M.V. Sangaranarayanan

The estimation of electrochemical quartz crystal microbalance (EQCM) frequencies from a given cyclic voltammetric data is analysed using underpotential deposition (UPD) of metals as an illustrative process. The crucial role played by the surface roughness of electrodes and electrosorption valency of the depositing species is pointed out. The computed EQCM frequency shifts for the UPD of Cd and Tl on polycrystalline Ag electrodes are in satisfactory agreement with the experimental data. © Springer-Verlag 2005.

The applicability of tin submicroparticles modified glassy carbon electrodes for sensing of nitrite ions is demonstrated. Tin submicroparticles have been electrodeposited on a glassy carbon electrode using constant potential deposition. The detection of nitrite ions is carried out with differential pulse voltammetry, amperometry and electrochemical impedance spectroscopy. The lowest detection limit of 0.5μM with a linear range of 5μM-1000μM is inferred from the differential pulse voltammetry. The interference from different compounds such as urea, glucose and nitrate ions is also analyzed.

The interfacial behavior of thallium ions on polycrystalline silver electrodes is analyzed using cyclic voltammetric and chronocoulometric and impedance studies. The specificity associated with bromide ions leading to the anion-induced adsorption of the thallium complex is pointed out and the stoichiometry of the thallium complex is deduced. © 2004 Elsevier Inc. All rights reserved.

The analysis of underpotential deposition (UPD)-based systems for the development of electrochemical supercapacitors is investigated employing the UPD of Tl on Ag in the presence of bromide ions, as an illustrative example. The specific capacitance is estimated with the help of multi-cycle voltammograms, galvanostatic charge/ discharge experiments and impedance spectroscopy. The equivalent circuit for the system is constructed and the parameters are deduced from the simulation. The deduced magnitude of ∼102 F g -1 in conjunction with the satisfactory number of charge/discharge cycles obtained from Galvanostatic experiments indicate the feasibility of these systems as supercapacitors. © Springer 2006.

The potentiodynamic polymerization of pyrrole is carried out on Pt electrodes using sodium dodecyl sulphate and the coated electrode is employed for sensing of urea non-enzymatically. Employing amperometric and impedimetric methods, urea is estimated in mildly acidic conditions. A detection limit of 40 μM is obtained along with a linearity of 80-1440 μM and a sensitivity of 1.11 μA μM-1 cm-2 from the amperometric data. The Nyquist plot is employed for the construction of the calibration curve from the impedance analysis. The interference of different compounds such as ascorbic acid, uric acid, sodium chloride and calcium chloride is also analyzed. © 2012 Elsevier B.V.

The influence of Triton X-100 in enhancing the capacitance of polyaniline-based nickel electrodes is reported. Cyclic voltammetric experiments, galvanostatic charge-discharge studies and impedance analysis were carried out in order to investigate the applicability of the system as an electrochemical supercapacitor. A qualitative interpretation of the enhancement is provided. Fourier transform infrared (FTIR), X-ray diffraction and scanning electron microscopy techniques were employed for characterization of the electrode. © 2005.