Sharif Digital Repository

Electrochemical oxidation of acetaminophen (N–acetyl–p–aminophenol) (1) has been studied in the presence of dimethylamine (2) as a nucleophile in aqueous solution, by means of cyclic voltammetry and controlled-potential coulometry. The results indicate the participation of electrochemically generated N-acetyl-p-quinoneimine (1a) in Michael reaction with dimethylamine (2). Based on ECE mechanism, the observed homogeneous rate constant (kobs) of the above mentioned reaction is estimated by comparing the experimental cyclic voltammograms with the digital simulated results. Further more; kinetics and mechanism of the reaction were studied with ab initio calculation, Monte Carlo and QM/MM... 

Simultaneous enhancement of osseointegration and bacterial infection prohibition through surface modifications is a challenging but promising approach to achieve durable implantation. To that end, we present a multifunctional surface coating composed of graphene nanolayers and hierarchical well-aligned TiO2 nanotubes with a nanoporous top layer (cRTNT). FESEM studies reveal tunable increasing island morphologies of graphene nanolayers (G) on cRTNT by a cyclic voltammetry process. XPS analysis shows that the enhanced interface chemistry is due to TiO2-carbon bonding. The roughness of the sample containing a medium amount of graphene, cRTNT-75%GO, was calculated ∼289 nm, which was 543% higher... 

Cyclic voltammetry, j-t transients and transient time measurements have been used to characterize the Au-Ni alloy deposition and to obtain the nucleation and growth mechanism. The electrodeposition of gold, nickel and gold-nickel alloys was studied in cyanide-citrate electrolytes. The analysis of the voltammograms and j-t transients clearly shows that deposition of the Au and hence, of Au-Ni alloys, is affected by adsorbed cyanide ligands mainly at low overpotentials and a direct reduction occurs at high overpotentials. In this case, the Au deposition is kinetically favored, while the Ni deposition is controlled by the cyanide-citrate adsorbed adlayer. In an alloy electrolyte, the Au and Ni... 

In this work, uniform and monodisperse hollow carbon spheres (HCSs) are synthesized through two different processes using polydopamine (PDA), as a carbon precursor, and silica core as a template, under the modified Stöber condition. The surface morphology of the synthesized structures is characterized by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared spectroscopy (FT-IR). In the next step, the electrochemical behavior of isoprenaline (ISPN) is investigated by using glassy carbon electrode modified with a thin film of the synthesized hollow carbon spheres. The electrochemical characterization of the modified electrodes is... 

The electrocatalytic oxidation of hydrazine was studied over Ni, Cu, Co and Ni-based ternary alloy on graphite electrodes in alkaline solution. The catalysts were prepared by cycling the graphite electrode in solutions containing Ni, Cu and Co ions at cathodic potentials. The synergistic effects and the catalytic activity of the modified electrodes were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). It was found that, in the presence of hydrazine, the modified Ni-based ternary alloy electrode (G/NiCuCo) exhibited a good catalytic activity for the oxidation of hydrazine at a reduced overpotential and it has a significant high... 

The electrodeposition of cadmium is studied by electrochemical techniques with the presence of the organic agents. The cyclic voltammetry results clearly show that the electrodeposition of cadmium is a diffusion-controlled process associated with a typical nucleation process. With addition of the thiourea, 3-Picolin and benzyl alcohol organic agents simultaneously in sulfate solution, the redox potential of cadmium is shifted to more negative potentials. In this case, the current transients reveal an instantaneous nucleation with a typical three-dimensional (3D) growth mechanism, while it shows progressive nucleation mechanism without the ternary-species organic agents. In addition, the... 

A simple and low-cost electrochemical deposition method is used to prepare reduced graphene oxide/polypyrrole/Cu2O-Cu(OH)2 (RGO/PPy/Cu2O-Cu(OH)2) ternary nanocomposites as the electrode material for supercapacitor application. First, graphene oxide-polypyrrole (GO/PPy) nanocomposite is electrochemically synthesized on Ni foam by electro-oxidation of pyrrole monomer in an aqueous solution containing GO and Tiron. Subsequently, the GO/PPy film is converted to the corresponding reduced form (RGO/PPy) by an effective and eco-friendly electrochemical reduction method. Then, a thin layer of Cu2O-Cu(OH)2 is formed on RGO/PPy film by chronoamperometry. The RGO/PPy/Cu2O-Cu(OH)2 nanocomposite is... 

We report improved performance of Li-ion polymer batteries through advanced gel polymer electrolytes (GPEs). Compared to solid and liquid electrolytes, GPEs are advantageous as they can be fabricated in different shapes and geometries; also ionic properties are significantly superior to that of solid and liquid electrolytes. We have synthetized GPE in form of membranes by trapping ethylene carbonate and propylene carbonate in a composite of polyvinylidene fluoride and N-methylpyrrolidinore. By applying phase-transfer method, we synthetized membranes with micro-pores, which led to higher ionic conductivity. The proposed membrane is to be modified further to have higher capacity, stronger... 

Nickel modified graphite electrodes (G/Ni) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol, ethanol, 1-propanol and 2-propanol in alkaline solutions. The methods of cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (EIS) were employed. In CV studies, the electrochemical response, peak current varied in the order of MeOH > EtOH > 1-PrOH > 2-PrOH. Under the CA regime, a higher catalytic rate constant obtained for methanol oxidation was in agreement with CV measurements. Lower charge transfer resistance was obtained for low carbon alcohols oxidation and significantly higher... 

Layers of cobalt and manganese oxides were co-deposited or deposited on top of each other or next to each other by potentiostatic method onto stainless steel substrate. Deposition potentials of 1 and -1 V for the anodic and cathodic depositions were employed. Specific capacitance values in the range of 38.5-78 F g -1 were found with cobalt oxide on top of manganese oxide having the lowest and manganese oxide on top of cobalt oxide having the highest capacitances. The usefulness of the electrodes was characterized by cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy in 2 M NaOH electrolyte for redox supercapacitor applications. The latter presented the... 

Electro-oxidation of methanol in alkaline solution at a glassy carbon electrode electrochemically modified by a conductive polymeric meso-tetra(4-carboxyphenyl)porphyrinato nickel(II), abbreviated as poly-NiTCPP and also meso-tetra(4-carboxyphenyl)porphyrin with incorporated nickel(II) cations, abbreviated as, poly-TCPP/Ni, were investigated and compared. Both films were prepared by oxidative electro-polymerization of complexes by repetitive cyclic voltammetry (RCV) in 0.1 M NaOH aqueous solution. The electrochemical properties and behaviors and also kinetic values of both films have been characterized and compared using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical... 

Semiconducting lead sulfide film was deposited on Stainless Steel (SS) electrode by cyclic voltammetry (CV) at room temperature. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry were used to investigate the electrochemical properties of PbS film in Na2SO4 solution. The voltammetric results showed that oxidative dissolution of PbS film occurred at about 0.21 V vs. Ag/AgCl and total film detachment from the surface occurs with increasing potential. It is concluded that the electrode surface was not passivated by sulfur produced from oxidative dissolution of PbS film. Also, cathodic reduction of the film continued to beyond the hydrogen evolution at -1.35 V vs. Ag/AgCl....