Volatile organic compounds (VOCs) can be considered as a major source of air pollution, and in many cases, legislation has already been introduced to reduce their emissions. O-xylene, one of VOCs, is widely used in industry as solvent and also the raw material of o-Phthalic anhydride (PA). The subjects of this research are divided into four parts, they are screening activity of catalysts, incineration efficiency with various operation parameters, physical properties of catalysts and kinetic model derivation. In screening activity of catalysts, Four kinds of metal ions (Cu, Mn, Zn, Fe; the molar ratio of metal/Fe is 1/2), three different temperature (70¢J, 80¢J, 90¢J) and pH (9, 10, 11) were the parameters of FP to manufactured 36 ferrospinel catalysts. Under the same reaction conditions (o-xylene conc.=1600 ppm, GHSV=71150 hr-1, O2=21%, temperature=298K~673K), it¡¦s found that the most efficient catalyst was Cu/Fe ferrospinel and its synthesis condition was pH at 9 and temperature at 90¢J. The operation parameters to determine incineration efficiency were temperature at 373K ~ 673K, inlet o-xylene concentration at 600 ~ 1600 ppm, GHSV at 47450 ~ 71150 hr-1, O2 concentration at 21 ~ 40%. The results showed that the conversion was proportional to the increase of inlet o-xylene concentration, temperature and inlet oxygen content and was inverse proportional to the increase of GHSV. To realize the physical properties of catalysts, XRD, SEM and EDS were applied. The results indicated that there was no physical difference between fresh and used catalysts. Besides, two kinetic models, Power rate law and Mars-Van Krevelen model were used to demonstrate the decomposition of o-xylene. It¡¦s discovered that Power rate law was more reasonable to illustrate the catalytic o-xylene oxidation. Further, the reaction rate was increased with the increase of inlet o-xylene and oxygen concentration and reaction temperature.

Abstract Aluminum oxide was utilized as a carrier of active metals copper and manganese. Catalysts with various metal ratios and weight loadings were produced by incipient impregnation to treattoluene. From the 24 catalysts we prepared, this investigation selected the most effective catalyst, based on the conversion rate of toluene and CO2 yield. The influence of operating parameters of toluene oxidization on the conversion rate and long-term variations in catalytic activity were investigated, and the physical properties of catalysts were determined by SEM and XRD. The conversion rate for toluene and CO2 yield reached 95% when the Cu/Mn catalyst was used with a metal ratio of 1:1 and 20% loading at 350¢XC, an influent toluene concentration of 1000ppm, oxygen concentration of 21%, a space velocity of 12000 hr-1, and relative humidity of 26%. The toluene conversion rate increased as reaction temperature and influent concentration of oxygen increased, but decreased as the initial toluene concentration and space velocity increased. The long-term test proceeded for seven days at a constant influent toluene concentration of 1000ppm, constant oxygen concentration of 21%, constant space velocity of 12000hr-1 and constant relative humidity of 26%. The stability of the Cu/Mn catalyst structure was assessed. Differences between fresh and aged catalysts were analyzed using analytical instruments such as SEM, and XRD. No obvious deactivation of the catalytic surface was detected. Keywords aluminum oxide, Cu/Mn catalyst, toluene, and operational parameters

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ABSTRACT This study investigated the influence of temperature and humidity on the decomposition efficiency of benzene vapor in a packed-bed UV/TiO2 photocatalytical reactor. The packed-bed annular photocatalytical reactor illuminated by a 15-watt ultraviolet lamp was originally designed for this particular study. Pyrex glass beads coated with Degussa P-25 TiO2 (80 % anatase) were packed in the photocatalytical reactor. The operating parameters investigated in this study included reaction temperature (100-260¢J), water vapor concentration (0-1.58¡Ñ104 mg/m3), retention time (3.1-10.3 sec), and inlet benzene concentration (239-478 mg/m3). Experimental results indicated that the decomposition efficiency of benzene increased with reaction temperature whish was lower than 180¢J, for oxygen content of 21 %, water vapor concentration of 4.69¡Ñ103- 1.58¡Ñ104 mg/m3, and reaction temperature lower then 180¢J. However, the decomposition efficiency of benzene could not be further increased for reaction temperature higher than 180¢J. In addition, the decomposition efficiency of benzene increased with water vapor concentration which was lower than 1.16¡Ñ104 mg/m3. For water vapor concentration higher than 1.16¡Ñ104 mg/m3, the decomposition of benzene could not be further enhanced significantly. In this study, up to 100% of benzene decomposition could be achieved at water vapor concentration of 1.58¡Ñ104 mg/m3 and reaction temperature of 180¢J. Moreover, the decomposition efficiency of benzene increased from 57 to 100% as retention time increased from 3.1 to 10.3 seconds, while decreased from 100 to 65% as benzene concentration increased from 239 to 478 mg/m3. Modified Langmiur-Hinshewood kinetic model was applied to simulate the photocatalytic decomposition of benzene in the annular packed-bed photocatalytic reactor. The simulation of experimental results was successfully developed to describe the reaction rate of benzene for various reaction temperatures (160-260¢J) during the UV/TiO2 photocatalytical reaction process. Furthermore, reaction rate constant (KLH) and adsorption equilibrium constant (Kc and Kw) were functions of reaction temperature, where can the described by the Arrihenius Law. The rate controlling steps were either photocatalytic reaction on the surface adsorption of reaction products from the surface photocatalysts.

Zeolites ZSM-5 (SiO2/Al2O3=30~280) and Y(SiO2/Al2O3=5.2~80) are bound with silica gel (Ludox HS-40 and Ludox AS-40) and alumina (γ- Al2O3 and boehmite) by different binding methods, namely, gel-mixing, powder-mixing and powder-wet-mixing methods. The acidities of the bound catalysts and the zeolite powder are determined by NH3-TPD and FTIR. The textures of these catalysts are analyzed on a BET machine with nitrogen as a probe molecule. The micropore surface area and micropore volume are determined by t-plot method. Micropore volume distribution is determined by Horvath-Kawazoe approach with a cylindrical pore model. Mesopore volume distribution is determined by BJH method from the nitrogen desorption isotherm. Silica from the binder may react with extra-framework alumina in zeolites to form a new protonic acid. SiO2-bound catalysts have less strong acidity, Bronsted acidity and Lewis acidity than the zeolite powder. Also, the strength of strong acid sites of the zeolites is reduced when silica is embedded. Micropore surface area and micropore volume are reduced by about 19% and 18%, respectively, indicating some micropores of ZSM-5 are blocked on binding with silica. SiO2-bound ZSM-5 catalysts have less catalytic activity for butane transformation (cracking and disproportionation) and ethylene oligomerization than ZSM-5 powder. When alumina is used as a binder, both the total acid sites and Lewis acid sites are increased. Micropore surface area and micropore volume of ZSM-5 powder are reduced by 26% and 23%, respectively, indicating some micropores of ZSM-5 are blocked by the alumina binder. Alumina-bound catalysts showed a lower activity for butane transformation and ethylene oligomerization than ZSM-5 powder. Alkaline metals content in the binder is a crucial factor that influences the acidity of a bound catalyst. The metal cations neutralize more selectively Bronsted acid sites than Lewis acid sites. Alkaline metal cations in the binder and micropore blockage cause the bound catalysts to have a lower catalytic activity than the zeolite powder.

The degradation of phosphate triesters is efficiently catalyzed by organophosphate hydrolases (OPH). While a number of recent studies have focused on optimizing the rate of hydrolysis observed with the native enzyme, no dinuclear complexes that mimic the function of OPH have been reported or investigated. Our present research focuses on the synthesis of dinuclear metal complexes and on the study of their catalytic abilities. An important aspect of this research concerns the investigation of the coordination chemistry of dinuclear ligands designed to hold two metal cations in well defined positions. The ability of the different complexes to catalyze the degradation of thiophosphate triester is presented. Out of several complexes studied, ortho-metallated Pd (II) complexes have been found to display the highest catalytic activity for the hydrolysis of parathion.

Due to the micro-pillar-structured electrodes were made in the gas diffusion layer (GDL) of the proton exchange membrane fuel cell (PEMFC), the cell performance was raised significantly; the study therefore aims to understand whether the same cell performance can be achieved if the micro-pillar-structures were made in the direct methanol fuel cell (DMFC) of the anode. At room temperature and naturally breathed air, the performance of the micro-pillar-structured electrodes was the same as the conventional electrodes. The performance of the electrodes does not rely on the surface area between the micro porous layers and the catalyst. The experimental results inference indicates that no efficiency can be completed. The study then changed the experimental condition, i.e. increased the temperature of the methanol-water solution to 50¢J and reduced the methanol concentrations to 0.5M. The purpose was to carry out the reaction of the surface between the methanol and the catalyst layer. However, the experimental result shows no variation between the micro-pillar- structured electrodes and the conventional electrodes. Because of the test of the current density of the DMFC was carried out in a small power (0~25mW/cm2). The current density of the PEMFC was carried out in a high power (400mW/cm2 ~). The study proposed that the cell operating temperature can be raised and the oxygen can be put in the cathode, the performance of the micro-pillar-structured electrodes can thus be enhanced if the reaction was in a high current density. At the finals, the study tried to compare the efficiency between self-made electrodes and commercial electrodes (E-TEK). The result showed that both max power densities can reach 17mW/cm2 at room temperature and naturally breathed air.

Catalysts are essential for technological advances, because of their indispensable role in chemical and material manufacturing, energy conversion, and pollution control systems. Developing better catalysts is a highly desired goal that is impeded by the complexity of heterogeneous catalysts. This makes it extremely difficult to obtain information regarding active sites and reaction mechanisms, which is critical for improving catalyst design and performance. My research work has led to the understanding of how specific catalytic surface sites affect the performance of catalysts by constructing conceptually simpler planar model catalysts for kinetics and mechanism studies using model surface science tools and batch reaction testing. The work in this dissertation has demonstrated that planar model catalysts are versatile tools to probe reaction mechanisms on industrial catalysts. Supported gold nanoparticles have shown remarkable catalytic activity in a variety of reactions. However, many fundamental aspects of gold catalysts are still unclear, especially about the identity of active sites and oxidizing species. A Au(111) single crystal, the most stable and abundant facet on gold nanoparticles, is utilized to understand the reaction mechanisms of partial oxidation of 2-butanol and allyl alcohol. By controlling oxygen coverage on the surface, 100% selectivity to corresponding ketone and aldehyde, the desirable products, can be achieved. Two model catalysis systems, gold nanoclusters supported on a TiO₂(110) substrate and iron oxide dispersed on a Au(111) surface, were employed to understand the reaction pathways of CO oxidation and probe the role of the oxide/metal interface. The mechanistic and kinetic studies have shown that planar model catalysts are useful tools to probe reactions on industrial catalysts. The mechanistic understanding obtained from model catalyst studies can be used to create better catalysts. / text

Catalyst development is important to the contemporary world as suitable catalysts can allow chemical processes to proceed with reduced energy consumption and waste production. In order to design catalysts with improved performance, the fundamental studies that correlate catalytic properties with surface structures are essential as they can provide mechanistic insights into the reaction mechanism. Pd−Au bimetallic catalysts have shown exceptional performance for a number of chemical reactions, however, the interplay between the reactive species and surface properties are still unclear at the molecular level. In this dissertation, the catalytic chemistry of Pd−Au surfaces was investigated via model catalyst studies under ultrahigh vacuum conditions. A range of Pd−Au model surfaces were generated by annealing Pd/Au(111) surfaces and characterized/tested by surface science techniques. The findings in this dissertation may prove useful to enhance the fundamental understanding of structure-reactivity relation of Pd−Au catalysts in associated reactions.

The racemic (±)-2,4-di-tert-butyl-6-(((2-(dimethylamino)cyclohexyl)(methyl) amino)methyl)phenol ((±)-(NNMeOtBu)H), (±)-2,4-di-tert-butyl-6-((2-(dimethylamino) cyclohexylamino)methyl)phenol ((±)-(NNHOtBu)H), and (±)-2-(((2-(dimethylamino) cyclohexyl)(methyl)amino) methyl)phenol ((±)-(NNMeOH)H) are chiral ancillary NNO proligands, which synthesis was adapted from a published procedure. Reaction of (±)-(NNMeOtBu)H ((±)-2), (±)-(NNMeOH)H ((±)-3) and (±)-(NNHOtBu)H ((±)-1) with ZnEt2 successfully yielded the corresponding zinc ethyl complexes (±)-5, (±)-6 and (±)-7 respectively; the enantiomerically pure (R,R)-5 was synthesized from (R,R)-2. NMR spectroscopy experiments and X-ray crystallography allowed identification of two stereoisomers for (±)-5, which were observed in solution and in the solid state. The two stereoisomers, 5-α and 5-β, are in equilibrium in solution, with 5-β being thermodynamically favored. The zinc ethyl complexes were found to be unreactive towards weakly acidic alcohols (methanol, ethanol, isopropanol). However, the zinc chloride complex (±)-(NNMeOtBu)ZnCl ((±)-8) and the zinc phenoxide (NNMeOtBu)ZnOPh ((±)-9 and (R,R)-9) could be isolated and characterized. Comparison of the reactivity of both (±)-5 and the reported L₁ZnEt (L₁ = 2,4-di-tert-butyl-6- {[(2'-dimethylaminoethyl) methylamino]methyl}phenolate) in presence of pyridine led to the proposal of a dissociative mechanism explaining the fundamental difference between the two zinc ethyl species. Polymerization of rac-lactide catalyzed by 9 showed that the complex, in its racemic or enantiomerically pure version, has a slow activity and is not stereoselective.