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Changwon, South Korea

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

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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