Recently biodiesel has drawn much attraction as renewable enegy due to its environmental benefits and the fact that it is made from renewable resources. However, the production cost of biodiesel is one of the main hurdle to commercialize it. One of the way to reduce the biodiesel production cost is to use the waste cooking oil as feedstock. In the conventional transesterification process of waste cooking oils for biodiesel production, the presence of free fatty acids and water causes severe problems such as formation of soap and decreasing of catalyst yield. Much effort has been devoted to solve the above problems and one of the promising way is the supercritical methanol treatment which is performed at the methanol supercritical environment (>239.45℃, >8.10 Mpa)one of the serious problems of the application of SCM process for the biodiesel production is the tough operation condition(high pressure, high temperature. In this study, we have studied about the supercritical methanol treatment for the biodiesel production with the soybean waste cooking oil as a feedstock in the present of various heterogeneous solid catalysts such as mesoporous silica and acid-doped mesorpous silica. Biodiesel conversion was increased at more mild opreation condition to the previous studies by using the catalysts. The conversion was more enhanced by modifying the catalysts.

Alumina-supported catalysts containing different transition metals such as Cu, Cr, Mn, Zn, Co, W were investigated for their activity in the selective oxidation of toluene. Catalytic oxidation of toluene was investigated at atmospheric pressure in a fixed bed flow reactor system over transition metals with Al2O3 catalyst. The result showed the order of catalytic activities for the complete oxidation of toluene was Mn > Cu> Cr> Co> W> Zn for 5wt.% transition metals/Al2O3. Mn/Al2O3 catalysts containing different amount of Mn were characterized by X-ray diffraction spectroscopy for decision of loading amount of metal to alumina. 5 wt.%Mn/Al2O3 catalyst exhibits the highest catalytic activity, over which the toluene conversion was up to 90% at a temperature of 289℃.

The present work has been devoted to the catalytic reduction of N2O by H2 with Pt/SiO2 catalysts at very low temperatures, such as 110oC, and their nanoparticle sizes have been determined by using H2-N2O titration, X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM) measurements. A sample of 1.72% Pt/SiO2, which had been prepared by an ion exchange method, consisted of almost atomic levels of Pt nanoparticles with 1.16 nm that are very consistent with the HRTEM measurements, while a Pt/SiO2 catalyst possessing the same Pt amount via an incipient wetness technique did 13.5 nm particles as determined by the XRD measurements. These two catalysts showed a noticeable difference in the on-stream deN2O activity maintenance profiles at 110℃. This discrepancy was associated with the nanoparticle sizes, i.e., the Pt/SiO2 catalyst with the smaller particle size was much more active for the N2O reduction. When repeated measurements of the N2O reduction with the 1.16 nm Pt catalyst at 110oC were allowed, the catalyst deactivation occurred, depending somewhat on regeneration excursions.

Simulated waste-derived synthesis gas has been tested for hydrogen production through water gas shift (WGS) reaction in the temperature range of 240oC ~ 400oC over supported Pt catalysts prepared by an incipient wetness impregnation method. MG30, MgO, ZrO2, Al2O3 and CeO2 were employed as supports for WGS reaction in this study. 1 wt.% Pt/ CeO2 catalyst exhibited the highest CO conversion as well as 100% CO2 selectivity. This is due to easier reducibility of Pt/CeO2 and high oxygen mobility and oxygen storage capacitiy of CeO2. Pt/CeO2 catalyst can be a promising catalyst for WGS reaction from waste-derived synthesis gas.

The purpose of this study is to synthesize transition metal doped mesoporous silica catalyst and to characterize its surface in an attempt to decomposition of N2O. Transition metal used to surface modification were Ru, Pd, Cu and Fe concentration was adjusted to 0.05 M. The prepared mesoporous silica catalysts were characterized by X-ray diffraction, BET surface area, BJH pore size, Scanning Electron Microscopy and X-ray fluorescence. The results of XRD for mesoporous silica catalysts showed typical the hexagonal pore system. BET results showed the mesoporous silica catalysts to have a surface area of 537 ∼973 m2/g and pore size of 2∼4 nm. The well-dispersed particle of mesoporous silica catalysts were observed by SEM, the presence and quantity of transition metal loading to mesoporous surface were detected by XRF. The N2O decomposition efficiency on mesoporous silica catalysts were as follow: Ru>Pd>Cu>Fe. The results suggest that transition metal doped mesoporous silica is effective catalyst for decomposition of N2O.

Ti-SBA-15 catalysts doped with samarium ion were synthesized using conventional hydrothermal method. The physical properties of Sm/Ti-SBA-15 catalysts have been characterized by XRD, FT-IR, DRS and PL. In addition, we have also examined the activity of these materials on the photocatalytic decomposition of methylene blue. The Sm/ Ti-SBA-15 was shown to have the mesoporous structure regardless of Sm ion doping. With doping amount of 1% lanthanide ion, the pore size and pore volume of Sm(Er, Cs)/Ti-SBA-15 decreased and the surface area increased. For the purpose of vibration characteristics on the Ti-SBA-15 and Sm/Ti-SBA-15 photocatalysts, the IR absorption at 960 cm-1 commonly accepted the characteristic vibration of Ti-O-Si bond. 1% of Sm/Ti-SBA-15 had the highest photocatalytic activity on the decomposition of methylene blue but the catalysts doped with Er ions had lower activity in comparison with pure Ti-SBA-15 catalyst.

TiO2- and SiO2-supported Co3O4, Pt and Co3O4-Pt catalysts have been studied for CO and C3H8 oxidations at temperatures less than 250℃ which is a lower limit of light-off temperatures to oxidize them during emission test cycles of gasoline-fueled automotives with TWCs (three-way catalytic converters) consisting mainly of Pt, Pd and Rh. All the catalysts after appropriate activation such as calcination at 350℃ and reduction at 400℃ exhibited significant dependence on both their preparation techniques and supports upon CO oxidation at chosen temperatures. A Pt/TiO2 catalyst prepared by using an ion-exchange method (IE) has much better activity for such CO oxidation because of smaller Pt nanoparticles, compared to a supported Pt obtained via an incipient wetness (IW). Supported Co3O4-only catalysts are very active for CO oxidation even at 100℃, but the use of TiO2 as a support and the IW technique give the best performances. These effects on supports and preparation methods were indicated for Co3O4-Pt catalysts. Based on activity profiles of CO oxidation at 100℃ over a physical mixture of supported Pt and Co3O4 after activation under different conditions, and typical light-off temperatures of CO and unburned hydrocarbons in common TWCs as tested for C3H8 oxidation at 250℃ with a Pt-exchanged SiO2 catalyst, this study may offer an useful approach to substitute Co3O4 for a part of platinum group metals, particularly Pt, thereby lowering the usage of the precious metals.

Characteristics of the transesterification reaction between triglycerides in soy bean oil and methanol were investigated in the presence of acid catalysts. such as sulfuric acid and PTS (p-toluene sulfonic acid). Concentrations of diglyceride and monoglyceride which were intermediates in the reaction mixtures, were far below 10% of triglyceride under any reaction conditions. Thus, conversion of the reaction could be determined from the concentration of triglyceride. Dried PTS had more superior catalytic power than sulfuric acid for transesterification reaction between soy bean oil and methanol. When transesterification reaction of soy bean oil was catalyzed by 1 wt% of PTS at methanol stoichiometric mole ratio of 2 and 65℃, final conversion reached 95% within 48 hours. If FAME (fatty acid methyl ester) was added into reaction mixture of soy bean oil, methanol and PTS catalyst, it converted reaction mixture into homogeneous phase, and substantially increased reaction rate. When reaction mixture was freely boiling which had equal volumetric amount of FAME to soy bean oil, methanol stoichiometric mole ratio of 2 and 1 wt% of PTS, final conversion achieved value of 94% and temperature approached to 110℃ within 2 hours.

This study examined the catalytic destruction of 1,2-dichlorobenzene on V2O5/TiO2 nanoparticles. The V2O5/TiO2 nanoparticles were synthesized by the thermal decomposition of vanadium oxytripropoxide and titanium. The effects of the synthesis conditions, such as the synthesis temperature and precursor heating temperature, were investigated. The specific surface areas of V2O5/TiO2 nanoparticles increased with increasing synthesis temperature and decreasing precursor heating temperature. In addition, the removal efficiency of 1,2-dichlorobenzene was promoted by a decrease in heating temperature. However, the removal efficiency of 1, 2-dichlorobenzene was decreased by an anatase to rutile phase transformation at temperatures 1,300℃.

The formation of ConTiOn+₂ compounds, i.e., CoTiO₃ and Co2TiO₄, in a 5 wt% CoOx/TiO2 catalyst after calcination at different temperatures has been characterized via scanning electron microscopy (SEM), Raman and X-ray photoelectron spectroscopy (XPS) measurements to verify our earlier model associated with Co3O4 nanoparticles present in the catalyst, and laboratory-synthesized ConTiOn+₂ chemicals have been employed to directly measure their activity profiles for CO oxidation at 100˚C. SEM measurements with the synthetic CoTiO₃ and Co2TiO₄ gave the respective tetragonal and rhombohedral morphology structures, in good agreement with the earlier XRD results. Weak Raman peaks at 239, 267 and 336 cm-1 appeared on 5 wt% CoOx/TiO₂ after calcination at 570oC but not on the catalyst calcined at 450˚C, and these peaks were observed for the ConTiOn+₂ compounds, particularly CoTiO3. All samples of the two cobalt titanate possessed O 1s XPS spectra comprised of strong peaks at 530.0±0.1 eV with a shoulder at a 532.2-eV binding energy. The O 1s structure at binding energies near 530.0 eV was shown for a sample of 5 wt% CoOx/TiO₂, irrespective to calcination temperature. The noticeable difference between the catalyst calcined at 450 and 570˚C is the 532.2 eV shoulder which was indicative of the formation of the ConTiOn+₂ compounds in the catalyst. No long-life activity maintenance of the synthetic ConTiOn+₂ compounds for CO oxidation at 100˚C was a good vehicle to strongly support the reason why the supported CoOx catalyst after calcination at 570˚C had been practically inactive for the oxidation reaction in our previous study; consequently, the earlier proposed model for the Co₃O₄ nanoparticles existing with the catalyst following calcination at different temperatures is very consistent with the characterization results and activity measurements with the cobalt titanates.

Oxidative TCE decomposition over TiO2-supported single and complex metal oxide catalysts has been conducted using a continuous flow type fixed-bed reactor system. Different types of commercial TiO2 were used for obtaining the supported catalysts via an incipient wetness technique. Among a variety of titanias and metal oxides used, a DT51D TiO2 and CrOx would be the respective promising support and active ingredient for the oxidative TCE decomposition. The TiO2-based CrOx catalyst gave a significant dependence of the catalytic activity in TCE oxidation reaction on the metal loadings. The use of high CrOx contents for preparing CrOx/TiO2 catalysts might produce Cr2O3 crystallites on the surface of TiO2, thereby decreasing catalytic performance in the oxidative decomposition at low reaction temperatures. Supported CrOx-based bimetallic oxide systems offered a very useful approach to lower the CrOx amounts without any loss in their catalytic activity for the catalytic TCE oxidation and to minimize the formation of Cl-containing organic products in the course of the catalytic reaction.

Catalytic combustion of toluene was investigated on CuOx/SnO2-ZrO2, CuOx/SnO2, CuOx/ZrO2 catalysts prepared by impregnation. Characteristics of catalysts loaded on binary support and single support were observed by TPR, TPO, XRD, XPS techniques. The results on catalytic combustion showed that binary supports improve the activity of copper in the combustion of toluene. The reason for high catalytic activity on toluene combustion of CuOx/SnO2-ZrO2 catalyst was ascribed to oxidation·reduction activity at low temperatures and stability of oxidation state after reduction.

Activity of manganese oxide supported on γ-Al2O3 was increased when cerium was added. Also, cerium-added manganese oxide on γ-Al2O3 was more effective in oxidation of toluene than that without cerium. XRD result, it was observed that MnO2+CeO2 crystalline phases were present in the samples. For the used catalyst, a prominent feature has increased by XPS. TPR/TPO profiles of cerium-added manganese oxide on γ-Al2O3 changed significantly increased at a lower temperature. The activity of 18.2 wt% Mn+10.0 wt% Ce/γ-Al2O3 increased at a lower temperature. The cerium added on the manganese catalysts has effects on the oxidation of toluene.

Catalytic wet oxidation of trichloroethylene (TCE) in water has been conducted using TiO2-supported cobalt oxides at 36oC with a weight hourly space velocity of 7,500 h-1. 5% CoOx/TiO2, prepared by using an incipient wetness technique, might be the most promising catalyst for the wet oxidation although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on TiO2 surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. XPS spectra of both fresh and used Co surfaces gave different surface spectral features for each CoOx. Co 2p3/2 binding energy for Co species in the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of CoTiOx such as Co2TiO4 and CoTiO3. The used catalyst exhibited a 780.3-eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly Co3O4. XRD patterns for 5% CoOx/TiO2 catalyst indicated that the phase structure of Co species in the catalyst even before reaction is quite comparable to the diffraction lines of external Co3O4 standard. A model structure of CoOx present predominantly on titania surfaces would be Co3O4, encapsulated in thin-film CoTiOx species consisting of Co2TiO4 and CoTiO3, which may be active for the decomposition of TCE in a flow of water.

Esterification of soybean oil with methanol was investigated. First of all, liquid-liquid equilibriums for systems of soybean oil and methanol were measured at temperatures ranging from 40 to 65oC. Profiles of conversion of soybean oil with time were determined from the glycerine content in reaction mixtures for the different kinds of catalysts, such as NaOH, CaO, Ca(OH)2, MgO, Mg(OH)2, and Ba(OH)2. The effects of dose of catalyst, cosolvent and reaction temperature on final conversion were examined. Esterification of waste vegetable oil with methanol was investigated and compared to the case of soybean oil. Solubility of methanol in soybean oil was substantially greater than that of soybean oil in methanol. When the esterification reaction of soybean oil was catalyzed by solid catalyst, final conversion was strongly dependent on the alkalinity of the solid catalyst, and increased with the alkalinity of the metal. Hydroxides from the alkali metals were more effective than oxides. When Ca(OH)2 was used for the esterification catalyst, maximum value of final conversion was measured at dose of 4%. When CHCl3 as a cosolvent, was added into the reaction mixture of soybean oil which catalyzed by Ba(OH)2, maximum value of final conversion was appeared at dose of 3%. When waste vegetable oil was catalyzed by NaOH and solid catalysts, high final conversion, over 90%, and fast reaction rate were obtained.

Photocatalytic degradation of phenol was carried out with UV-illuminated TiO2- SiO2 in aqueous suspension. TiO2-SiO2 catalysts were prepared by sol-gel method from the titanium isopropoxide and tetraethylorthosilicate at different Ti/Si ratio and some commercial TiO2 catalysts were used as purchased. All catalysts were characterized by X-ray Diffraction(XRD) and BET surface area analyzer. The effect of reaction conditions, such as initial concentration of phenol, reaction temperature and catalyst weight on the photocatalytic activity was studied. In addition, TiO2-SiO2(49:1) prepared by sol-gel method showed higher activity than commercial TiO2 catalysts on the photocatalytic degradation of phenol. The addition of SiO2 into TiO2 hepled to increase the thermal stability of titania which suppressed the formation of anatase into rutile. The photocatalytic degradation of phenol showed pseudo-1st order reaction and the degradation rate increases with decreasing initial phenol concentration.