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Catalytic activity of TiO 2 nanotubes modified with carbon and Pt nanoparticles for detection of dopamine
, Article ECS Transactions ; Volume 35, Issue 35 , 2011 , Pages 53-62 ; 19385862 (ISSN) ; 9781607682950 (ISBN) ; Mahshid, S. S ; Ghahremaninezhad, A ; Askari, M ; Dolati, A ; Yang, L ; Luo, Sh ; Cai, Q ; Sensor; Organic and Biological Electrochemistry ; Sharif University of Technology
2011
Abstract
Catalytic activity of carbon/Pt nanoparticles modified TiO 2 nanotubes electrode was studied by using dopamine contained solutions. The TiO 2 nanotubes electrode was prepared using anodizing method in aqueous solution. The electrochemical pulse method was then applied for electrodeposition of Pt nanoparticles onto the TiO 2 nanotubes. Further modification was achieved by decomposition of polyethylene glycol in a tube furnace to have a carbon/Pt nanoparticles modified TiO 2 nanotubes electrode. The final modified electrode could successfully detect the electro-oxidation of dopamine in a ImM contained solution using cyclic voltametry method. Also, a high sensitivity towards the oxidation of...
Glassy carbon electrode modified with a bilayer of multi-walled carbon nanotube and polypyrrole doped with new coccine: Application to the sensitive electrochemical determination of Sumatriptan
, Article Electrochimica Acta ; Volume 56, Issue 27 , November , 2011 , Pages 10032-10038 ; 00134686 (ISSN) ; Kamalzadeh, Z ; Saberi, R. S ; Sharif University of Technology
2011
Abstract
A promising electrochemical sensor was developed based on a layer by layer process by electro-polymerization of pyrrole in the presence of new coccine (NC) as dopant anion on the surface of the multi-walled carbon nanotubes (MWCNTs) pre-coated glassy carbon electrode (GCE). The modified electrode was used as a new and sensitive electrochemical sensor for voltammetric determination of sumatriptan (SUM). The electrochemical behavior of SUM was investigated on the surface of the modified electrode using linear sweep voltammetry (LSV). The results showed a remarkable increase (∼12 times) in the anodic peak current of SUM in comparison to the bare GCE. The effect of experimental variables such...
Bioelectricity generation enhancement in a dual chamber microbial fuel cell under cathodic enzyme catalyzed dye decolorization
, Article Bioresource Technology ; Volume 102, Issue 12 , June , 2011 , Pages 6761-6765 ; 09608524 (ISSN) ; Kariminia, H. R ; Roshandel, R ; Sharif University of Technology
2011
Abstract
Enzymatic decolorization of reactive blue 221 (RB221) using laccase was investigated in a dual-chamber microbial fuel cell (MFC). Suspended laccase was used in the cathode chamber in the absence of any mediators in order to decolorize RB221 and also improve oxygen reduction reaction in the cathode. Molasses was utilized as low cost and high strength energy source in the anode chamber. The capability of MFC for simultaneous molasses and dye removal was investigated. A decolorization efficiency of 87% was achieved in the cathode chamber and 84% COD removal for molasses was observed in the anode chamber. Laccase could catalyze the removal of RB221 and had positive effect on MFC performance as...
TiO 2 fibers enhance film integrity and photovoltaic performance for electrophoretically deposited dye solar cell photoanodes
, Article ACS Applied Materials and Interfaces ; Volume 3, Issue 3 , February , 2011 , Pages 638-641 ; 19448244 (ISSN) ; Rahman, M ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
2011
Abstract
Nanoparticulated TiO 2 fibers as one-dimensional long structures were introduced into TiO 2 P25 nanoparticle films using coelectrophoretic deposition. This prevented the usual crack formation occurring in wet coatings, and resulted in less porosity and higher roughness factor of the films that provided more favorable conditions for electron transport. The films used as the photoanode of a dye solar cell (DSC) produced 65% higher photovoltaic efficiency. TiO 2 fibers can be excellent binders in single-step, organic-free electrophoretic deposition of TiO 2 for DSC photoanode
Anodic behavior of clioquinol at a glassy carbon electrode
, Article Bioelectrochemistry ; Volume 80, Issue 2 , 2011 , Pages 175-181 ; 15675394 (ISSN) ; Fernandes, I. P. G ; Oliveira, S. C. B ; Shahrokhian, S ; Oliveira-Brett, A. M ; Sharif University of Technology
2011
Abstract
Clioquinol is an antifungal, antiprotozoal and an Alzheimer's disease drug with cytotoxic activity toward human cancer cells. The electrochemical behavior of clioquinol and its oxidation product was studied using cyclic, differential pulse and square-wave voltammetry over a wide pH range on a glassy carbon electrode. The results revealed that the oxidation of clioquinol is an irreversible pH-dependent process that proceeds with the transfer of one electron and one proton in an adsorption-controlled mechanism and results in the formation of a main oxidation product, which adsorbs very strongly on the glassy carbon surface. The charge transfer coefficient was calculated as 0.64. The adsorbed...
Visible light active Au:TiO2 nanocomposite photoanodes for water splitting: Sol-gel vs. sputtering
, Article Electrochimica Acta ; Volume 56, Issue 3 , January , 2011 , Pages 1150-1158 ; 00134686 (ISSN) ; Sangpour, P ; Moshfegh, A. Z ; Sharif University of Technology
2011
Abstract
In this study, pure TiO2 and Au:TiO2 nanocomposite thin films are both synthesized using sol-gel and RF reactive co-sputtering methods. Physical and photoelectrochemical properties of the thin films deposited by each method are compared. The optical density spectra and scanning electron microscopy images of the Au:TiO2 films reveal formation of gold nanoparticles in the all nanocomposite films synthesized by two methods. Moreover, the optical bandgap energy of the thin films decreases with addition of Au nanoparticles. X-ray photoelectron spectroscopy indicates that the presence of gold in metallic state and the formation of TiO2 is stoichiometric. The photoelectrochemical properties of the...
Self-organized titanium oxide nanotubes prepared in phosphate electrolytes: Effect of voltage and fluorine concentration
, Article ECS Transactions, 25 April 2010 through 30 April 2010 ; Volume 28, Issue 7 , April , 2010 , Pages 67-74 ; 19385862 (ISSN) ; 9781607681830 (ISBN) ; Dolati, A ; Goodarzi, M ; Askari, M ; Ghahramaninezhad, A ; ECS All Divisions ; Sharif University of Technology
2010
Abstract
TiO2 a nanotube array was prepared using an anodization process. The process proceeded in a two-electrode cell containing of platinum sheet as the cathode electrode. Two phosphate-base electrolyte solutions containing different amounts of HF and NH4F were prepared. Different concentration of fluorine ions were examined in respected electrolytes. Current transient techniques were used to produce the TiO2 nanotubes at constant voltage of 18-25V. It was revealed that anodization at 18-22V, in so-called electrolytes would end up to nano-tubular structure. However the tubular structure prepared at 20V and from phosphate electrolyte containing of 0.5 wt% NH4F as well as 0.5 wt% HF, was recognized...
Diffusion-controlled growth model for electrodeposited cobalt nanowires in highly ordered aluminum oxide membrane
, Article ECS Transactions, 25 April 2010 through 30 April 2010, Vancouver, BC ; Volume 28, Issue 17 , 2010 , Pages 13-25 ; 19385862 (ISSN) ; 9781607681939 (ISBN) ; Dolati, A ; Sharif University of Technology
2010
Abstract
This work studies the electrochemical growth behavior of cobalt nanowires in highly ordered aluminum oxide membrane. Considering the electrodeposition of metallic nanowires, cation concentration profile in each nano pore was calculated. With assumption of linear diffusion zone on the growing surface of nanowires, a modified Cottrell equation was evaluated. To confirm the model, the Co nanowires were electrodeposited into porous anodic aluminum oxide (AAO) templates and the mechanism of deposition was studied. Comparing the results of model and the experiments has proved the accuracy of the model. Also, it was observed that the growth of the Co nanowires was controlled mainly by diffusion...
Electrochemical oxidation of saccharose on copper (hydr)oxide-modified electrode in alkaline media
, Article Cuihua Xuebao/Chinese Journal of Catalysis ; Volume 31, Issue 11 , 2010 , Pages 1351-1357 ; 02539837 (ISSN) ; Rashvand Avei, M ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2010
Abstract
A stable copper (hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1000 mV. It can be used for electrochemical studies in the range of -250 to 1000 mV without interfering peaks because there is no oxidation of copper. During an anodic potential sweep, the electro-oxidation of saccharose on Cu occurred by the formation of CuIII and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials. A mechanism based on the electro-chemical generation of CuIII active sites and their subsequent consumption by saccharose was proposed, and the rate law and kinetic parameters were...
New smart carrageenan-based superabsorbent hydrogel hybrid: Investigation of swelling rate and environmental responsiveness
, Article Journal of Applied Polymer Science ; Volume 117, Issue 6 , September , 2010 , Pages 3228-3238 ; 00218995 (ISSN) ; Pourjavadi, A ; Seidi, F ; Eftekhar Jahromi, P ; Soleyman, R ; Sharif University of Technology
2010
Abstract
Synthesis of novel natural-based superabsorbents with improved properties is of prime importance in many applications. In this article we report an efficient synthesis of new polysaccharide-based superabsorbent hybrid composing carrageenan, acrylic acid, sodium acrylate, and 2-hydroxyethyl acrylate through homogenous solution polymerization process. Infrared spectroscopy and thermogravimetric analysis (TGA) were carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy (SEM). To deeper studies on the structure-property relation in SAP hydrogels, three hydrogels with different acrylic acid/2-hydroxyethyl...
Fabrication of self-organised highly ordered titanium oxide nanotube arrays by anodic oxidation and characterisation
, Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 297-309 ; 17469392 (ISSN) ; Ahadian, M. M ; Iraji Zad, A ; Taghavinia, N ; Dolati, A. G ; Sharif University of Technology
2010
Abstract
Self-organised and vertically oriented titanium oxide nanotube array (TNTA) has been synthesised by potentiostat anodisation of Ti foil in fluoride-based electrolyte. By varying the anodisation voltage from 8 V to 24 V it was possible to gradually change the topologies of nanotubes. The size of TNTAs was measured using SEM images and also determined based on a non-destructive optical method. In addition, photoelectrochemical properties of nanotubular TiO2/Ti electrodes were examined by anodic photocurrent response, potentiodynamic polarisation measurements and electrochemical impedance spectroscopy. A general equivalent circuit model was proposed for photoelectrochemical system consists of...
Electrochemically Assisted Photocatalytic Oxidation of Methanol on TiO2 Nanotube Arrays
, Article Journal of Materials Science and Technology ; Volume 26, Issue 6 , June , 2010 , Pages 535-541 ; 10050302 (ISSN) ; Irajizad, A ; Taghavinia, N ; Rahman, M ; Ahadian, M. M ; Sharif University of Technology
2010
Abstract
The influence of an externally applied bias on photocatalytic performance of crystallized TiO2/Ti nanotubular electrode formed by anodization in fluoride-based electrolyte were investigated and compared to the behavior of multiporous TiO2 electrode. The photoelectrocatalytic oxidation behavior of methanol over the nanotubular electrode has been studied by measuring photocurrent response, potentiodynamic polarization spectroscopy and using electrochemical impedance spectroscopy (EIS). It was found that the photoelectrocatalytic oxidation and the charge transfer rate constant of reaction on TiO2/Ti nanotubular electrode can significantly be increased by applying electrochemical bias. Moreover,...
Selective voltammetric determination of d-penicillamine in the presence of tryptophan at a modified carbon paste electrode incorporating TiO2 nanoparticles and quinizarine
, Article Journal of Electroanalytical Chemistry ; Volume 644, Issue 1 , Jan , 2010 , Pages 1-6 ; 15726657 (ISSN) ; Beitollahi, H ; Taleat, Z ; Naeimi, H ; Taghavinia, N ; Sharif University of Technology
2010
Abstract
A carbon paste electrode (CPE) chemically modified with TiO2 nanoparticles and quinizarine (QZ) was used as a selective electrochemical sensor for the simultaneous determination of minor amounts of d-penicillamine (D-PA) and tryptophan (Trp). This modified electrode showed very efficient electrocatalytic activity for anodic oxidation of both d-PA and Trp. Substantial decreases of anodic overpotentials for both compounds made this analysis possible. Results of square wave voltammetry (SWV) using this modified electrode showed two well-resolved anodic waves for the oxidation of d-PA and Trp, which makes the simultaneous determination of both compounds possible. The peak potential for the...
The effect of growth parameters on photo-catalytic performance of the MAO-synthesized TiO2 nano-porous layers
, Article Materials Chemistry and Physics ; Volume 120, Issue 2-3 , 2010 , Pages 582-589 ; 02540584 (ISSN) ; Golestani Fard, F ; Moshfegh, A. Z ; Sharif University of Technology
2010
Abstract
In this research, the effect of applied voltage and electrolyte concentration on structure, chemical composition, optical properties, and especially photo-catalytic activity of the TiO2 layers containing micro/nano-sized pores are discussed. TiO2 layers were synthesized by micro arc oxidation (MAO) process using different electrolyte concentrations and applied voltages. Surface structure of the layers was studied by scanning electron microscope (SEM); furthermore, energy dispersive spectrophotometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques were employed to determine phase structure and chemical composition of the layers. Photo-activity of the...
Simultaneous determination of epinephrine and acetaminophen concentrations using a novel carbon paste electrode prepared with 2,2′-[1,2 butanediylbis(nitriloethylidyne)]-bis-hydroquinone and TiO2 nanoparticles
, Article Colloids and Surfaces B: Biointerfaces ; Volume 76, Issue 1 , 2010 , Pages 82-87 ; 09277765 (ISSN) ; Beitollahi, H ; Sheikh Mohseni, M. A ; Benvidi, A ; Naeimi, H ; Nejati Barzoki, M ; Taghavinia, N ; Sharif University of Technology
2010
Abstract
A carbon paste electrode (CPE) modified with 2,2′-[1,2 butanediylbis(nitriloethylidyne)]-bis-hydroquinone (BBNBH) and TiO2 nanoparticles was used for the sensitive voltammetric determination of epinephrine (EP). The electrochemical response characteristics of the modified electrode toward EP and acetaminophen (AC) were investigated by cyclic and differential pulse voltammetry (CV and DPV). The results showed an efficient catalytic activity of the electrode for the electrooxidation of EP, which leads to a reduction in its overpotential by more than 270 mV. The effects of pH and potential sweep rate on the mechanism of the electrode process were investigated. The modified electrode exhibits an...
A preliminary study of the electro-oxidation of l-ascorbic acid on polycrystalline silver in alkaline solution
, Article Journal of Power Sources ; Volume 195, Issue 1 , 2010 , Pages 165-169 ; 03787753 (ISSN) ; Gobal, F ; Sharif University of Technology
2010
Abstract
Electrochemical oxidation of l-ascorbic acid on polycrystalline silver in alkaline aqueous solutions is studied by cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (IS). The anodic electro-oxidation starts at -500 mV versus SCE and shows continued anodic oxidation in the cathodic half cycle in the CV regime signifying slowly oxidizing adsorbates. Diffusion coefficient of ascorbate ion measured under both voltammetric regimes is around 1.4 × 10-5 cm2 s-1. Impedance spectroscopy measures the capacitances associated with double layer and adsorption around 50 μF cm-2 and 4 mF cm-2 as well as the adsorption and decomposition resistances (rates). © 2009 Elsevier B.V. All...
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...
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...
Electrochemical determination of l-dopa in the presence of ascorbic acid on the surface of the glassy carbon electrode modified by a bilayer of multi-walled carbon nanotube and poly-pyrrole doped with tiron
, Article Journal of Electroanalytical Chemistry ; Volume 636, Issue 1-2 , 2009 , Pages 40-46 ; 15726657 (ISSN) ; Asadian, E ; Sharif University of Technology
Elsevier
2009
Abstract
There are high attractions in the development of conducting polymer (CP) coatings to improve the electrochemical properties and biocompatibility of electrodes in the area of biosensors. A new type of the modified electrodes is prepared in a layer-by-layer process by using multi-walled carbon nanotube (MWCNT) and poly-pyrrole. In this procedure, the glassy carbon electrode is casted by a drop suspension of MWCNT, which leads to form a thin film of nanotube on its surface. In the second step, electrochemical polymerization of pyrrole in the presence of tiron (used as doping anion) is performed on the surface of the MWCNT pre-coated electrode. The modification procedure led to fabrication of a...
Electrocatalytic oxidation of glucose on Ni and NiCu alloy modified glassy carbon electrode
, Article Journal of Solid State Electrochemistry ; Volume 13, Issue 8 , 2009 , Pages 1171-1179 ; 14328488 (ISSN) ; Forouzandeh, F ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2009
Abstract
Nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox processes and electro-catalytic activities towards the oxidation of glucose in alkaline solutions. The methods of cyclic voltammetry (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. It is also observed that the overpotential for O 2 evolution increases for NiCu alloy modified electrode. In CV studies, NiCu alloy modified electrode yields significantly higher...