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Raoof J.-B.,Electroanalytical Chemistry Research Laboratory | Karimi M.A.,Payame Noor University | Hosseini S.R.,Electroanalytical Chemistry Research Laboratory | Mangelizadeh S.,Payame Noor University
Journal of Electroanalytical Chemistry | Year: 2010

In this work, m-toluidine is electropolymerized at the surface of carbon paste electrode using consecutive cyclic voltammetry in 20 mM monomer aqueous solution in the presence of 6 mM cetyltrimethyl ammonium bromide (CTAB) as surfactant. Then transition metal of nickel is incorporated into the polymer by electrodepositing of Ni (II) from 1.5 M NiSO4 acidic solution using chronoamperometry technique (-1.0 V versus Ag|AgCl|KCl (3 M) for 15 min). In alkaline medium (i.e. NaOH 0.1 M) a good redox behavior of Ni (III)/Ni (II) couple at the surface of Ni/poly (m-toluidine) modified carbon paste electrode (Ni/PMT/MCPE) in the absence and presence of CTAB (Ni/CTAB-PMT/MCPE) can be observed. Electrocatalytic oxidation of methanol has been studied on Ni/PMT/MCPE and Ni/CTAB-PMT/MCPE. The results show that CTAB significantly enhances the catalytic efficiency of nickel particles on the oxidation of methanol in aqueous alkaline media. Moreover, the effects of various parameters such as concentration of CTAB, concentration of methanol, electrodepositing time, film thickness and monomer concentration on the electrooxidation of methanol as well as long-term stability of the Ni/CTAB-PMT/MCPE have also been investigated. This polymeric modified electrode can oxidize the methanol with high current density (over 40 mA cm-2). © 2009 Elsevier B.V. All rights reserved.

Raoof J.-B.,Electroanalytical Chemistry Research Laboratory | Ojani R.,Electroanalytical Chemistry Research Laboratory | Kiani A.,University of Isfahan | Rashid-Nadimi S.,Electroanalytical Chemistry Research Laboratory
International Journal of Hydrogen Energy | Year: 2010

The nanoporous copper foam was prepared by electrochemical reduction of copper ion at the copper substrate. The as-prepared substrate was used as three-dimensional templates for preparation of Pt coated nanostructured Cu-foam by galvanic replacement of Cu with platinum by simply immersing the prepared nanoporous copper foam in a K2PtCl6 aqueous solution. The structure and nature of the fabricated Pt coated nanostructured Cu-foam was characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. Pt coated nanostructured Cu-foam modified copper electrode exhibited remarkable electrocatalytic activity for the hydrogen evolution reaction. The effect of electrodeposition time during Cu-foam formation on the kinetic constants for hydrogen evolution reaction was comparatively investigated. © 2009 Professor T. Nejat Veziroglu.

Hejazi M.S.,Tabriz University of Medical Sciences | Raoof J.-B.,Electroanalytical Chemistry Research Laboratory | Ojani R.,Electroanalytical Chemistry Research Laboratory | Golabi S.M.,Electroanalytical Chemistry Research Laboratory | Asl E.H.,Electroanalytical Chemistry Research Laboratory
Bioelectrochemistry | Year: 2010

A new electrochemical DNA biosensor is presented based on carbon past electrode (CPE) for immobilization and detection of short DNA sequences with brilliant cresyl blue (BCB) as electroactive label. The interaction of BCB with DNA is electrochemically detected and BCB displays different signals in the interaction to ssDNA and dsDNA and variation in the BCB signal represents the extent of hybridization at the electrode surface. The effect of solution pH on electrochemical behavior of BCB was investigated. Additionally, the effect of solution pH on BCB accumulation on the CPE was studied. Furthermore, experiments showed that the solution pH could influence the differential pulse voltammetry (DPV) signal of BCB accumulated on the electrode and the highest BCB signal was obtained in pH 7.00. The effect of electrochemical pretreatment of CPE on the ability of electrode in probe adsorption, BCB accumulation and conditions of probe immobilization including potential and time was investigated and optimum conditions were suggested. The peak currents of BCB were linearly related to the concentration of the target oligonucleotide sequence in the range of 1.0 × 10- 8 to 5.0 × 10- 6 M. The detection limit of this approach was 9.00 nM. The selectivity of the biosensor was studied using noncomplementary oligonucleotide. © 2009 Elsevier B.V. All rights reserved.

Raoof J.B.,Electroanalytical Chemistry Research Laboratory | Ojani R.,Electroanalytical Chemistry Research Laboratory | Esfeden S.A.,Electroanalytical Chemistry Research Laboratory | Nadimi S.R.,Electroanalytical Chemistry Research Laboratory
International Journal of Hydrogen Energy | Year: 2010

The film of poly(8-hydroxyquinoline) was formed by cyclic voltammetery method on the surface of glassy carbon electrode and poly(8-hydroxyquinoline) modified glassy carbon electrode, p(8-HQ)MGCE, was prepared. Cu2+ ion was adsorbed on the polymer matrix due to complexation with 8-hydroxyquinoline units Copper nanoparticles were deposited onto p(8-HQ)MGCE by applying potential and prepared copper nanoparticles galvanic replaced with platinum to fabricate poly(8-hydroxyquinoline)-Pt/Cu composite on the surface of GCE. Stripping voltammetery of Cu in aqueous 0.1 M KSCN + Britton-Robinson buffer, pH = 2.0, solution was used to quantify the copper present on the electrode surface. The amount of platinum was estimated from the electrooxidation peak of Pt in aqueous 0.1 M H2SO4 solution. The nature of Cu/Pt-p(8-HQ) on the surface of GCE was characterized by scanning electron microscopy. Cu/Pt-p(8-HQ) modified GCE can be used as a convenient conducting substrate for electrocatalytic hydrogen evolution reaction (HER). The effects of different parameters such as number of cycles, replacement time, scan rate of potential, and etc were investigated to obtaining optimum condition for HER. © 2010 Professor T. Nejat Veziroglu.

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