Tesis sobre el tema "Réduction catalytique du CO2"
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Savourey, Solene. "Nouveaux procédés de réduction catalytique du CO2 en consommables chimiques". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV051/document.
Texto completoFossil resources have been extensively used for the past 200 years allowing a fast paced industrializationin our society. However we are facing today several challenges to preserve our way of life 1) CO2 shouldbe captured and stored/used to avoid large quantity of CO2 to be released in the atmosphere 2) Bypassthe use of fossil resource by using another source of carbon for the synthesis of chemicals 3) Developefficient energy storage technologies to rely more on renewable intermittent energy sources. As CO2 is acheap widely available resource, this waste could be used as well as a source of carbon for the synthesisof value added chemicals but also as a way to store energy in the tandem CO2/MeOH. However as it isan inert gas few processes using CO2 have been industrialized so far.Inspired by Nature’s way to use CO2 we decided to design new reactions from carbon monoxide andformic acid, two derivatives easily available from CO2 that could enable us to overcome the limitationwe faced with CO2. We therefore studied the transformation of CO2 to methanol using formic acid as anintermediate and a reductant and we subsequently used this reaction to perform the methylation ofaromatic amines using formic acid. Finally we developed a new reaction of amines homologation withcarbon monoxide allowing the formation of several C–C bonds
Gregoire, Manon. "Valorisation catalytique du CO2 via l’hydrogénation pour la production de méthane". Electronic Thesis or Diss., Littoral, 2024. http://www.theses.fr/2024DUNK0713.
Texto completoThis study focuses on the recovery of CO2 by the methanation process. It aims to develop efficient and stable catalytic materials for this reaction. First, we focused our work on nickel catalysts supported on different silicas in order to study the influence of particle size. The first, Ni/SiO2 is the conventionally used nickel catalyst on commercial silica with metal particle sizes of about 12 nm quite high and located mainly outside the silica. The second, Ni/IWI, has Ni NPs confined in the mesopores of SBA-15 with an average size of 9 nm. The third, Ni/MIA, with NI NPs confined in the micropores of SBA-15 and an average size of 3 nm. The best catalytic performance is achieved with the Ni/MIA catalyst with a maximum efficiency of 86 % at 430 °C. It therefore offers great potential for use due to its ability to resist sintering due to the confinement of Ni nanoparticles. Then, a series of x%Ni/Phyllo (with x = 5 %, 10 %, 20 % and 40 % nickel) was synthesized in order to study the influence of Ni content. Catalytic tests showed that 20%Ni/Phyllo had interesting catalytic activities. In order to study the influence of the phyllosilicate reduction temperature on the methanation reaction, this material was reduced to several temperatures and it was the reduction to 800 °C that allowed better catalytic performance, with a CH4 yield of 92 % at 350 °C. Post-test characterizations do not show particle sintering or carbon formation on the surface of the materials. In addition, the material showed no deactivation after 48 hours. Subsequently, the gaseous composition and reduction duration were studied on reduced materials at lower temperatures in order to approximate the performance of a reduced material at 800 °C. However, the results were inconclusive. Finally, several series of perovskites have been synthesized. Indeed, these materials offer a large number of interesting properties for the methanation reaction. A number of perovskites have been synthesized from LaNiO3, completely or partially modifying the A and B cations and modifying the lanthanum stoichiometry. The B cation with the best catalytic performance is nickel and the ideal stoichiometry for lanthanum is 0.9. On the other hand, substituting the A cation with other alkaline earth elements may be beneficial. Indeed, strontium, sodium and calcium increase the catalytic performance up to 80 % at 330 °C for La0.9Sr0.1NiO3. Finally, cation A has been completely substituted and calcium offers promising results thanks to the presence of carbonates. It has therefore been calcined at a lower temperature in order to promote the formation of carbonates and allows a CH4 yield of 89 % at 300 °C
Adamowska, Malgorzata. "Réduction sélective catalytique des oxydes d'azote issus de la combustion du charbon, à l'aide des hydrocarbures émis, sur Rh/CeO2-ZrO2". Paris 6, 2007. http://www.theses.fr/2007PA066275.
Texto completoCruz, neto Daniel H. "Photophysical investigations of reversible charge accumulation in photocatalytic molecular systems". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP098.
Texto completoInspired by nature’s masterpiece of evolution, the conversion of solar energy through artificial photosynthesis is one of the most promising solutions to the ongoing global energy crisis. Deploying functional artificial mimics of the photosynthetic apparatus, however, requires a deep understanding of the processes embedded in the functioning of naturally photosensitizing organisms as they provide the roadmap to realize artificial photosynthetic devices. These processes include light harvesting, charge separation, multiple charge transfer steps leading to effective charge accumulation and, finally, efficient catalysis. In this work, we investigate all of these elementary steps by employing state-of-the-art time-resolved spectroscopic approaches with the goal of exploring the photophysics of different biomimetic molecular systems devoted to the photoreduction of carbon dioxide (CO₂) to produce energy-rich solar fuels. We start with the development of a novel pump-pump-probe experimental setup that is capable of triggering and detecting the stepwise accumulation of charge through the powerful lens of a resonance-enhanced Raman scattering probe. A model system containing the methyl viologen dication (MV²⁺) as a dual electron acceptor, the prototypical [Ru(bpy)₃]²⁺ complex as a photosensitizer, and ascorbate as a reversible electron donor is used for a proof-of-concept of the technique. Indeed, with the first pump, MV•⁺ is formed and detected through its fingerprint vibrational mode at 1356 cm⁻¹. When the transient concentration of MV•⁺ peaks, we fire the second laser pump and show the possibility of tracking the reversible formation of the two-electron accumulated MV⁰ species through a unique vibrational mode at 992 cm⁻¹. We then move on to investigating catalytically active systems featuring iron porphyrin derivatives as CO₂ reduction catalysts. These porphyrins are integrated into multicomponent biomimetic systems that similarly contain [Ru(bpy)₃]²⁺ and ascorbate as photosensitizer and reversible electron donor, respectively. For the urea-functionalized derivative (FeUr), a catalyst with a hydrogen-bonding network lodged in its second coordination sphere, we provide a full mechanistic depiction of all photoinduced processes leading to charge accumulation and its activation towards CO₂. In inert atmosphere, starting from Feˡˡˡ, we report the stepwise formation of the formal Feˡ species as a result of the double pump excitation strategy. Remarkably, under catalytic conditions in the presence of CO₂, our spectroscopy-based approach provides compelling evidence that the Feˡ oxidation state of FeUr, product of two consecutive electron transfer steps, is already catalytically active, evidenced by the accumulation of the stable Feˡˡ‒CO intermediate of the CO₂ reduction cycle. Going beyond FeUr, we show that Feˡ is catalytically active irrespective of the design strategy used in the functionalization of the porphyrin macrocycle, challenging the classical picture of CO₂ reduction catalysis promoted by iron porphyrins. Finally, we move away from the prototypical [Ru(bpy)₃]²⁺ complex and dive into the photophysics of different photosensitizers based on earth-abundant elements, including copper(I)-based complexes, a perfluorinated zinc porphyrin derivative (ZnF₂₀), and a fully organic triazatriangulenium carbocationic dye (TATA⁺). Importantly, we show that the TATA⁺ dye is capable of photosensitizing charge accumulation on the active FeUr-based system, activating it towards the reduction of CO₂. The characterization of new photosensitizing units based on abundant elements is fundamental for the development of artificial photosystems with real-world applications
Zsoldos, Daniela. "Complexes mono et bis bipyridine carbonyle de ruthénium(II), précurseurs de polymères organométalliques : propriétés électrochimiques et applications à l'électrocatalyse de la réduction du CO2 en milieu aqueux". Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10027.
Texto completoFlura, Aurélien. "Réduction sélective catalytique des NOx par des composés oxygènes". Poitiers, 2011. http://nuxeo.edel.univ-poitiers.fr/nuxeo/site/esupversions/e54ad33f-a463-4cb3-bb36-07c5b01f48c3.
Texto completoLately, Diesel engines have been extensively studied because they emit lesser CO2 than gasoline engine of equivalent power, since they work in lean condition, i. E. In excess oxygen. However, they produce NOx (NO and NO2), which are pollutants hardly transformed in nitrogen in oxidizing atmosphere. The point of this manuscript is to propose a catalyst active in NOx reduction by ethanol (EtOH-SCR) at 200°C, which is the average temperature of Diesel exhaust gas. In order to answer to this problem, a catalyst known to be active at 300°C in EtOH-SCR has been chosen: Ag/Al2O3. The first part of this manuscript details the modifications made to the reference catalyst (Ag/Al2O3) in order to broaden its activity window toward low temperature. The alumina support has been modified by adding transition metals (Mn, Fe, Ti, Zn), then a second metal has been added in addition to silver over alumina (Ru, Ir, Cu, Co, Gd, In and Sc). This part shows that the Ag/Al2O3 catalyst activity is limited up to 300°C: maximum conversion of NOx to N2 (34%) is obtained with the catalyst modified with ruthenium Ag-Ru(0. 5wt%)/Al2O3. The following parts try to explain why the catalysts activity is limited at low temperature. Ethanol is mostly transformed into acetaldehyde and ethylene during the NOx reduction reaction. It has been showed that acetaldehyde and ethylene can react with NOx to yield nitrogen, but the SCR reaction with acetaldehyde begin at 300°C, whereas the reaction with ethylene starts at 550°C. Only the reaction between ethanol and NO can lead to nitrogen formation below 300°C. It is finally showed that this reaction is limited at 150°C by the ethanol activation over alumina acid-base pairs, which appears by Al2O3 dehydration at about 250°C. The reaction is then limited at 250°C because nitrates hardly react with ethanol to yield N2 below 300°C. Above 300°C, it is showed that nitrogen formation is in competition with NH3 formation
Plédran-Pinéda, Carole. "Réduction catalytique des nitrates et des nitrites en milieu aqueux". Poitiers, 1999. http://www.theses.fr/1999POIT2314.
Texto completoMalfoy, Philippe. "Réduction catalytique de NO et N2O par H2, CO ou C3H8". Lille 1, 1997. http://www.theses.fr/1997LIL10183.
Texto completoFREYSZ, JEAN-LUC. "Reduction catalytique selective des oxydes d'azote par le propene en exces d'oxygene sur platine supporte nouvelle methode d'analyse temporelle simultanee de la surface catalytique et de la phase gaz par couplage irtf - sm". Caen, 2000. http://www.theses.fr/2000CAEN2019.
Texto completoDacquin, Jean-Philippe. "Réduction catalytique simultanée des oxydes d'azote (N2O et NO) provenant d'effluents gazeux d'installations industrielles : application d'un procédé catalytiquee à basse température". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10075.
Texto completoAs part of the abatement policy of greenhouse gases engaged by the ADEME, the purpose of the thesis was to develop catalysts for their application to the catalytic reduction of nitrogen oxides from stationary sources. Elimination of N2O and NO take place at low temperature with the presence of O2 and H20. ln these conditions, two reaction pathways could be envisaged. Firstly, we examined the catalytic decomposition but the inhibitors effects of O2 and H2O are difficult to avoid. Consequently, the second way is the catalytic reduction to attenuate these effects. The treatment of exhaust gases containing nitrogen oxides currently involves supported noble metal catalysts. ln these conditions, the use of perovskite could be an interesting way. Indeed, perovskite attenuates the inhibiting effect and avoid the particle growth. ln a first part, we examined the catalytic properties of perovskite modified by palladium for the catalytic decomposition of N2O. Deposition of palladium on LaCoO3 leads to higher activity in comparison with alumina. This different catalytic behaviour cannot be completely explained by changes in the metal dispersion but also by the extent of the metal/support interaction. ln a second part, we examined the catalytic reduction with H2 on supported platinum catalysts. After reduction, Pt supported on alumina and on perovskite both exhibit small nanoparticIes of Pt. Stabilisation of these particles on perovskite occurs during thermal ageing instead of sintering of Pt which predominates on alumina, as evidenced by spectroscopic characterisations. These observations are accompanied by promotional effects both on the conversion of NO and N2O in the former case
Kieger, Stéphane. "Réduction catalytique sélective des oxydes d'azote par l'ammoniac sur catalyseurs Cu-zéolithe". Montpellier 2, 1998. http://www.theses.fr/1998MON20258.
Texto completoHamon, Cyrille. "Préparation et auto-assemblage de nanobâtonnets fonctionnalisés pour la photo oxydo-réduction catalytique". Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S056/document.
Texto completoWith the recent development of chemical synthesis in colloidal suspension, new photosensitizers with high surface area have been considered in this thesis to support redox reactions induced by light. This work is therefore in the scope of finding new energy sources to meet the problems posed by the depletion of fossil fuels. Quantum nanorods with a core@shell composition and gold nanorods were synthesized. Their shape anisotropy permits to assemble them in liquid crystal phases. Thanks to an original method of drying, hierarchical assemblies were obtained, which is promising to perform photoredox reactions on these assemblies thereafter. Furthermore, a natural catalyst, a hydrogenase was successfully grafted onto the nanocrystals and studied in electrochemistry. These systems would improve the performance of biofuel cells
Carnevillier, Christelle. "Modification de catalyseurs de reformage platine-iridium/alumine par ajout d'étain introduit par réaction d'oxydo-réduction de surface". Poitiers, 2003. http://www.theses.fr/2003POIT2307.
Texto completoEl-Alj, Khalid. "Réduction catalytique en phase liquide du parachloronitrobenzène sur métaux de Raney à base nickel". Grenoble 1, 1990. http://www.theses.fr/1990GRE10107.
Texto completoDurupt, Nicolas. "Etude de la réduction catalytique du nitrate d'uranyle par l'hydrogène : dimensionnement d'un réacteur triphasique". Toulouse, INPT, 1995. http://www.theses.fr/1995INPT021G.
Texto completoEnsuque, Elisabeth. "Réduction catalytique sélective des oxydes d'azote par le décane en atmosphère riche en oxygène". Montpellier 2, 1996. http://www.theses.fr/1996MON20145.
Texto completoGravejat, Paul. "Réduction catalytique sélective des NOx par les hydrocarbures : approches Haut-Débit et microcinétique expérimentale". Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10100.
Texto completoThe aim of this study was to discover a catalytic material for NOx reduction by HC-SCR in Diesel exhaust which is active at the lowest temperatures and hydro thermally stable at high temperatures by using High Throughtput experiments (HTE). A library of 150 catalysts was synthesized. Catalysts are supported Ag, Au, Cu on Al2O3, TiO2, ZrO2, CeO2 and further doped with different dopants (Ga, Mo, …). They were tested in a 16-parallel reactor (SWITCH-16) using a Temperature Program Reaction (TPR) protocol with a model feed (100ppm NO / 350ppm C3H6 / 15% O2 /11% H2O). The best catalyst formulation 5%Ag/1%P/Al2O3, which was further improved, exhibits a light off temperature of 50°C lower than a reference commercial catalyst and is stable after ageing at 750°C in presence of water for 16 hrs. For pilot testing, the best catalyst was deposited by sol-gel method on a 1x2 inch monolith (300 cpsi). We showed the consistency of catalytic results obtained in the parallel fixed beds match with monolith bench testing. In parallel a experimental microkinetic approach of surface elementary steps involved in the HC-SCR of NO on Ag/Al2O3 catalyst has been performed to reveal the elementary steps controlling the conversion of the NO reactant taking into account the competitive chemisorption between NO and CO that is present in an exhaust gas. We identified the elimination of Oads species adsorbed on Ag° sites as the limiting step for the N2 production and suggested a new orientation of a HTE study
Rolland, Matthieu. "Des limites à la réduction d'échelle en réacteur de test catalytique en lit fixe?" Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10142/document.
Texto completoIn order to lower costs, testing of catalytic pellets (spheres or extrudates) is performed in ever smaller fixed bed reactors whereas catalytic pellet size is unchanged. The object of this thesis is to explore domains where downsizing leads to new questions in terms of physics, repeatability and modeling. The thesis is built in 5 chapters, 1) a detailed introduction of the context and a review of the literature on small fixed bed reactors, 2) a discussion about flow patterns in fixed beds filled with fine powder where capilary effects are not negligible, 3) a presentation of a methodology to assess the impact of sampling small number of pellets out of a non uniform set and results for internally mass transfer limited reactions, 4) a study of the effect of randomness in fixed beds first through a pore network model with a good ability to predict trends but lacking accuracy, then using direct numerical simulation of a reactive flow in fixed beds made of 8 cylinders arranged in several configuration showing that packing effects occur, concurrently with external mass transfer limitations, when cross flow diffusion is not fast enough to level out convection and reaction induced gradients, 5) a conclusion that summarizes design criteria and offers a few perspectives for R&D in downsizing
Barreau, Mathias. "Étude de la réduction catalytique sélective (SCR) des NOx par un mélange éthanol-ammoniac". Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT2283/document.
Texto completoThe NOx Selective Catalytic Reduction is an efficient process for exhaust gas treatment. However, for Diesel vehicles, the activity at low temperature (175-250°C, starting phase of vehicles) remains limited. In addition, the NH3-SCR catalysts are sensitive to the NO2/NOx ratio, with an optimum for NO2/NOx = 0.5. Unfortunately, at low temperature, the proportion of NO2 is low because the oxidation catalyst (DOC) placed upstream is also weakly efficient.Ethanol (EtOH) is another possible reductant, mainly associated with Ag/Al2O3 catalysts. This system also has a limited activity at low temperature, although the oxidation of EtOH is accompanied by NO2 formation. In this work, the association of EtOH and NH3 for the SCR of NO on a Ag/Al2O3 catalyst was studied. A synergistic effect was obtained, with a high gain of conversion at low temperature. This gain neither results from a reaction between NH3 and EtOH or its oxidation by-products (CH3CHO, CO…), nor only by the reaction between NO2 (formed by reaction of NO with EtOH) and NH3. Characterization of adsorbed species by FTIR and (H2+NH3)-SCR experiments led to the conclusion that H* species, resulting from ethanol dehydrogenation, react with NOx to yield HNOx species highly reactive with NH3.Finally, in order to use the remaining NH3, NO and NO2, the use of a dual bed (2%Ag/Al2O3 + NH3-SCR catalyst) allowed a NOx conversion between 46 and 95% from 175 to 250°C. This system consequently allows a high NOx conversion at low temperature, avoiding the NO2 lack at low temperature (low DOC activity)
Wang, Lianke. "Réduction catalytique du dioxygène et des protons par des complexes dinucléaires de Fe(II)". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAV020/document.
Texto completoThis thesis presented the design and synthesis of several bioinspired iron complexes bearing thiolate groups. Their structural, electronic, magnetic properties and their relationship also have been investigated by using different spectroscopic methods in combination with computational ones.This manuscript mainly focused on their catalytic or electrocatalytic propreties towards the reduction of O2. A non-heme diiron(II) complex with an unique thiol group has been synthesized and characterized. The thiol group can be deprotonated by base to derivate a neutral iron(II) thiolate complex. Both complexes displayed highly reactivity towards O2 to yield μ-hydroxo and μ-oxo bridged diron(III) complexes. Iron complex with thiol is an efficient ORR catalyst with 100% selectivity for H2O2 production in the presence of one-electron reducing agent and protons. When the catalysis is electrochemically-driven, H2O is the main product during electrocatalysis (~14-20% of H2O2). Based on the fact that hydrogen peroxide is generated in both cases (quantitatively or in a 20% amount in chemical and electrochemical catalysis, respectively), it can be proposed that a common intermediate, i.e. the calculated iron-peroxo complex, is generated during catalysis. The mechanism has been experimentally and theoretically investigated revealing that the control of the selectivity arises from the efficiency of the electron donor system (reducing chemical or applied potential).Another asymmetric diiron(II) complex with an FeCOCp unit has also been synthesized and well characterized in its two forms in MeCN. This asymmetric diiron (II) complex is active electrocatalyst for H2 production in an E(ECEC) mechanism with an activation step. The possible intermediates in the catalytic cycle have been generated and characterized by different spectroscopies. It should be noted that the bipyridine moiety in ligand acts as electron reservoir in the catalytic cycle.In addition, the first iron-based thiolate/disulfide interconversion system has been presented in this manuscript, which enriched the family of the metal-promoted interconversion between thiolate and disulfide. Interesingly, the iron-based system not only showed hailde-induced interconversion, but also the solvent-dependent properties.Finally, mononuclear iron(III)-thiolate complexes had interesting intermediate spin ground state. Susceptibility measurements, powder cw X- and Q-band EPR spectra, and zero-field powder Mössbauer spectra showed that all complexes display distinct magnetic anisotropy. Theoretical approach demonstrated that the main factor driving the magnetic anisotropy is the spin-orbit coupling (SOC)
Gotico, Philipp. "Stratégies bio-inspirées pour la réduction catalytique et la valorisation du dioxyde de carbone". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS283/document.
Texto completoThe criticality of global warming urges for the advancement of science to reduce carbon dioxide (CO₂) emissions in the atmosphere. At the heart of this challenge is the development of sustainable catalysts that can help capture, activate, reduce, and eventually valorize CO₂. This PhD work tried to respond to this call by developing molecular mimics inspired by natural systems in the larger scheme of artificial photosynthesis. Firstly, it involved tracking the journey of a photon of visible light and how it is transformed to a reducing power able to reduce CO₂. Secondly, in search for more efficient and stable catalysts, new mimics were synthesized inspired by the exceptional performance of CO dehydrogenase enzymes (CODH) in reducing CO₂. Lastly, further understanding of CODH also led to a proof-of-concept that directly valorizes the photo-produced CO for the synthesis of isotopically-labelled amide bonds, a common motif in pharmaceutically-relevant drugs
Gomes, Christophe. "Une approche diagonale pour la transformation catalytique du dioxyde de carbone". Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00954408.
Texto completoVillanueva, Adrian. "Réduction catalytique du NO par le propylène sur les pérovskites LaCr1-xCuxO3 et LaGa1-xCuxO3". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24977/24977.pdf.
Texto completoVillanueva, Adrian. "Réduction catalytique du NO par le propylène sur les pérovskites LaCr₁₋xCuxO₃ et LaGa₁₋xCuxO₃". Master's thesis, Université Laval, 2007. http://hdl.handle.net/20.500.11794/19468.
Texto completoLiger, Emmanuelle. "Rôle catalytique des oxyhydroxydes de Fe(III) : réduction de U(VI) par Fe(II) adsorbé". Grenoble 1, 1996. http://www.theses.fr/1996GRE10266.
Texto completoMauvezin, Mathias. "Réduction catalytique de N2O par NH3 sur catalyseurs à base de zéolithe bêta contenant du fer". Montpellier 2, 2000. http://www.theses.fr/2000MON20098.
Texto completoAyala, Villagomez Enrique. "Réduction catalytique sélective de NO par NH3 sur Cu-faujasite : effet de l'acidité et approche mécanistique". Montpellier 2, 2003. http://www.theses.fr/2003MON20089.
Texto completoPirez, Marion. "Réduction catalytique sélective des oxydes d'azote (NOx) provenant d'effluents gazeux industriels par l'hydrogène ou le méthane". Lille 1, 2004. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2004/50376-2004-197.pdf.
Texto completoPétaud, Guillaume. "Réduction catalytique sélective des oxydes d’azotes par l’ammoniac : cinétique, mécanisme et modélisation du système cuivre Chabazite". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1230.
Texto completoThe reduction of atmospheric pollution from stationary and mobile engines is a serious challenge associated with stringent environmental regulations. For nitrogen oxides (NOx) abatement in particular, the selective catalytic reduction using urea or ammonia (urea- or NH3-SCR) over copper- and iron-based catalysts is one of most effective and economic technologies. In this respect, revisiting after-treatment systems by a deep comprehension of the catalyst behavior at different scale may significantly improve their eco- and health-friendliness. This study targets the development of a multi-site kinetic model using a series of copper chabazite-based catalysts, as a selected model SCR catalyst. To qualify these materials as beyond-state-of-the-art catalysts and to better understand the impact on different active site configurations, three catalysts were synthetized by different preparation methods (impregnation, ionic exchange and one-pot), finely characterized by different techniques and their ability to abate NOx via the ubiquitous NH3-SCR reaction was extensively assessed under several operating conditions. Each catalyst behavior was quantified and associated to their respective main active sites (five different configurations described). The diffusion, water impact, adsorption competition between key reactants and storage sites were also ones of the main points spotlighted in this study. In-situ characterization of these catalysts was also performed, using Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS) to understand the surface dynamical properties of the catalyst, and to unveil the mechanistic of the catalytic processes
Perazio, Alessandro. "Electrolyzer and Catalyst Engineering for Acidic CO2 Reduction". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS438.
Texto completoThe project focuses on the electrochemical reduction of CO2 with heterogeneous catalysts. Thanks to the "gas-fed flow cell" configuration developed in the group, high current densities can be achieved at moderate overpotentials. The first part of the project is more focused on the overall efficiency of the electrolyzer. To optimize it, we work to find the best acidic electrolyte for the system and, in parallel, we try to increase the fraction of CO2 that is converted into the desired products. The second part of the project focused on optimizing the reactor voltage, aiming to minimize the energy consumption of the reduction process. Finally, the last part was devoted to the surface modification of the catalyst in order to obtain better selectivity for the most valuable carbon products
Kobl, Kilian. "Aspects mécanistiques et cinétiques de la production catalytique de méthanol à partir de CO2/H2". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF023/document.
Texto completoIn view of the climate change and the energy transition, this work is part of the ANR project VItESSE2 about renewable electric energy storage and CO2 valorization by methanol hydrogenation on copper catalysts. During this thesis, an analytical method for copper surface measurement by N2O chemisorption was developed. Based on catalytic tests at 50 bar, kinetic models for Cu/ZnO/Al2O3 and Cu/ZnO/ZrO2 catalysts were elaborated. For the study of the mechanism, a diffuse reflection infrared setup was developed in order to study different catalysts for methanol synthesis and water-gas shift reaction. The setup was used for in situ catalytic tests at 34 bar under reaction flow. The study was complemented by temperature programmed desorption experiments with different probe molecules. The results suggest that the Cu/ZnO/ZrO2 catalyst is more selective for methanol than Cu/ZnO/Al2O3 and that a preparation method which favors Cu–ZnO–ZrO2 interactions can be beneficial for catalytic activity
Miquel, Pierre. "Réduction catalytique de NOx par les hydrocarbures sur des catalyseurs à base de perovskite : application à la dépollution de moteurs Diesel". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10162/document.
Texto completoThis study aims to develop a catalyst able to reduce nitrous oxides (NOx) pollutants in Diesel-engine conditions by hydrocarbons and/or hydrogen. The first goal was to eliminate rhodium and platinum based catalysts, which were replaced by palladium deposited on perovskite supports. The major drawback of deposited noble metals is the low N2 selectivity in lean –burn conditions. From a practical point of view, adding reducing agents enhancing NOx conversion, especially at low temperature, is a distinct possibility. Moreover, N2 selective conversion needs promotion. Indeed, N2O formation is often observed at low temperature and low NOx conversion. This phenomenon must be avoided due to the high greenhouse power of N2O. This reaction was carried out on palladium impregnated LaFeO3 perovskite with high oxygen, carbon dioxide and water content. Results were highly dependent of support preparation method or modifications as well as of impregnation precursor. Interactions between noble metal and perovskite support seem to play a key role in NOx conversion preservation after ageing under reactive conditions. This effect is attributed to better stabilization of palladium dispersion on perovskite surface compared to conventional supports like alumina
Massicot, Fabien. "Nanoparticules mono- ou bimétalliques à base de nickel ou de palladium : De leur structure à leur activité catalytique". Nancy 1, 2000. http://docnum.univ-lorraine.fr/public/SCD_T_2000_0065_MASSICOT.pdf.
Texto completoKouakou, N'Guessan Anita. "Valorisation de l'hydrogène pour la réduction des NOx en moteur diesel". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10201/document.
Texto completoThis thesis aims to investigate the feasibility of coupling a NOxTrap with a SCR catalyst. The efficiency of such a system running in sequential conditions depends on the extent of NH3 formed during the purge of the NOxTrap. The impact of Rh for further optimization has been investigated. An evaluation in real exhaust conditions on a driving bench showed that it is only possible to form NH3 during the purge of a NOxTrap by injecting extra reducing agent via a reformate mainly composed of CO and H2. Once formed NH3 can be stored on the SCR catalyst placed downstream and then react with NOx when the catalyst is exposed in lean conditions during the storage phase. The efficiency of this system depends not only on the purge duration and but also on the temperature. In fact, the performance of this system is linked to the quantity of NH3 formed during the purge of a NOxTrap and the NH3 storage capacity of the SCR catalyst. Similar trends were observed on a micro-reactor at the lab-scale. Further IR operando study showed that nitrates and nitrites are stored on alumina and mostly on barium oxide during the storage phase. Their ability to react during the purge follows a process in two stages when the purge duration is long enough. The selectivity in N2, N2O and NH3 depends on the quantity and on the nature of the reducing agents. H2 is probably the best one with a high efficiency in NOx reduction even at low temperature providing selectivity enhancement in NH3. However, the presence of CO was found to inhibit the storage and the reduction of NOx at low temperature. Above 250°C the formation of isocyanates on Al2O3 and BaO takes place and would produce NH3 via hydrolysis
Guzman, Vargas Ariel. "Réduction catalytique des oxydes d'azote (Nox et N2O) par NH3 et le n-décane sur Fe-zéolithes". Montpellier 2, 2003. http://www.theses.fr/2003MON20105.
Texto completoJoubert, Emmanuel. "Etude du mécanisme réactionnel de la réduction catalytique des oxydes d'azote par des hydrocarbures en milieu oxydant". Poitiers, 1999. http://www.theses.fr/1999POIT2372.
Texto completoMangue, Jordan. "Synthèse de complexes de cuivre bio-inspirés pour la réduction catalytique de l'oxyde nitreux et du dioxygène". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAV050/document.
Texto completoN2O is the third most important global warming gas and one of the most aggressive gas against ozone layer. A bio-inspired approach from N2Oreductase (N2Or), enzyme catalysing the two electron reduction of N2O with a four sulfur-bridged copper ions centre, helps for the design of new systems. Six mixed valent copper complexes containing the minimum Cu2(µ-S) core were then synthetized. It has been shown that these structures are affected by solvents in solution. Indeed, in a non-coordinating solvent like acetone, all these complexes have an intermetallic bond and a delocalized valence at room temperature. However in a coordinating solvent, the acetonitrile coordination makes it impossible to form a Cu-Cu bond and localize the valences.To test the N2Or activity, a prototype allowing a constant N2O bubbling in a UV cuve using a closed system was designed. The aim is to develop a catalytic reduction using sacrificial reductant and proton source. However, the gas bottle used for activity tests seems to contain a small amounts of O2 preventing results interpretation. The aim is now to optimize the prototype by adding a system that can purify N2O before activity tests.In a second time, the O2 reduction using two electrons to produce H2O2 (a soft oxidant) or four electron to produce H2O (useful in fuel cells) are of interest. It has been shown that all these new complexes are capable of catalytically reducing O2 in acetone and that only the one without exchangeable position can do it in acetonitrile. The latter has also demonstrate its ability to change its selectivity to produce H2O2 or H2O by changing the sacrificial reductant concentration. These results bring interesting insights for O2 activation with bio-inspired copper complexes
Gillot, Sylvain. "Développement de catalyseurs SCR à base de vanadium thermiquement stables en vue d'un couplage avec un filtre à particules". Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10126.
Texto completoThis study relates to a part of the objectives concerning the elaboration of compact post-treatment systems used for the elimination of combustion gas in Diesel vehicles. This manuscript is about the development of thermally stable catalysts for the selective reduction of NOx by ammonia. Afterwards the most promising catalysts could be integrated inside a particulate filter. The first results of this PhD indicate that it is possible to stabilize the state of the vanadium dispersion inside a tetragonal CeVO4 phase after a hydrothermal ageing until 600°C. The study realized on realist gas mixtures shows interesting catalytic results after an ageing at 500°C in Fast-SCR (NO/NOx = 0,5), Standard-SCR (NO/NOx = 1) and NO2-SCR (NO/NOx = 0,7) conditions. For intermediate ageing temperatures, the partial extraction of VOx species from the structure could explain the superior activity of these catalysts compared to the common V2O5 supported catalysts. However, a hydrothermal treatment at 850°C speeds up these transformations, leading to an important loss of activity. A partial substitution of the vanadium by the tungsten allows to obtain an increase of the activity after an ageing at 600°C and 850°C attributed to a better stabilization of the VOx species. Globally, the presence of tungsten strengthens the acid and redox properties. These improvements could explain the superior conversion occuring on a wider temperature range. CeV0.95W0.05O4, an optimized formulation, is able to get a NOx conversion superior to 75% between 250 and 400°C in Fast-SCR condition after an ageing at 850°C
Dacquin, Jean-Philippe. "Réduction catalytique simultanée des oxydes d'azote (N2O et NO) provenant d'effluents gazeux d'installations industrielles : application d'un procédé catalytiquee à basse température". Electronic Thesis or Diss., Lille 1, 2008. http://www.theses.fr/2008LIL10075.
Texto completoAs part of the abatement policy of greenhouse gases engaged by the ADEME, the purpose of the thesis was to develop catalysts for their application to the catalytic reduction of nitrogen oxides from stationary sources. Elimination of N2O and NO take place at low temperature with the presence of O2 and H20. ln these conditions, two reaction pathways could be envisaged. Firstly, we examined the catalytic decomposition but the inhibitors effects of O2 and H2O are difficult to avoid. Consequently, the second way is the catalytic reduction to attenuate these effects. The treatment of exhaust gases containing nitrogen oxides currently involves supported noble metal catalysts. ln these conditions, the use of perovskite could be an interesting way. Indeed, perovskite attenuates the inhibiting effect and avoid the particle growth. ln a first part, we examined the catalytic properties of perovskite modified by palladium for the catalytic decomposition of N2O. Deposition of palladium on LaCoO3 leads to higher activity in comparison with alumina. This different catalytic behaviour cannot be completely explained by changes in the metal dispersion but also by the extent of the metal/support interaction. ln a second part, we examined the catalytic reduction with H2 on supported platinum catalysts. After reduction, Pt supported on alumina and on perovskite both exhibit small nanoparticIes of Pt. Stabilisation of these particles on perovskite occurs during thermal ageing instead of sintering of Pt which predominates on alumina, as evidenced by spectroscopic characterisations. These observations are accompanied by promotional effects both on the conversion of NO and N2O in the former case
Tisseraud, Céline. "Origine et impact de la synergie Cu-ZnO sur l'hydrogénation catalytique du CO2 en méthanol". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2295/document.
Texto completoThe catalytic CO2 hydrogenation is considered to be one of the most promising methods for methanol production. This synthesis, often accompanied by a CO formation, had been the subject of many studies in the literature. However, the results obtained on Cu and ZnO based catalysts demonstrated that the reaction is not as simple as it appear to be. There is still a lot of controversies and interrogations concerning the nature of the active sites and the different reactional steps involved during the reaction. The objective of this work is a better understanding of the nature of the active sites and their role on CO2 an H2 activation. A study on model catalysts (mechanical mixtures and materials prepared by coprecipitation) allowed to demonstrate that the synergetic effect between Cu and ZnO linked to a migration phenomenon. This work showed that the methanol production was closely linked to the CuxZn(1-x)Oy oxide phase creation (with oxygen vacancies) induced by a Kirkendall effect on Cu-ZnO interface, thereby promoting the hydrogen spillover. Different mathematical models were developed to determine the concentration of contacts between Cu and ZnO. The results obtained demonstrated that it is possible to directly correlate the catalyst’s activity with the concentration of contacts between Cu and ZnO, which in turn allowed predicting optimal catalyst chemical composition for a particular design of a material. The full expertise of the design-activity relationship allowed the development of Cu-ZnO core-shell type materials with a 100% selective to methanol
Try, Rasmey. "Étude expérimentale et modélisation dynamique d'un réacteur catalytique modulaire pour l'hydrogénation du CO2 en méthane". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1038/document.
Texto completoThis work is within the Power-to-Gas framework, which aims to store the electrical energy surpluses from renewable energy in chemicals, here the methane. The intermittency of the electrical production requires the methanation system to have a certain level of flexibility with respect to temporal changes of operational conditions. In this context, the work carried out during this thesis is dedicated to the study of the dynamic behavior of a catalytic fixed-bed heat-exchanger methanation reactor. A reactor-exchanger highly equipped with thermocouples is designed and is used for the experimental study of the performances and the dynamics behavior of such a reactor. In particular, phenomena of thermal wave fronts, overshoot and inverse responses are found. The hydrodynamic and thermal parameters of the bed have been experimentally characterized. Modeling of the reactor-exchanger is also established and simulations of the reactor behavior are done. The experimental results are compared with the simulation results, allowing the precise analysis of the behaviors observed in the reactor
Dao, Duy Quang. "Technologies de recombustion avancée des oxydes d'azote : études expérimentale et cinétique sur pilote semi-industriel". Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10008/document.
Texto completoThe aim of this study is firstly to evaluate the influences of principal working parameters on the NO reduction efficiency of the Reburning and Selective Non Catalytic Reduction (SNCR) processes that use respectively methane (CH4) and ammonia (NH3) as reducing agent. The parametric studies of NO reduction were performed in a lab-scale plug flow reactor. The gaseous influents were analyzed by an analytic system of Fourier Transform lnfrared spectroscopy (FTlR). The principal operating parameters such as: the flue gas temperature, the residence time, the NO initial concentration and the reducing agent amount were systematically evaluated in the Reburning and SNCR mode. As a result. the maximum NO reduction efficiencies up to 90% and 80% are respectively obtained in the Reburning and classical SNCR mode. Several chemical compounds such as CH4, C2H2, C2H4, C2H6, CH3OH, C2H5OH, CO and H2 are tested as additives of the NO reduction process by NH3. The experimental results obtained in the Reburning mode are compared with the modeling ones obtained by the SENKIN-CHEMKIN Il calculation code in using four detailed kinetic mechanisms: GDF-Kin®3.0_NCN (El Bakali et col, 2006), GIarborg (Glarbarg et col, 1998), GRI3.0 (Smith, et col,1999) et Konnov (Kannov et col, 2005). The detailed mechanism AA2006 (Coda Zabetta and Hupa, 20(8) is modified in order to analyze the chemical kinetic aspect of the intluences of additives on the NO reduction performance of SNCR process
Lou, Yaoyin. "Electrochemical processes as a pre-treatment step before biological treatment : Application to the removal of organo-halogenated compounds". Thesis, Rennes, Ecole nationale supérieure de chimie, 2019. http://www.theses.fr/2019ENCR0057.
Texto completoElectrochemical process coupling with a biological treatment is a promising alternative for the degradation of biorecalcitrant organo-halogenated compounds in the environment. The electroreduction treatment, known to cut selectively carbon-halogen bonds, was first implemented to decrease the toxicity of the target molecules and increase their biodegradability before a complete mineralization of the pollutants by a biological treatment. To improve the dechlorination efficiency, the cathode was modified by silver nanoparticles after a previous nickelisation, since silver is considered as one of the best electrocatalysts to selectively cleave the carbonhalogen bond. The graphite felt was chosen as the electrode support due to its high specific surface area. For alachlor herbicide, deschloroalachlor, the main by-product after dechlorination, was still biorecalcitrant. To overcome this issue, electro-Fenton treatment, in which hydroxyl radicals were generated to degrade the target pollutants, was implemented. Significant improvement of biodegradability of the alachlor solution was observed after electro-Fenton treatment, which was further improved when the chlorine atom was beforehand removed from the alachlor structure by the electroreduction process. Bismuth was also used as electrode support due to its high overpotential for hydrogen evolution. A high selectivity of chloroacetamide herbicides reduction was observed on the bismuth based cathode. As an extended application of the bismuth based cathode, the electrochemical reduction of carbon dioxide was performed on Bi electrode modified by silver nanoparticles
Castellanos, Cordero Ingrit Carolina. "Etude de la réduction catalytique sélective des nox par acétylène via des zéolithes échangées aux métaux de transition". Caen, 2016. http://www.theses.fr/2016CAEN2060.
Texto completoAmong NOX emission sources, the automotive industry and specifically Diesel engines are the main pollutants. An already commercialized technology to reduce NOX to N2, consists in the dosage of an additive, AdBlue® that acts as a reducing agent precursor (NH3). However, this technology is restricted due to transport security, rather low efficiency and some applied catalysts are even expensive or toxic. This study focuses on the alternative application of acetylene (C2H2) as a reducing agent to remove these NOX. This hydrocarbon presents a reasonable efficiency and activity using zeolite catalysts. However, the nature of the intermediate species involved in the reduction catalytic loop has not yet been clarified. Moreover, the process selectivity should be improved in order to lower the CO production due to incomplete oxidation of C2H2. In order to enhance one of the elementary steps in the NOX reduction (NO to NO2 oxidation), the used catalysts (FER, MOR and BEA) were modified by metal loading (Fe, Co, Cu, Cu and Pd). The redox properties of these materials were then studied by adsorption of probe molecules followed by IR spectroscopy. Regarding the catalytic activity evaluated in the IR operando mode, various NO/NOX ratios and O2 contents were studied. The FER structure shows promising performances and under NO2 SCR conditions the Co based formulation leads to the best efficiency. The reaction mechanism involves the formation of CxHyNOz species whose further transformation leads to HCN and NCO- intermediate species active in DeNOx. New Pd based catalytic formulations were considered to improve the CO oxidation but without any relevant result in SCR conditions
Bitar, Ziad. "Electrocatalyse de la réduction sélective du dioxyde de carbone sur électrodes à diffusion de gaz". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENV030/document.
Texto completoThis thesis concerns the valorization of CO2 by electrochemical means. It is largely devoted to the preparation and physico-chemical study of gas diffusion electrodes (GDE) in order to better understand the mechanisms and key parameters for electrocatalytic reduction of CO2 using this type of porous electrode. This study revolves around two main axes, the first is related to metal catalysts and the second is focused on molecular catalysts.The first axis deals with the preparation, characterization and electrochemical properties of Cu, Co, In, Zn, Bi, Pb and Fe catalysts supported on porous carbon powder. Their implementation to form GDE and their electrocatalytic activity toward CO2 reduction were studied. In aqueous medium, the GDE containing indium allowed obtaining the highest Faraday yields for electroreduction of CO2 to formic acid. In comparison with a metallic indium foil, the GDE-In/C showed improved catalytic performance and improved resistance to the electrolyte's impurities. We demonstrated that in the aqueous phase, a continuous flow of CO2 through a GDE resulted in an improved reactivity of the supported catalyst. This highlights the advantage of using dispersed metal particles on GDE rather than metal foil electrodes.The second axis of this study focuses on three dimeric ruthenium complexes with the general formula [Ru(L)(CH3CN)(CO)2]2(PF6)2. The study of the redox properties of these catalyst precursors containing variously substituted L (bipyridine) ligands, allowed the formation of polymer bonds of Ru-Ru by electroreduction to be demonstrated. The ligand with a pyrrole functional group allows for the prior formation of a polypyrrole film, conferring improved catalyst stability and enhancing the catalytic performance. Different ways of immobilizing the complex on porous carbon have been used to obtain modified GDE. This study provided insight into the interaction between the molecular catalyst and the catalyst carrier during the CO2 reduction. We have demonstrated that the electrocatalytic activity of the catalyst deposited on the GDE is maintained in an aqueous medium.Alongside this fundamental work, a laboratory pilot was developed to perform the electrocatalytic reduction of CO2 in the gas phase, in order to overcome limitations encountered in an aqueous medium, such as CO2 solubility and reaction products separation. This under development study has not only identified obstacles, including the nature of the ion exchange membrane, but has also identified the nature and proportion of the polymer electrolyte used in the formulation of the catalyst layer. This work has provided fundamental knowledge and concrete answers which probably allow one day that such a process as CO2 valorization may be viable on an industrial scale
Stanbury, Matthew. "Réduction photo et électro-assistée sélective du dioxyde de carbone sur des catalyseurs moléculaires". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV094/document.
Texto completoThe general context of this thesis is on CO2 valorisation, and recounts fundamental research aimed at finding new molecular catalysts in order to achieve CO2 conversion. The results obtained provide additional knowledge in view of developing an efficient and selective catalytic CO2 reduction process. The first chapter begins with the general picture of CO2 utilisation and contains a bibliographical overview on the use of molecular catalysts for CO2 photo- and electroreduction. This short review demonstrates the wide variety of transition metal complexes used as catalysts, in particularly those based on rhenium. An analysis on the current state of CO2 reduction research using molecular catalyst complexes of the manganese carbonyl type is then reported. In Chapter II, the discussion begins with a brief overview of the research developed during this thesis relating to new complexes of the general formula: [Mn(L)(CO)3(X)] (X = Br, n = 0 ou CH3CN, n = 1; L = terpyridine derivatives). The interest in these complexes is twofold, as their physico-chemical properties give them potential catalytic CO2 reduction applications, as well as applications in the field relating to controlled CO release molecules. Developing new complexes based on ligands derived from terpy is one of the main routes that were chosen for catalyst performance optimisation and improvement. In this context, Mn complexes were synthesised, their photo- and electrochemical properties were studied in detail, before testing their activity with respect to catalytic CO2 reduction. The most remarkable result comes from the unique ability of these species to release one of their carbonyl ligands in a controlled fashion, which led to the discovery of novel Mn dicarbonyl complexes which are selective catalysts for CO2 reduction, and also to new molecules which are applicable in the release of small quantities of CO for therapeutic purposes.Chapter III covers the study of the complex [Mn(phen-dione)(CO)3(X)]n+ (X = Br, n = 0 ou CH3CN, n = 1). This complex was synthesised with the aim in mind of obtaining complexes soluble in aqueous media. While this objective was ambitious, it was soon found that these species showed no catalytic activity for CO2 reduction in the target aqueous medium. Nevertheless, electrocatalytic activity was demonstrated in hydro-organic media and photocatalytic applications in organic media proved promising. This work allowed us to gain a better understanding of the physicochemical properties and catalytic mechanisms of a Mn complex containing a redox-active ligand.The results presented in Chapter IV are based on the study of another new Mn carbonyl complex family. The study concentrated mainly on the complex [Mn(pyperNH)(CO)3(CH3CN)]+. The pyperNH ligand, with its aromatic system and NH functional group, plays a major role and is redox-active. After a section dedicated to its synthesis and characterisation, this chapter devotes a large part to the role that different experimental parameters can play on the efficiency of the catalytic CO2 reduction reaction. The Mn complexes described in this chapter have remarkable redox properties. A preliminary study of the catalytic activity of these complexes for CO2 reduction has allowed us to have an initial idea about the potential role of the N-H functional group of the ligand on the catalytic mechanism and reaction selectivity. This research was extended beyond the pyperNH ligand into a complex class of similar ligand structures, and the preliminary results obtained are original and promising, and open the way towards new perspectives
Van, Der Heyden Angéline Nadia. "Etude d'auto-assemblages supramoléculaires de lipides insaturés, d'hydrophobines et de calix[4]arènes : élaboration d'un système catalytique d'oxydo-réduction". Nancy 1, 2003. http://www.theses.fr/2003NAN10064.
Texto completoThe objective of my thesis was elaboration of a catalytic redox system of unsaturated lipids, based on calixarene-cupper(I)/(II) complexes. During this research, I have demonstrated that such a redox system has, indeed, a catalytic character. In order to fix the catalyst on a solid support, we used a fungal protein, called hydrophobin. We have demonstrated that this protein self-assemble on different surfaces and that it can be used as a molecular glue to immobilize stably the calixarene ligands. These ligands immobilized via hydrophobin on glassy carbon electrodes keep their ability to complex cupper cations present in solution. The overall results demonstrate that the calixarene-hydrophobin supramolecular system is functional and can be used as an electrochemical sensor of unsaturated lipids
Hallery, Isabelle. "Epoxydation catalytique à partir de l'oxygène moléculaire active par réduction électrochimique en présence de complexes non-porphyriniques de fer". Paris 11, 1989. http://www.theses.fr/1989PA112383.
Texto completoThe reactivity of the Gif-Orsay, electrochemical system for saturated hydrocarbon oxygenation, was oriented to the alkene epoxidation by modifying the reaction medium. Thus, by electrochemical reduction of dioxygen in DMF, in presence of an iron non-porphyrinic catalyst and a strong acid (or anhydride}, the selective epoxidation of varied simple alkenes (cis- and trans-stilbene, norbornene, cyclohexene, etc. . . ) with an electronic efficiency up to 30% was observed. The electronic yield was also improved by 2, 2' dipyridyl addition. The chemically analogous system (H202 oxidont) having the same oxidative selectivity allows us to define the parameters of our system, and the determining role of the solvent. Voltamperometric studie of iron catalyst and acid (or anhydride) influence on the dioxygen reduction correlated with the preparative epoxidation results allow us to propose a mechanism where the acid or anhydride) activates the heterolytic cleavage of 0-0 bond of dioxygen similar to previously described biomimetic models of Cp450
Ducere, Jean-Marie. "Modélisation de la réactivité du cuivre dans la faujasite - application à la réduction catalytique sélective de NO par NH3". Montpellier 2, 2003. http://www.theses.fr/2003MON20167.
Texto completoNguyen, Duy Luan. "Catalyseurs à base d'or pour la réduction catalytique sélective des oxydes d'azote par les hydrocarbures provenant de sources mobiles". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10133/document.
Texto completoNowadays, emissions of atmospheric pollutants from mobile sources such as nitric oxides (NOx) are submitted to more stringent regulations especially within the next Euro 6 which will be implemented in Europe at the beginning of 2014. Up to now commercialized technologies available for the abatement of NOx from lean burn engine (running with a large excess of oxygen) are not capable to remove simultaneously NOx and particulates in lean atmosphere. This study is essentially focused on the NOx conversion to nitrogen via the Selective Catalytic Reduction by using hydrocarbons (HC-SCR) in representative Diesel exhaust gas conditions. This technology is more feasible than the Lean-NOx trap and Urea-SCR systems. Supported gold catalysts on alumina have been developped for the replacement of Pt and Pd less selective. Particular attention was paid to the thermal stability under reaction conditions at 500°C. Among the different synthesis protocols investigated (Deposition-precipitation, Anionic exchange), it was found that the anionic exchange method leads to the best compromise with a larger operating window after ageing. In addition, the reduction of NOx to nitrogen seems structure sensitive, the largest particles being more active than the smallest ones usually thermodynamically instable at high temperature. In this context, such behavior should be profitably used for further practical developments since post-combustion catalysts essentially run at rather high temperature. The second part of this study was dedicated to the modification of Au/Al2O3 catalysts after silver incorporation. Different strategies implemented for Ag incorporation have been examined. Coprecipitation and grafting lead to the formation of bimetallic particles with homogeneous distribution of gold and silver especially via the coprecipitation method. Strong interaction between Au and Ag with further modification of their electronic and adsorptive properties leads to strong deactivation. On the other hand, the segregation of both metals on alumina preserving their intrinsic properties improves the catalytic performances especially after ageing. The influence of different operating condition has been examined showing the best compromise when gold is successively impregnated on Ag/Al2O3