Mohammad Mahjani - Academia.edu (original) (raw)

Papers by Mohammad Mahjani

Journal of Physics A: Mathematical and General, 2002

Chemical potential is a property which involves the effect of interaction between the components ... more Chemical potential is a property which involves the effect of interaction between the components of a system, and it results from the whole system. In this paper, we argue that for two particles which have interacted via their spins and are now spatially separated ,the so-called Bell's locality condition implies that the chemical potential of each particle is an individual property. Here is a point where quantum statistical mechanics and the local hidden variable theories are in conflict. Based on two distinct concepts of chemical potential, the two theories predict two different patterns for the energy levels of a system of two entangled particles. In this manner, we show how one can distinguish the non-separable features of a two-particle system.

Pluronic P123, a type of Poloxamers materials, was examined as an inhibitor for decreasing zinc c... more Pluronic P123, a type of Poloxamers materials, was examined as an inhibitor for decreasing zinc corrosion in alkaline media (4.0 M NaOH). This material was used in the form of the particles dispersed in electrolyte (suspension form). Its effect was examined by electrochemical methods potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM) was used to analysis the electrode surface in presence and abcense of the inhibitor. The obtained results indicate that P-123 inhibits zinc corrosion in 4.0 M NaOH electrolyte and zinc corrosion decreases with increasing the value of P-123 particles. Moreover, the results of potentiodynamic polarization reveal that the inhibitor affects both the anodic and cathodic branch, so it is mix type. The obtained inhibition efficiency from potentiodynamic polarization and EIS showed a reasonable agreement. In addition, for battery application, it was found that P-123 increases Zn/CuO battery ...

Entropy as a measure of uncertainty was used to represent the results of the wavelet technique in... more Entropy as a measure of uncertainty was used to represent the results of the wavelet technique in electrochemical noise analysis. The experimental signals were obtained by recording the electrochemical potential and current noise of 7075 aluminum alloy in 3.5%wt NaCl solution. The electrochemical potential and current noise were decomposed into 16 levels using Daubechies wavelets. Wavelet output entropy was calculated using a kernel density estimator and the Shanon equation. The entropy contribution to high frequency scales decreased with the appearance of pits and as the pits increased and enlarged on the electrode surfaces (detected by scanning electron microscopy). The amount of reduction in entropy magnitude was attributed to the severity of pitting corrosion. It appears that a waveletentropy plot is a promising method to differentiate between different types and the severity of corrosion.

International Journal of Nanoscience, 2009

Hydrogen adsorption isotherms for (8, 0) platinum-decorated single-walled carbon nanotube were st... more Hydrogen adsorption isotherms for (8, 0) platinum-decorated single-walled carbon nanotube were studied using molecular dynamics simulation. Adsorption isotherms were obtained for both internal and external surfaces of nanotube at several temperatures from 77 K up to 400 K. The results were compared with the bare nanotube at the same conditions. Adsorption coverage, isosteric heat, binding energy, hydrogen desorption, and readsorption were calculated for both internal and external surfaces of nanotube. At low temperatures, hydrogen molecules were adsorbed significantly, but at higher temperatures, thermal energies reduced this capacity. Under the same conditions, the platinum-decorated single-walled carbon nanotube hydrogen adsorption is significantly higher than the bare one.

Journal of Electroanalytical Chemistry, 2010

The coexistence of multiple attractors in the Koper-Gaspard model of the electrochemical oscillat... more The coexistence of multiple attractors in the Koper-Gaspard model of the electrochemical oscillatory reactions on the rotating-disk electrode (RDE) has already been investigated. It is held that the Koper-Gaspard model dynamics has many multiple attractors between simple harmonic oscillations or chaos and mixed-mode oscillations in many ranges of two-dimensional parametric space. Qualitative comparison of multiple attractors demonstrates bizarre winding of trajectories round themselves due to nointersection theorem. Two-and three-dimensional basins of attraction have been scrutinized showing complex stripped-pattern basins which make predictability difficult in some regions of basins. Physico-chemical interpretation of the results has been discussed according to the feedback loops of electrochemical variables. Physical interpretation of the model multiple attractors implies that electrochemical oscillatory reactions are very sensitive dependence on initial values of electrochemical variables such as applied voltage or concentrations of electroactive species. This may change the entire pattern of behavior by slight shifting of initial conditions into the other basin. Such complex phenomena may provide sensible unpredictability for electrochemical time series.

Turkish Journal of Chemistry, Sep 29, 2011

Electrochemical impedance spectroscopy (EIS) was employed to investigate diffusion of AlCl − 4 io... more Electrochemical impedance spectroscopy (EIS) was employed to investigate diffusion of AlCl − 4 ions in basic (AlCl 3-NaCl-KCl) molten salt. Nyquist plots in different DC offset potentials showed finite and restricted aluminum ion diffusion due to insertion and blocking in the graphite electrode. The general Warburg, open Warburg, and short Warburg impedance in the complex Nyquist plot of this system showed the anomalous diffusion behavior of the ions in the graphite electrode. The diffusion coefficient of the AlCl − 4 ions was calculated from the slope of the Warburg line in a totally blocking film in the graphite electrode and was found to be 2.8 × 10 −10 cm 2 /s.

2021 7th International Conference on Signal Processing and Intelligent Systems (ICSPIS), 2021

Indian journal of chemistry. Sect. A: Inorganic, physical, theoretical & analytical, 2005

Platinum microparticles electrodeposited at a glassy carbon surface (Pt/GC) and within a poly-ort... more Platinum microparticles electrodeposited at a glassy carbon surface (Pt/GC) and within a poly-ortho-aminophenol film formed on a GC substrate (Pt/PoAP/GC) have been used for investigating their catalytic activity towards hydrogen evolution reaction and methanol oxidation by cyclic voltammetry, impedance spectroscopy and chronoamperometry. The effect of the deposition time (t d e p ) of the Pt particles dispersed into GC and PoAP electrodes and of the acid anions (SO 4 2 - , ClO 4 - ) on the hydrogen adsorption/desorption peaks and hydrogen evolution reaction has been studied. It has been shown that the main cause of immediate blocking of the PoAP-SO 4 2 - pores with platinum microparticles is its smaller scaling yardstick. The higher electrocatalytic activity of the PoAP as compared to that of GC due to its higher surface area for the methanol oxidation has been proved by a substantial improvement in transition current in chronoamperometric and in the maximum anodic current of the m...

The direct methanol fuel cells (DMFC) have recently received a good deal of attention in both mob... more The direct methanol fuel cells (DMFC) have recently received a good deal of attention in both mobile and stationary applications due to their advantages of low operating temperature (<100 ○C), easy transportation and storage of fuel, high-energy efficiency and fast start-up of fuel. The mechanism and kinetics of methanol oxidation have been studied under a wide range of conditions and on a variety of electrodes including Pt, binary and ternary alloys, modified electrodes, nano-composites and nickel. One approach to the development of DMFC is to use alkaline electrolyte which is based on the assumption that electro-catalysis is generally more facile and inexpensive in this medium[1]. The purpose of the present work is to study the electrochemical oxidation of methanol on a nickel modified glassy carbon electrode in a solution of 1 M NaOH.

Journal of Theoretical Biology

International Journal of Control, 2015

In this paper, an energy-based control methodology is proposed to satisfy the Reynolds three rule... more In this paper, an energy-based control methodology is proposed to satisfy the Reynolds three rules in a flock of multiple agents. First, a control law is provided that is directly derived from the passivity theorem. In the next step, the Number of Neighbours Alignment/Repulsion algorithm is introduced for a flock of agents which loses the cohesion ability and uniformly joint connectivity condition. With this method, each agent tries to follow the agents which escape its neighbourhood by considering the velocity of escape time and number of neighbours. It is mathematically proved that the motion of multiple agents converges to a rigid and uncrowded flock if the group is jointly connected just for an instant. Moreover, the conditions for collision avoidance are guaranteed during the entire process. Finally, simulation results are presented to show the effectiveness of the proposed methodology.

Journal of Solid State Electrochemistry, 2015

Discharge characteristics of nanorods (NRs), microsized and nanosized copper (II) oxide (CuO) par... more Discharge characteristics of nanorods (NRs), microsized and nanosized copper (II) oxide (CuO) particles prepared via thermal decomposition and thermal oxidation routes are examined as cathode materials of a Zn/CuO cell without membrane separators. The electrochemical discharge is examined galvanostatically at a current density of 500 mAg−1 and reveals that the first discharge cycles of all the CuO materials contain one potential plateau; subsequent discharge cycles involve three potential plateaus. Each potential plateau is due to an electrochemical reaction. The first, second, and third potential plateaus are attributed to Cu2O3, CuO, and Cu2O discharges, respectively. Moreover, the first and the second plateaus are higher than the plateau of the early discharges. The electrochemical performance of CuO as a cathode material is enhanced by improving its morphology and changing its size. Nanorod CuO exhibits more specific energies, 317 Whkg−1, in the first discharge cycle, than microsized and nanosized CuO. The maximum current efficiencies of subsequent discharges are near 100 % at charging rates of 250, 500, 1000, 2000, 3000, and 4000 mAg−1 within 60 s for each. In addition, significant alterations in charge transfer resistances (Rct) and capacitive loops of Nyquist plots are observed during the charge/discharge of the cells through electrochemical impedance spectroscopy (EIS).

RSC Adv., 2015

Poly tyramine–NiO as an efficient electrocatalyst was prepared by in situ electropolymerization o... more Poly tyramine–NiO as an efficient electrocatalyst was prepared by in situ electropolymerization of tyramine in the presence of the SDS under ultrasonic irradiation.

Composites of multi-walled carbon nanotubes (MWCNTs) and poly ortho aminophenol (POAP) with good ... more Composites of multi-walled carbon nanotubes (MWCNTs) and poly ortho aminophenol (POAP) with good uniformity for use as electrodes in electrochemical capacitors were prepared by electropolymerization by using the ionic surfactant as electrolyte, for dispersing CNTs within conducting polymer/carbon nanotube composite films. The capacitance properties were investigated with cyclic voltammetry (CV), discharge tests and ac impedance spectroscopy. The composite electrode shows much higher specific capacitance, better power characteristics and is more promising for application in the capacitor than a pure POAP electrode. The effect and role of MWCNT in the composite electrode are discussed in detail. In comparison with a Ni-POAP/glassy carbon (GC), a Ni-MWCNT-POAP/GC electrode shows a better catalytic performance for the electrocatalytic oxidation of methanol.

Bulletin of the Chemical Society of Japan, 2015

Electrochemical deposition and characterization of PbS nanocrystals on Pb electrodes in alkaline ... more Electrochemical deposition and characterization of PbS nanocrystals on Pb electrodes in alkaline solution containing thiourea are carried out by cyclic voltammetry (CV) and electrochemical impedanc...

Bulletin of the Chemical Society of Japan, 2015

ABSTRACT Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) under chr... more ABSTRACT Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) under chronoamperometry technique. The SEM images showed that the hexagonal sheets of CdS deposited on the ITO surface. The X-ray diffraction (XRD) analysis confirmed this structure for CdS crystals and the average of crystalline size and the lattice constant parametersare approximately 39.54 and a=0.4136, c=0.6696nm respectively.Photo-electrochemical investigations were performed by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. CdS band edges and density of states (DOS) were determined by CV technique. The band gap energy (Ebg) was measured by ultraviolet-visible (UV-Vis) spectroscopy and electrochemical methods. Mott-Schottky plots were used to find the values of flat band potential (Efb), donor density (ND) and Debye length (LD). Also, the position of surface states was investigated by Mott-Schottky and LSV techniques. EIS was employed to confirm our electrochemical findings and investigate the charge transfer mechanism.

Chinese Journal of Catalysis - CHIN J CATAL, 2010

Oxygen reduction on a polycrystalline silver electrode was studied by cyclic voltammetry and elec... more Oxygen reduction on a polycrystalline silver electrode was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The reaction occurred by a two-electron pathway. The steps in the mechanism were observed in the cyclic voltammograms recorded with different scan rates. The intermediates formed in the steps were detected by electrochemical impedance spectroscopy.

Synthetic Metals, 2012

This paper aims to investigate the relationship between surface morphology of poly ortho aminophe... more This paper aims to investigate the relationship between surface morphology of poly ortho aminophenol (POAP) films and synthesis conditions. POAP with different particle sizes was deposited on a glassy carbon (GC) electrode using direct current (DC) and pulse techniques. POAP nanoparticles with good electrochemical stability and high doping degree were obtained by applying ultra short on time current pulse for polymerization. The surface morphology of POAP films was revealed by using the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge studies showed that the polymer obtained by pulses have higher electrochemical performance in acidic solution. Moreover, nanoparticles of POAP have a highly porous structure, high fractal dimension and large specific surface area, which can be employed as an excellent electrode material in supercapacitors. It was also found that the morphology of POAP varies with the synthesis conditions of the pulse.

Journal of Electroanalytical Chemistry, 2013

ABSTRACT The poly ortho aminophenol (POAP) films were electropolymerised on graphite electrode us... more ABSTRACT The poly ortho aminophenol (POAP) films were electropolymerised on graphite electrode using potentiostatic method. POAP films were also characterized by electrochemical impedance spectroscopy (EIS) in wide frequency range. The fractal dimension of poly ortho aminophenol (POAP) films in the presence of different counter ions was investigated. The effect of different anions on the electron conduction of POAP was explained in terms of their abilities to reduce repulsive interactions between redox sites and fractal dimension of the polymer. Diffusion coefficient of counter ions calculated from the slope of the Warburg line of impedance response of the film. A value of γ that is the characteristic of anomalous diffusion is obtained by EIS method and then the relation between fractal dimension and anomalous diffusion has been investigated. The resulting Mott-Schottky plot of the polymer capacitance describes the reduced polymer as a p-type semiconductor. © 2013 Elsevier B.V. All rights reserved.

Electrochimica acta, 2007

... a Departement of Chemistry, KN Toosi University of Technology, PO Box 15875-4416, Tehran, Ira... more ... a Departement of Chemistry, KN Toosi University of Technology, PO Box 15875-4416, Tehran, Iran. b Departement of chemistry, Sharif University of Technology, PO Box 11365-9516, Tehran, Iran. Received 24 September 2006 ...

Journal of Physics A: Mathematical and General, 2002

Chemical potential is a property which involves the effect of interaction between the components ... more Chemical potential is a property which involves the effect of interaction between the components of a system, and it results from the whole system. In this paper, we argue that for two particles which have interacted via their spins and are now spatially separated ,the so-called Bell's locality condition implies that the chemical potential of each particle is an individual property. Here is a point where quantum statistical mechanics and the local hidden variable theories are in conflict. Based on two distinct concepts of chemical potential, the two theories predict two different patterns for the energy levels of a system of two entangled particles. In this manner, we show how one can distinguish the non-separable features of a two-particle system.

Pluronic P123, a type of Poloxamers materials, was examined as an inhibitor for decreasing zinc c... more Pluronic P123, a type of Poloxamers materials, was examined as an inhibitor for decreasing zinc corrosion in alkaline media (4.0 M NaOH). This material was used in the form of the particles dispersed in electrolyte (suspension form). Its effect was examined by electrochemical methods potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM) was used to analysis the electrode surface in presence and abcense of the inhibitor. The obtained results indicate that P-123 inhibits zinc corrosion in 4.0 M NaOH electrolyte and zinc corrosion decreases with increasing the value of P-123 particles. Moreover, the results of potentiodynamic polarization reveal that the inhibitor affects both the anodic and cathodic branch, so it is mix type. The obtained inhibition efficiency from potentiodynamic polarization and EIS showed a reasonable agreement. In addition, for battery application, it was found that P-123 increases Zn/CuO battery ...

Entropy as a measure of uncertainty was used to represent the results of the wavelet technique in... more Entropy as a measure of uncertainty was used to represent the results of the wavelet technique in electrochemical noise analysis. The experimental signals were obtained by recording the electrochemical potential and current noise of 7075 aluminum alloy in 3.5%wt NaCl solution. The electrochemical potential and current noise were decomposed into 16 levels using Daubechies wavelets. Wavelet output entropy was calculated using a kernel density estimator and the Shanon equation. The entropy contribution to high frequency scales decreased with the appearance of pits and as the pits increased and enlarged on the electrode surfaces (detected by scanning electron microscopy). The amount of reduction in entropy magnitude was attributed to the severity of pitting corrosion. It appears that a waveletentropy plot is a promising method to differentiate between different types and the severity of corrosion.

International Journal of Nanoscience, 2009

Hydrogen adsorption isotherms for (8, 0) platinum-decorated single-walled carbon nanotube were st... more Hydrogen adsorption isotherms for (8, 0) platinum-decorated single-walled carbon nanotube were studied using molecular dynamics simulation. Adsorption isotherms were obtained for both internal and external surfaces of nanotube at several temperatures from 77 K up to 400 K. The results were compared with the bare nanotube at the same conditions. Adsorption coverage, isosteric heat, binding energy, hydrogen desorption, and readsorption were calculated for both internal and external surfaces of nanotube. At low temperatures, hydrogen molecules were adsorbed significantly, but at higher temperatures, thermal energies reduced this capacity. Under the same conditions, the platinum-decorated single-walled carbon nanotube hydrogen adsorption is significantly higher than the bare one.

Journal of Electroanalytical Chemistry, 2010

The coexistence of multiple attractors in the Koper-Gaspard model of the electrochemical oscillat... more The coexistence of multiple attractors in the Koper-Gaspard model of the electrochemical oscillatory reactions on the rotating-disk electrode (RDE) has already been investigated. It is held that the Koper-Gaspard model dynamics has many multiple attractors between simple harmonic oscillations or chaos and mixed-mode oscillations in many ranges of two-dimensional parametric space. Qualitative comparison of multiple attractors demonstrates bizarre winding of trajectories round themselves due to nointersection theorem. Two-and three-dimensional basins of attraction have been scrutinized showing complex stripped-pattern basins which make predictability difficult in some regions of basins. Physico-chemical interpretation of the results has been discussed according to the feedback loops of electrochemical variables. Physical interpretation of the model multiple attractors implies that electrochemical oscillatory reactions are very sensitive dependence on initial values of electrochemical variables such as applied voltage or concentrations of electroactive species. This may change the entire pattern of behavior by slight shifting of initial conditions into the other basin. Such complex phenomena may provide sensible unpredictability for electrochemical time series.

Turkish Journal of Chemistry, Sep 29, 2011

Electrochemical impedance spectroscopy (EIS) was employed to investigate diffusion of AlCl − 4 io... more Electrochemical impedance spectroscopy (EIS) was employed to investigate diffusion of AlCl − 4 ions in basic (AlCl 3-NaCl-KCl) molten salt. Nyquist plots in different DC offset potentials showed finite and restricted aluminum ion diffusion due to insertion and blocking in the graphite electrode. The general Warburg, open Warburg, and short Warburg impedance in the complex Nyquist plot of this system showed the anomalous diffusion behavior of the ions in the graphite electrode. The diffusion coefficient of the AlCl − 4 ions was calculated from the slope of the Warburg line in a totally blocking film in the graphite electrode and was found to be 2.8 × 10 −10 cm 2 /s.

2021 7th International Conference on Signal Processing and Intelligent Systems (ICSPIS), 2021

Indian journal of chemistry. Sect. A: Inorganic, physical, theoretical & analytical, 2005

Platinum microparticles electrodeposited at a glassy carbon surface (Pt/GC) and within a poly-ort... more Platinum microparticles electrodeposited at a glassy carbon surface (Pt/GC) and within a poly-ortho-aminophenol film formed on a GC substrate (Pt/PoAP/GC) have been used for investigating their catalytic activity towards hydrogen evolution reaction and methanol oxidation by cyclic voltammetry, impedance spectroscopy and chronoamperometry. The effect of the deposition time (t d e p ) of the Pt particles dispersed into GC and PoAP electrodes and of the acid anions (SO 4 2 - , ClO 4 - ) on the hydrogen adsorption/desorption peaks and hydrogen evolution reaction has been studied. It has been shown that the main cause of immediate blocking of the PoAP-SO 4 2 - pores with platinum microparticles is its smaller scaling yardstick. The higher electrocatalytic activity of the PoAP as compared to that of GC due to its higher surface area for the methanol oxidation has been proved by a substantial improvement in transition current in chronoamperometric and in the maximum anodic current of the m...

The direct methanol fuel cells (DMFC) have recently received a good deal of attention in both mob... more The direct methanol fuel cells (DMFC) have recently received a good deal of attention in both mobile and stationary applications due to their advantages of low operating temperature (<100 ○C), easy transportation and storage of fuel, high-energy efficiency and fast start-up of fuel. The mechanism and kinetics of methanol oxidation have been studied under a wide range of conditions and on a variety of electrodes including Pt, binary and ternary alloys, modified electrodes, nano-composites and nickel. One approach to the development of DMFC is to use alkaline electrolyte which is based on the assumption that electro-catalysis is generally more facile and inexpensive in this medium[1]. The purpose of the present work is to study the electrochemical oxidation of methanol on a nickel modified glassy carbon electrode in a solution of 1 M NaOH.

Journal of Theoretical Biology

International Journal of Control, 2015

In this paper, an energy-based control methodology is proposed to satisfy the Reynolds three rule... more In this paper, an energy-based control methodology is proposed to satisfy the Reynolds three rules in a flock of multiple agents. First, a control law is provided that is directly derived from the passivity theorem. In the next step, the Number of Neighbours Alignment/Repulsion algorithm is introduced for a flock of agents which loses the cohesion ability and uniformly joint connectivity condition. With this method, each agent tries to follow the agents which escape its neighbourhood by considering the velocity of escape time and number of neighbours. It is mathematically proved that the motion of multiple agents converges to a rigid and uncrowded flock if the group is jointly connected just for an instant. Moreover, the conditions for collision avoidance are guaranteed during the entire process. Finally, simulation results are presented to show the effectiveness of the proposed methodology.

Journal of Solid State Electrochemistry, 2015

Discharge characteristics of nanorods (NRs), microsized and nanosized copper (II) oxide (CuO) par... more Discharge characteristics of nanorods (NRs), microsized and nanosized copper (II) oxide (CuO) particles prepared via thermal decomposition and thermal oxidation routes are examined as cathode materials of a Zn/CuO cell without membrane separators. The electrochemical discharge is examined galvanostatically at a current density of 500 mAg−1 and reveals that the first discharge cycles of all the CuO materials contain one potential plateau; subsequent discharge cycles involve three potential plateaus. Each potential plateau is due to an electrochemical reaction. The first, second, and third potential plateaus are attributed to Cu2O3, CuO, and Cu2O discharges, respectively. Moreover, the first and the second plateaus are higher than the plateau of the early discharges. The electrochemical performance of CuO as a cathode material is enhanced by improving its morphology and changing its size. Nanorod CuO exhibits more specific energies, 317 Whkg−1, in the first discharge cycle, than microsized and nanosized CuO. The maximum current efficiencies of subsequent discharges are near 100 % at charging rates of 250, 500, 1000, 2000, 3000, and 4000 mAg−1 within 60 s for each. In addition, significant alterations in charge transfer resistances (Rct) and capacitive loops of Nyquist plots are observed during the charge/discharge of the cells through electrochemical impedance spectroscopy (EIS).

RSC Adv., 2015

Poly tyramine–NiO as an efficient electrocatalyst was prepared by in situ electropolymerization o... more Poly tyramine–NiO as an efficient electrocatalyst was prepared by in situ electropolymerization of tyramine in the presence of the SDS under ultrasonic irradiation.

Composites of multi-walled carbon nanotubes (MWCNTs) and poly ortho aminophenol (POAP) with good ... more Composites of multi-walled carbon nanotubes (MWCNTs) and poly ortho aminophenol (POAP) with good uniformity for use as electrodes in electrochemical capacitors were prepared by electropolymerization by using the ionic surfactant as electrolyte, for dispersing CNTs within conducting polymer/carbon nanotube composite films. The capacitance properties were investigated with cyclic voltammetry (CV), discharge tests and ac impedance spectroscopy. The composite electrode shows much higher specific capacitance, better power characteristics and is more promising for application in the capacitor than a pure POAP electrode. The effect and role of MWCNT in the composite electrode are discussed in detail. In comparison with a Ni-POAP/glassy carbon (GC), a Ni-MWCNT-POAP/GC electrode shows a better catalytic performance for the electrocatalytic oxidation of methanol.

Bulletin of the Chemical Society of Japan, 2015

Electrochemical deposition and characterization of PbS nanocrystals on Pb electrodes in alkaline ... more Electrochemical deposition and characterization of PbS nanocrystals on Pb electrodes in alkaline solution containing thiourea are carried out by cyclic voltammetry (CV) and electrochemical impedanc...

Bulletin of the Chemical Society of Japan, 2015

ABSTRACT Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) under chr... more ABSTRACT Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) under chronoamperometry technique. The SEM images showed that the hexagonal sheets of CdS deposited on the ITO surface. The X-ray diffraction (XRD) analysis confirmed this structure for CdS crystals and the average of crystalline size and the lattice constant parametersare approximately 39.54 and a=0.4136, c=0.6696nm respectively.Photo-electrochemical investigations were performed by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. CdS band edges and density of states (DOS) were determined by CV technique. The band gap energy (Ebg) was measured by ultraviolet-visible (UV-Vis) spectroscopy and electrochemical methods. Mott-Schottky plots were used to find the values of flat band potential (Efb), donor density (ND) and Debye length (LD). Also, the position of surface states was investigated by Mott-Schottky and LSV techniques. EIS was employed to confirm our electrochemical findings and investigate the charge transfer mechanism.

Chinese Journal of Catalysis - CHIN J CATAL, 2010

Oxygen reduction on a polycrystalline silver electrode was studied by cyclic voltammetry and elec... more Oxygen reduction on a polycrystalline silver electrode was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The reaction occurred by a two-electron pathway. The steps in the mechanism were observed in the cyclic voltammograms recorded with different scan rates. The intermediates formed in the steps were detected by electrochemical impedance spectroscopy.

Synthetic Metals, 2012

This paper aims to investigate the relationship between surface morphology of poly ortho aminophe... more This paper aims to investigate the relationship between surface morphology of poly ortho aminophenol (POAP) films and synthesis conditions. POAP with different particle sizes was deposited on a glassy carbon (GC) electrode using direct current (DC) and pulse techniques. POAP nanoparticles with good electrochemical stability and high doping degree were obtained by applying ultra short on time current pulse for polymerization. The surface morphology of POAP films was revealed by using the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge studies showed that the polymer obtained by pulses have higher electrochemical performance in acidic solution. Moreover, nanoparticles of POAP have a highly porous structure, high fractal dimension and large specific surface area, which can be employed as an excellent electrode material in supercapacitors. It was also found that the morphology of POAP varies with the synthesis conditions of the pulse.

Journal of Electroanalytical Chemistry, 2013

ABSTRACT The poly ortho aminophenol (POAP) films were electropolymerised on graphite electrode us... more ABSTRACT The poly ortho aminophenol (POAP) films were electropolymerised on graphite electrode using potentiostatic method. POAP films were also characterized by electrochemical impedance spectroscopy (EIS) in wide frequency range. The fractal dimension of poly ortho aminophenol (POAP) films in the presence of different counter ions was investigated. The effect of different anions on the electron conduction of POAP was explained in terms of their abilities to reduce repulsive interactions between redox sites and fractal dimension of the polymer. Diffusion coefficient of counter ions calculated from the slope of the Warburg line of impedance response of the film. A value of γ that is the characteristic of anomalous diffusion is obtained by EIS method and then the relation between fractal dimension and anomalous diffusion has been investigated. The resulting Mott-Schottky plot of the polymer capacitance describes the reduced polymer as a p-type semiconductor. © 2013 Elsevier B.V. All rights reserved.

Electrochimica acta, 2007

... a Departement of Chemistry, KN Toosi University of Technology, PO Box 15875-4416, Tehran, Ira... more ... a Departement of Chemistry, KN Toosi University of Technology, PO Box 15875-4416, Tehran, Iran. b Departement of chemistry, Sharif University of Technology, PO Box 11365-9516, Tehran, Iran. Received 24 September 2006 ...