Search for: catalytic-activity
Total 37 records
Thesis Title Synthesis and Characterization of Metal Nano Oxids and Investigation of their Catalytic Activity, M.Sc. Thesis Sharif University of Technology ; Gholami, Mohammad Reza
In this project, the catalytic properties of CuO and ZnO were investigated in reduction reactions.MOFs were used as a precursor to preparation of these metal oxides. Gold and silver nanoparticles were used to improve the catalytic properties of the prepared metal oxides. Structural characteristics of nanocatalysts were stydied by SEM, TEM, XRD and FT-IR techniques. The prepared nanocomposites were applied in the catalytic reduction of paranitrophenol in the presence of sodium borohydride and the kinetics and mechanism were investigated according to the structure of the prepared catalysts
M.Sc. Thesis Sharif University of Technology ; Gholami, Mohammad Reza
In this work ،we used the hydrothermal method for prepared the Bivo4 nano particles. For the best photocatality property these nano particles stabilized on the different basis. This catalysis characterized by UV-vis, XRD, BET, FTIR and SEM. The size of zeolites catalyst were 22 nm and size of Bivo4 were 54 nm and the SEM showed that the BivO4 were sphere. By addition of BiVO4 nano particles to the surface of zeolite, the surface area was increase, but addition of BiVO4 nano particles to surface, the average of holes size decreased and distribution of holes will be monotonous and the surface area increased. In the continue for investigation of photo catalyst activity of nano particle, we used...
Synthesis and Characterization of Tungsten (VI)Complex with Oxazine Ligand and its Catalytic Application in Oxidation of Sulfides to Sulfoxides, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba
In this study a novel oxo-diperoxo tungsten(VI) complex [WO(O2)2(phox)] was prepared by reaction of WO3 in H2O2 with oxazine-type ligand, 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine (Hphox). The complex was characterized by FTIR, 1H NMR and elemental analysis. The single-crystal X-ray diffraction studies revealed a seven coordinate tungsten center with a distorted octahedral geometry. The [WO(O2)2(phox)] complex was applied as a catalyst in efficient, and selective oxidation of sulfide to sulfoxide using 30% H2O2 or UHP as oxidants. This catalyst showed excellent catalytic activities and high selectivities in producing a variety of aryl and alkyl sulfoxides under mild conditions. To get...
Study of Catalytic Activity of Zirconium-Based Metal-Organic Frameworks in the Epoxide Ring-Opening Reactions, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba
In current research, two zirconium-based metal-organic frameworks, MIP-202 (Zr) and UIO-66(CO2H)2 were employed as catalysts in the epoxy ring-opening reactions by amino and alcoholic nucleophiles. Firstly, these metal-organic frameworks were prepared under mild synthetic conditions and then characterized by means of spectral techniques such as X-ray diffraction (XRD), nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FT-IR), electron microscopy Scanning (SEM) and X-ray energy diffraction (EDAX) spectroscopy were confirmed. Finally, their catalytic activity in epoxy ring-opening reactions was investigated and in to determine optimal conditions, the...
Synthesis and crystal structures of a series of (μ-thiophenolato)(μ-pyrazolato-N,N′) double bridged dipalladium(II) complexes and their application in Mizoroki-Heck reaction as highly efficient catalysts, Article Inorganica Chimica Acta ; Volume 440 , 2016 , Pages 107-117 ; 00201693 (ISSN) ; Tavakoli, G ; Assoud, A ; Bagherzadeh, M ; Boghaei, D. M ; Sharif University of Technology
Elsevier S. A
Three new binucleating S-protected ligand precursors, 2-(N,N-dimethylthiocarbamato)-5-methylisophthalaldehyde di-2′-hydroxy 5′-methylanil (1b), 2-(N,N-dimethylthiocarbamato)-5-tert-butylisophthalaldehyde di-2′-hydroxyanil (2a) and 2-(N,N-dimethylthiocarbamato)-5-tert-butylisophthalaldehyde di-2′-hydroxy 5′-methylanil (2b), have been synthesized. The reaction of these ligand precursors with PdCl2 in the presence of pyrazole under Pd-mediated S-C cleavage yielded a series of binuclear palladium(II) complexes of general formula [LPd2(pz)], where pz is the exogenous bridging pyrazolyl ligand and L3- represents a series of pentadentate thiophenol-based bridging ligands originated from their...
Synthesis and Characterization of Bis[2-(2׳-Hydroxyphenyl)- -oxazolinato]Ni(II) Complex and Investigation of it׳s Catalytic Activity in C-C Coupling Heck Reaction, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba
In this study a new Ni(II)-¬oxazoline complex was synthesized by reaction of Ni(CH3COO)2.4H2O and 2-(2׳-hydroxyphenyl)-2-oxazoline ligand in MeOH solvent. The resulting complex bis[2-(2׳-hydroxyphenyl)-2-oxazolinato]Ni(II), was characterized by different spectroscopic methods. X-ray diffraction showed that this complex is four coordinated with a square planner geometry. The complex was applied as an efficient homogeneous catalyst in C-C coupling Heck reaction of arylhalides with olefins such as methylacrylate. Investigation of the catalytic activity of the complex in Heck reaction between arylhalides and olefins showed high yield and selectivity. For example reaction between iodobenzene and...
Preparation of Metal Nanoparticles/Ionic Liquid Composites and Investigation of Their Catalytic Activity, M.Sc. Thesis Sharif University of Technology ; Gholami, Mohammad Reza ; Salari, Hadi
In this research Fe3O4 magnetic nanoparticles were prepared. To protect against oxidation, a shell of SiO2 was deposited on Fe3O4. Graphene oxide was prepared by the modified Hummer method and supported on the Fe3O4@SiO2 core-shell. Then, ionic liquid layer was impregnated on it. Afterward, PtAu nano alloy were synthesized on the surface of nanocomposite with the different molar ration including 100:0, 75:25, 50:50, 25:75 and 0:100. The as-prepared nanocomposite was characterized by SEM, XRD, and FT-IR analytical methods.For investigation of kinetically activity of catalysts, reduction of 4-nitrophenol with NaBH4 as reducer was used. The adsorption in different times was obtained by UV-vis...
Design and Synthesis of Heterogeneous Nanocatalysts Based on Immobilized Metals on Polymeric Substrates and their Applications in Organic Reactions, Ph.D. Dissertation Sharif University of Technology ; Pourjavadi, Ali
Today, catalysts have shown the growing applications in chemical industries especially for drug synthesis. Using immobilized heterogeneous catalysts is a sensible way to benefit from advantages of both heterogeneous and homogeneous catalysts. In this regards, homogeneous catalysts are immobilized on to a solid support through various methods. However, low loading amount of homogenous part and subsequently insufficient catalytic activity are main limitations of immobilized heterogeneous catalysts. For this reason, polymeric supports have been introduced to immobilize metal ions or nanoparticles. These polymeric supports not only possess advantages such as anti-corrosive properties, simple...
Experimental Study of the Aging Effect on the Oxidation Catalyst Performance as an Emission Control Device for 4-stroke Gasoline Carburetor Motorcycles, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh
There are more than one million motorcycles in the city of Tehran that are responsible for significant amounts of various air pollutants emissions such as carbon monoxide and hydrocarbons. Oxidation catalysis, as the exhaust aftertreatment system of motorcycles, can reduce the emission of CO and hydrocarbon pollutants. The efficiency of these catalysts under typical operating conditions of vehicle exhaust gas has been studied in the literature. However, due to the specific features of motorcycles exhaust gas in Tehran, such as ultra-rich combustion, low air to fuel ratio (lambdas as low as 0.6-0.7), different exhaust gas composition and significant amount of lubricating oil consumption,...
Modeling Catalyst Deactivation in Catalytic Wet Air Oxidation of Phenol in Fixed Bed Three-Phase Reactors, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad ; Khorasheh, Farhad
In the present work, wet air oxidation of phenol over 7/3 MnO2/CeO2 composite oxide catalyst in trickle-bed and packed-bubble column reactors was modeled. Complexity of wet air oxidation reactions and catalyst poisoning with carbonaceous groups, on the surface and in the pores of catalyst, make the modeling process complicated. Plurality of mass balance equations which are confirmed in the catalyst pellet and in dynamic and static bed phase, also the equation of catalyst deactivation, lead us solve them simultaneously. In addition, the equations are two dimension and unsteady state and carbon of oxidation intermediates are present which make the modeling process more complicated. We are...
Rosmarinus officinalis directed palladium nanoparticle synthesis: Investigation of potential anti-bacterial, anti-fungal and Mizoroki-Heck catalytic activities, Article Advanced Powder Technology ; Volume 31, Issue 4 , 2020 , Pages 1402-1411 ; Bagherzadeh, M ; Kiani, M ; Ghadiri, A. M ; Sharif University of Technology
Elsevier B.V 2020
The present work was aimed to account a green and eco-friendly synthesis of palladium nanoparticles using Rosmarinus officinalis leaves extracts for the first time, therefore, that can be an acceptable replacement for chemical media to improve potential biological properties. The synthesized palladium nanoparticles were fully characterized using FT-IR, XRD, FESEM, TEM and UV/Vis spectroscopy techniques. Catalytic activity was investigated by Mizoroki-Heck reaction, and optimized based on solvent, temperature and time of the reaction, and the best results were found in water as a green media without any additional reagents. Biological activity of the synthesized nanoparticles were evaluated...
Examination of Activity of Oxidation Catalysts Toward Co and Hydrocarbon Emission Reduction from 4-Stroke Gasoline Carburetor Scooters in Tehran, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh ; Hosseini, Vahid
Over one million motorcycles operating in Tehran produce significant amounts of CO and unburnt hydrocarbons, thereby considered as one of the major contributors to air pollution in the city of Tehran. Oxidation catalysts, as emission control device, can reduce CO and hydrocarbon emissions from motorcycles. The efficiency of these catalysts under typical operating conditions of vehicles exhaust gas has been studied in the literature. However, due to the specific features of motorcycles exhaust gas in Tehran, such as low air to fuel ratio, different exhaust gas composition and significant amount of lubricating oil consumption, selection of a highly active, durable and cost-effective catalyst...
Examination of Activity of Three-Way Catalysts Toward CO and Hydrocarbon Emission Reduction from Tehran Gasoline Taxis, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh ; Hosseini, Vahid
Air pollution is one of the main environmental problems in Iran's metropolises, especially in the city of Tehran. Taxis have a significant contribution to pollution due to the long distances they travel during the day. Due to the fact that the operation of automotive three-way catalysts is a function of their operating conditions, and considering the different fuel composition in Iran and the specific conditions of engine performance, exhaust gas composition can be different from similar cases abroad. A commercial three-way catalyst was tested to evaluate its performance under conditions relevant to the exhaust gas of Tehran's taxis fleet. In this study, CO and C3H6 were considered as the...
Synthesis and Characterization of Transition Metal Complexes with Carboxamide Ligands and Nanostructures for Catalytic and Antibacterial Activites Application, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba
Carboxamide ligands have been part of the growing research in the field of coordination chemistry of transition metal complexes. The solvent used in the classical method of synthesis of these compounds is pyridine, a solvent which is extremely toxic. In this project, we have developed a new method of synthesis using ionic liquids as the reaction media and have prepared Hqcq (1), Htp(2) under optimum conditions for Pd(II) and Pt(II) complexes of Hqcq and Co(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes of Htp with the formula:[Pd(qcq)(OAc)] (1a), [Pt(qcq)(Cl)] (1b), [Co(Htp)2(H2O)2].C2H5OH (2a), Co3O4 (2b), [Cu(tp)2(H2O)].CHCl3 (2c), CuO (2d), [Zn(tp)2(H2O)2] (2e), [Cd(tp)2(H2O)2].CH3OH...
Microwave-Assisted Coke Resistance and Mesoporous Ni-Co Catalyst in two Steps for Methane Steam Reforming, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam
Methane steam reforming (MSR) is an assuring reaction using steam to produce H2 as clean energy over a nickel-based catalyst. We synthesized monometallic NiMgAl2O4 and bimetallic NiCoMgAl2O4 catalysts in a two-step combustion method using urea, glycine, and sucrose, as fuel. BET-BJH, XRD, TGA, TPR, FESEM, and EDX-mapping characterized surface area, porosity, morphology, crystalline structure, and metal-support interaction behavior. The products exhibited well-structured, simple MgAl2O4 spinel and NiO without NiAl2O4, in both specimens. The MSR evaluation tests at 750℃ under atmospheric pressure, CH4: H2O feed ratio of 1:1.6 showed the bimetallic catalyst has the highest conversion (99.30%)...
Electrodeposition and electrocatalytic properties of Pt/Ni-Co nanowires for non-enzymatic glucose detection, Article Journal of Alloys and Compounds ; Volume 554 , 2013 , Pages 169-176 ; 09258388 (ISSN) ; Mahshid, S ; Dolati, A ; Ghorbani, M ; Yang, L ; Luo, S ; Cai, Q ; Sharif University of Technology
A nanowire arrays system consisting of an ordered configuration of Pt, Ni and Co was constructed in single-bath solution through pulse electrodeposition. This structure was evaluated as a potential amperometric non-enzymatic sensor to detect glucose in alkaline solution. We observed a strong and fast amperometric response at low applied potential of 0.4 V vs. SCE over linear ranges of 0-0.2 mM and 0.2-8 mM glucose with sensitivities of 1125 and 333 μA mM-1 cm-2, respectively. We also observed a low detection limit for glucose of 1 μM. Correlation of the electronic and geometric modifications with the electrochemical performance characteristics enhanced catalytic activity of the electrode by...
A preliminary study of the electro-catalytic reduction of oxygen on Cu-Pd alloys in alkaline solution, Article Journal of Electroanalytical Chemistry ; Volume 647, Issue 1 , 2010 , Pages 66-73 ; 15726657 (ISSN) ; Arab, R ; Sharif University of Technology
Copper-palladium alloys of different compositions are electrodeposited on nickel from aqueous solutions. These alloys are characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The catalytic activity of these alloys toward oxygen reduction reaction (ORR) in alkaline solution is investigated using rotating disk electrode (RDE). The number of electrons transferred per O2 molecule (n) obtained at different potentials is close to 2 at low overpotential indicating HO2- formation and gradually increases to 4 at higher overpotentials indicating full reduction to OH-. It is shown that Cu-Pd alloys are better electrocatalysts than Pd with Pd-Cu-1 having 24.5%...
Mechanochemical green synthesis of exfoliated edge-functionalized boron nitride quantum dots: application to vitamin c sensing through hybridization with gold electrodes, Article ACS Applied Materials and Interfaces ; Volume 10, Issue 34 , 2018 , Pages 28819-28827 ; 19448244 (ISSN) ; Hatamie, A ; Ghanbari, H ; Simchi, A ; Sharif University of Technology
American Chemical Society 2018
Two-dimensional boron nitride quantum dots (2D BNQDs) with excellent chemical stability, high photoluminescence efficiency, and low toxicity are a new class of advanced materials for biosensing and bioimaging applications. To overcome the current challenge about the lack of facile, scalable, and reproducible synthesis approach of BNQDs, we introduce a green and facile approach based on mechanochemical exfoliation of bulk h-BN particles in ethanol. Few-layered hydroxylated-functionalized QDs with a thickness of 1-2 nm and a lateral dimension of 2-6 nm have been prepared. The synthesized nanocrystals exhibit a strong fluorescence emission at 407 and 425 nm with a quantum efficiency of ∼6.2%....
Article Journal of Physics D: Applied Physics ; Volume 42, Issue 23 , 2009 ; 00223727 (ISSN) ; Sharif University of Technology
In this review, the importance of nanoparticles (NPs), with emphasis on their general and specific properties, especially the high surface-to-volume ratio (A/V), in many technological and industrial applications is studied. Some physical and chemical preparation methods for growing several metallic and binary alloy NP catalysts are reviewed. The growth and mechanism of catalytic reactions for synthesis of 1D nanostructures such as ZnO nanowires and multiwall carbon nanotubes (MWCNTs) are discussed. Gas-phase production with emphasis on dependence of catalytic activity and selectivity on size, shape and structure of NPs is also investigated. Application of NP catalysts in several...
Silver nanoparticles modified carbon nanotube paste electrode for simultaneous determination of dopamine and ascorbic acid, Article Journal of Electroanalytical Chemistry ; Volume 633, Issue 1 , 2009 , Pages 85-91 ; 15726657 (ISSN) ; Hormozi Nezhad, M. R ; Khodavesi, J ; Javadi, S ; Sharif University of Technology
A novel modified carbon-paste electrode was employed for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) with good selectivity and high sensitivity. Silver nanoparticle and carbon nanotube modified carbon-paste electrode (Ag/CNT-CPE) displayed excellent electrochemical catalytic activities towards dopamine (DA) and ascorbic acid (AA). The oxidation overpotentials of DA and AA were decreased significantly compared with those obtained at the bare CPE. Differential pulse voltammetry was used for the simultaneous determination of DA and AA. The peak separation between DA and AA was 67 mV. The calibration curves for DA and AA were obtained in the range of 8.0 × 10-7-6.4 ×...