<p>The awareness of the effect emissions have on the environment and climate has risen in the last decades. This has caused strict regulations of greenhouse gas emissions. Greenhouse gases cause global warming which may have devastating environmental effects. Most of the fuels commercially available today are fossil fuels. There are two major effects of using fuels with fossil origin; the source will eventually drain and the usage results in an increase of greenhouse gases in the atmosphere. Fuels that are created from a renewable feedstock are often referred to as alternative fuels and under ideal conditions they are greenhouse gas neutral, meaning that the same amount of greenhouse gases is released during combustion as the source of the fuel have absorbed during its growth period. This evaluation method is known as a well-to-wheel analysis which besides emissions also evaluates energy efficiencies during both the production and the combustion phases.</p><p>By evaluating results of well-to-wheel analyses along with fuel properties and engine concept characteristics, this report presents which driving scenario that is suitable for different powertrain configurations. For example, vehicles operating in high populated areas, as cities, have a driving scenario that includes low velocities and multiple stops while vehicles in low populated areas often travel long distances in higher speeds. This implies that different powertrains are suitable in different regions. By matching favorable properties of a certain powertrain to the properties important to the actual driving scenario this report evolves a fuel infrastructure that is suitable in Sweden.</p>

In this study, the OMCVD method is demonstrated as a powerful, fast, economic and environmental friendly method to produce a set of PGMelectrocatalysts with different supports, metal content and metal alloys in one step and without the multiple processing stages of impregnation, washing, drying, calcinationsand activation.

<p>In this study, the OMCVD method is demonstrated as a powerful, fast, economic and environmental friendly method to produce a set of PGMelectrocatalysts with different supports, metal content and metal alloys in one step and without the multiple processing stages of impregnation, washing, drying, calcinationsand activation.</p>

In this thesis, firstly, carbon-supported platinum nanoparticle catalysts have been prepared by using PtCl4 and H2PtCl6 as starting materials and 1-hexanethiol, and tert-octanethiol, as surfactants for the first time. Secondly, these prepared catalysts were heated to 200 &deg / C, 300 &deg / C, and 400 &deg / C for 4 h under argon gas. Lastly, PtRu/C catalysts, which have different atomic percent ratios of Pt and Ru (Pt/Ru: 0.8, 2.1 and 3.5), were prepared using PtCl4 and RuCl3 as starting materials and tert-octanethiol as a surfactant. Each was characterized by X-ray diffraction, transmission electron microscopy, energy dispersive analysis, X-ray photoelectron spectroscopy, cyclic voltammetry, and elemental analysis, and their activities were determined toward the methanol oxidation reaction. It has been found that all prepared catalysts are more active toward methanol oxidation reaction compared to the commercial catalysts. It was also found that increasing the temperature during the heat treatment process results in an enlargement of platinum particle size and a decrease in catalytic activity in the methanol oxidation reaction. Transmission electron microscopy shows that platinum nanoparticles are homogeneously dispersed on the carbon support and exhibited a narrow size distribution with an average particle size of about 2-3 nm in diameter. X-ray photoelectron spectra of all catalysts indicated that most of the platinum nanoparticles (&gt / 70 %) have an oxidation state of zero and rest (&lt / 30 %) have a +4 oxidation state with (Pt 4f7/2) binding energies of 71.2-72.2 and 74.3-75.5 eV, respectively.

The awareness of the effect emissions have on the environment and climate has risen in the last decades. This has caused strict regulations of greenhouse gas emissions. Greenhouse gases cause global warming which may have devastating environmental effects. Most of the fuels commercially available today are fossil fuels. There are two major effects of using fuels with fossil origin; the source will eventually drain and the usage results in an increase of greenhouse gases in the atmosphere. Fuels that are created from a renewable feedstock are often referred to as alternative fuels and under ideal conditions they are greenhouse gas neutral, meaning that the same amount of greenhouse gases is released during combustion as the source of the fuel have absorbed during its growth period. This evaluation method is known as a well-to-wheel analysis which besides emissions also evaluates energy efficiencies during both the production and the combustion phases. By evaluating results of well-to-wheel analyses along with fuel properties and engine concept characteristics, this report presents which driving scenario that is suitable for different powertrain configurations. For example, vehicles operating in high populated areas, as cities, have a driving scenario that includes low velocities and multiple stops while vehicles in low populated areas often travel long distances in higher speeds. This implies that different powertrains are suitable in different regions. By matching favorable properties of a certain powertrain to the properties important to the actual driving scenario this report evolves a fuel infrastructure that is suitable in Sweden.

In this thesis, carbon supported platinum nanoparticle catalysts were prepared using PtCl4 and H2PtCl6 as starting materials and 1-heptanethiol, tert-nonyl mercaptan, 1-hexadecanethiol, 1-octadecanethiol as surfactants. These new catalysts were employed for methanol oxidation reaction which are used for direct methanol fuel cells. Tert-nonyl mercaptane was used for the first time in this type of reaction and the other surfactants were used for comparison of the catalysts performance. Cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used in order to determine the nature of the catalysts. The average platinum crystallite particle sizes of all prepared catalysts were determined by both X-ray diffraction and transmission electron microscopy. It was found that platinum crystallizes in face-centered cubic structure and the surfactant play an important role on the size of platinum nanoparticles, branch surfactant, such as tert-nonyl mercaptane, causes an increase in the size of platinum nanoparticles, about 3 nm, compared to linear surfactant, such as 1-heptanethiol, about 2 nm. The oxidation states of platinum and their ratios were determined by XPS technique. These results indicated that platinum has two different oxidation states, zero and +4, and Pt(0) to Pt(IV) ratio is about 7.5 to 2.5. In addition to this, O 1s region of XPS was also examined and found that the surface of all of the catalysts covered by adsorbed hydroxide except the catalyst which was prepared by PtCl4 and tert-nonyl mercaptane (Catalyst IIa), where adsorption of water were observed and the catalyst which was prepared by H2PtCl6 and tert-nonyl mercaptane (Catalysts IIb), where adsorption of 65% of hydroxide and 35% of water were identified. Electrochemical studies indicated that Catalyst IIa has the maximum activity (&amp / #61566 / 342 A/gPt at 0.612 V) towards methanol oxidation reaction while Catalyst IIIb (H2PtCl6 and 1-hexanethiol were used to prepare this catalyst) has the minimum activity (&amp / #61566 / 91A/gPt at 0.580V). XRD, TEM and XPS results indicated that the optimum catalyst for methanol oxidation reaction contains about 3 nm of platinum nanoparticles, adsorbed hydroxide and water on the surface of catalyst, but sulphur. These results are in agreement with the proposed mechanism.

In this work, two groups of carbon supported Pt-Pd catalysts have been prepared in order to investigate the effect of Pd, as a second metal, and surfactants on the catalytic activity towards methanol and ethanol oxidation reactions used in the direct methanol and ethanol fuel cells. In the first group (group a), 1- hexanethiol was used as a stabilizing agent while in the second group (group b), 1,1 dimethyl hexanethiol was utilized. Cyclic voltammetry (CV), chronoamperometry (CA), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used in order to determine the nature of the catalysts. The average crystalline size of the metal particles in the catalysts was explored by XRD and TEM. TEM results revealed the uniform distribution of the metal nanoparticles on carbon support with a narrow size distribution in the range of 3.0 to 3.7 nm and the average crystalline sizes of metal particles for group &ldquo / b&rdquo / catalysts were larger than that of group &ldquo / a&rdquo / catalysts which can be explained by the surfactant effect. These results were in good agreement with XRD data. The oxidation states of platinum (Pt(0) and Pt(IV)) and palladium (Pd(0) and Pd(II)) and their ratios were investigated by XPS and for the most active catalyst, catalyst Ib, these ratios were found to be as 6.94 and 13.7, respectively. Electrochemical activities of the catalysts towards methanol and ethanol oxidation reactions were recorded and compared with that of Pt/C and the commercial Pt (ETEK 20 %wt) catalysts. The results indicated that the group &lsquo / b&rsquo / catalyst has greater catalytic activities than that of group &lsquo / a&rsquo / catalysts. Catalyst Ib comes into prominence as the most active catalyst due to its superior characteristics that it possess such as highest extent of alloying with respect to the palladium amount used, active surface area, CO-tolerance, stability and Pt (0) to Pt (IV) and Pd (0) to Pd (II) ratios.

D. Tech. Mechanical Engineering. / Discusses how to reduce the negative impacts of petroleum oil based fuels in reciprocating engines on the environment through the use of oxygenated (alcohol) blends, while not deteriorating engine performance. The specific objectives are as follows: To evaluate the performance characteristics of n-butanol-diesel blends: B5, B10 and B20, in a direct-injection turbo-charged diesel engine and to compare findings with a study that was carried out by others (Sayin, 2010). To compare the performance, combustion and emission characteristics of dual alcohol-gasoline with single alcohol-gasoline blends fired in a naturally-aspirated (NA) spark ignition (SI) engine. To compare the combustion and emission characteristics of dual alcohol (methanol-n-butanol-gasoline) blends with single alcohol (methanol-gasoline) blends in a single-cylinder SI engine. To evaluate the combustion and regulated emission characteristics of DF and n-butanol/diesel blends (B5, B10, and B20 where B5 represents 5 % shared volume of n-butanol to 95 % diesel fuel) fired in a high load turbo-charged diesel engine and to compare the findings with a study that was conducted by Raslavicius & Bazaras, (2010).

The covalent bond formed between a N-heterocyclic carbene and an aryl-isothiocyanate was discovered to be thermally-reversible. This bond was incorporated into the backbone of an aromatic polymer which, when subjected to heat and excess monomer, would depolymerize to smaller oligomers. In addition these small molecules contain active chain ends and could be repolymerized to reform the original polymer. The high molecular weight material was made into freestanding sheets with desirable mechanical properties and could be made conductive by treatment with iodine. A new poly(triazene) was formed from the reaction of a facially opposed, annulated, bis-N-heterocyclic carbene (NHC) and an organic bis-azide. The NHC as well as the azide were varied and combined to produce a series of polymers which were characterized by GPC, TGA, and NMR. These thermally robust polymers were also coated onto glass slides and rendered electrically conductive by exposure to iodine vapor. A new reagent for Reversible Addition Fragmentation Chain Transfer Polymerization (RAFT) is described. This imidazolium based reagent shows unusually fast kinetics which allows it to control polymerizations at significantly reduced loadings compared to the more traditional neutral dithiocarbamates or dithioesters. The fast kinetics is explained by the rapid rotation of the dithioester about the plane of the cationic N-heterocycle. Sulfonated poly(ether ether ketone) (sPEEK) membranes were blended with imidazoles with varying pKas. The proton conductivity of the membranes was evaluated as a function of pKa and temperature. Interestingly, the conductivity of the dry membranes showed a non-monotonous profile over a temperature range of 25 – 150 C. We use a theoretical model to better understand the mechanistic origins of the observed temperature–conductivity profiles. This model is based on the reaction equilibria between sPEEK’s sulfonic acid groups and the basic sites of the added heterocycles. Using the copper-catalyzed 1,3-dipolar “click” cycloaddition reaction, poly(sulfone)s containing pendant azide moieties were functionalized with various amounts of sodium 3-(prop-2-ynyloxy)propane-1-sulfonate and crosslinked with 1,7-octadiyne. The degree of sulfonation as well as the degree of cross-linking was systematically varied by changing the ratios of the aforementioned reagents. The polymers were cast into membranes, acidified, and then tested for proton conductivity, methanol permeability, and membrane-electrode assembly (MEA) performance. / text

Dimethylether is a non-toxic liquefied gas, which is projected to become one of the fundamental chemical feedstock in the future. Dimethylether can be produced from syngas via a two-step (indirect) process that involves synthesis of methanol by hydrogenation of CO/CO2 over a copper based catalyst and subsequent dehydration of methanol to DME over an acidic catalyst. Alternatively, DME can be produced in an one-step (direct) process using a hybrid (bifunctional) catalyst system that permits both methanol synthesis and dehydration in a single process unit. In the present research work the production of DME has been studied by applying both the indirect and direct processes. Firstly, the methanol synthesis and methanol dehydration reactions involved in the indirect process have been studied separately. Afterwards, these two reactions have been combined in the direct DME production process by using a hybrid catalyst comprising a methanol synthesis and a methanol dehydration component. The methanol synthesis by CO2 hydrogenation has been investigated over commercial and home-made CuO/ZnO/Al2O3 catalysts with the aim to identify optimal experimental conditions (CO2:H2 ratio, flow rate, temperature) that could be then used in the direct conversion of CO2/H2 mixtures into methanol/DME. Obtained results reveal that the conversion of CO2 and the yields of reaction products (CH3OH and CO) increase when the concentration of H2 in the feed and the reaction contact time are increased. It was found that both Cu+/Cu0 species are important for the conversion of CO2/H2, although the presence of Cuo seems to be more important for selectivity/yield of methanol. The stability of the CuO/ZnO/Al2O3 catalyst has been also investigated. It was observed that the main reason for the deactivation of catalyst is the water produced via the methanol synthesis and reverse water gas shift reactions. However, the catalytic activity and products selectivity were recovered slowly to their original levels after applying a regeneration procedure, indicating that deactivation by water is reversible. The dehydration of methanol to dimethylether (DME) has been investigated over a range of catalysts including alumina, silica-alumina and zeolites with different physicochemical characteristics. The effects of temperature and the presence of water vapour in the feed on catalytic performance have been studied in detail. The reactivity of catalysts has been evaluated by determining the reaction rates per gram of catalyst per acid site (total: Brönsted+Lewis) and per Brönsted/Lewis mole ratio. In addition, the reaction mechanism has been investigated over a selected catalyst, with the use of transient-MS and in situ DRIFTS techniques. Results obtained for alumina catalysts show that the catalytic activity and selectivity are determined to a large extent by the textural properties, degree of crystallinity and total amount of acid sites of catalysts. In particular, the methanol conversion curve shifts toward lower reaction temperatures with an increase of specific surface area. However, the enhanced catalytic activity of high-SSA samples cannot be attributed solely to the higher amount of surface acid sites, implying that the reaction rate is determined to a large extent from other parameters, such as textural properties and degree of crystallinity. Results of mechanistic studies indicate that interaction of methanol with the Al2O3 surface results in the formation of two kinds of methoxy groups of different adsorption strength. Evidence is provided that DME evolution is associated with methoxy species that are weakly adsorbed on the Al2O3 surface, whereas more strongly held species decompose to yield surface formate and, eventually, CH4 and CO in the gas phase. Results obtained over zeolite catalysts show that catalytic performance depends on the topology of zeolites due to differences in micropore structure and Si/Al ratio as well as on the number, strength and nature of active acid sites. The activity of zeolite catalysts for the methanol dehydration to DME follows the order ZSM-5 > Ferrierite > Mordenite ~ Beta ~ USY > H-Y. The strong Brönsted acid sites of ZSM-5 zeolites with relatively high Si/Al ratio represent the most active sites in methanol dehydration to DME reaction. However, the overall reactivity of the ZSM-5 zeolites is also affected by the balance of the Brönsted to Lewis acid sites. The activity of Beta and USY zeolites is determined by both Lewis and Brönsted acid sites. The moderate/low reactivity of Ferrierite, Mordenite and H-Y zeolite are determined by the abundant Brönsted acid sites of relatively weak/moderate strength. The direct CO2 hydrogenation to methanol/DME has been investigated using admixed catalysts comprising a methanol synthesis (commercial copper based catalyst: CZA1) and a methanol dehydration component (different alumia/zeolite catalysts: γ-Al2O3, ZSM-5, W/γ-Al2O3, USY(6), Ferrierite(10)). It has been revealed that the conversion of CO2 is always lower than the corresponding equilibrium values predicted by thermodynamics, indicating operation in the kinetic regime. The nature of the methanol dehydration component of the admixed catalysts was found to be important for both CO2 conversion and methanol dehydration. In particular, DME selectivity/yield, depends strongly on the nature of acid sites (both Lewis and Brönsted) as well as the textural (meso/macro porosity) and topological properties of methanol dehydration component of the admixed catalysts. The yield of DME obtained at a temperature of 250oC decreases following the order CZA1/ZSM-5, CZA1/USY(6) > CZA1/Ferrierite(10) > CZA1/ W/γ-Al2O3 >> CZA1/γ-Al2O3. The long-term stability experiments conducted over selected bifunctional catalytic systems revealed that the catalysts deactivate with time-on-stream, mainly due to water produced via methanol synthesis, methanol dehydration and reverse water gas shift reactions. In case of the CZA1/ZSM-5 admixed catalyst the catalytic activity and products selectivity were almost recovered after regeneration indicating that deactivation by water is reversible. / --