Electrochemistry Research Group

Changwon, South Korea

Electrochemistry Research Group

Changwon, South Korea
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Bhakta A.K.,University of Namur | Detriche S.,University of Namur | Martis P.,Loyola Center for Research and Innovation | Mascarenhas R.J.,Electrochemistry Research Group | And 2 more authors.
Journal of Materials Science | Year: 2017

A simple, reliable, reproducible, and efficient method to decorate multi-wall carbon nanotubes (MWCNTs) with iron nanoparticles is presented. Purified MWCNTs are first functionalized with mono- and tricarboxylic aryl diazonium salts generated in situ, then iron nanoparticles are formed using iron (II) acetate. Different characterization techniques (XPS, TEM, PXRD, and FESEM) are used to assess the properties of the resulting materials. Homogeneous distribution of iron nanoparticles on MWCNTs is evidenced with a Gaussian mean diameter of ∼2.7 ± 0.2 and ∼3.8 ± 0.3 nm for monocarboxylic and tricarboxylic functionalizations, respectively. Obtaining such a small size homogeneously distributed iron nanoparticles on MWCNTs is the main achievement of this work. Furthermore, nanoparticles based on tricarboxylic aryl diazonium functions, used for the first time to functionalize CNTs, are more crystalline and essentially in the metallic state. This opens interesting perspectives for nanotechnology. The present methodology is also applicable to large-scale preparation. © 2017 Springer Science+Business Media New York

D'Souza O.J.,Bharathiar University | Mascarenhas R.J.,Bharathiar University | Mascarenhas R.J.,Electrochemistry Research Group | Satpati A.K.,Bhabha Atomic Research Center | And 2 more authors.
Ionics | Year: 2015

The electrocatalytic oxidation of l-tyrosine (Tyr) was investigated on a carboxylic acid functionalised multi-walled carbon nanotubes modified carbon paste electrode using cyclic voltammetry and amperometry. The surface morphology of the electrodes was studied using field emission (FE)-SEM images, and the interface properties of bare and modified electrodes were investigated by electrochemical impedance spectroscopy (EIS). The influence of the amount of modifier loading and the variation of the pH of the solution on the electrochemical parameters have been investigated. Cyclic voltammetry was carried out to study the electrochemical oxidation mechanism of Tyr, which showed an irreversible oxidation process at a potential of 637.0 mV at modified electrode. The anodic peak current linearly increased with the scan rate, suggesting that the oxidation of Tyr at modified electrode is an adsorption-controlled process. A good linear relationship between the oxidation peak current and the Tyr concentration in the range of 0.8–100.0 μM was obtained in a phosphate buffer solution at pH 7.0 with a detection limit of 14.0 ± 1.36 nM (S/N = 3). The practical utility of the sensor was demonstrated by determining Tyr in spiked cow’s milk and human blood serum. The modified electrode showed excellent reproducibility, long-term stability and antifouling effects. © 2015 Springer-Verlag Berlin Heidelberg

D'Souza O.J.,Bharathiar University | Mascarenhas R.J.,Bharathiar University | Mascarenhas R.J.,Electrochemistry Research Group | Satpati A.K.,Bhabha Atomic Research Center | And 4 more authors.
Ionics | Year: 2016

A simple and rapid method was employed for the modification of carbon paste electrode with iron nanoparticle-decorated multiwalled carbon nanotubes (MCPE/Fe-MWCNTs). The synergistic effect of iron nanoparticle and multiwalled carbon nanotubes results in the electrocatalytic oxidation of folic acid (FA). MCPE/Fe-MWCNTs were characterized by FESEM by recording surface morphological images; the elemental analysis of the electrode was carried out by EDX and electrochemical impedance spectroscopy to investigate surface-interface properties between solid electrode surface and the solution. The electronic transitions during the electrochemical oxidation of FA were investigated using spectroelectrochemical data. Cyclic voltammetry and differential pulse voltammetric techniques were used for the qualitative and quantitative analysis of FA respectively at physiological pH. MCPE/Fe-MWCNTs produced a linear response to FA over a wide concentration range with a detection limit of 2.4 ± 0.9 nM (S/N = 3). The fabricated sensor was successfully utilized as an effective tool for the determination of FA in food samples, human blood serum, and pharmaceuticals. [Figure not available: see fulltext.] © 2016 Springer-Verlag Berlin Heidelberg

Park M.,Electrochemistry Research Group | Lim J.-H.,Electrochemistry Research Group | Lim D.C.,Electrochemistry Research Group | Lee K.H.,Electrochemistry Research Group
Korean Journal of Materials Research | Year: 2011

The electro-deposition of compound semiconductors has been attracting more attention because of its ability to rapidly deposit nanostructured materials and thin films with controlled morphology, dimensions, and crystallinity in a costeffective manner (1). In particular, low band-gap A2B3-type chalcogenides, such as Sb2Te3 and Bi2Te3, have been extensively studied because of their potential applications in thermoelectric power generator and cooler and phase change memory. Thermoelectric SbxTey films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containing different ratios of TeO2 to Sb2O3. The stoichiometric SbxTey films were obtained at an applied voltage of -0.15V vs. SCE using a solution consisting of 2.4 mM TeO2, 0.8 mM Sb2O3, 33 mM tartaric acid, and 1M HNO3. The stoichiometric SbxTey films had the rhombohedral structure with a preferred orientation along the [015] direction. The films featured hole concentration and mobility of 5.8 × 1018/cm3 and 54.8 cm2/V·s, respectively. More negative applied potential yielded more Sb content in the deposited SbxTey films. In addition, the hole concentration and mobility decreased with more negative deposition potential and finally showed insulating property, possibly due to more defect formation. The Seebeck coefficient of as-deposited Sb2Te3 thin film deposited at -0.15V vs. SCE at room temperature was approximately 118 μV/K at room temperature, which is similar to bulk counterparts.

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