Complex reaction kinetics of the solid acid alkylation of isobutane with butenes over a proton-exchanged Y-zeolite has been modeled at the elementary step level. Starting with a computer algorithm that generated the reaction network based on the fundamentals of the carbenium ion chemistry, the formation of over 100+ product species has been modeled in order to gain understanding of the underlying phenomena leading to rapid catalyst deactivation and product selectivity shifts observed in experimental runs. An experimental investigation of the solid acid alkylation process was carried out in a fixed bed catalytic reactor operating with an excess of isobutane under isothermal conditions at moderate temperatures (353-393 K) in liquid phase. Experimental data varying with run-time for a set of butene space-times and reaction temperatures were collected for parameter estimation purposes. A kinetic model was formulated in terms of rate expressions at the elementary step level including a rigorous modeling of deactivation through site coverage. The single event concept was applied to each rate coefficient at the elementary step level to achieve a significant reduction in the number of model parameters. Based on the identification of structural changes leading to the creation or destruction of symmetry axes and chiral centers in an elementary step, formulae have been developed for the calculation of the number of single events. The Evans-Polanyi relationship and the concept of stabilization energy were introduced to account for energy levels in surface-bonded carbenium ions. A novel functional dependency of the stabilization energy with the nature of the carbenium ion and the carbon number was proposed to account for energy effects from the acid sites on the catalyst. Further reductions in the number of parameters and simplification of the equations for the transient pseudohomogeneous one-dimensional plug-flow model of the reactor were achieved by means of thermodynamic constraints. Altogether, the single event concept, the Evans-Polanyi relationship, the stabilization energy approach and the thermodynamic constraints led to a set of 14 parameters necessary for a complete description of solid acid alkylation at the elementary step level.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21118号 / 工博第4482号 / 新制||工||1696(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 阿部 竜, 教授 安部 武志, 教授 作花 哲夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Electrolytic cells convert chemical energy directly into electrical energy cleanly and efficiently. An integral component of a fuel cell and an electrolytic cell is the electrolyte, a material that conducts ions. Liquid electrolytes can be aqueous as in the phosphoric acid and alkaline fuel cells, or molten, as in the molten carbonate fuel cells. A solid electrolyte is preferable because it allows sturdier, more efficient and corrosion resistant systems to be built. The main objective of this work is to develop a solid electrolyte for hydrogen production by electrolysis of hydrogen sulfide. Barium Hydrogen Phosphate, Barium Dihydrogen Phosphate, Cesium Hydrogen Carbonate, and Ammonium Iodide received brief attention but Cesium Hydrogen Sulfate was the primary candidate considered. Initial investigation has verified that Cesium Hydrogen Sulfate undergoes an impressive first-order phase transition at approximately 140°C at which the proton conductivity increases by almost four orders of magnitude. An electrochemical cell was designed and developed by Erik Todd for the production of hydrogen. Hydrogen sulfide can electrolyzed into hydrogen and sulfur in an electrochemical cell. Sulfur is in a low viscosity molten state at a temperature of 150°C. A cell with cesium hydrogen sulfate electrolyte canoperate at this temperature where liquid sulfur and gaseous hydrogen can move out of the cell as they are formed. Consequently, the electrolyte must possess a high conductivity at this temperature to facilitate the migration of hydrogen ions to the negative electrode through the electrolyte. Cesium Hydrogen Sulfate is known to act as an insulator at room temperature and a protonic conductor at 140°C. Hence it comes as an obvious choice as an electrolyte in a hydrogen sulfide electrochemical cell. The structural and chemical properties of Cesium Hydrogen Sulfate were investigated. • The CsHSO4 electrolyte was prepared by the reaction of cesium carbonate and cesium sulfate with sulfuric acid respectively. • A punch, die and base were designed and fabricated to 0.5" and 2.0" diameter pellets for that purpose. • X-ray diffraction was performed on the 0.5" diameter pellets to identify and characterize the polycrystalline phases of the solid acid electrolyte. • Differential Scanning Calorimetry was performed so as to ascertain the phase transition temperature. • The temperature at which the phase transition occurs was further confirmed by impedance measurements. A test setup was built in order to perform impedance measurements. An experiment to measure the impedance of a 0.5" diameter pellet of silver iodide was performed in order to test the validity of the setup. • An infrared analysis was performed on the prepared sample CsHSO4 in order to identify the bond environment of the electrolyte. • Differential scanning calorimetry was performed with Barium Hydrogen Phosphate, Barium Dihydrogen Phosphate, Cesium Hydrogen Carbonate and Ammonium Iodide to identify their phase transition temperatures. • A successful electrolysis of steam experiment was carried out using the CsHSO4 electrolyte to evaluate its performance. • Finally, the CsHSO4 electrolyte was tested in the hydrogen sulfide electrochemical cell for the production of hydrogen and sulfur.

In the present article, electrodes containing a composite of platinum on top of a plasma-oxidized multi-layer graphene film are investigated as model electrodes that combine an exceptional high platinum utilization with high electrode stability. Graphene is thereby acting as a separator between the phosphate-based electrolyte and the platinum catalyst. Electrochemical impedance measurements in humidified hydrogen at 240 °C show area-normalized electrode resistance of 0.06 Ω·cm−2 for a platinum loading of ∼60 µgPt·cm−2, resulting in an outstanding mass normalized activity of almost 280 S·mgPt−1, exceeding even state-of-the-art electrodes. The presented platinum decorated graphene electrodes enable stable operation over 60 h with a non-optimized degradation rate of 0.15% h−1, whereas electrodes with a similar design but without the graphene as separator are prone to a very fast degradation. The presented results propose an efficient way to stabilize solid acid fuel cell electrodes and provide valuable insights about the degradation processes which are essential for further electrode optimization.

Na primeira parte do trabalho, foram investigados materiais ativos para eletro-oxidar etanol e acetaldeído seletivos para a rota C2 (Carbono 2) e, também, ativos para eletro-oxidar hidrogênio molecular, visando a aplicação em células a combustível de hidrogênio indireto. Neste tipo de célula, um processador de combustível externo desidrogena o etanol e os produtos desta reação, contendo H2, acetaldeído e, possivelmente, etanol residual, são direcionados para alimentar o ânodo. Neste sentido, o eletrocatalisador anódico pode ser ativo para a eletro-oxidação de etanol residual, bem como acetaldeído, mas este deve catalisar a reação via C2 com o objetivo de evitar a formação de espécies que envenenam a superfície catalítica (CO ou CHx), ou seja, a ligação C-C deve permanecer intacta. Os eletrocatalisadores bimetálicos foram formados por M/Pt/C (onde M = W, Ru ou Sn) e os produtos reacionais foram analisados por DEMS On-line. Os resultados mostraram que Ru/Pt/C e Sn/Pt/C apresentaram maiores taxas de reação global, no entanto, eles não foram seletivos. Por outro lado, W2/Pt3/C foi mais seletivo para a rota C2, dada a não formação de CH4 e CO2. Além disso, este material também foi ativo e estável para a eletro-oxidação de H2, mesmo na presença de acetaldeído, o que o torna um potencial catalisador para aplicação no ânodo de células a combustível de hidrogênio indireto. Na segunda parte do trabalho, o objetivo foi relacionado com o estudo de eletrocatalisadores seletivos para a rota C1 (Carbono 1). A oxidação eletroquímica do etanol e de seus produtos reacionais foram investigados por DEMS on-line em temperatura ambiente e intermediária (245oC). Para temperatura ambiente, utilizou-se solução aquosa de ácido sulfúrico (H2SO4) e, para temperatura intermediária, utilizou-se ácido sólido (CsH2PO4) como eletrólito. Os eletrocatalisadores investigados foram formados por SnOxRuOx-Pt/C e Pt/C. Em temperatura ambiente, os resultados de polarização potenciodinâmica mostraram uma maior atividade eletrocatalítica para o material SnOxRuOx-Pt/C, com eficiência de corrente para formação de CO2 de 15,6% contra 15,2% para Pt/C, sob condições estagnantes, sem controle por transporte de massa. O stripping de resíduos reacionais, após a eletro-oxidação de etanol bulk, sob condições de fluxo, mostraram o acúmulo de espécies com 1 átomo de carbono (CO e CHx) que causam o bloqueio dos sítios ativos e são oxidadas eletroquimicamente somente em mais altos potenciais (ca. 1,0 V). Por outro lado, as curvas de polarização a 245oC mostraram maiores valores de eficiências de correntes para formação de CO2 (45% para Pt/C em ambos potenciais 0,5 V e 0,8 V contra 36% e 50% para SnOxRuOx-Pt/C em 0,5 V e 0,8 V respectivamente) quando comparado com os valores obtidos em temperatura ambiente, mas com atividades similares para SnOxRuOx-Pt/C e Pt/C. Para ambos os eletrocatalisadores, os estudos de espectrometria de massas a 245oC evidenciaram que as rotas eletroquímicas ocorrem em paralelo com rotas puramente químicas, envolvendo catálise heterogênea, de decomposição do etanol, produzindo H2 e CO2 como produtos majoritários. / In the first part of this study were investigated active materials to electro-oxidize ethanol and acetaldehyde selective for the C2 route (Carbon 2), besides active to electro-oxidize molecular hydrogen, in order to apply into indirect hydrogen fuel cells. In this type of cell, ethanol can be dehydrogenated in the external fuel processor and the products generated in this reaction, containing H2, acetaldehyde and, possibly, unreacted ethanol are used to feed the fuel cell anode. Therefore, the anode electrocatalyst has to be active to electro-oxidize residual ethanol and acetaldehyde, however, it has to catalyze the reaction via C2 route aiming to avoid the species formation that poison the catalyst surface (CO and CHx), in the other words, the C-C bond should remain intact. The bimetallic electrocatalysts were formed by W, Ru and Sn-modified Pt nanoparticles. The reaction products were followed by on-line differential electrochemical mass spectrometry (DEMS) experiments. The results showed that Ru/Pt/C and Sn/Pt/C presented higher overall reaction rate when compared to the other studied materials, however, they were non-selective. On the other hand, W/Pt/C with high W content was more selective to the C2 route, evidenced by the absence of the DEMS signals for molecules with one carbon atom such as CH4 and CO2. Additionally, this material was active and stable for H2 electro-oxidation even in the acetaldehyde presence, what turns it into a potential electrocatalyst for application in the anode of indirect hydrogen fuel cells. In the second part of this work, we investigated conditions and electrocatalysts selective to the C1 route. The ethanol electro-oxidation and its reaction products were investigated by on-line DEMS at room and intermediate temperature. At room, and intermediate temperature (245oC), the electrolytes were aqueous sulfuric acid and solid-state acid (CsH2PO4), respectively. The catalysts investigated were SnOxRuOx-Pt/C and Pt/C. The results of potentiodynamic polarizations at room temperature showed much higher electrocatalytic activity for the SnOxRuOx-Pt/C material, with current efficiency for CO2 formation of 15.6% against 15.2% for Pt/C under stagnant conditions. The reaction residues stripping after the ethanol electro-oxidation, under continuous flow conditions, showed the accumulation of species containing 1 carbon atom (CO and CHx), which are oxidized just at high potentials (ca. 1.0 V) and they cause the obstruction of the active sites. On the other hand, the polarization curves at 245oC showed higher values of current efficiencies (45% for Pt/C for both potentials 0.5 V and 0.8 V against 36% and 50% to SnOxRuOx-Pt/C at 0.5 V and 0.8 V respectively) for the CO2 formation than at ambient condition, however, with similar activities for SnOxRuOx-Pt/C and Pt/C. For both electrocatalysts, in parallel with the electrochemical pathways, heterogeneous chemical catalysis of ethanol decomposition also takes place, producing H2 and CO2, as major products.

Na primeira parte do trabalho, foram investigados materiais ativos para eletro-oxidar etanol e acetaldeído seletivos para a rota C2 (Carbono 2) e, também, ativos para eletro-oxidar hidrogênio molecular, visando a aplicação em células a combustível de hidrogênio indireto. Neste tipo de célula, um processador de combustível externo desidrogena o etanol e os produtos desta reação, contendo H2, acetaldeído e, possivelmente, etanol residual, são direcionados para alimentar o ânodo. Neste sentido, o eletrocatalisador anódico pode ser ativo para a eletro-oxidação de etanol residual, bem como acetaldeído, mas este deve catalisar a reação via C2 com o objetivo de evitar a formação de espécies que envenenam a superfície catalítica (CO ou CHx), ou seja, a ligação C-C deve permanecer intacta. Os eletrocatalisadores bimetálicos foram formados por M/Pt/C (onde M = W, Ru ou Sn) e os produtos reacionais foram analisados por DEMS On-line. Os resultados mostraram que Ru/Pt/C e Sn/Pt/C apresentaram maiores taxas de reação global, no entanto, eles não foram seletivos. Por outro lado, W2/Pt3/C foi mais seletivo para a rota C2, dada a não formação de CH4 e CO2. Além disso, este material também foi ativo e estável para a eletro-oxidação de H2, mesmo na presença de acetaldeído, o que o torna um potencial catalisador para aplicação no ânodo de células a combustível de hidrogênio indireto. Na segunda parte do trabalho, o objetivo foi relacionado com o estudo de eletrocatalisadores seletivos para a rota C1 (Carbono 1). A oxidação eletroquímica do etanol e de seus produtos reacionais foram investigados por DEMS on-line em temperatura ambiente e intermediária (245oC). Para temperatura ambiente, utilizou-se solução aquosa de ácido sulfúrico (H2SO4) e, para temperatura intermediária, utilizou-se ácido sólido (CsH2PO4) como eletrólito. Os eletrocatalisadores investigados foram formados por SnOxRuOx-Pt/C e Pt/C. Em temperatura ambiente, os resultados de polarização potenciodinâmica mostraram uma maior atividade eletrocatalítica para o material SnOxRuOx-Pt/C, com eficiência de corrente para formação de CO2 de 15,6% contra 15,2% para Pt/C, sob condições estagnantes, sem controle por transporte de massa. O stripping de resíduos reacionais, após a eletro-oxidação de etanol bulk, sob condições de fluxo, mostraram o acúmulo de espécies com 1 átomo de carbono (CO e CHx) que causam o bloqueio dos sítios ativos e são oxidadas eletroquimicamente somente em mais altos potenciais (ca. 1,0 V). Por outro lado, as curvas de polarização a 245oC mostraram maiores valores de eficiências de correntes para formação de CO2 (45% para Pt/C em ambos potenciais 0,5 V e 0,8 V contra 36% e 50% para SnOxRuOx-Pt/C em 0,5 V e 0,8 V respectivamente) quando comparado com os valores obtidos em temperatura ambiente, mas com atividades similares para SnOxRuOx-Pt/C e Pt/C. Para ambos os eletrocatalisadores, os estudos de espectrometria de massas a 245oC evidenciaram que as rotas eletroquímicas ocorrem em paralelo com rotas puramente químicas, envolvendo catálise heterogênea, de decomposição do etanol, produzindo H2 e CO2 como produtos majoritários. / In the first part of this study were investigated active materials to electro-oxidize ethanol and acetaldehyde selective for the C2 route (Carbon 2), besides active to electro-oxidize molecular hydrogen, in order to apply into indirect hydrogen fuel cells. In this type of cell, ethanol can be dehydrogenated in the external fuel processor and the products generated in this reaction, containing H2, acetaldehyde and, possibly, unreacted ethanol are used to feed the fuel cell anode. Therefore, the anode electrocatalyst has to be active to electro-oxidize residual ethanol and acetaldehyde, however, it has to catalyze the reaction via C2 route aiming to avoid the species formation that poison the catalyst surface (CO and CHx), in the other words, the C-C bond should remain intact. The bimetallic electrocatalysts were formed by W, Ru and Sn-modified Pt nanoparticles. The reaction products were followed by on-line differential electrochemical mass spectrometry (DEMS) experiments. The results showed that Ru/Pt/C and Sn/Pt/C presented higher overall reaction rate when compared to the other studied materials, however, they were non-selective. On the other hand, W/Pt/C with high W content was more selective to the C2 route, evidenced by the absence of the DEMS signals for molecules with one carbon atom such as CH4 and CO2. Additionally, this material was active and stable for H2 electro-oxidation even in the acetaldehyde presence, what turns it into a potential electrocatalyst for application in the anode of indirect hydrogen fuel cells. In the second part of this work, we investigated conditions and electrocatalysts selective to the C1 route. The ethanol electro-oxidation and its reaction products were investigated by on-line DEMS at room and intermediate temperature. At room, and intermediate temperature (245oC), the electrolytes were aqueous sulfuric acid and solid-state acid (CsH2PO4), respectively. The catalysts investigated were SnOxRuOx-Pt/C and Pt/C. The results of potentiodynamic polarizations at room temperature showed much higher electrocatalytic activity for the SnOxRuOx-Pt/C material, with current efficiency for CO2 formation of 15.6% against 15.2% for Pt/C under stagnant conditions. The reaction residues stripping after the ethanol electro-oxidation, under continuous flow conditions, showed the accumulation of species containing 1 carbon atom (CO and CHx), which are oxidized just at high potentials (ca. 1.0 V) and they cause the obstruction of the active sites. On the other hand, the polarization curves at 245oC showed higher values of current efficiencies (45% for Pt/C for both potentials 0.5 V and 0.8 V against 36% and 50% to SnOxRuOx-Pt/C at 0.5 V and 0.8 V respectively) for the CO2 formation than at ambient condition, however, with similar activities for SnOxRuOx-Pt/C and Pt/C. For both electrocatalysts, in parallel with the electrochemical pathways, heterogeneous chemical catalysis of ethanol decomposition also takes place, producing H2 and CO2, as major products.

Chemical catalysts are divided into two traditional categories: homogeneous and heterogeneous catalysts. Although homogeneous (molecular) catalysts tend to have high activity and selectivity, their wide application is hampered by the difficulties in catalyst separation. In contrast, the vast majority of industrial scale catalysts are heterogeneous catalysts based on solid materials. Immobilized catalysts, combining the advantages of homogeneous and heterogeneous catalysts, have developed into an important field in catalysis research. This dissertation presents synthesis, characterization and evaluation of several novel immobilized catalysts. In the first part, MNP supported aluminum isoproxide was developed for ROP of Є-caprolactone to achieve facile magnetic separation of catalysts from polymerization system and reduce toxic metal residues in the poly(caprolactone) product. Chapter 3 presents a silica coated MNP supported DMAP catalyst that was synthesized and displayed good activity and regio-selectivity in epoxide ring opening reactions. In Chapter 4, hybrid sulfonic acid catalysts based on polymer brush materials have been developed. The unique polymer brush architecture permits high catalyst loadings as well as easy accessibility of the active sites to be achieved in this catalytic system. In Chapter 5, aminopolymer-silica composite supported Pd catalysts with good activity and selectivity were developed for the selective hydrogenation of alkynes. In this case, the aminopolymer composite works as a stabilizer for palladium nanoparticles, as well as a modifier to tune the catalyst selectivity. All in all, the general theme of the thesis is developing new immobilized catalysts with improved activity/selectivity as well as easy separation via rational catalyst design.

La catalyse solide acide a été pendant longtemps l'objet d'activité de recherche intense, en particulier pour l'industrie pétrochimique. Aujourd'hui, les catalyseurs solides acides sont de plus en plus étudiés dans d'autres domaines et en particulier dans celles liées à la «chimie verte» et à la valorisation des bioressources, telles que la synthèse de biodiesel et la transformation des polysaccharides. L’objectif de la thèse est d’étudier le potentiel des matériaux poreux sulfonés ayant une porosité contrôlée dans des réactions catalysées par un acide en condition eau surchauffé telle que l'hydrolyse de la cellobiose. Dans une première partie, nous décrivons la préparation et la caractérisation des organosilicates mésoporeux périodiques sulfonés de type SBA-15, SBA-1 et KIT-6 par co-condensation de 1,4-bis (triéthoxysilyl) benzène (BTEB). Les matériaux ont été acidifiés suivant des voies différentes à l'aide de 3-mercaptopropyltriméthoxysilane (MPTMS)/H2O2 ou d'acide chlorosulfonique (ClSO3H). Leur propriété acide a été étudiée par adsorption d’NH3 suivie par calorimétrie et par la réaction de déshydratation d'isopropanol (IPA) comme réaction modèle en phase gazeuse. Contrairement à notre attente, l'adsorption d’NH3 suivie par calorimétrie a mis en évidence l'hétérogénéité de la force des sites suggérant la présence de sites distincts de la sulfonation. Les solides sulfonés avec l'acide chlorosulfonique ont une activité équivalente à celle de la résine sulfonée, Amberlyst 15, mais ils sont moins stables en raison de la libération des espèces de soufre. Les catalyseurs préparés en utilisant un groupement mercapto-propyle suivie d’une oxydation sont moins acides et ils ont donné des niveaux d'activité plus basse dans la réaction de déshydratation d'IPA. Pour l'hydrolyse de la cellobiose, de bonnes performances ont été obtenues à 150°C, mais, ces matériaux se sont montrés instables dans des conditions hydrothermales avec une lixiviation totale de soufre réalisant alors la réaction en phase homogène. Un lavage dans l'eau surchauffée des matériaux contenant des groupements propyles-SO3H conduit à une diminution de leur efficacité dans l'hydrolyse de la cellobiose, mais un gain de stabilité a été obtenu, permettant le recyclage de ces matériaux. Dans une deuxième partie, des répliques carbonées sulfonées par l’acide chlorosulfonique ou l’acide sulfurique ont été synthétisé. La sulfonation par l’acide sulfurique suivi par un lavage dans l’eau bouillante puis un prétraitement thermique à 300°C sous azote, de ces matériaux aboutissent au meilleur catalyseur en termes d’activité/stabilité. / Catalysis with solid acids has been for a long time the subject of intense research activities, especially for the petrochemical industry. Nowadays, solid acid catalysts are more and more studied in other areas and particularly in those related to “green chemistry” and bioresources valorization such as biodiesel synthesis and now polysaccharides transformations. The present work aimed to investigate the potential of acidic ordered mesoporous materials with a controlled local environment of the acid sites for applications in acid catalyzed reactions in hot water such as cellobiose hydrolysis. First we described the synthesis of periodic mesoporous organosilicas SBA-15, SBA-1 and KIT-6 types, from the condensation of 1,4-Bis(triethoxysilyl)benzene. The material was sulfonated using 3-mercaptopropyltrimethoxysilane further oxidized with H2O2 or chlorosulfonic acid to give Brønsted solid acids which were fully characterised. Their acidic properties were studied by calorimetry of NH3 adsorption and in the model reaction of gas phase isopropanol dehydration. The calorimetry of NH3 adsorption has evidenced the heterogeneity of the acid strength distribution suggesting the presence of distinct sites of sulfonation contrary to our expectation. For gas phase isopropanol (IPA) dehydration, the solids sulfonated with the chlorosulfonic acid exhibited an activity equivalent to that of the sulfonated resin, Amberlyst 15, but were less stable due to sulphur species release, assumed to be sulfonated silanols. The acidic organosilicas obtained via H2O2 oxidation of the mercapto-propyl group are less acidic catalysts, showing a low activity for gas phase IPA dehydration. In the hydrolysis reaction, the solids were active at 150 °C however sulfur leaching analysis showed that the reaction preceded mainly homogeneously, especially for the material acidified with chlorosulfonic acid. A hot washing pre-treatment applied to the catalysts containing the sulfonated propyl groups, led to a decrease of their hydrolysis activity but along with a gain of stability allowing recycling. Second we described the synthesis of ordered mesoporous carbon and their sulfonation with chlorosulfonic acid or sulfuric acid. Sulfonation of carbon replicas with sulfuric acid followed by washing in hot water and thermal pretreatment at 300°C under nitrogen, lead to the best catalyst in terms of activity / stability.

Ce travail est en relation avec la thématique "Chimie Verte" en particulier, le rôle de la catalyse,l’utilisation des matières premières renouvelables et l’élimination des produits nocifs.- Quatre échantillons commerciaux de zircone tungstatée de Mel-Chemicals.- deux séries de zircone tungstatée préparées par deux méthodes différentes avec une teneuren WO3 de 1 à 20 % en masse.- des oxydes binaires tels que WO3-ZrO2, B2O3-ZrO2, Al2O3-ZrO2, Ga2O3-ZrO2 et In2O3-ZrO2.- des oxydes binaires tels que WO3-Me2O3 (Me = B, Al, Ga et In) et finalement des oxydesternaires WO3/(Me2O3-ZrO2) (Me = B, Al, Ga et In) ont été étudiés et préparés lors de cettethèse.La performance catalytique de ces catalyseurs a été évaluée dans l’hydrolyse de la cellobiose, ladéshydratation du fructose et la réduction catalytique sélective des NOx. Les propriétés acides etredox de surface ont été corrélées aux performances catalytiques. En général, la conversion totale est liée à l’acidité des catalyseurs. Les catalyseurs les plus sélectifs pour la déshydratation du fructose et en deNOx sont ceux présentant une acidité modérée. / This work is related to the subject “Green Chemistry” in particular the role of the catalyst, the useof renewable raw materials and the decrease of hazardous materials.- Four commercial tungstated zirconia provided by Mel-Chemicals.- Two series of tungstated zirconia catalysts prepared by two different methods in a range of(1-20) WO3 wt.% loading- Binary zirconia-based oxides WO3-ZrO2, B2O3-ZrO2, Al2O3-ZrO2, Ga2O3-ZrO2 and In2O3-ZrO2.- Binary oxides WO3-Me2O3 (Me = B, Al, Ga and In) and ternary oxides WO3/(Me2O3-ZrO2)(Me = B, Al, Ga and In) were prepared and studied during my PhD thesis.The catalytic activity of these mixed oxide catalysts was evaluated in cellobiose hydrolysis, fructosedehydration and selective catalytic reduction of NOx. The catalysts were thoroughly characterizedin terms of their acidic and redox properties in order to find correlations between the identifiedactive sites and the catalytic properties. The total conversion is related in general to the acidity ofthe tested catalysts and the most selective catalysts for fructose dehydration and deNOx are thosewith moderate acidity.

No description available.