Sharif Digital Repository

Due to the increasing consumption of fuel, the use of new methods with high efficiency to remove sulfur from fossil fuels is felt more than ever. Hydrogenation and oxidation of sulfur organic matter, such as thiophenes, is an old method of desulfurization of liquid fuels. Using a photocatalyst, everything can be done in an environment that is very low cost. In this study, the photocatalytic elimination of dibenzothiophene was investigated. For this purpose, carbon-doped thiamine dioxide was used as the photocatalytic base, which is synthesized by hydrothermal method. This method is the same source of titanium and carbon. To increase the performance of the catalyst, platinum metal was loaded... 

The kinetics of side reactions in dehydrogenation of propane over a supported platinum catalyst modified by tin was investigated. Catalytic dehydrogenation over a commercial Pt-Sn/γ-Al2O3 was carried out in a laboratory-scale plug-flow reactor at 580 to 620oC under atmospheric pressure. Several kinetic models derived from different reaction mechanisms were tested using experimental data obtained over a range of reaction conditions. It was found that the kinetics of the main dehydrogenation reaction was best described in terms of a Langmuir-Hinshelwood mechanism where adsorption of propane was the rate controlling step. Simple power low rate expressions were used to express the kinetics of... 

With increasing pollution and decrease in global reservoirs of fossil fuels, a lot of interest has been attracted to fuel cells as efficient and clean energy sources. Polymeric (membrane) fuel cells are special type of fuel cells, which can be built in small dimensions and power. These cells use hydrogen (and oxygen or air) and produce water. In these cells, platinum is used as electrode (and electrocatalyst) both in anode and cathode, due to its low overvoltage for both hydrogen and oxygen. To increase the efficiency of these coatings, it is best to produce platinum particles with maximum area and it automatically leads to nanometric particles. In this thesis, platinum particles are... 

Diesel oxidizing catalysts (DOCs) based on precious metals of Platinum and Palladium are among the most important and most widely used catalysts in the exhaust aftertreatment system of diesel cars. DOCs are used to oxidize CO and hydrocarbons to reduce their emissions to the environment. In spite of the excellent performance of DOCs, sulfur exposure can lead to their deactivation. Sulfur is mainly in the form of SO2 at the combustion chamber exit, which can be further oxidezed to SO3 on the DOC. The deactivation impact of SO2 and SO3 on DOCs are different, with SO3 leadig to higher degrees of deactivation. In this study, a kinetic model for SO2 oxidation on a bimetallic Pt-Pd-based catalyst... 

Platinum is one of the most used catalysts in refining and petrochemical industries. Also, Platinum uses in other industries like automobile catalytic convertor. As respect to importance of Platinum in these industries, growth of its consumption in recent decades and its very high price, recovery of Platinum is essential. Hence, many of various methods including hydro-metallurgy are applied. In despite of these wide spreading experimental investigations, due to low information about the reactions and the nature of reaction products, a few investigations were done on kinetics of Platinum recovery. A new method that used iodine solution to extract Platinum from spent reforming catalysts was... 

Silver(I) complex of [Ag2(μ-dppm)2(μ-phth)(phth)](BF4)2 (1) (dppm = bis(diphenylphosphino)methane and phth = phthalazine) has been prepared from the reaction of [Ag(CH3CN)4]BF4 with phthalazine and dppm in a 1:1 molar ratio. The structure of 1 was determined using X-ray crystallography in solid state and by multinuclear NMR spectroscopy in solution. Complex 1 shows a dynamic process including rotation of phthalazine ligand around the [Ag2(μ-dppm)2] unit wich was investigated by 1H NMR, 31P NMR and 13C NMR spectroscopy. Also, the complex 1 shows the aggregation induced emission (AIE) probably by restriction of internal motions (RIM). The trimethyl platinum(IV) complex [PtMe3(phth)3]+X- (2)... 

In this project, we prepared two new tetranuclear clusters with linear Pt2Ag2 and Pt2Au2 metal cores. First, The tetranuclear cluster [Ag2Pt2(Cl2)(bhq2)(μ-(PPh2)2py)2](OTf)2, 1, from the reaction of 1 equivalent of Pt(bhq)Cl(SMe2), with 1 equivalent of AgOTf and μ-(PPh2)2py ligand has been prepared. Secondly, the tetranuclear cluster [Au2Pt2 (μ-(PPh2)2py)2(Cl2)(bhq2)]( PF6 )2, 3, by the reaction of 1 equivalent of the mononuclear complex [Au(μ-(PPh2)2py)2]PF6 with 1 equivalent of PtbhqClSMe2 and μ-(PPh2)2py ligand has been prepared. Structure of complexes has been fully characterized in solution, solid and gas states using multinuclear NMR spectroscopy, X-ray crystallography and ESI-MS... 

In the current study, we prepared two new tetranuclear clusters with linear and nonlinear Pt2Ag2, Pt2Au2, and Pt2Cu2 metal cores.First, the tetranuclear cluster [Ag2Pt2(μ-Cl)2(bhq)2(μ-(PPh2)2py)2](OTf)2, 1, from the reaction of 1 equivalent of Pt(bhq)Cl(SMe2), with 1 equivalent of AgOTf and μ-(PPh2)2py ligand has been prepared.Secondly, the tetranuclear cluster [Au2Pt2(μ-(PPh2)2py)2(Cl)2(bhq)2](PF6)2, 3, by the reaction of 1 equivalent of the mononuclear complex [Au(μ-(PPh2)2py)2]PF6 with 1 equivalent of PtbhqClSMe2 and (PPh2)2py ligand has been prepared.The third complex [Cu2Pt2(μ-Cl)2(bhq)2(μ-(PPh2)2py)2](OTf)2 has been prepared by the reaction of 1 equivalent of AgOTf and CuBrSMe2 with... 

The cyclometalated platinum(II) complex [Pt(Me)(bhq)(2-vpy)], 2, in which bhq = benzo{h}quinolone, 2-vpy = 2-vinylpyridine, has been prepared by reaction of the cyclometalated complex [Pt(Me) bhq)(SMe2)], 1 with one equiv 2-vinylpyridine. The similar complex [Pt(p-tolyl)(ppy)(2-vpy)], 3 in which ppy = 2-phenyl pyridine, has been prepared from reaction of the platinum(II) complex cis-[Pt(p-MeC6H4)2(SMe2)2] with one equiv 2-phenylpyridine and one equiv 2-vinylpyridine. Reaction of 2 with one equiv Br2 in acetone gave the cyclometalated platinum(IV) complex [Pt(bhq)Me(Br)(NC5H4CHCH2Br)], 4. The structure of the complexes 1-3 were determined using NMR Spectroscopy. The crystal structure of 3... 

The heteronuclear complexes [MePt(bhq)(μ-dppy)Au(PPh3)]PF6, 2, [MePt(bhq)(dppy)Tl]PF6, 3 and [Me2Pt2(bhq)2(dppy)2Tl]PF6, 4 in which bhq=benzo{h}quinoline and dppy=2-diphenylphosphinopyridine, were prepared by reaction of the mononuclear complex [MePt(bhq)(dppy)] 1 with 1 equivAuCl(PPh3), 1equiv TlPF6 and 1/2 equiv TlPF6 respectively. All the complexes were fully characterized using multinuclear NMR spectroscopy and ESI-MS spectrometry. In addition molecular structures of complexes 2 and 3 in solid state have been determined by X-ray crystallography that shown strong dative bonds between platinum and gold or thallium atoms. As shown by ESI-MS spectrometry, the Pt-Au bond in complex 2... 

In this research binuclear platinum(IV) complexes with coinage metals have been synthesized and characterized. the trimethyl platinum(IV) complex [PtMe3(phthalazine)3]+X- has been prepared by the reaction of [PtMe3(THF)]4 with 3 equiv. phthalazine and used as initial material. The first complex, [PtMe3(µ-(phthalazine)2Cl)PtMe3], synthesized via reaction of 2 equiv. [Pt(Me)3(Phthalazine)3] with 1 equiv. [AuClSMe2]. The second complex, [PtMe3(µ-phthalazine)3Ag][BF4], synthesized by reaction of one equiv. of each compound [Ag(CH3CN)4]BF4 and [Pt(Me)3(Phthalazine)3] And the third complex, [PtMe3(µ-phthalazine)3Cu][PF6], synthesized like second one via reaction of [Cu(CH3CN)4]PF6 and... 

Preparation of two new Bis-N-heterocyclic carbene (Bis-NHC) platinum (ІІ) complexes have been described. The reaction of the Bis-NHC complex [PtMe2(Bis-NHC)], 1, in which Bis-NHC = 1,1’-methylene-3,3’-di(tert-Bu)imidazole ylidene, with two equivalent trifluoroacetic acid give the new Bis-NHC platinum [Pt(Bis-NHC)(CF3COO)2], 2. Complex 2 has been characterized by multinuclear NMR spectroscopy in solution and its solid state structure determined using X-ray crystallography. The mono-methyl Bis-NHC platinum(ІІ) complex, {PtMe(Bis-NHC)[OHB(C6F5)3]}, 3, has been prepared by the reaction of one equivalent B(C6F5)3 with [PtMe2(Bis-NHC)], 1. The mono-methyl complex 1 has a labile ligand... 

The present study was aimed at investigating the use of platinum and platinum nanoparticles stabilized on zeolite as catalyst for the reduction reaction of p-nitrotoluene as one of the dangerous pollutants. The adsorption properties of platinum based on zeolite have been studied for some heavy metals. Monodispersed platinum nanoparticles were synthesized through reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer, and then were immobilized on four types of zeolites. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. In order to investigate the catalytic properties, operating... 

In this project, TiO2 nanoparticles were prepared by the sol gel method. The band gap of TiO2 was modified with transition metal ions Pt, Pd, Ni. The kinetics and photocatalytic degradation of AB92 investigated. The effect of some parameters such as pH and amount of photocatalysis and calcination tempreture were examined. Also effect of transition metal increase on surface morphology and photocatalytic activity were investigated by XRD, BET, SEM, DRS and FT-IR Techniques. Dyes are an abundant class of colored organic compounds that represent and increasing environmental danger. Azo dyes are well-known carcinogenic organic substances. Advanced oxidation processes (AOPs) have been proposed as... 

Platinum nanotubes were deposited inside the pores of polycarbonate template with the pore size of 200 nm by electrochemical methods. In this regard a solution containing of 0.05 M H2PtCl6 and 0. 1 M H2SO4 in doubly distilled water was utilized. The electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. It was observed that the process was conducted in several stages including; nucleation and growth in steady state regime. Furthermore, it was concluded that electrodeposition was affected by mass transport restriction and was controlled by a diffusion process. In this regard, all the voltammograms were shifted to more negative... 

The bis-cyclometalated platinum(II) complexes [Pt(ptpy)2], 3, and [Pt(fppy)2], 4, in which, ptpy = 2-(p-tolyl)pyridine and fppy = 2-(2,4-difluorophenyl)pyridine have been prepared. The reaction of 3 with one equiv [Au(PPh3)]+ (prepared from the reaction between AuCl(PPh3) and AgOTf) gave the heterobinuclear complex [Pt(ptpy)2Au(PPh3)].OTf, 5, by formation of a Pt→Au dative bond. The structure of all complexes were characterized using multinuclear NMR spectroscopy in solution phase and the structures of 4 and 5 determined using X-ray crystallography in solid state. The structure of heterobinuclear complex 5 shows an unusual Pt-Au bond that supported by Au-Cipso bond. The absorption and... 

The bis(cyclometalated) platinum(II) complexes of the type [Pt(ppy)(p′py)], in which ppy = p′py = 2-(p-tolyl)pyridine, 6; ppy = 2-(3-bromophenyl)pyridine, p′py = 2-(p-tolyl)pyridine, 7; ppy = 2-(2,4-difluorophenyl)pyridine, p′py = 2-(p-tolyl)pyridine, 8; ppy = 2-(2,4-difluorophenyl)pyridine, p′py = 2-(2,4-difluorophenyl)pyridine, 9, have been prepared from the reaction of the cyclometalated platinum(II) complex [Pt(ppy)Me(SMe2)] with one equiv p′py and one equiv B(C6F5)3. The structure of 6, 7 and 10 determined using X-ray crystallography in solid state. However NMR spectroscopy methods have been used for structural characterization of the complexes in solution phase. The bis(cyclometalated)... 

Liquide phase catalytic exchange (LPCE) between liquid water and hydrogen is an important reaction for separation of the hydrogen isotope from liquid water. One of the application of this reaction is heavy water production. This method is mainly used hydrophobic catalysts with Pt active metal. The use of hydrophobic catalyst is necessary, because liquid water in the LPCE reaction, resulted in block the catalyst pores and loss of catalyst activity. Design of experiment has been done by using of Design Expert 7.0.0 for determination of number of tests and optimization of Pt weight percent. Alumina and carbon (included graphene, single-walled and multi-walled carbon nanotube) supported 5% wt Pt... 

According to the reports of the Tehran Air Quality Control Company, mobile sources are responsible for the emission of 70-85% of air pollutant in this metropolis. Over the past decades, compressed natural gas (CNG) is known as a cleaner fuel and a suitable alternative to gasoline and diesel fuels in the transportation section in some countries. However, methane emissions from natural gas vehicles is a significant challenge because it is a potent greenhouse gas and plays important role in global warming. In addition, because of another pollutant emissions from these vehicles, exhaust gas treatment is a crucial issue. Using Three-Way catalysts (TWC) is the conventional method in order to... 

The present work describes sensing application of modified TiO2 nanotubes towards detection of dopamine. The TiO2 nanotubes electrode was prepared using anodizing method at different conditions, among which NaF/ NaHSO4 solution and voltage of 15 V was chosen as the optimum condition. In order to improve the performance, surface modification with metal nanoparticles (Pd, Pt and Au) and carbon is required using “pulse electrodeposition” and “decomposition of polyethylene glycol at 600 °C” respectively. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. In this regard two type of electrodes were proposed: Pd-Pt-Au-TiO2 and C-Ni(Pt)-TiO2....