Browsing by Author "S.K. Aggarwal"

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Electro-oxidation of phenyl hydrazine on a modified electrode constructed using nanocomposite of ruthenium terpyridyl complex, multiwalled carbon nanotubes and nafion
(2012) Ida Tiwari; Mandakini Gupta; Priti Sinha; S.K. Aggarwal
A modified glassy carbon electrode has been constructed using a 4′-(4-carboxyphenyl)-2, 2′: 6′, 2′′- terpyridine(1, 10-phenanthroline)chloride ruthenium (II) tetrafluoroborate complex along with multiwalled carbon nanotubes and nafion. The synthesized composite has been characterized using scanning electron microscopy, Transmission electron microscopy, and UV-Visible spectroscopy and IR spectroscopy. Electrochemical behaviour and stability of modified electrode has been investigated by cyclic voltammetry. Electrocatalytic activity of the modified electrode was investigated for the oxidation of phenyl hydrazine in 0.1 M phosphate buffer solution of pH 7.4. We observed Ruthenium complex/MWCNTs/ionomer composite has better electrochemistry, electrical properties and firm adhesion of the material with homogeneous dispersion at the electrode surface. The modified electrode showed electro-catalytic response to the oxidation of phenyl hydrazine at the potential of 600 mV. The linear range and detection limit for the detection of phenyl hydrazine in the optimum condition was found to be 5 × 10 -6 to 0.2 × 10 -3 M and 0.15 μM respectively. The modified electrode also exhibited several attractive features such as simple preparation, fast response, good stability and repeatability. © 2012 Elsevier Ltd. All rights reserved.
Electroanalytical properties and application of anthraquinone derivative-functionalized multiwalled carbon nanotubes nanowires modified glassy carbon electrode in the determination of dissolved oxygen
(2012) Ida Tiwari; Manorama Singh; Mandakini Gupta; S.K. Aggarwal
We herein report a simple, low cost and green preparation of nanowires of (anthraquinone-2-carboxylic acid/amino functionalized) multiwalled carbon nanotubes (HOOC-2-AQ/AMWCNTs) which has been further employed for the development of highly sensitive oxygen sensor. The prepared composite has been characterized by TEM and electrochemical studies. The glassy carbon electrode modified with composite shows an irreversible and good electrocatalytic activity for the reduction of oxygen. The reduction potential of the oxygen was shifted 460 mV towards the positive potential with this modified electrode as compared to bare glassy carbon electrode. The prepared material was stable with no leaching observed of the mediator. A linear response range of 0.2-6.8 mg L -1, with a sensitivity of 5.0 μA L mg -1 and a detection limit of 0.02 mg L -1 were obtained with this sensor. © 2012 Elsevier Ltd. All rights reserved.