Дисертації з теми "Catalyst ink"
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Jacobs, Clayton Jeffrey. "Influence of catalyst ink mixing procedures on catalyst layer properties and in-situ PEMFC performance." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22932.
DELMONDO, LUISA. "Development and characterization of nanostructured catalysts." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2709352.
Hepola, Jouko. "Sulfur transformations in catalytic hot-gas cleaning of gasification gas /." Espoo [Finland] : Technical Research Centre of Finland, 2000. http://www.vtt.fi/inf/pdf/publications/2000/P425.pdf.
TOLOD, KRISTINE. "Visible light-driven catalysts for water oxidation: towards solar fuel biorefineries." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2732969.
Baker, Jenny. "Development and characterisation of graphene ink catalysts for use in dye sensitised solar cells." Thesis, Swansea University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678272.
ANNAMALAI, ABINAYA. "Electrochemical Energy Conversion Catalysts for Water Oxidation and CO2 Reduction." Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1086344.
AMJAD, UM-E.-SALMA. "Noble Metal based Catalysts for Natural Gas Steam Reforming Activity, Endurance and Kinetics." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2588279.
PEZZOLATO, LORENZO. "Fe-N-C non-noble catalysts for applications in Fuel Cells and Metal Air Batteries." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2809320.
Turtayeva, Zarina. "Genesis of AEMFC (anion exchange membrane fuel cell) at the lab scale : from PEMFC’s inks composition toward fuel cell bench tests in alkaline media." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0285.
Anion exchange membrane fuel cells (AEMFCs) have recently attracted significant attention as low-cost alternative fuel cells to traditional proton exchange membrane fuel cells as a result of the possible use of platinum-group metal-free electrocatalysts. Although AEMFC is a mimic of PEMFC but working in an alkaline medium, water management issues are more severe in AEMFC because ORR in alkaline media requires water, while at the same time water is produced at the anode side. To better understand water management in this type of fuel cell, it is necessary first to develop and gain experience with this kind of fuel cell on the laboratory scale. Since no ready-to-use materials are available at the beginning of the project, the necessity of fabricating homemade MEAs from commercially available materials becomes a reality that we must face. As MEA fabrication is a new topic to LEMTA's researchers, this is why this thesis was divided into two parts: one part dedicated to the formulation, preparation, and optimization of MEAs for PEMFC through physico-chemical and electrochemical characterizations; another part dedicated to the development of AEMFC. The results indicated that ink deposition, composition, and preparation systematically change the electrode structure and thus affect fuel cells performance. Furthermore, the study provides information on the AEMFC procedures and methods. Here, we would like to share our know-how with newcomers in the field of preparation of MEA in ion exchange membrane fuel cells
ERCOLINO, GIULIANA. "Catalytic combustion of methane in lean conditions on Pd/Co3O4 : from powdered to open-cell foam supported catalysts." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2675699.
Carreño, Gonzalez Ivon Maritza. "Desoxigenação de Etilenoglicol sobre catalisadores de Ni, Mo e NiMo/A 'I IND. 2' 'O IND. 3'." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266784.
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
Made available in DSpace on 2018-08-20T14:34:27Z (GMT). No. of bitstreams: 1 CarrenoGonzalez_IvonMaritza_M.pdf: 7134932 bytes, checksum: acf616348074122010d96651cd1436a7 (MD5) Previous issue date: 2012
Resumo: Sólidos monometálicos e bimetálicos de níquel e molibdênio suportado em alumina foram impregnados com 3% de teor metálico variando a ordem de impregnação até umidade incipiente, os quais podem ter efeitos significativos sobre o seu desempenho. As amostras foram calcinadas e caracterizadas, e utilizadas na desoxigenação catalítica do etilenoglicol. Esses materiais apresentaram áreas superficiais entre 177 e 160 m²g-¹. Os difratogramas de raios X de todos os sólidos obtidos exibiram a fase 'gama'-alumina e mediante o detector de energia dispersiva de raios X se confirmou a presença dos metais nos sólidos. Os testes catalíticos foram realizados em um reator de leito fixo, nas temperaturas de 533, 553, 573, 593 e 613 K e pressões de vapor do etilenoglicol de 13148 e 8662 Pa; a massa dos sólidos utilizada foi 35mg. Os compostos identificados foram a água, hidrogênio, metano, etano, éter etílico, acetaldeído e etanol. Foi realizado o balanço de mols do sistema e os valores dos graus de avanço de cada reação. Os cálculos dos efeitos difusivos demonstraram que as transferências de massa interna e externa e a transferência de energia externa não foram limitantes nas reações. Seis reações principais foram observadas e mediante os graus de avanço permitiu a avaliação de cada reação na formação dos determinados produtos de reação. Baseados na literatura se utilizaram expressões da taxa de reação para as reações propostas neste estudo. A seletividade aos produtos e conversão na desoxigenação do etilenoglicol apresentou mudanças baseadas na forma da ordem de impregnação dos sólidos. Igualmente foram realizados os cálculos das energias de ativação, fatores préexponenciais e as constantes da taxa
Abstract: Monometallic and bimetallic catalysts of nickel and molybdenum supported on alumina were prepared by incipient wetness with 3% metal content by varying the order of impregnation. The samples were calcined, characterized and used in the catalytic deoxygenation of ethylene glycol. The surface areas of the solids varied between 177 and 160 m²g-¹. The X-ray diffraction patterns of all solids had only 'gamma'-alumina phase. Analysis by X-ray dispersive energy confirmed the presence of both Ni and Mo in the solids. The catalytic tests were carried out in a fixed bed reactor and the reaction temperatures varied between 533 and 613 K while the vapor pressures of ethylene glycol were 8662 and 13148 Pa. The mass of the catalyst was kept constant at ca. 35mg. The identified compounds were water, hydrogen, methane, ethane, diethyl ether, acetaldehyde and ethanol. A mass balance for the reaction system was carried out and the extent of reaction was calculated for each reaction. The effect of diffusion was calculated and the results suggest that no internal or external mass transfer and external energy transfer were limiting in the reaction conditions used in this work. Rate expressions from the literature were used in this work. The results of conversion and selectivity to products in the deoxygenation of ethylene glycol reaction suggest that changes in the order of impregnation of the solid are important
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
Bonifacio, Rafael Nogueira. "Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-29082011-151940/.
Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of kW of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm-2) suitable for cathodes and 0.4 mgPt.cm-2 for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 mA.cm-2 by 600 mV to 25 cm2 MEA area. The MEA cost production for MEAs of 247.86 cm2, that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor.
MARIN, FIGUEREDO MIGUEL JOSE. "Metal Oxide Catalysts for the Abatement of Volatile Organic Compounds and Carbonaceous Particulate Matter." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2966339.
CRISTIANO, GIUSEPPE. "STEAM REFORMING AND OXIDATIVE STEAM REFORMING OF METHANE AND BIOGAS OVER STRUCTURED CATALYSTS." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2540087.
Ricca, Antonio. "Innovative catalysts for process intensification of methane reforming and propane dehydrogenation reactions." Doctoral thesis, Universita degli studi di Salerno, 2014. http://hdl.handle.net/10556/1769.
In the early decade, a rapid increase in oil consumption was recorded, that led to a widening between the predicted demand for oil and the known oil reserves. Such trend, mainly due to the growing new economies, is causing a quick increasing in oil price, that effect on European chemical industry competitiveness. In this dramatic scenario, characterized by higher cost of naphtha from crude oil, the ability to exploit novel feeds such as natural gas, coal and biomass may be the keystone for the chemical industry revival. Innovating chemical processes are thus essential for the future of the chemical industry to make use of alternative feedstock in the medium and long term future. In this direction, to open new direct routes with rarely used and less reactive raw feedstock such as short-chain alkanes and CO2 appears one of the most promising breakthrough, since in one hand it may reduce the current dependency of European chemical industry on naphtha, in the other hand may reduce the energy use and environmental footprint of industry. Despite light alkanes (C1–C4) and CO2 are stable molecules hard to activate and transform directly and selectively to added-value products, these challenges could be overcome thanks to relevant process intensifications along with the smart implementation of catalytic membrane reactors. Process intensification consists of the development of novel apparatuses and techniques, as compared to the present state-of-art, to bring dramatic improvements in manufacturing and processing, substantially decreasing equipment size/production capacity ratio, energy consumption, or waste production. The past decade has seen an increase in demonstration of novel membrane technology. Such developments are leading to a strong industrial interest in developing membrane reactors for the chemical industry. The main target of the CARENA is to address the key issues required to pave the way to marketing CMRs in the European chemical industry. The UNISA contribution in CARENA project is to study and optimize supported and unsupported catalysts in order to match to membrane reactors aimed to methane reforming and propane dehydrogenation processes. The guideline of this work was fully jointed to the UNISA involving in CARENA project. The methane reforming routes (steam- and/or auto-thermal-) are processes widely analyzed in the literature, and many studies identified Ni and Pt-group as most active catalysts, as well as the benefits of bimetallic formulation. Moreover, the crucial role of ceria and zirconia as chemical supports was demonstrated, due to their oxygen-storage capacity. In this work, great effort was spent in the reforming process intensification, in order to maximize catalyst exploit in reforming process. In order to minimize mass transfer limitations, without precluding the catalyst-membrane coupling, several foams were selected as catalytic support, and were activated with a catalytic slurry. The performances of such catalysts in the auto-thermal reforming and steam reforming of methane were investigated. Catalytic tests in methane auto-thermal reforming conditions were carried out in an adiabatic reactor, investigating the effect of feed ration and reactants mass rate. Tested catalysts showed excellent performances, reaching thermodynamic equilibrium even at very low contact time. By comparing foams catalyst performances to a commercial honeycomb catalyst, the advantages due to the foam structure was demonstrated. The complex foam structure in one hand promotes a continuous mixing of the reaction stream, in the other hand allows conductive heat transfer along the catalyst resulting in a flatter thermal profile. As a result, the reaction stream quickly reaches a composition close to the final value. Steam reforming catalytic tests were carried out on foam catalysts at relatively low temperature (550°C) and at different steam-to carbon ratios and GHSV values. The catalytic tests evidenced the relevance of heat transfer management on the catalytic performances, since the samples characterized by the highest thermal conductivity showed the best results in terms of methane conversion and hydrogen yield. The beneficial effect was more evident in the more extreme conditions (higher S/C ratios, higher reactants rates), in which the heat transfer limitations are more evident. The selective propane dehydrogenation (PDH) was one of the most attractive challenges of the CARENA project, that points to insert a membrane-assisted PDH process in a wider scheme characterized by the process stream recirculation. This approach requires to minimize inerts utilization and side-products formation. Moreover, no papers are present in literature on the concentrated-propane dehydrogenation, due to the severe thermodynamic limitations. A wide study is present in this work aimed to identify and select an optimal catalytic formulation and the appropriate operating conditions that allows the process intensification for the PDH reaction by means of a membrane reactor. In a first stage, the relevance of side-reactions in the catalytic volume and in the homogeneous gas phase was analyzed, resulting in the optimization of the reaction system. Platinum-tin catalysts were prepared, in order to study the role of each compound on the catalytic performances and lifetime. Preliminary studies have defined the optimal operating conditions, able to minimize the coke formation and then to slow down catalyst deactivation. Several studies on catalyst support highlighted the requirement to use a basic supports with a high specific surface, able to minimize cracking phenomena. Basing on such indications, CARENA partners provided two catalytic formulations optimized with respect the indicated operating conditions, that showed excellent activity ad selectivity. On these catalyst, the effect of the water dilution, the operating pressure and the presence of CO and CO2 was investigated, in order to understand the catalytic formulation behavior in the real scheme conditions. [edited by author]
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OLIANI, BENEDETTA. "Sviluppo di tecniche in regime transitorio per lo studio di reazioni di catalisi eterogenea." Doctoral thesis, Università degli studi di Padova, 2022. http://hdl.handle.net/11577/3448079.
The research activities reported in this PhD thesis focus on one class of time-depending input variables: temperature and reactant concentration. Specifically, reactivity parameters (reagents conversion and products formation) were recorded as a function of temperature in temperature-programmed experiments with variable feed conditions (reducing or oxidizing atmospheres) and spent materials were characterized with surface analyses (SEM, EDS) to correlate their activity to chemical (mass and heat transfer) and physical (aggregation, segregation) phenomena. Also, the common feature between the catalytic materials investigated is the oxygen-storage capacity, i.e. their ability to store and release oxygen in oxygen-lean conditions, that represents a critical feature for more flexible operations, highly-selective oxidations and safer working conditions. Two model materials were selected as oxygen-donors for two distinct applications: CuO was chosen to correlate the effect of different reaction parameters to its morphological features, long-time stability during redox cycles (H2-O2) and formation of peculiar superficial nanostructures while LaFeO3 (perovskite) was identified as a possible candidate for the oxidative function, in automotive converter by taking advantage of oxygen diffusion in the lattice to transform CO into CO2. The last class of materials (CuY zeolites) was studied in CH4 activation to assess their potential application to an industrial-relevant reaction (methane-to-methanol, MTM) in which the oxygen provided by the zeolites selectively reduces the extent of over-oxidation products in favour of the partial oxidation to methanol.
Pisano, Domenico. "High thermal conductivity catalysts for the CO-WGS process intensification." Doctoral thesis, Universita degli studi di Salerno, 2016. http://hdl.handle.net/10556/2463.
Today, the increasingly serious lack of resources and the obsolescence of the plants present on the whole planet led to develop new ways that go beyond “traditional” chemical engineering. The research is now focusing on novel equipment and techniques that potentially could change the concept of chemical plants and lead to compact, safe, energy-efficient, and environment-friendly sustainable processes. These developments share a common focus on “process intensification” — an approach that has truly emerged in the past few years as a special and interesting discipline of chemical engineering, because of the reasons enounced above. Process intensification tends its aim to the reduction of the total costs (fixed and operating) in an industrial plant. This “saving” in economic terms is possible not only by making a minimization of the equipment’s volume, but it’s also related to both chemical and physical aspects of one industrial process. The principle targets of a process intensification are: 1. Improved control of reactor kinetics giving higher selectivity/reduced waste products. 2. Higher energy efficiency. 3. Reduced capital costs. 4. Reduced inventory/improved intrinsic safety/fast response times. In order to reach all of these targets, it must be considered that transport phenomena play a very important role for the process intensification of an industrial reactor. Also improvements in environmental impact is another aspect that is constantly faced today, regarding all the processes in which there is the need of eliminating one dangerous chemical species. Taking into accounts all these reasons, one possible candidate for process intensification is represented by the Water Gas Shift process (WGS). It is the first purification stage of a hydrogen production plant, and involves the conversion of CO in CO2, while at the same time there is an increase in H2 yield in syngas. It also provides a H2/N2 mixtures with the appropriate ratio for the production of an important chemical product, such as ammonia. The WGS is an exothermic reaction, thermodynamically favored at low temperature, however kinetic limitations make it convenient to work with a two-stage process, i.e. two different catalytic systems: a first stage (HTS), carried out in the temperature range 350-600°C, where the most of the CO conversion is obtained (but thermodynamic limitations effect the theoretically reachable conversion); a second stage (LTS) carried out in the temperature range of 180-350°C, with slow kinetics (the thermodynamic conditions allow to obtain very low CO concentration, less than 10 ppm). Although this type of configuration is very effective, it shows several disadvantages: as a first, the global system kinetics is very slow, requiring a high mass of catalyst, that in turn results in long activation time; moreover, the presence of the inter-cooling unit increases not only the energy requirements of the process, but also the plant cost itself; furthermore, the LTS catalyst shows pyrophoricity, resulting not able to sustain frequent start up and shut down stages, and then not suitable for mobile fuel cell applications. Definitely, the actual WGS plant configuration would be of course the biggest unity of an integrated fuel processor. For these reasons, a process intensification is needed. Considering a conventional adiabatic reactor, the exothermicity and the equilibrium characteristics of the WGS reaction, together with the catalysts performances, reflects negatively on the CO conversion, disfavoring the reaction rate at the inlet of the catalytic bed, where the temperature is low, and limiting the very high conversion values at the outlet, where the temperature is high. So, a process intensification for this type of process should accounts for a modification both of the catalytic phase and the catalyst bed thermal profile. In order to reach the first target, it is necessary to find a good catalytic formulation that is able to be efficient in the low temperature range. Moreover, by considering the influence of the heat transport on the whole system, the use of a high conductive catalyst could play a crucial role, with the possibility of redistributing the heat of reaction along the catalytic bed to obtain a flatter thermal profile with a lower outlet temperature and, consequently, a higher CO conversion. The aim of this PhD thesis was to investigate the influence of the catalyst thermal properties on the Water Gas Shift (WGS) process, by using a structured carrier with high thermal conductivity. The research line was followed in order to verify if it is possible to increase the backdiffusion of the reaction heat throughout the structured catalyst bed, modifying the adiabatic temperature profile, obtaining, with respect to a typical packed bed reactor, a higher temperature at the inlet section and a lowered temperature at the outlet bed section, overcoming respectively, the kinetic and thermodynamic limits, achieving so an increased CO conversion. Accordingly, this approach would ensure that a conventional double staged WGS reactors with intermediate heat exchange could be replaced with a single WGS reactor, characterized by a "quasi isothermal" temperature profile. In this context, during the PhD project different phases have been followed to reach the intended objective. 1. CHOICE OF THE STRUCTURED CARRIER In order to reach the desired heat transfer properties, metal foams were chosen as structured carriers. They are open-cell structures that may be fabricated in a variety of shapes from a wide range of materials, and they exhibit very high porosities with good interconnectivity. These characteristics result in a lower pressure drop than that observed with packed beds and high convection in the tortuous megapores, which, in turn, enhances mass and heat transfer. Moreover, they are also easily coated with high-surface-area catalytic components, using well-established techniques. In general, mainly two parameters effect on overall heat transfer coefficient: the void fraction (or porosity) and the pore density (PPI), in addition to the bulk thermal conductivity. The first two parameters can highly influence the third one, because the first one is related to the amount of solid material and the second one to the way in which the solid material is distributed in the structured carrier. Moreover, the conventionally applicable foams for a catalytic process must be highly porous, otherwise pressure drops can increase dramatically. In order to find an efficient open cell foam for the purposes of this PhD project, the heat transfer through different structured metal foams was investigated. The thermal properties, in particular the thermal conductivity and the gas phase heat transfer coefficient of the structured supports were estimated by means of a mathematical model, developed on the basis of other similar heat transfer models accounted for honeycomb monoliths. An experimental set up was built, including an oven for heating the whole system at different temperatures, a quartz tube in which the metal foam was inserted, and a set of thermocouples to measure temperature in different points of the carrier. The experimental results were used to optimize the mathematical model and validate it, and the thermal properties estimated were used as basis for a comparison between the carriers and the choice of the best one in terms of heat transfer. 2. CHOICE OF THE CATALYTIC PHASES The literature research revealed that reducible oxides supported platinum based catalysts are today the best choice for obtaining a highly active and efficient catalytic system for the WGS reaction. These types of catalysts, instead of gold ones, are more stable and, if high dispersed on a reducible oxide, can prevent phenomena such as sintering of the active metal particles. On the basis of this review, different platinum based catalysts, supported on ceria, ceria-zirconia and ceria-alumina were prepared, through the wet impregnation method, followed by drying at 120°C and calcination in muffle. A wide characterization of the samples was done, including the specific surface area estimation (BET method), the XRF and XRD analysis, the use of the Raman shift and the study on the reducibility properties of the samples, through the technique of the temperature programmed reduction (TPR). The Water Gas Shift tests were made by fixing the operative conditions, in order to have a benchmark for this initial screening. The CO concentration was set to 5%, water at 25% and helium balance, as inert component. These activity and selectivity tests were made at atmospheric pressure, in a range of temperature between 150°C and 400°C, with a gas hourly space velocity of 5000 h-1. All the samples were reduced to particles with a size between 180 and 355 m. the aim of this experimental campaign was to find a good and efficient catalytic formulation, active in a very low temperature range. The best catalyst, from those investigated, was also tested by increasing the space velocity of one order of magnitude and by verifying its durability, in order to investigate about possible critical issue to be corrected. 3. DEPOSITION OF THE CATALYTIC PHASES ON THE STRUCTURED CARRIER In order to anchor the catalytic phases to the structured carrier, it is necessary to formulate a good washcoat. A washcoat is a chemical species that in catalysis is used to disperse the materials over a large surface area. Washcoat materials must form a rough surface, which greatly increases the surface area compared to the smooth surface of the bare structured carrier. This in turn maximizes the catalytically active surface available to react. So, the washcoat was formulated on the basis of what enounced above. The catalyst preparation was divided into three stages. All these stages were followed by drying at 120°C and calcination at 450°C for 3 hours. Firstly, the washcoat was anchored to the foam surface by using the dip-coating procedure. Then, chemical support was added to the washcoat by the wet impregnation method. Finally, the sample was impregnated with a solution of the platinum precursor. The same catalyst formulation was also prepared in powder form, and employed as reference. The stability of the washcoat on the foam surface was tested via sonication, to verify the adhesion of the chemical species on the structured support. The specific surface area (SSA) was determined by the BET method. The Scanning Electron Microscope (SEM) was used to study the morphology of the foams and to check the washcoat on the surface of the foam. It was possible to estimate the pores average diameter and the fibers diameter, and it was also verified that the washcoating procedure led to a homogeneous deposition on the surface of the structured carrier. The temperature programmed reduction (TPR) was performed in a stainless steel tube with an internal diameter of 22 mm. A 5% H2/N2 gas mixture (flow rate: 1000 Ncm3/min) was fed to the reactor, and temperature was raised up to 400°C with a heating rate of 10°C/min. The WGS catalytic tests were performed at atmospheric pressure, in typical conditions for the LTS process (a temperature range of 200-400°C). The reacting mixture consisted of 8% CO, 30% H2O and N2 balance. The catalysts activity was tested in the same reactor as the TPR. The gas hourly space velocity (GHSV) was set up to 10000 h-1. 4. DEVELOPMENT OF A “QUASI” ADIABATIC SYSTEM: COMPARISON BETWEEN PACKED BED AND STRUCTURED FOAM CATALYST An important phase of the PhD was dedicated to the development of a “quasi” adiabatic system, in order to exploit the high conduction of the structured catalyst, prepared in the previous phase, with respect to a conventional packed bed catalyst. In order to evaluate the influence of the thermal transport properties of the foams on the WGS reaction, a laboratory system able to avoid thermal dispersions was set up. This target was reached by increasing the total flow rate, keeping constant the L/D ratio of the structured foam catalyst. The experimental set up was used to drive a WGS reaction in the following conditions: inlet T = 260 °C, P = 1 atm, CO molar fraction = 8 vol%, H2O molar fraction = 30 vol%, N2 balance, WHSV = 2.4 gCO/gcat-1/h-1, linear flow velocity = 18.2 cm/s-1. In order to compare the performances of the different samples, two thermocouples were installed, one at the inlet section of the catalyst and the other one at the outlet section, while the CO conversion was continuously monitored with the aid of an ABB detector. After making a comparison between the performances of a foam catalyst with those of a packed bed catalyst, the developed experimental set up was used to perform different WGS tests on different types of foam. The aim of these tests was to investigate how the void fraction and the pore density can influence the heat transfer, and so the performances of the structured catalyst. 5. MODELING OF THE WGS ADIABATIC REACTOR In order to validate the results obtained by the tests made with the “quasi” adiabatic system, the model of the adiabatic reactor was developed with the aid of the finite element software COMSOL Multiphysics 5.0 (License number: No.13073437,00-0f-fe-0a-73-34). The comparison has been done between the structured foam catalyst and a conventional packed bed adiabatic reactor. The process has been modeled coupling transport phenomena and reaction kinetics. The reactor model was implemented exclusively with the CFD. A simplified geometry of the real system was built. By assuming no dependence of the transport parameters with the tangential coordinate, it was possible to reduce the volume domain to ¼ of the real one. In particular, the simulated geometry was built as follows. The gas stream flows axially, along the z-coordinate, through the reactor (internal diameter of 22 mm, tickness of 2.5 mm). The catalytic zone was put in the middle of the reactor (catalyst diameter of 16.5 mm). The length of the catalytic zone was set to 88 mm, while the total length of the reactor was 400 mm. The use of COMSOL allowed to simulate the packed bed adiabatic reactor and the structured foam catalyst, in order to exploit the high thermal properties of the latter in view of an intensification of the Water Gas Shift process. The developed model will be the basis for the design of an industrial reactor, where the catalyzed structured foam technology is applied. [edited by author]
XIV n.s.
Fuss, Botti Renata. "Development of Structured Porous Heterogeneous Catalyst for Biodiesel Production by Transesterification of Vegetable Oil." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3426343.
Molti problemi ambientali sono causati dall'uso dei combustibili fossili nei motori. Il biodiesel è un'opzione promettente per sostituire questi carburanti perché è rinnovabile, biodegradabile e non tossico. Il processo più utilizzato per preparare il biodiesel è la transesterificazione omogenea degli oli vegetali, utilizzando NaOH o KOH, ma produce un'alta concentrazione di impurità nel prodotto. Per superare questo, l'uso di catalizzatori eterogenei viene sempre più studiato. Geopolymer (GP) è un materiale inorganico con una composizione chimica simile alla zeolite e una microstruttura variabile, ottenuta dalla reazione di alluminosilicati con un mezzo altamente alcalino che forma una rete 3D continua. Può essere usato come catalizzatore eterogeneo, a causa dell'elevato contenuto di metalli come Na e/o K, nonché di un'elevata basicità e di una superficie specifica. Il grande vantaggio dell'utilizzo di catalizzatori eterogenei è che possono essere recuperati mediante filtrazione e riutilizzati nel processo, rendendo la produzione di biodiesel più economica e generando meno effluenti da trattare. Questo lavoro ha indagato su GP che agisce come catalizzatori eterogenei per produrre biodiesel mediante la reazione di transesterificazione dell'olio di soia con metanolo. Sono stati prodotti tre tipi di polvere GP miscelando metacaolino con una soluzione alcalina attivante: GP a base di Na, a base di K e una miscela tra loro; sono stati trattati a 110, 300, 500 e 700 °C, quindi i GP a forma di reticolo sono stati progettati e prodotti da DIW, aggiungendo PEG e filler nella precedente formulazione e quindi, sono stati essiccati a 110 °C. Sono state prodotte strutture porose con Ø ~ 24 mm x 9,6 mm di altezza e parti non supportate. Tutti i materiali sono stati caratterizzati. La reazione di transesterificazione è stata effettuata utilizzando tutti i campioni come catalizzatore eterogeneo per valutare la resa di biodiesel riguardante la composizione GP, le condizioni di reazione e la morfologia dei campioni. In base ai risultati ottenuti in questo studio, è stato verificato che l'utilizzo di GP sia in polvere sia nella struttura come catalizzatore, è stato possibile ottenere biodiesel dalla transesterificazione dell'olio di soia. Confrontando i materiali con gli stessi rapporti molari, Na.K_GP trattato a 500 °C (polvere) ha ottenuto la conversione più alta (~98%). Per la struttura 3D testata nella reazione (3D_Na_GP1, 110 °C) è stata osservata una conversione, ma inferiore (~41%) rispetto a Na.K_GP, anche nella sua versione in polvere (~53%). Per verificare l'efficienza di conversione delle altre strutture (3D_K_GP1, Na.K_GP) sono necessari ulteriori studi.
Pirola, C. "Novel Supported iron Fischer Tropsch catalysts : preparation, characterization and applications." Doctoral thesis, Università degli Studi di Milano, 2008. http://hdl.handle.net/2434/57056.
ARIF, Omer. "Self-catalyzed and catalyst-free III-V semiconductor nanowire grown by CBE." Doctoral thesis, Scuola Normale Superiore, 2021. http://hdl.handle.net/11384/105824.
THALLURI, SITARAMANJANEYA MOULI. "Design of Visible-light driven catalysts for water oxidation and VOC degradation." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2588775.
PAMPARARO, GIOVANNI. "Nanostructured catalysts for the bio-ethanol conversion to acetaldehyde: development and optimization." Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1073525.
ALIJANI, SHAHRAM. "EFFECT OF THE PREPARATION OF THE CATALYST AND PROTECTIVE AGENT IN LIQUID PHASE HYDROGENATION REACTIONS." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/816935.
SAPIO, FRANCESCO. "Diesel After-Treatment Systems Modeling Optimization Techniques." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2842513.
OSMIERI, LUIGI. "Non-noble metal catalysts for oxygen reduction reaction in low temperature fuel cells." Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2640183.
Al-zaidi, Bashir Yousif Sherhan. "The effect of modification techniques on the performance of zeolite-Y catalysts in hydrocarbon cracking reactions." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-effect-of-modification-techniques-on-the-performance-of-zeolitey-catalysts-in-hydrocarbon-cracking-reactions(6f64393c-ea13-4ec4-85d3-60e650e26be7).html.
Comazzi, A. "SYNTHESIS, CHARACTERIZATION AND RIG TESTS OF SUPPORTED FE AND CO-BASED NANOSTRUCTURED CATALYSTS ACTIVE IN THE THERMOCHEMICAL BTL/CTL/GTL-FT PROCESSES." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/475923.
MOROSANU, EDUARD ALEXANDRU. "Catalytic processes for CO2 conversion into Synthetic Methane." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2841162.
GADHI, TANVEER AHMED. "Design of Visible Light Driven Bismuth based Catalysts for Degradation of Organic Pollutants." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2702932.
Freitas, Fernanda Gabriel de [UNESP]. "Catalisadores nanoestruturados contendo ligas de 'PT' e 'TI''O IND.2' para a oxidação eletroquímica de etanol." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110850.
Neste trabalho, foi estudada a influência da adição de TiO2 na atividade catalítica para a reação de oxidação de etanol sobre nanocatalisadores PtRu e PtSn. O efeito da quantidade de TiO2 adicionado também foi investigado para os catalisadores bimetálicos de PtSn. Os estudos foram realizados de modo comparativo para catalisadores suportados em carbono com a mesma parte metálica (Pt, PtRu ou PtSn), com e sem modificação com TiO2. A síntese das nanopartículas de PtRu e PtSn de composição nominal 50:50 e 70:30 (em átomos), respectivamente, foi realizada pelo método do poliol modificado, enquanto o TiO2 foi sintetizado separadamente pelo processo sol-gel. Com o intuito de avaliar as diferenças na atividade catalítica promovidas pela presença do óxido, mantendo idênticas as propriedades da parte metálica, as nanopartículas em estado coloidal foram separadas em frações: uma foi utilizada para a preparação do catalisador sem óxido e as outras para a preparação dos materiais contendo TiO2. Os nanocatalisadores preparados foram caracterizados por difração de raios X (DRX), microscopia eletrônica de transmissão (TEM), espectroscopia de fotoelétrons excitados por raios X (XPS) e espectroscopia de absorção de raios X (XAS) in situ. O comportamento eletroquímico geral foi avaliado por voltametria cíclica em solução ácida ou alcalina e as atividades eletrocatalíticas para a oxidação de etanol foram estudadas por varreduras de potencial e cronoamperometria. De maneira geral, os resultados mostram que a presença do TiO2 promove um aumento da atividade catalítica para a oxidação de etanol em meio ácido que, em baixos potenciais, resultaria das mudanças na vacância da banda 5d da Pt promovida pelas interações metal-óxido. Os estudos realizados variando a quantidade de TiO2 mostraram que os efeitos do teor de óxido são significativos tanto em meio ácido quanto em meio alcalino. Experimentos utilizando a...
In this work, the influence of the addition of TiO2 on the catalytic activity toward ethanol oxidation reaction on PtRu and PtSn nanocatalysts was studied. The effect of the amount of TiO2 added was also investigated for the PtSn bimetallic catalysts. The studies were comparatively performed for carbon-supported catalysts with the same metallic component (Pt, PtRu or PtSn) with and without modification with TiO2. The synthesis of PtRu and PtSn nanoparticles with nominal composition equal to 50:50 and 70:30 (in atoms), respectively, was carried out by a modified polyol method, while TiO2 was synthesized separately by a sol-gel process. In order to evaluate the differences in the catalytic activity promoted by the presence of the oxide, while maintaining the same properties of the metallic part, the colloid of nanoparticles was separated into fractions: one was used to prepare the catalyst without oxide and the others were used for preparation of the TiO2 containing materials. Nanocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and in situ X-ray absorption spectroscopy (XAS). The general electrochemical behavior was evaluated by cyclic voltammetry in acidic or alkaline solution and the electrocatalytic activity for ethanol oxidation was studied by potential sweeps and chronoamperometry. Overall, the results show that the presence of TiO2 enhances the catalytic activity for ethanol oxidation in acid medium in the low potential region, because of the changes in the Pt 5d band vacancy promoted by metal-oxide interactions. The studies involving the variation of the amount of TiO2 showed that the effects of oxide content are significant both in acidic and in alkaline medium. Experiments using in situ Fourier transform infrared reflection-absorption spectroscopy (FTIRAS) were performed in order to analyze qualitatively the products of alcohol oxidation at each...
Freitas, Fernanda Gabriel de. "Catalisadores nanoestruturados contendo ligas de 'PT' e 'TI''O IND.2' para a oxidação eletroquímica de etanol /." Araraquara, 2014. http://hdl.handle.net/11449/110850.
Co-orientador: Sandra Helena Pulcinelli
Banca: Joelma Perez
Banca: Antônio Carlos Dias Ângelo
Banca: Margarida Juri Saeki
Banca: Flávio Colmati Júnior
Resumo: Neste trabalho, foi estudada a influência da adição de TiO2 na atividade catalítica para a reação de oxidação de etanol sobre nanocatalisadores PtRu e PtSn. O efeito da quantidade de TiO2 adicionado também foi investigado para os catalisadores bimetálicos de PtSn. Os estudos foram realizados de modo comparativo para catalisadores suportados em carbono com a mesma parte metálica (Pt, PtRu ou PtSn), com e sem modificação com TiO2. A síntese das nanopartículas de PtRu e PtSn de composição nominal 50:50 e 70:30 (em átomos), respectivamente, foi realizada pelo método do poliol modificado, enquanto o TiO2 foi sintetizado separadamente pelo processo sol-gel. Com o intuito de avaliar as diferenças na atividade catalítica promovidas pela presença do óxido, mantendo idênticas as propriedades da parte metálica, as nanopartículas em estado coloidal foram separadas em frações: uma foi utilizada para a preparação do catalisador sem óxido e as outras para a preparação dos materiais contendo TiO2. Os nanocatalisadores preparados foram caracterizados por difração de raios X (DRX), microscopia eletrônica de transmissão (TEM), espectroscopia de fotoelétrons excitados por raios X (XPS) e espectroscopia de absorção de raios X (XAS) in situ. O comportamento eletroquímico geral foi avaliado por voltametria cíclica em solução ácida ou alcalina e as atividades eletrocatalíticas para a oxidação de etanol foram estudadas por varreduras de potencial e cronoamperometria. De maneira geral, os resultados mostram que a presença do TiO2 promove um aumento da atividade catalítica para a oxidação de etanol em meio ácido que, em baixos potenciais, resultaria das mudanças na vacância da banda 5d da Pt promovida pelas interações metal-óxido. Os estudos realizados variando a quantidade de TiO2 mostraram que os efeitos do teor de óxido são significativos tanto em meio ácido quanto em meio alcalino. Experimentos utilizando a...
Abstract: In this work, the influence of the addition of TiO2 on the catalytic activity toward ethanol oxidation reaction on PtRu and PtSn nanocatalysts was studied. The effect of the amount of TiO2 added was also investigated for the PtSn bimetallic catalysts. The studies were comparatively performed for carbon-supported catalysts with the same metallic component (Pt, PtRu or PtSn) with and without modification with TiO2. The synthesis of PtRu and PtSn nanoparticles with nominal composition equal to 50:50 and 70:30 (in atoms), respectively, was carried out by a modified polyol method, while TiO2 was synthesized separately by a sol-gel process. In order to evaluate the differences in the catalytic activity promoted by the presence of the oxide, while maintaining the same properties of the metallic part, the colloid of nanoparticles was separated into fractions: one was used to prepare the catalyst without oxide and the others were used for preparation of the TiO2 containing materials. Nanocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and in situ X-ray absorption spectroscopy (XAS). The general electrochemical behavior was evaluated by cyclic voltammetry in acidic or alkaline solution and the electrocatalytic activity for ethanol oxidation was studied by potential sweeps and chronoamperometry. Overall, the results show that the presence of TiO2 enhances the catalytic activity for ethanol oxidation in acid medium in the low potential region, because of the changes in the Pt 5d band vacancy promoted by metal-oxide interactions. The studies involving the variation of the amount of TiO2 showed that the effects of oxide content are significant both in acidic and in alkaline medium. Experiments using in situ Fourier transform infrared reflection-absorption spectroscopy (FTIRAS) were performed in order to analyze qualitatively the products of alcohol oxidation at each...
Doutor
ANDANA, TAHRIZI. "Roles of morphology and foreign metals of ceria-based catalysts in improving oxidations of Diesel vehicle pollutants." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2669105.
RIPANDELLI, SIMONE. "1,3-Dihydroxypropan-2-one (DHA) synthesis from Glycerol for pharmaceutical applications." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2605356.
SIRACUSANO, STEFANIA. "Development and characterization of catalysts for electrolytic hydrogen production and chlor–alkali electrolysis cells." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1337.
The topics of this PhD thesis are concerning with Chlor alkali electrolysis and PEM water electrolysis. • Chlor alkali electrolysis. The industrial production of chlorine is today essentially achieved through sodium chloride electrolysis, with only a minor quantity coming from hydrochloric acid electrolysis. The main problem of all these processes is the high electric energy consumption which usually represents a substantial part of the total production cost. Therefore, in order to improve the process, it is necessary to reduce the power consumption. The substitution of the traditional hydrogen-evolving cathodes with an oxygen-consuming gas diffusion electrode (GDE) involves a new reaction that reduces the thermodynamic cell voltage and leads to an energy savings of 30-40%. My research activity was addressed to the investigation of the oxygen reduction at gas-diffusion electrodes as well as to the surface and morphology analysis of the electrocatalysts. Specific attention was focused on deactivation phenomena involving this type of GDE configuration. The catalysts used in this study were based on a mixture of micronized silver particles and PTFE binder. In this study, fresh gas diffusion electrodes were compared with electrodes tested at different times in a chlor-alkali cell. Electrode stability was investigated by life-time tests. The surface of the gas diffusion electrodes was analyzed for both fresh and used cathodes by scanning electron microscopy and X-ray photoelectron spectroscopy. The bulk of gas diffusion electrodes was investigated by X-ray diffraction and thermogravimetric analysis. • PEM water electrolysis. Water electrolysis is one of the few processes where hydrogen can be produced from renewable energy sources such as photovoltaic or wind energy without evolution of CO2. In particular, an SPE electrolyser is considered as a promising methodology for producing hydrogen as an alternative to the conventional alkaline water electrolysis. A PEM electrolyser possesses certain advantages compared with the classical alkaline process in terms of simplicity, high energy efficiency and specific production capacity. This system utilizes the well know technology of fuel cells based on proton conducting solid electrolytes. Unfortunately, electrochemical water splitting is associated with substantial energy loss, mainly due to the high over-potentials at the oxygen-evolving anode. It is therefore important to find the optimal oxygen-evolving electro-catalyst in order to minimize the energy loss. Typically, platinum is used at the cathode for the hydrogen evolution reaction (HER) and Ir or Ru oxides are used at the anode for the oxygen evolution reaction (OER). These metal oxides are required, compared to the metallic platinum, because they offer a high activity, a better long-term stability and less efficiency losses due to corrosion or poisoning. My work was mainly addressed to a) the synthesis and characterisation of IrO2 and RuO2 anodes; b) conducting Ti-suboxides support based on a high surface area. a) Nanosized IrO2 and RuO2 catalysts were prepared by using a colloidal process at 100°C; the resulting hydroxides were then calcined at various temperatures. The attention was focused on the effect of thermal treatments on the crystallographic structure and particle size of these catalysts and how these properties may influence the performance of oxygen evolution electrode. Electrochemical characterizations were carried out by polarization curves, impedance spectroscopy and chrono-amperometric measurements. b) A novel chemical route for the preparation of titanium suboxides (TinO2n−1) with Magneli phase was developed. The relevant characteristics of the materials were evaluated under operating conditions, in a solid polymer electrolyte (SPE) electrolyser, and compared to those of the commercial Ebonex®. The same IrO2 active phase was used in both systems as electrocatalyst.
Michelon, Nicola. "Modelling and experimental investigation of microkinetic in heterogeneous catalysis: hydrogen combustion and production." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424703.
Questa tesi investiga sia la combustion che la produzione di idrogeno, con particolare attenzione verso aspetti fondamentali della ossidazione catalizzata da platino e la reazione di steam reforming del metano su catalizzatori a base di nickel. Per quanto riguarda il primo aspetto, siamo partiti dall’osservare ed approfondire discrepanze sulla struttura e sui risultati di modelli cinetici di reazioni superficiali presenti in Letteratura, per la reazione di H2 e O2 su Pt. I confronti quantitativi sono stati fatti utilizzando un Modello di reattore chiuso ben mescolato con le superfici interne catalitiche. Le differenze nelle perizie dei diversi modelli sembrano discendere da differenze nei dati sperimentali su cui sono stati calibrati. Il fatto che se non state utilizzate diverse configurazioni sperimentali, e probabilmente strutture delle superfici di Pt , ci ha stimolato a intraprendere una campagna sperimentale per ottenere dati propri, utilizzando superfici di platino planari in opportuni reattori. Un nuovo reattore di laboratorio, a flusso stagnante, per indagare reazioni su Pt in forma di dischi e stato progettato sulla base di una` modellazione dettagliata e realizzato in laboratorio. I risultati sperimentali hanno dimostrato che l’attivita del Pt può variare enormemente. Pretrattamenti con H2 o O2 Hanno chiarito il meccanismo della competizione per siti superficiali e la possibilita di ristrutturazione la superficie. Sono state misurate trasformazioni di lunga durata, soprattutto dopo pretrattamenti con O2, che non trova una spiegazione in nessuno dei modelli cineticidettagliati di letteratura. Mediante misure in rampa di temperatura si e studiato` l’innesco di miscele povere di H2 in aria. Il confronto con dati di letteratura suggerisce una plausibile interpretazione della discrepanza dei dati riportati. Successivamente simulazioni transitorie della combustione di idrogeno in canali rivestiti di platino e stato utilizzato per valutare il comportamento della`reazione eterogenea con e senza reazione omogenea. L’effetto delle proprieta`del supporto del catalizzatore sono stati confrontati, considerando leghe Fe-Cre cordierite. Le implicazioni pratiche per l’operativita di questi reattori sono state`delineate. Per quanto riguarda la produzione di idrogeno abbiamo studiato sia dal punto di vista teorico che sperimentale la reazione di reforming di gas naturale mediante7 vapore. Abbiamo identificato intervalli significativi da un punto di vista industriale per le variabili operative, per studiare la cinetica dei catalizzatori. Abbiamo progettato un reattore di laboratorio mediante regole di scala rispetto a un impianto modello industriale di riferimento, con l’obiettivo di studiare la reazione a pressioni elevate (10bars). Abbiamo confrontato tre catalizzatori basati su Nickel con formulazioni diverse, modificando rapporto vapore/carbonio in alimentazione, per avvicinarsi alle condizioni stechiometriche. Si sono raccolti numerosi ,dati sia di attivita cataliticha che di formazione di carbone, utili per uno sviluppo di modelli` cinetici dettagliati della reazione superficiale.
DOSA, MELODJ. "Nanostructured ceria-based catalysts for automotive application - Formulation of nanostructured systems for diesel and gasoline-type engines." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2903500.
MONCADA, QUINTERO CARMEN WILLIANA. "Ceramic open cell foams as catalytic support for endothermic and exothermic reactions: Focus on lean methane combustion." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2929756.
Niemelä, Marita. "Reactions of synthesis gas on silica supported transition metal catalysts /." Espoo : Technical Research Centre of Finland, 1997. http://www.vtt.fi/inf/pdf/publications/1997/P310.pdf.
Reinikainen, Matti. "Cobalt and ruthenium-cobalt catalysts in CO hydrogeneration and hydroformylation /." Espoo : Technical Research Centre of Finland, 1998. http://www.vtt.fi/inf/pdf/publications/1998/P363.pdf.
Boffito, D. C. "BIODIESEL PRODUCTION FROM NON-FOODSTUFF: CHEMISTRY, CATALYSIS AND ENGINEERING." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/214934.
OTTONE, MELIS CARMINNA SOPHIA. "Heterogeneous and Heterogenized Catalysts for Water Oxidation Reaction as Studied by Means of Sacrificial Oxidant." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2594356.
FRONZO, A. DI. "BIOMASS TO LIQUID PROCESS: NEW KIND OF COBALT AND IRON BASED CATALYSTS FOR THE FISCHER-TROPSCH SYNTHESIS." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229549.
SALOMONE, FABIO. "Addressing the challenges of the Power-to-Fuel technologies from a catalyst development and techno-economic point of view." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2907012.
Cade, Christine Elizabeth. "Isoniazid-Resistance Conferring Mutations in Mycobacterium tuberculosis KatG: Catalase, Peroxidase, and INH-NADH Adduct Formation Activities." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-10292009-100009/.
Smith, Rachel. "Probing crystal growth in methanol-to-olefins catalysts." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/probing-crystal-growth-in-methanoltoolefins-catalysts(83b999a1-775e-4e55-8e94-47403d2a86c6).html.
MONTENEGRO, CAMACHO YEIDY SORANI. "Green hydrogen production from biogas autothermal reforming processor coupled with soot trap." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2674736.
SCELFO, SIMONE. "Metal oxides catalysts for the synthesis of value-added chemicals from 2nd generation sugars and sugar derivatives." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2675152.
Alshmimri, Sultan. "The behaviour of β-triketimine nickel complexes in ethylene polymerization". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/the-behaviour-of-triketimine-nickel-complexes-in-ethylene-polymerization(3374d8ea-3d60-46ea-a51a-6a6b5239a1c2).html.
Kiviaho, Jari. "Fischer-Tropsch synthesis catalysed by cobalt-rhodium and cobalt-ruthenium carbonyl clusters on silica /." Espoo : Technical Research Centre of Finland, 1996. http://www.vtt.fi/inf/pdf/publications/1996/P290.pdf.
Barakat, Jean-Baptiste. "Croissance auto-catalysée de nanofils d'InP sur silicium par épitaxie par jets moléculaires en mode vapeur-liquide-solide : application aux interconnexions optiques sur puce." Thesis, Ecully, Ecole centrale de Lyon, 2015. http://www.theses.fr/2015ECDL0027/document.
Monolithic integration of III-V semiconductors materials on Si substrate is essential for the Si photonic development. We aim at achieving an optical microsource based on a regular array of III-V (InAsP/InP) nanowires (NWs) standing on top a Si waveguide. Due to their ability to be fully relaxed, nanowires growth is of deep interest. This PhD thesis has been oriented towards such context especially among self-catalyzed InP NWs growth by epitaxy. Thus we have shown that highly dense and vertical self-catalyzed InP NWs accomplishment is related to Si substrate surface oxide. A monomodal or bimodal NWs distribution have been reached through a control of indium droplets formation or growth parameters. A critical pressure and a critical temperature have been found to delimit favorable growth regime. Intrinsic optical properties have been determined to be goal sufficient. Optical simulation modeling and characterization of the polarization light state in NWs and in the Si waveguide have led us to establish functional specifications to grow vertical NWs on SOI as way that their optical modes could be coupled efficiently at telecommunications wavelength