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Xavier B.,Stella Maris College Autonomous | Ramanand A.,Loyola College Autonomous | Sagayaraj P.,Loyola College Autonomous
Der Pharma Chemica | Year: 2012

We report a modified solvothermal route to synthesize Au/SnO2 nanocomposites. A rapid one step wet chemical procedure is adopted to synthesize colloidal gold nanoparticles, by mixing an aqueous solution of HAuCl4, CTAB and NaBH4 in appropriate ratio. The gold solution is added to the mixture containing SnCl2, NaOH and CTAB in an appropriate ratio and solvothermal treatment is adopted for the formation of Au/SnO2 nanocomposites. The asformed Au/SnO2 nanocomposite was subjected to structural, optical and morphological characterization studies. Source


Xavier B.,Stella Maris College Autonomous | Ramanand A.,Loyola College Autonomous | Sagayaraj P.,Loyola College Autonomous
Der Pharma Chemica | Year: 2012

We report the rapid synthesis of gold (Au) nanoparticles by mixing an aqueous solution of HAuCl4, CTAB and ascorbic acid by appropriate ratio, followed by the addition suitable amount of NaOH to maintain the pH of the solution. We have studied the formation of nanosized Au particles by both microscopic and spectroscopic characterization. The UV-Vis absorption spectrum of the sample shows the appearance of absorption band at 529 nm, which proves the quantum confinement of gold particles at the nanometer range. TEM image suggests that the as synthesized Au nanoparticles are spherical in shape and the particle size is in the range of 7-20 nm. The synthesized particles are found to be stable and hence suitable for potential application in various fields. Source


Delavictoire M.R.J.,Loyola College Autonomous | Nathan D.M.G.T.,Loyola College Autonomous | Sukany D.,Loyola College Autonomous | George M.,Stella Maris College Autonomous | Sagayaraj P.,Loyola College Autonomous
Der Pharma Chemica | Year: 2015

The need for sustainable energy sources has led to the increased investigations over Li-ion batteries (LIBs). In order to achieve high power and long life LIBs, various electrode materials are studied in the recent past. Among them, spinel lithium titanate (Li4Ti5O12) is an interesting anode material and is a potential candidate owing to its unique zero strain insertion nature. In this work, efforts have been made to synthesize Li4Ti5O12 (LTO) nanoparticles solvothermally, using TiO2 and LiOH.H2O as the starting materials in the presence of ethanol /water mixture at two different reaction conditions, based on time viz. 12 h and 24 h. These two samples are labeled as LT-12 and LT-24, respectively. The crystallinity of the as-prepared LTO was confirmed from X-ray Diffraction (XRD) patterns. The XRD pattern of LT-24 has more intense peaks in comparison to LT-12, indicating better crystallinity of the Li4Ti5O12 nanoparticles obtained. The surface morphology of both LT-12 and LT-24 was identified from Field Emission Scanning Electron Microscopy (FESEM). The High Resolution Transmission Electron Microscopy (HRTEM) imaging illustrates the cubic shape of LTO nanoparticles. The vibrational frequencies of elements present in LTO are obtained from Fourier Transform Infrared (FTIR) spectra. The Electrochemical Impedance Spectroscopy (EIS) was used to study the electrochemical performance of Li4Ti5O12 spinels. The shape of impedance curve depicts both the charge transfer impedance and diffusion of Li-ions and validates the better use of LT-24 as anode material for LIBs. Source


Delavictoire M.R.J.,Loyola College Autonomous | Manovah David T.,Loyola College Autonomous | Muthu Gnana Theresa Nathan D.,Loyola College Autonomous | George M.,Stella Maris College Autonomous | And 2 more authors.
International Journal of ChemTech Research | Year: 2015

Lithium titanate proves to be an important anode material for Li-ion batteries. Its unique characteristics make it a promising material for portable electronic devices, hybrid and non hybrid electric vehicles. An efficient and facile solvothermal method has been employed in this paper to prepare spinel structured lithium titanate nanostructures at different durations of time. The Li4Ti5O12 nanoparticles were prepared from reaction between TiO2 and LiOH·H2O in water/ethanol mixture with subsequent heat treatment. As a lithium intercalation material, high crystallinity is important for Li4Ti5O12. X-ray diffraction analysis (XRD) of the synthesized nanoparticles showed good crystallinity and phase purity which is important for Li4Ti5O12 as a lithium ion intercalation anode material. The morphology and electrochemical performance is found to be strongly dependent on the experimental conditions. The morphology of the particles observed from field emission scanning electron microscope (FESEM) was found to be rod-like, cubical and spherical in shape subjected to different time durations. The transmission electron microscope (TEM) analysis supports the morphological structures observed from FESEM. Also the chemical composition of the material analyzed from energy dispersive X-ray analysis (EDX) confirms the presence of Ti and O with their respective ratios. The electrochemical test indicates good electrochemical performance of the lithium titanate nanoparticles which finds its application in energy storage systems. © 2015, Sphinx Knowledge House. All rights reserved. Source


Delavictoire M.R.J.,Loyola College Autonomous | Nathana D.M.G.T.,Loyola College Autonomous | George M.,Stella Maris College Autonomous | Sagayaraja P.,Loyola College Autonomous
Der Pharma Chemica | Year: 2016

Spinel Li4Ti5O12(LTO) has been considered as a promising anode material in lithium-ion batteries (LIBs). But its disadvantage of low electronic conductivity limits its application to spread wide. This is overcome by dopingsome of the metal ions in the crystal lattice site of LTO. In this regardYttrium metal ions dopedLTO(YxLTO) nanoparticles were fabricated using solvothermal method from TiO2, LiOH.H2O and Y(NO3)3.6H2O as reactants. The synthesized products were subjected to X-ray diffraction analysis (XRD) which showed no change in the crystal structure owing to the substitution of yttrium ions in the titanium site. Also the increased lattice constant, increases the rate of lithium ion diffusion in the electrode material. The morphological studies were performed from Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM) along with particle size analysis obtained for varying dopant concentrations. The vibrational groups present in LTO were also identified from Fourier Transform Infrared analysis (FT-IR). Moreover their lithiation-delithiation process were characterized by electrochemical measurement that showedYxLTOto exhibit good cyclic stability, enhanced cyclic behavior and performance in comparison to undoped Li4Ti5O12 nanoparticles (NPs) that could serve as better anodes for LIBs. Source

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