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Bi(OTf)3-catalysed domino Friedel-Crafts alkylation of arenes with aldehydes: An upgraded method for efficient synthesis of triarylmethanes and anthracene derivatives
, Article Tetrahedron ; Volume 72, Issue 11 , March , 2016 , Pages 1433–1439 ; 00404020 (ISSN) ; Mohammadpoor Baltork, I ; Tangestaninejad, S ; Moghadam, M ; Mirkhani, V ; Kia, R ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
A variety of novel triarylmethanes including bis-(dihexyloxyphenyl)arylmethanes and diveratrylmethanes were prepared by the domino Friedel-Crafts alkylation of arenes with aldehydes catalysed by Bi(OTf)3. The reaction of veratrole with aromatic dialdehydes afforded different results based on the molar ratio of reactants and the nature of aromatic dialdehydes. Bi(OTf)3/O2 is shown to be a highly efficient reagent system to promote the tandem three-step reaction of acylals with bis-(dihexyloxyphenyl)arylmethanes or diveratrylmethanes for the preparation of 9,10-disubstituted-2,3,6,7-tetraalkoxyanthracenes. The substrate scope, the simplicity of the reactions and work-up processes, besides a...
Bi(OTf)3-catalysed domino Friedel-Crafts alkylation of arenes with aldehydes: An upgraded method for efficient synthesis of triarylmethanes and anthracene derivatives
, Article Tetrahedron ; Volume 72, Issue 11 , 2016 , Pages 1433-1439 ; 00404020 (ISSN) ; Mohammadpoor Baltork, I ; Tangestaninejad, S ; Moghadam, M ; Mirkhani, V ; Kia, R ; Sharif University of Technology
Elsevier Ltd
Abstract
A variety of novel triarylmethanes including bis-(dihexyloxyphenyl)arylmethanes and diveratrylmethanes were prepared by the domino Friedel-Crafts alkylation of arenes with aldehydes catalysed by Bi(OTf)3. The reaction of veratrole with aromatic dialdehydes afforded different results based on the molar ratio of reactants and the nature of aromatic dialdehydes. Bi(OTf)3/O2 is shown to be a highly efficient reagent system to promote the tandem three-step reaction of acylals with bis-(dihexyloxyphenyl)arylmethanes or diveratrylmethanes for the preparation of 9,10-disubstituted-2,3,6,7-tetraalkoxyanthracenes. The substrate scope, the simplicity of the reactions and work-up processes, besides a...
Mechanochemically prepared BiOCl nanoplates for removal of rhodamine B and pentachlorophenol
, Article Monatshefte fur Chemie ; Volume 147, Issue 4 , 2016 , Pages 685-696 ; 00269247 (ISSN) ; Akhavan, O ; Bijanzad, K ; Moghaddasi Khiavi, M ; Sharif University of Technology
Abstract
BiOCl was synthesized using bismuth nitrate pentahydrate and sodium chloride via ball milling for 15 (B15), 30 (B30), and 60 (B60) min. Scanning electron microscopy studies revealed the isolated nanoplate morphology for B15, an aggregated structure composed of nanoplates for B30, and a special three-dimensional morphology for B60. The X-ray diffraction patterns showed the purity and crystallinity of the products improved by increasing the milling time. Fourier transform infrared spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption analysis using the Brunauer-Emmett-Teller technique were also used to study the products. Diffuse reflectance spectroscopy studies...
Preparation and Charactrization of Bismuth Vanadate Nanoparticles as a Visible Light Photocatalyst for Degradation of Environmental Pollutants
, M.Sc. Thesis Sharif University of Technology ; Rahman Setayesh, Shahrbanoo (Supervisor) ; Gholami, Mohammad Reza (Supervisor)
Abstract
Bismuth Vanadate (BiVO4) nanoparticles were prepared from two different precursors by precipitation method. The samples were characterized by Fourier transformed infrared (FT-IR), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and BET. The photocatalytic activities were examined by degradation of Acid Blue 92 under visible light. The results revealed that all the BiVO4 samples were in a monoclinic phase in nano range. The photocatalytic activity of BiVO4 depend on the calcination temperature and the concentration of photocatalyst. The photocatalytic activity increases with the amount of catalyst loading and decreases with increasing the...
Quantum transport through 3D Dirac materials
, Article Annals of Physics ; Volume 359 , 2015 , Pages 64-72 ; 00034916 (ISSN) ; Jafari, S. A ; Sharif University of Technology
Academic Press Inc
2015
Abstract
Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer-Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears...
P-Doped g-C3N4Nanosheet-Modified BiVO4Hybrid Nanostructure as an Efficient Visible Light-Driven Water Splitting Photoanode
, Article ACS Applied Energy Materials ; Volume 5, Issue 10 , 2022 , Pages 12283-12296 ; 25740962 (ISSN) ; Akhundi, A ; Rahimi, K ; Jaleh, B ; Moshfegh, A. Z ; Sharif University of Technology
American Chemical Society
2022
Abstract
Here, a solution combustion method was employed to construct a photoanode based on bismuth vanadate (BV) composition. To curtail the fast charge recombination, phosphorus-doped g-C3N4 nanosheets (PCNS) in combination with BV are considered a potential approach. The prepared solution combustion facilitated the formation of a BiVO4-PCNS (BV-PCNS) hybrid photoanode with worm-like morphology with a simple setup. The weight ratio of PCNS/BiVO4 and the loading volume/cm2 were optimized to determine the most efficient photoanode. The highest photocurrent density of 0.5 mA/cm2 at 1.23 V vs reversible hydrogen electrode (RHE) under 1 sun illumination was achieved for the hybrid nanostructure at 2 wt...
Synthesis of Piezoelectric Nanomaterials and Kinetics Investigation of Their Performance for Degradation of Organic Pollutants Under Ultrasonic Vibrations
, M.Sc. Thesis Sharif University of Technology ; Rahman Setayesh, Shahrbanoo (Supervisor)
Abstract
In this research, BiFeO3/Bi2WO6 nanocomposite was synthesized by hydrothermal method and utilized for piezocatalytic degradation of methyl orange dye. This nanocomposite was characterized by XRD, FE-SEM, FT-IR, DRS, PL and Raman spectroscopy. The results of XRD patterns confirmed the rhombohedral crystal structure of BiFeO3 nanoparticles and orthorhombic crystal structure of Bi2WO6 nanosheets. FT-IR and Raman spectroscopy approved the existence of chemical bonds and non-centrosymmetric structure of catalysts. The FE-SEM images displayed the formation of BiFeO3 nanodisks and the Bi2WO6 nanosheets and the decoration of BiFeO3 nanodisks on the Bi2WO6 nanosheets. By using the data of DRS...
Continuous-wave amplification in bismuth-oxide fiber optical parametric amplifiers
, Article 2011 IEEE Winter Topicals, WTM 2011, 10 January 2011 through 12 January 2011, Keystone, CO ; 2011 , Pages 161-162 ; 9781424484287 (ISBN) ; Jamshidifar, M ; Govan, D ; Marhic, M. E ; Sharif University of Technology
Abstract
We review our investigations on bismuth-oxide fiber as an amplifying medium for parametric amplifiers with continuous-wave pumping. The results lead to new applications in demultiplexing, which are discussed
Investigation of dark and light conductivities in calcium doped bismuth ferrite thin films
, Article Materials Letters ; Volume 65, Issue 19-20 , October , 2011 , Pages 3086-3088 ; 0167577X (ISSN) ; Ahadi, K ; Nemati, A ; Sharif University of Technology
2011
Abstract
Electrical conductivities in dark and light were investigated in Calcium doped Bismuth Ferrite thin films. Higher dark conductivity, in the order of 10 times higher than conductivity of bismuth ferrite, was observed for Bi 0.85Ca0.15FeO3 - δ. Structural analyses using Rietveld refinement showed a deviation from volume reduction for Bi 0.85Ca0.15FeO3 - δ which could be the reason of abnormally high conductivity for this compound. Although higher calcium doping reduced conductivity, photoconductivity was observed again. Atomic Force Microscopy investigations showed that surface roughness and grain size decreased with increasing calcium concentration. Enhanced photoconductivity is reported for...
Local moment formation in Dirac electrons
, Article Journal of Physics: Conference Series, 14 January 2015 through 15 January 2015 ; Volume 603, Issue 1 , January , 2015 ; 17426588 (ISSN) ; Mahyaeh, I ; Jafari, S. A ; Suzumura Y ; Matsuura H ; Fuseya Y ; Ogata M ; Sharif University of Technology
Institute of Physics Publishing
2015
Abstract
Elemental bismuth and its compounds host strong spin-orbit interaction which is at the heart of topologically non-trivial alloys based on bismuth. These class of materials are described in terms of 4x4 matrices at each v point where spin and orbital labels of the underlying electrons are mixed. In this work we investigate the single impurity Anderson model (SIAM) within a mean field approximation to address the nature of local magnetic moment formation in a generic Dirac Hamiltonian. Despite the spin-mixing in the Hamiltonian, within the Hartree approximation it turns out that the impuritys Green function is diagonal in spin label. In the three dimensional Dirac materials defined over a...
Solid state preparation and photocatalytic activity of bismuth oxybromide nanoplates
, Article Research on Chemical Intermediates ; Volume 42, Issue 3 , 2016 , Pages 2429-2447 ; 09226168 (ISSN) ; Tadjarodi, A ; Akhavan, O ; Moghaddasi Khiavi, M ; Sharif University of Technology
Springer Netherlands
2016
Abstract
A mechanochemical method was applied to prepare bismuth oxybromide (BiOBr) nanoplates using bismuth nitrate pentahydrate and potassium bromide for 15 (A15), 30 (A30) and 60 (A60) minutes. Scanning electron microscopy studies showed that all the products were comprised of nanoplates. Aggregated nanoplates along with microblocks were observed for A15 and A30 and the entire morphology was not homogenous. The morphology of A60 was uniform and consisted of thin and isolated nanoplates. Evaluation of the X-ray diffraction patterns showed that the purity and crystallinity of the products improved by increasing the milling time. The energy dispersive X-ray analysis confirmed the high purity of the...
Synergistic effect of polyindole decoration on bismuth neodymium ferrite powder for achieving wideband microwave absorber
, Article Ceramics International ; Volume 48, Issue 17 , 2022 , Pages 25049-25055 ; 02728842 (ISSN) ; Dong, S ; Mehrez, S ; Niaz Akhtar, M ; Tra Giang, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Recently, composite materials with outstanding absorption properties, like extraordinary absorbing capability, light weight, and thin in size, are required to solve the challenges of electromagnetic pollution. In addition, most of the work is based on the optimization of absorber material structure, and microstructure. In the current work, we improved the reflection loss feature of Bi0.5Nd0.5FeO3 nanopowders via decoration with polyindole polymer by tuning the filler loading of the nanocomposite in the matrix. XRD, UV–Vis, XPS, and FESEM were used to determine the physicochemical features of the as-prepared nanocomposite. The minimum RL was lowered further with the increasing filler loading...
Tunable magneto-optical and interfacial defects of Nd and Cr-doped bismuth ferrite nanoparticles for microwave absorber applications
, Article Journal of Colloid and Interface Science ; Volume 608 , 2022 , Pages 1868-1881 ; 00219797 (ISSN) ; Lu, Y ; Hu, E ; Wang, B ; Niaz Akhtar, M ; Noor, A ; Akbar, M ; Yousaf Shah, M. A. K ; Wang, F ; Zhu, B ; Sharif University of Technology
Academic Press Inc
2022
Abstract
Tunable microwave absorption characteristics are highly desirable for industrial applications such as antenna, absorber, and biomedical diagnostics. Here, we report BiNdxCrxFe1-2xO3 (x = 0, 0.05, 0.10, 0.15) nanoparticles (NPs) with electromagnetic matching, which exhibit tunable magneto-optical and feasible microwave absorption characteristics for microwave absorber applications. The experimental results and theoretical calculations demonstrate the original bismuth ferrite (BFO) crystal structure, while Nd and Cr injection in the BFO structure may cause to minimize dielectric losses and enhance magnetization by producing interfacial defects in the spinel structure. Nd and Cr co-doping plays...
BiFeO3 Thin Films Deposition by Sol-Gel and Dip Coating Process
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Alizadeh, Masoud (Supervisor)
Abstract
Dark and light conductivity has been investigated in Ca-doped bismuth ferrite thin films. Higher conductivity in the order of 105 magnitude of pure Bismuth ferrite has been observed for Bi0.85Ca0.15FeO3-δ. Structural analysis using Rietveld refinement showed a deviation from volume reduction for Bi0.85Ca0.15FeO3-δ that could be the reason of the abnormally high conductivity for this compound. Although higher calcium doping reduced conductivity but photoresponse could be revived. Atomic Forec Microscopy investigations showed that surface roughness decreases with increasing calcium concentration. Enhanced photoconductivity is reported for Bi0.7Ca0.3FeO3-δ with ~2.9 eV direct optical band gap...
Three Dimensional Dirac Materials in Weak Links
, Ph.D. Dissertation Sharif University of Technology ; Jafari, Akbar (Supervisor)
Abstract
We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM).We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon...
Evaluation Effects of Mo, Bi &Sn Biocides On the Anti-Fouling Paints
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this research Feasibility of application of oxide compounds of bismuth, molybdenum and tin as biocide was studied. So some epoxy paints with different ratio of these compounds were formulated. Afterward some tests were performed to assessment paints properties such as leaching rate, antifouling activity, adhesion, corrosion resistance and impact resistance. Results of leaching rate test showed that increase in the ratio of bismuth oxide from 10% to 60%, led to increase leaching rate from 0.029mg.day-1.cm-2 to 0.126mg.day-1.cm-2. beside that Microscopic results showed proved that the ratio of bismuth oxide in the cured coating is 25% of the paint formulate. In similar ratio of biocides,...
Production of Fuel from Carbon Dioxide Using Elements Doped on the Photocatalytic Nanoparticles of Titanium Oxide
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Khorasheh, Farhad (Supervisor) ; Larimi, Afsaneh Sadat (Co-Supervisor)
Abstract
Carbon dioxide photocatalytic reduction is one of the promising methods used to produce a wide range of renewable hydrocarbon fuels using sunlight in the presence of photocatalysts. In this study, a series of Nickel and Bismuth doped titanium dioxide samples were synthesized by Sol-gel method. After performing photocatalytic carbon dioxide recovery experiments and finding the optimum percentage of Nickel and Bismuth doped titanium dioxide,Ni and Bi co-doped TiO2 sample showed the highest photocatalytic activity. Amount of methane production was 21.13 μmol/gcat in the presence of co-doped sample that was about 6.5 times higher than the amount of methane produced in the presence of pure TiO2...
Photocatalytic Treatment of Azo based Textile Pollutants by Modified Bismuth Vanadate
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manoochehr (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
In recent years, because of the increase in population and more accessibility of health facilities for people, an increase has occurred in water resources consumption. Recycling water has become so much valuable as the freshwater of the world is limited. Besides the advantages of treated water has for people, discharging the untreated wastewater to the rivers could cause many problems for human health. Many kinds of pollutions, such as textile effluent, are not easy to be treated by traditional methods because of their resistance to them. As these types of wastewater have severe negative effects on living things (both humans and animals), new treatment technologies should be considered. The...
Synthesis, Characterization and Photoelectrochemical Properties of BiVO4 Porous Thin Films
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Zirak, Mohammad (Co-Supervisor)
Abstract
Synthesis, characterization and photoelectrocatalytic performance evaluation of worm-like BiVO4 porous films have been conducted in this research. An in situ combustion approach was employed to prepare BiVO4 nanolayers on glass and ITO/glass by using drop casting, spin coating, dip coating and pulsed spray pyrolysis deposition techniques. The precursor solution of vanadium and bismuth include ~0.0233g ammonium metavanadate (NH4VO3) and ~0.0970g bismuth (III) nitrate pentahydrate (Bi(NO3)3.5H2O) in 2.5 mL ethylene glycol. Different deposition parameters were investigated for each of the aforementioned deposition techniques to obtain a uniformly-deposited BiVO4 nanolayer with high adhesion to...
Kinetics Investigation of Oxygen Evolution from Water Oxidation in the Presence of Bismuth Vanadate Nanocatalysts
, M.Sc. Thesis Sharif University of Technology ; Rahman Setayesh, Shahrbanoo (Supervisor)
Abstract
In this project, BiVO4 , Mn3O4 and BiVO4- Mn3O4 nanocatalysts were synthesized using the hydrothermal method. The properties of these nanocatalysts were determined by XRD, SEM, FT-IR, DRS, PL, ICP, EDX, BET and AA techniques. Analysys XRD patterns and SEM images of samples confirmed monoclinic structure for BiVO4 and tetragonal structure for Mn3O4. The DRS and PL spectra showed adctrease in the band gap and electron – hole pair recombination for BM 60:40 relative to BiVO4. Oxygen production was studied in the presence of different percentages of BiVO4 and Mn3O4 in BiVO4 - Mn3O4 nanocomposite and was observed that the 60:40 wt.% (Bismuth vanadate 60% and manganese oxide 40%) produced more...