Faculty Publications

Now showing 1 - 4 of 4

Colorimetric receptors for naked eye detection of inorganic fluoride ion in aqueous media using ICT mechanism
(Royal Society of Chemistry, 2012) Kigga, M.; Nityananda Shetty, A.N.; Trivedi, D.R.
A new series of receptors were designed and synthesized based on benzohydrazide for the colorimetric detection of fluoride ion. The receptors L1 and L2 are highly selective towards fluoride ion over other anions. These receptors are able to detect inorganic fluoride such as NaF in aqueous solutions. The presence of two carbonyl groups in the receptor molecule makes the -NH proton highly acidic and hence these receptors are capable of competing with water molecules to bind fluoride ion. The receptors L1 and L2 showed a significant colour change from colourless to yellow in aqueous solutions of NaF with a ??max of 149 nm and 147 nm respectively. The mechanism involved in the colour change was deprotonation, formation of imidic acid intermediate followed by stabilization of complex through Intramolecular Charge Transfer (ICT). This was further confirmed by 1H NMR titrations where the formation of imidic acid was observed. The receptor L1 proved itself to be potentially useful for real-life applications by detecting fluoride ion quantitatively in sea water and commercially available mouth wash. © 2012 The Royal Society of Chemistry.
Insights into the electrooptical anion sensing properties of a new organic receptor: Solvent dependent chromogenic response and DFT studies
(Royal Society of Chemistry, 2016) Pangannaya, P.; Tarafder, K.; Nityananda Shetty, A.N.; Trivedi, D.R.
A highly selective hydrazine based electrooptical receptor featuring solvent based color transition properties in the presence of acetate ions has been developed. The AcO- ion mediated color transition properties of a new organic receptor in solvents of varying polarity highlights the influence of dipole moment in stabilizing the excited state. Selective detection of acetate ions by a new organic receptor in the presence of DMSO : Tris HCl buffer (9 : 1, v/v) has been the pivotal concept of the present work. 1H-NMR titration and DFT studies provide quantitative proof of the underlying detection mechanism. Solution and solid state sensing response of anions by the receptor reflects the practical utility in real time sample analysis. © 2016 The Royal Society of Chemistry.
Electrochemical corrosion study of Mg-Al-Zn-Mn alloy in aqueous ethylene glycol containing chloride ions
(Elsevier Editora Ltda, 2017) Medhashree, H.; Nityananda Shetty, A.N.
Nowadays most of the automobiles use magnesium alloys in the components of the engine coolant systems. These engine coolants used are mainly composed of aqueous ethylene glycol along with some inhibitors. Generally the engine coolants are contaminated by environmental anions like chlorides, which would enhance the rate of corrosion of the alloys used in the coolant system. In the present study, the corrosion behavior of Mg-Al-Zn-Mn alloy in 30% (v/v) aqueous ethylene glycol containing chloride anions at neutral pH was investigated. Electrochemical techniques, such as potentiodynamic polarization method, cyclic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of Mg-Al-Zn-Mn alloy. The surface morphology, microstructure and surface composition of the alloy were studied by using the scanning electron microscopy (SEM), optical microscopy and energy dispersion X-ray (EDX) analysis, respectively. Electrochemical investigations show that the rate of corrosion increases with the increase in chloride ion concentration and also with the increase in medium temperature. © 2016 Brazilian Metallurgical, Materials and Mining Association.
Durable and high energy yielding PANI/Ni(OH)2 nanocomposites and its supporting electrolyte improved supercapacitance
(Elsevier Ltd, 2024) Viswanathan, A.; Nityananda Shetty, A.N.
The driving force behind supercapacitor research is to enhance the energy density (E) to the level of Li-ion batteries, and achieving high power density (P). This task is accomplished by using nanocomposites of polyaniline (PANI) and Ni(OH)2 (PN) as the electrode material for supercapacitors. These nanocomposites were synthesized using acetic acid (PN - AA) (PANI 75% and Ni(OH)2 25%) and methane sulphonic acid (PN - MSA) (PANI 83.33% and Ni(OH)2 16.67%) as dopants for PANI through an in-situ single-step method. The PN – MSA exhibited higher energy storage characters than PN – AA with 1 M H2SO4 (SA) as electrolyte. PN - MSA exhibited high-energy characteristics, including a specific capacitance (Cs) of 735.29 F g‒1, an energy density (E) of 147.05 W h kg‒1 (comparable to Li-ion batteries), and a power density (P) of 2.3466 kW kg‒1 at 1 A g‒1. In addition, it also exhibited an exceptional cyclic stability up to 58,800 cycles at 0.4 V s‒1. The energy characters of PN-AA are also substantially high and are a Cs of 641.02 F g‒1, an E of 128.20 W h kg‒1 (in the same order of Li-ion batteries), a P of 2.0385 kW kg‒1 at 1 A g‒1 and a cyclic stability up to 18,400 cycles was also obtained at 0.4 V s‒1. Both PN - AA and PN - MSA demonstrated an impressive feature of an increase in energy storage with an increase in the number of charge/discharge cycles. PN - MSA exhibited an improvement in energy storage characteristics of up to 44% when a mixture of sulphuric acid and methane sulphonic acid with concentrations of 1 M and 0.33 M, respectively, was used as an electrolyte. © 2024 Elsevier Ltd

Faculty Publications

Browse

Filters

Settings

Sort By

Results per page

Search Results