pu être associées à un ordre à longue distance des oxygènes interstitiels (ordre observé aussi par diffraction des neutrons). Une modulation incommensurable apparaît comme le principal type d’ordre dans cette catégorie d’oxydes. Un caractère seulement partiellement réversible de l’intercalation de l’oxygène dans le nickelate de néodyme à été mis en évidence in situ par diffraction des neutrons lors de l’insertion/désinsertion électrochimique de l’oxygène. La phase finale montre un basculement ordonné des octaèdres de coordination. La faible distance inter-plans conduit à un site tétraédrique fortement distordu pour l’oxygène inséré et à une mobilité ionique plus faible, comparée à celle des composés au praséodyme. De plus, des mesures de transport ionique par profilométrie par échange isotopique ont montré une énergie d’activation très élevée dans le cas du nickelate de néodyme. La stabilité observée jusqu’à 1273K de nos monocristaux de nickelate de praséodyme montre l’importance cruciale du mode de synthèse, et remet en question les résultats antérieurs obtenus sur des échantillons synthétisés par réaction classique à l’état solide
Carrière, David. "Fonctionnalisation organique de nanoparticules d'oxyde de zirconium : application à la conduction protonique." Palaiseau, Ecole polytechnique, 2002. http://www.theses.fr/2002EPXX0033.
Full textEl, Jebbari Jamal Eddine. "Résonance paramagnétique électronique et conductivité électrique dans l'oxyde mixte semi-conducteur Co3 O4." Toulouse 3, 1987. http://www.theses.fr/1987TOU30088.
Full textTemga, Temga. "Mouvement et piégeage des charges électriques dans un matériau non-conducteur anisotrope : Application au rutile (TiO2)." Ecully, Ecole centrale de Lyon, 2004. http://bibli.ec-lyon.fr/exl-doc/ttemga.pdf.
Full textNon-conductive materials and particularly solid insulators have a capacity to trap electric charges under certain conditions. The characterization of the trapping mechanisms achieved by the space charge physic, which describes not only trapping and conduction mechanisms of electric charges but also the condition of the stability and relaxation of the charges distribution. In this report, the trapping mechanisms of electric in a wide band gap semi-conductor material, are studied by the Scanning Electron Microscopy Mirror Effect. The studies have shown that electric charges diffuse, with a great leakage surface current. The high value and the anisotropy of the dielectric constant induces respectively a screening effect and an anisotropy of the distribution of trapped charges (elliptical or circular, mirors images). From the fundamental point of view, an appropiate analytical model is propose to take into account these new caracteristics
Gazeau, Camille. "Développement d’outils numériques pour la sélection et l’optimisation de matériaux conducteurs mixtes pour l’oxycombustion." Thesis, Orléans, 2014. http://www.theses.fr/2014ORLE2031.
Full textMixed Conductors (MIECs) are promising membrane materials for oxygen separating from air at high temperature. The oxygen semi-Permeation is the most important property of the membrane. This property induces a chemical potential gradient, which is the origin of some membrane ruptures. Forecasting gradients in service and the knowledge of MIECs mechanical properties are necessary for predict the reliability of future power plants. While the diffusion is well described by the Wagner theory, no consensus has yet emerged regarding the surface exchange models proposed in the literature. Furthermore, these models describe the stationary state, and cannot be extended to the transient stage. In this thesis, a new surface exchange model is proposed. This model takes into account the association/dissociation of oxygen and the high energetic cost of oxygen reduction/oxidation thanks to the balance of a transient species only present at the surface. This model can reproduce stationary state and transient stage. In parallel, a test device for characterizing the mechanical properties of the MIECs has been developed at 900 ° C. The test is “pseudo-Brazilian test” instrumented by an optical measurement. Post-Processing is carried out by a "Integrated Digital Image Correlation" method. The elastic properties of seven mixed conductors have been characterized
SUDERON, HERMANN. "Conduction thermique des phases supraconductrices de UPt3." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10266.
Full textDailly, Julian. "Synthèse et caractérisation de nouveaux matériaux de cathode pour piles à combustible à conduction protonique PCFC (Protonic Ceramic Fuel Cell)." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2008. http://tel.archives-ouvertes.fr/tel-00416109.
Full textDans ce cadre, le but de nos recherche a été de concevoir de nouveaux matériaux de cathode pour pile PCFC présentant de bonnes propriétés de conduction mixte ionique et électronique ainsi qu'une activité catalytique élevée vis-à-vis de la réaction de réduction de l'oxygène, entre 400 et 600°C. Plusieurs matériaux à conduction mixte ont été synthétisés à l'ICMCB, notamment des perovskites et des oxydes de structure de type Ruddlesden-Popper (en particulier les oxydes A2MO4+). Des analyses thermogravimétriques ont été réalisées pour étudier la stabilité de ces phases sous air humide, ainsi qu'une éventuelle insertion d'eau dans la structure. Des demi-cellules symétriques ont été élaborées pour les caractérisations éléctrochimiques par spectroscopie d'impédance complexe et voltampérométrie (mesures de résistances spécifiques de surface, courbes de polarisation cathodique).
Les caractérisations physico-chimiques et électrochimiques ont permit de sélectionner les meilleurs composés et ont conduit à la réalisation de la première monocellule PCFC utilisant le matériau de cathode Pr2NiO4+. Des densités de puissance de 100 mW/cm² ont été mesurées pour une température de fonctionnement de 600°C.
Le, Boulbar Emmanuel. "Croissance par ablation laser pulsé de nouvelles phases d'oxyde de titane pour l'électronique transparente et la conversion de photons." Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00667730.
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