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catalytic-activities
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Nanoparticle catalysts
, Article Journal of Physics D: Applied Physics ; Volume 42, Issue 23 , 2009 ; 00223727 (ISSN) ; Sharif University of Technology
2009
Abstract
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...
Multi-walled carbon nanotubes with immobilised cobalt nanoparticle for modification of glassy carbon electrode: Application to sensitive voltammetric determination of thioridazine
, Article Biosensors and Bioelectronics ; Volume 24, Issue 11 , 2009 , Pages 3235-3241 ; 09565663 (ISSN) ; Ghalkhani, M ; Adeli, M ; Amini, M. K ; Sharif University of Technology
2009
Abstract
Multi-walled carbon nanotubes (MWCNTs) were immobilised with cobalt nanoparticles and analyzed by transmission electron microscopy. This modification procedure substantially improved colloidal dispersion of the immobilised MWCNTs in water and organic solvents, yielding uniform and stable thin films for modification of the glassy carbon electrode surface. The modified electrode showed an efficient catalytic role for the electrochemical oxidation of thioridazine (TR), leading to remarkable decrease in its oxidation overpotential of approximately 100 mV and enhancement of the kinetics of the electrode reaction, which can be confirmed by increasing in the peak current and sharpness of the peak....
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
Abstract
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%....
Kinetics investigation of the photocatalytic degradation of acid blue 92 in aqueous solution using nanocrystalline TiO2 prepared in an ionic liquid
, Article Progress in Reaction Kinetics and Mechanism ; Volume 34, Issue 1 , 2009 , Pages 55-76 ; 14686783 (ISSN) ; Rahimnejad, S ; Rahman Setayesh, S ; Hosseini, M ; Gholami, M. R ; Sharif University of Technology
2009
Abstract
TiO2 nanoparticles were prepared by the sol - gel process using 2-hydroxylethy- lammonium formate as an ionic liquid. Nanoparticles were crystallized at various temperatures (300-700°C). The products were characterized using X-ray diffraction (XRD), nitrogen adsorption - desorption isotherms and scanning electron microscopy (SEM) techniques. It was found that the resulting TiO2 nanoparticles had good thermal stability either to resist collapse or the anatase-to-rutile phase transformation during heat treatment. The photocatalytic activity of the nanocrystalline TiO2 was evaluated by the degradation of Acid Blue 92 (AB92) which is commonly used as a textile dye. The results showed that the...
How does the axial ligand of cytochrome p450 biomimetics influence the regioselectivity of aliphatic versus aromatic hydroxylation?
, Article Chemistry - A European Journal ; Volume 15, Issue 22 , 2009 , Pages 5577-5587 ; 09476539 (ISSN) ; Tahsini, L ; Nam, W ; Sharif University of Technology
2009
Abstract
The catalytic activity of highvalent iron-oxo active species of heme enzymes is known to be dependent on the nature of the axial ligand trans to the iron-oxo group. In a similar fashion, experimental studies on iron-oxo porphyrin biomimetic systems have shown a significant axial ligand effect on ethylbenzene hydroxylation, with an axial acetonitrile ligand leading to phenyl hydroxylation products and an axial chloride anion giving predominantly benzyl hydroxylation products. To elucidate the fundamental factors that distinguish this regioselectivity reversal in iron-oxo porphyrin catalysis, we have performed a series of density functional theory calculations on the hydroxylation of...
Highly efficient one-pot three-component mannich reaction under solvent-free conditions
, Article Scientia Iranica ; Volume 16, Issue 2 C , 2009 , Pages 94-98 ; 10263098 (ISSN) ; Ebrahimi, F ; Saidi, M. R ; Sharif University of Technology
2009
Abstract
A mild and practically-convenient one-pot procedure for the direct Mannich reaction has been developed using a condensation of amines, aldehydes and unmodified ketones under solvent free conditions in the presence of Znl 2 with good to excellent yields. The present methodology offers several advantages, such as excellent yields, simple procedures, short reaction times and milder conditions with very small amounts of catalyst. Furthermore, it is the first time that the catalytic activity of several catalysts under solvent free conditions has been studied. It was found that both the diastereoselectivity and the rate of reaction were improved with various Lewis acids and metal oxides. However,...
Encapsulation of palladium nanoparticles by multiwall carbon nanotubes-graft-poly(citric acid) hybrid materials
, Article Journal of Applied Polymer Science ; Volume 116, Issue 4 , 2010 , Pages 2188-2196 ; 00218995 (ISSN) ; Mehdipour, E ; Bavadi, M ; Sharif University of Technology
2010
Abstract
Citric acid was polymerized onto the surface of functionalized multiwall carbon nanotubes (MWCNTCOOH) and MWCNT-graft-poly(citric acid) (MWCNTg-PCA) hybrid materials were obtained. Due to the grafted poly(citric acid) branches, MWCNT-g-PCA hybrid materials not only were soluble in water but also were able to trap water soluble metal ions. Reduction of trapped metal ions in the polymeric shell of MWCNT-g-PCA hybrid materials by reducing agents such as sodium borohydride led to encapsulated metal nanoparticles on the surface of MWCNT. Herein palladium nanoparticles were encapsulated and transported by MWCNT-g-PCA hybrid materials (MWCNT-g-PCA-EPN) and their application as nanocatalyst toward...
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
2013
Abstract
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...
Electrochemical study of Azathioprine at thin carbon nanoparticle composite film electrode
, Article Electrochemistry Communications ; Volume 11, Issue 7 , 2009 , Pages 1425-1428 ; 13882481 (ISSN) ; Ghalkhani, M ; Sharif University of Technology
2009
Abstract
Thin carbon nanoparticle/Nafion film (CNP/N), as a novel electrode material, is formed on the surface of the glassy carbon electrode in a simple solvent evaporation process. The electrochemical behavior of Azathioprine (Aza) at the CNP/N-modified electrode is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of Aza, an irreversible cathodic peak is appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a four-electron process referring to the reduction of nitro group to the corresponding hydroxylamine. The prepared electrode showed...
Electrocatalytic oxidation of methanol on Ni and NiCu alloy modified glassy carbon electrode
, Article International Journal of Hydrogen Energy ; Volume 33, Issue 16 , August , 2008 , Pages 4367-4376 ; 03603199 (ISSN) ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2008
Abstract
Nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV) and chronoamperometry (CA) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution. In CV studies, in the presence of methanol NiCu alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel...
Biosynthesis of copper oxide nanoparticles with potential biomedical applications
, Article International Journal of Nanomedicine ; Volume 15 , 2020 , Pages 3983-3999 ; Bagherzadeh, M ; Kiani, M ; Ghadiri, A. M ; Etessamifar, F ; Jaberizadeh, A. H ; Shakeri, A ; Sharif University of Technology
Dove Medical Press Ltd
2020
Abstract
Introduction: In recent years, the use of cost-effective, multifunctional, environmentally friendly and simple prepared nanomaterials/nanoparticles have been emerged considerably. In this manner, different synthesizing methods were reported and optimized, but there is still lack of a comprehensive method with multifunctional properties. Materials and Methods: In this study, we aim to synthesis the copper oxide nanoparticles using Achillea millefolium leaf extracts for the first time. Catalytic activity was investigated by in situ azide alkyne cycloaddition click and also A3 coupling reaction, and optimized in terms of temperature, solvent, and time of the reaction. Furthermore, the...
A simple granulation technique for preparing high-porosity nano copper oxide(II) catalyst beads
, Article Particuology ; Volume 9, Issue 5 , 2011 , Pages 480-485 ; 16742001 (ISSN) ; Outokesh, M ; Hosseinpour, M ; Mousavand, T ; Sharif University of Technology
Abstract
A simple and efficient method was developed for fabricating spherical granules of CuO catalyst via a three-step procedure. In the first step, copper oxide nanoparticles were synthesized by hydrothermal decomposition of copper nitrate solution under supercritical condition. Then, they were immobilized in the polymeric matrix of calcium alginate, and followed by high-temperature calcination in an air stream as the third step, in which carbonaceous materials were oxidized, to result in a pebble-type catalyst of high porosity. The produced CuO nanoparticles were characterized by transmission electron microscopy (TEM) that revealed an average size of 5 nm, X-ray diffractometry (XRD), and thermo...
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
2010
Abstract
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%...
Application of pyrolytic graphite modified with nano-diamond/graphite film for simultaneous voltammetric determination of epinephrine and uric acid in the presence of ascorbic acid
, Article Electrochimica Acta ; Volume 55, Issue 28 , 2010 , Pages 9090-9096 ; 00134686 (ISSN) ; Khafaji, M ; Sharif University of Technology
2010
Abstract
A novel modified pyrolytic graphite electrode with nano-diamond/graphite was fabricated. The electrochemical response characteristics of the modified electrode toward the epinephrine (EN) and uric acid (UA) were studied by means of cyclic and linear sweep voltammetry. The structural morphology and thickness of the film was characterized by SEM technique. The prepared electrode showed an excellent catalytic activity in the electrochemical oxidation of EN and UA, leading to remarkable enhancements in the corresponding peak currents and lowering the peak potentials. The prepared modified electrode acts as a highly sensitive sensor for simultaneous determination of EN and UA in the presence of...
Application of carbon-paste electrode modified with iron phthalocyanine for voltammetric determination of epinephrine in the presence of ascorbic acid and uric acid
, Article Sensors and Actuators, B: Chemical ; Volume 137, Issue 2 , 2009 , Pages 669-675 ; 09254005 (ISSN) ; Ghalkhani, M ; Amini, M. K ; Sharif University of Technology
2009
Abstract
A carbon-paste electrode (CPE) modified with iron(II) phthalocyanine was used for the sensitive voltammetric determination of epinephrine (EN). The electrochemical response characteristics of the modified electrode toward EN, ascorbic acid (AA) and uric acid (UA) were investigated by cyclic and differential pulse voltammetry (CV and DPV). The results show an efficient catalytic activity of the electrode for the electro-oxidation of EN, which leads to improvement of reversibility of the electrode response and lowering its overpotential by more than 100 mV. The effect of pH and potential sweep rate on the mechanism of the electrode process was investigated. The modified electrode exhibits an...
Application of carbon nanoparticle/chitosan modified electrode for the square-wave adsorptive anodic striping voltammetric determination of Niclosamide
, Article Electrochemistry Communications ; Volume 12, Issue 1 , 2010 , Pages 66-69 ; 13882481 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
2010
Abstract
A new modified electrode formed by carbon nanoparticle/chitosan film (CNP/CS) was used for electrocatalytic reduction of Niclosamide (NA). The electrochemical behavior of NA at the CNP/CS modified electrode was investigated in detail by the means of cyclic voltammetry. The reduction mechanism of NA, corresponds to the redox chemistry of nitro group, was thoroughly investigated. The effect of the experimental parameters e.g. potential and time of accumulation, pH of the buffered solutions and potential sweep rate on the response of the electrode was studied. The prepared electrode showed high stability and uniformity in the composite film, short response time, good reproducibility and an...
An innovative, highly stable Ag/ZIF-67@GO nanocomposite with exceptional peroxymonosulfate (PMS) activation efficacy, for the destruction of chemical and microbiological contaminants under visible light
, Article Journal of Hazardous Materials ; Volume 413 , 2021 ; 03043894 (ISSN) ; Giannakis, S ; Moussavi, G ; Bensimon, M ; Gholami, M. R ; Pulgarin, C ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In this work, Ag nanoparticles were loaded on ZIF-67 covered by graphene oxide (Ag/ZIF-67@GO), and its catalytic performance was studied for the heterogeneous activation of peroxymonosulfate (PMS) under visible-light. The catalyst surface morphology and structure were analyzed by FT-IR, XRD, XPS, DRS, FE-SEM, EDX, TEM, BET, ICP-AES and TGA analysis. The efficacy of PMS activation by the Ag/ZIF-67@GO under visible light was assessed by phenol degradation and E. coli inactivation. Phenol was completely degraded within 30 min by HO•, SO4•− and O2•− generated through the photocatalytic PMS activation. In addition, total E. coli inactivation was attained in 15 min that confirmed the highly...
A new eco-friendly and efficient mesoporous solid acid catalyst for the alkylation of phenols and naphthols under microwave irradiation and solvent-free conditions
, Article Scientia Iranica ; Volume 16, Issue 2 C , 2009 , Pages 81-88 ; 10263098 (ISSN) ; Akhlaghi, M ; Hojabri, L ; Dekamin, M. G ; Sharif University of Technology
2009
Abstract
The catalytic activity of a mixture of ZnCl2: AlCl3 supported on silica gel was evaluated for the alkylation of phenols with benzyl alcohol, tret-butyl alcohol and styrene under microwave irradiation and solvent-free conditions. The catalyst preparation method, its characterization and reusability, were reported. The effect of the phenol to benzyl alcohol ratio and the time of reaction on the phenol conversion and distribution of products was investigated. A conversion percentage up to 97% was achieved when hydroquinone was used. A selective ortho- directed alkylation for phenol, α-naphthol and β-naphthol was observed. © Sharif University of Technology, December 2009