In response to the ever-increasing global energy demand and the need to move away from non-renewable and CO2-emitting fossil fuels as the primary energy production method, renewable energy sources have become more and more viable as energy production methods. However, given the unreliable and instantaneous nature of these energy sources, reliable, renewable energy storage methods are required. Hydrogen is an excellent candidate as a chemical energy store, as it is highly abundant, relatively easily produced as diatomic hydrogen (including from water electrolysis), and only produces water upon its complete combustion. Hydrogen also has the highest gravimetric energy density of any known chemical fuel, meaning that not very much of it is required relative to other chemical fuels. However, hydrogen gas is incredibly sparse, and therefore hydrogen has a very low volumetric energy density, making storage of the material a key challenge in the development of the so-called “hydrogen economy”. Most commonly, hydrogen is stored by compressing it to 70 MPa. However, this technique has a number of flaws, including the high expense of strong tanks (and in the case of light duty vehicles, lightweight materials are also required), and the inherent safety risks that high pressure, highly flammable gas poses. One of the alternatives to compression is to store hydrogen by adsorption, which uses high surface area materials to densify hydrogen via the formation of weak physical bonds. This research line is well developed, and a number of different materials has been created that show good potential as hydrogen storage materials, such as activated carbons and metal organic frameworks. However, the vast majority of materials developed for this purpose are tailored only with the hydrogen uptake in mind, which can cause issues as the focus of development shifts from small scale tests to full tank scale. One adsorptive that shows a number of highly useful engineering properties on the large scale, such as good thermal resistance and solution processability, is the polymer of intrinsic microporosity PIM-1. This material can be processed into a number of morphologies without losing porosity, and shows good thermal and mechanical resistance. However, its adsorption capacity is rather limited, with the BET surface area generally reported in the 700 – 800 m2 g-1 range, and hydrogen uptake of 1.45 wt% at 77 K and 1 MPa. This thesis presents two separate studies on attempting to improve the hydrogen uptake of PIM-1 without adversely affecting the material properties that make it attractive. The first of these was the creation of mixed-matrix-membrane style composite films solution cast from PIM-1 and the metal organic framework MIL-101. PIM-1 proved slightly difficult to synthesise consistently with high molecular weight, but MIL-101 is an easy hydrothermal synthesis. Film casting was successfully performed, producing flat, homogeneous films that maintained the MOF crystallinity. These materials were tested for their thermal properties – thermal decompositions proceeded according to the rule of mixtures of the two starting materials, whilst an increasing concentration of MOF was shown to decrease the specific heat capacity. Both PIM-1 and MIL-101 were shown to adsorb nitrogen as previously reported. The composites showed increasing uptake with MIL-101 content, but at a lower rate than the rule of mixtures. This was a common theme for the N2 (77 K), CO2 (293 K) and low pressure H2 isotherms performed. High pressure isotherms up to 17 MPa were performed on PIM-1 for the first time, showing a maximum excess uptake of 1.8 wt% on the powder and 1.6 wt% on the film, both at 77 K. The composites showed improved uptake with increasing MIL-101, but the maximum uptakes did not meet the rule of mixtures. The uptakes at the highest pressure did, however. Multiple temperature isotherm sets were performed on the PIM-1 film and powder, as well as the 30 wt% composite. These data sets were hampered largely by machine faults, but contained sufficient valuable data to be able to proceed with parameter fitting. The sensitivity of the isotherms produced in this study to the value of skeletal density is also examined closely. The second theme of improved H2 uptake in PIM-1 was to carbonise the material. TGA studies on PIM-1 showed good thermal stability in anoxic conditions, and TGA twinned with mass spectroscopy was able to confirm a previously proposed mechanism of thermal decomposition. Carbonised and activated PIM-1 film samples, and a carbonised powder, were produced using physical activation methods. The adsorption performance of the carbons was disappointing, as the uptakes of N2 and H2 (< 0.1 MPa) were reduced post-carbonisation, with little recovery in the activated film. CO2 uptakes were improved, however. High pressure H2 isotherms on both the carbonised and activated films showed unusual ‘stepping’ behaviour in the adsorption curve, but maximum uptakes for both (1.0 – 1.3 wt%) were less than that seen for PIM-1 alone. Parameter fitting was performed on all of the high pressure H2 isotherms performed in this study, using a method previously proposed by the Mays group. The parameter fits all showed effective hydrogen densification in the adsorbate layer, although the repeatability of parameter values, and the smoothness of the parameters as a function of temperature were undermined by the low quality of some of the isotherms. Using the parameters acquired, it was possible to calculate the isosteric enthalpy of adsorption for PIM-1 powder (-9.5 kJ mol-1), film (- 8.0 kJ mol-1) and the 30 wt% composite (-9.3 kJ mol-1). The stored and deliverable hydrogen contained within tanks featuring the tested materials were estimated, although only the MIL-101 powder on its own competes with other hydrogen storage adsorbents currently reported.

Transport of ions and molecules in solids is a very important process in many technological applications, for example, in drug delivery, separation processes, and in power sources such as ion diffusion in electrodes or in solid electrolytes. Progress in the understanding of the ionic and molecular transport mechanisms in solids can be used to substantially increase the performance of devices. In this dissertation we use ab initio calculations and molecular dynamics simulations to investigate the mechamisn of transport in solid. We first analyze molecular transport and storage of H2. Different lightweight carbon materials have been of great interest for H2 storage. However, pure carbon materials have low H2 storage capacity at ambient conditions and cannot satisfy current required storage capacities. Modification of carbon materials that enhance the interaction between H2 and absorbents and thus improve the physisorption of H2, is needed for hydrogen storage. In this dissertation, corannulene and alkali metal-doped corannulene are investigated as candidate materials for hydrogen storage. Molecularalso investigated. Using computational chemistry, we predict enhanced H2 adsorption on molecular systems with modification and hydrogen uptake can reach DOE target of 6.5wt% at at 294 bar at 273 K, and 309 bar at 300 K. In the second part of this dissertation, we study the lithium ion transport from a solid electrolyte phase to a solid electrode phase. Improvement of ionic transport in solid electrolytes is a key element in the development of the solid lithium ion batteries. One promising material is dilithium phthalocyanine (Li2Pc), which upon self-assembly may form conducting channels for fast ion transport. Computational chemistry is employed to investigate such phenomena: (1) to analyze the crystalline structure of Li2Pc and formation of conducting channels; (2) to understand the transport of Li ions inside channels driven by an electric field; (3) to study the continuity of the conducting channels through interface. The study shows Li2Pc has higher conductivity than PEO as electrolyte.

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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23199号 / 工博第4843号 / 新制||工||1756(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 邑瀬 邦明, 教授 宇田 哲也, 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

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ABSTRACT SYNTHESIS AND CHARACTERIZATION OF ETHANOL ELECTRO-OXIDATION CATALYSIS Demir-Kivrak, Hilal Ph.D., Department of Chemical Engineering Supervisor : Prof. Dr. Deniz &Uuml / ner Co-supervisor : Dr. Sadig Kuliyev October 2010, 196 pages In this study, the role of defects, the role of Sn in relation to defects, and the role of oxide phase of tin in ethanol electro-oxidation reaction were investigated. Firstly, adsorption calorimetry measurements were conducted on monometallic (1%Pt, 2%Pt, and 5%Pt) and bi-metallic (5% Pt-Sn) &gamma / -Al2O3 supported Pt catalysts. It was observed that while saturation coverage values decreased, intermediate heats remained same for Pt-Sn catalysts by the increasing amount of tin. The effect of particle size was investigated on Pt/C (pH=5), Pt/C (pH=11) catalysts at different scan rates. At high scan rates (quite above diffusion limitations), current per site activities were nearly the same for 20% Pt/C (E-Tek), Pt/C (pH=11), and Pt/C (pH=5) catalysts, which explained as electro-oxidation reaction takes place at the defects sites. Furthermore, the effect of support on ethanol electro-oxidation was investigated on CNT supported Pt catalyst. Results indicate that only the metal v dispersions improved ethanol electro-oxidation reaction and support did not have any effect on ethanol electro-oxidation reaction. Results on the 20% Pt-Sn/C (15:1 to 1:1 Pt: Sn atomic ratios) and 20% Pt-SnO2/C (6:1 and 1:1) catalysts indicated that ethanol electro-oxidation activity increased by increasing tin amount. For 20% Pt-Sn/C catalysts, Pt-Sn (6:1)/C indicated best activity. On the other hand, 20% Pt-SnO2 (6:1)/C catalyst was better than Pt-Sn (6:1)/C in terms of ethanol electro-oxidation activity due to the fact that there was low contact between Pt and tin oxide particles.

La carbonisation hydrothermale transforme les déchets municipaux (copeaux de bois, boues d'épuration, bagasse, feuilles…) en un produit solide appelé bio-charbon. Le produit hydrothermal connu sous le nom hydrochar est fréquemment utilisé comme carburant ou engrais, mais aussi il pourrait être converti en un produit à haute valeur ajoutée, à savoir le charbon actif. L‘objectif principal de cette thèse est d‘étudier la transformation de grignon d‘olive, précurseur lignocellulosique largement disponible en Tunisie et en pays méditerranéen, en hydrochar et en charbon actif. Dans cette étude, un réacteur discontinu de laboratoire a été conçu et construit. Les grignons d‘olive transformés en hydrochar ont été préparés à différentes sévérités et avec addition de sels, acide et ammoniac. Les hydrochars ont été caractérisés par plusieurs méthodes d‘analyse. L‘eau de traitement de la carbonisation hydrothermale a été analysée et les résultats montrent qu‘elle contient des composants à haute valeur ajoutée comme le furfural et le 5-HMF. Les charbons actifs ont été préparés à partir du hydrochar suivant des voies d‘activation physique (à l‘aide de l‘agent d‘activation CO2) et voies d‘activation chimique (par l‘agent d‘activation KOH). Les matériaux obtenus ont une surface spécifique élevée (1400 m2g-1) et aussi une chimie de surface riche en groupe fonctionnel. Les performances de ces charbons actifs dans l‘adsorption de molécules pharmaceutiques en phase liquide et de l‘hydrogène en phase gazeuse ont été examinées. Des capacités intéressantes ont été relevées pour les deux applications / Hydrothermal carbonization process uses green waste from municipalities (Wood chips, sewage sludge, bagasse, leaves …) to produce solid bio-coal. The solid HTC product known as hydrochar commonly used as a fuel or fertilizer but it could be converted also into high- value products like activated carbon. The principal purpose of this thesis is to study the conversion of olive stones, widely available lignocellulosic biomass in Tunisia and Mediterranean country, into hydrochar and then activated carbon. In this study, a laboratory scale batch reactor has been designed and built. The hydrothermally carbonized olive stones were prepared at different reaction severity and with addition of salts, acid or ammonia. All prepared hydrochar are characterized by different analysis methods. The HTC water was also analyzed and the results show that HTC-liquid contains high added value components such as furfural and 5-HMF. The hydrothermally carbonized olive stones were activated by both physical activation, using CO2 and chemical activation, using KOH. The materials had high surface area (as high as 1400 m2 g-1) and rich surface chemistry. The potential for pharmaceuticals (Ibuprofen and Metronidazole) and hydrogen adsorption were assessed for HTC-activated carbon and they showed good performance in both application

A flexible Metal–Organic Framework Zn4O(BenzTB)3/2 (DUT-13) was obtained by combination of a tetratopic linker and Zn4O6+ as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFs. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Le but principal de cette étude était la recherche de structures optimales de charbons activés capables d"atteindre l'objectif de stockage d'hydrogène fixé par le département de l"énergie américain (DOE) pour les applications mobiles en utilisant l"adsorption physique à la température ambiante et aux pressions en-dessous de120 bars. L'hydrogène est destiné à être stocké dans une cuve rempliée d"adsorbants et doit être utilisé dans les véhicules alimentés principalement par des piles à combustible. Les adsorbants à base de carbone connus ont une capacité de stockage faible. Par conséquent, dans ce travail, j'ai défini les paramètres responsables de l'insuffisance de capacité de stockage de ces matériaux. Une attention particulière a été accordée à la géométrie locale des pores des adsorbants. J'ai étudié la structure locale des pores des adsorbants à base de carbone et je présente le principe de la conception d"architectures tridimensionnelles de nouvelles structures de carbone ainsi que la capacité d'adsorption de l'hydrogène par ces structures, lesquelles constituent une classe prometteuse de matériaux pour le stockage d'hydrogène et qui n'ont pas été étudiées jusqu'ici. Hormis la maximisation de la densité de l'hydrogène absorbée par cette famille de structures, mon but était de caractériser l'adsorption dans cette nouvelle catégorie d'adsorbants. Cela permet d"apporter des informations quant à la méthodologie à utiliser pour ajuster les propriétés physiques de ces matériaux afin d'optimiser leurs propriétés de stockage. Les résultats obtenus semblent montrer que cet objectif est atteint et confirment que mon approche constitue une bonne base pour de futures recherches. / The main goal of research presented in this thesis has been a search for optimal carbon-based porous structure capable to achieve the hydrogen storage capacity defined by US Department of Energy (DOE) for mobile applications at room temperature by adsorption at medium-level pressures below 120 bars. The hydrogen is assumed to be stored in a tank filled with adsorbents to be used in transport application, mainly fuel-cell driven vehicles. The known carbon-based adsorbents have low storage capacity. Therefore in this work, I have defined the basic parameters which are responsible for the capacity deficiency of such materials. Special attention has been paid to local pore geometry of adsorbents. I have investigated the pore local structure of carbon-based adsorbents and I present the basis of design and hydrogen adsorption capacity in three-dimensional architecture of new carbon frameworks, a promising class of potential hydrogen storage materials that have not been studied so far. Apart from maximizing the density of hydrogen taken up by this family of structures, I have aimed at characterization of this new category of adsorbents. This is hoped to lead to a guidance how their physical properties can be designed, or `tuned', to optimize their storage properties, and the obtained results seem to achieve this aim and thus provide a good basis for future research.

A flexible Metal–Organic Framework Zn4O(BenzTB)3/2 (DUT-13) was obtained by combination of a tetratopic linker and Zn4O6+ as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFs. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.