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Author: search.filters.author.Balavijayalakshmi, JEnd date: 2019

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    ELECTROCHEMICAL INVESTIGATION OF NITROGEN DOPED GRAPHENE OXIDE/YTTRIUM OXIDE NANOCOMPOSITES
    (Journal of Nano- and Electronic Physics, 2019-10-25) Shanmugapriya, T; Balavijayalakshmi, J
    Graphene oxide is one of the most promising materials for electronic devices because of its unique properties. It is prepared from natural graphite flakes by modified Hummers method. A novel nitrogen doped graphene oxide/yttrium oxide (NGO/Y2O3) nanocomposites are prepared by chemical precipitation method. The X-ray diffraction analysis shows that the crystallite size of the NGO/Y2O3 is found to be around 23 nm, and scanning electron microscopy (SEM) reveals that the nanoparticles are uniformly dispersed on the surface of NGO sheets. FTIR spectra are employed to investigate the bonding interaction in GO and NGO/Y2O3 nanocomposites. The electrochemical activity of the prepared nanocomposites is investigated by cyclic voltammetry (CV) technique. The reduction peak current of NGO/Y2O3 is enhanced and reduction peak potential is increased which shows high current response in NGO/Y2O3 nanocomposites compared to Y2O3 nanocomposites. This suggests that the prepared nanocomposites have excellent electrochemical behavior and can be applied for supercapactior and solar cell applications.
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    POLYMER FUNCTIONALIZED CARBON/METAL NANOHYBRIDS AS A VERSATILE ELECTROCHEMICAL SENSOR FOR THE DETECTION OF P-AMINOPHENOL
    (IOP Publishing Ltd, 2019-04) Yuvashree, S; Balavijayalakshmi, J
    A novel electrochemical sensor to determine p-Aminophenol is fabricated using silver nanoparticles decorated reduced graphene oxide- chitosan nanocomposites. The RGO/CS/Ag nanocomposites are synthesized by chemical reduction method. The structural, spectral, morphological and elemental studies of the synthesized nanocomposites are characterized by x-ray powder diffraction (XRD), Fourier transform infrared spectrum (FTIR), Scanning electron microscopy (SEM) and Energy Dispersive x-ray Analysis (EDAX). The electrochemical investigations indicate that the Glassy carbon electrode modified nanocomposites possessed an excellent performance towards the detection of p-Aminophenol. Under the optimized conditions, the detection limit of p-Aminophenol obtained in this work is 10 μM and a wide linear range of detection is found to be 10 μM to 600 μM. Thus the proposed sensor can be applied in environment for the determination of p-Aminophenol.
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    INFLUENCE OF GOLD NANOPARTICLE CONCENTRATION ON POLYMER FUNCTIONALIZED REDUCED GRAPHENE NANOSHEETS AND ITS ELECTROCHEMICAL SENSING PERFORMANCE
    (IOP Publishing Ltd, 2019-04) Ramalakshmi, V; Balavijayalakshmi, J
    The different concentrations (0.002 M, 0.004 M, 0.006 M, 0.008 M and 0.01 M) of gold nanoparticles encapsulated β-cyclodextrin functionalized reduced graphene oxide nanocomposites (rGONS/β-CD/Au) synthesized via wet chemical method is reported. The synthesized rGONS/β-CD/Au nanocomposites are investigated using FTIR, XRD, SEM, EDS and TEM analysis. The FTIR spectra reveal that the blue shift in the bands may be due to the intermolecular interaction between reduced graphene oxide and cyclodextrin. From XRD analysis the average crystallite size is found to be around 10 nm, which is in good agreement with TEM analysis. The SEM analysis shows the spherical structure of the gold nanoparticles. The glassy carbon electrode (GCE) modified with the synthesized rGONS/β-CD/Au nanocomposites of 0.006 M concentration is employed for the sensitive detection of different nitrophenols such as ortho-nitrophenol (o-NP), para-nitrophenol (p-NP) and meta-nitrophenol (m-NP) by using electrochemical techniques and the result displays a wide detection range for all the nitrophenol isomers.
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    INVESTIGATION ON STRUCTURAL, SPECTRAL AND MORPHOLOGICAL ANALYSIS OF POLYMER FUNTIONALIZED GRAPHENE OXIDE—METAL OXIDE NANOCOMPOSITES FOR REMOVAL OF DYES FROM AQUEOUS SOLUTION
    (IOP Publishing Ltd, 2019-07) Reeshma, P; Balavijayalakshmi, J
    In this present work Graphene oxide/Chitosan/MnO2 nanocomposites are synthesized via chemical reduction method for various concentrations of Manganese oxide. The crystallite size is found to be around 19 nm and increases with the increase in the concentration of manganese oxide as investigated by x-ray diffraction analysis. Field emission scanning electron microscopy (FE-SEM) analysis shows the agglomerated spherical shaped MnO2 nanopartices found over the crumbled wave like GO/CS sheets. The presence of functional groups in the synthesized nanocomposites is studied by Fourier transform infrared spectroscopy (FT-IR) and the most prominent band of Mn–O is observed around 513 cm−1. The Energy dispersive spectroscopy analysis (EDAX) confirms the elemental presence of the nanocomposites without any impurities. The adsorption properties of Graphene oxide/chitosan/MnO2 towards the industrial dyes are investigated along with the measured effect of adsorption by initial concentration, contact time and pH values. The resulting adsorption isotherm is analyzed systematically. The prepared nanocomposites are found to be more efficient adsorbent for the removal of anionic industrial dyes such as methyl orange.
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    SYNTHESIS OF MOLYBDENUM DISULFIDE DOPED ZINC OXIDE NANOCOMPOSITES BY MICROWAVE ASSISTED METHOD
    (IOP Publishing Ltd, 2019-08) Krithika, S; Balavijayalakshmi, J
    Molybdenum disulfide (MoS2) is a layered transition metal dichalcogenides (TMDs) and is anistropic in nature. It has remarkable physio-chemical properties such as large surface-to-volume ratio, distinctive electronic characteristic, tunable band gap, high carrier mobility, friction, catalytic and optical properties. Zinc oxide is one of the most versatile materials due to its excellent inherent properties of wide band gap, large exciton binding energy and high chemical stability. Molybdenum disulfide doped zinc oxide nanocomposites exhibited high stability, good repeatability and high sensitivity. These nanocomposites are synthesized by Microwave assisted method. The prepared nanocomposites are characterized by Scanning Electron Microscopy (SEM), Transmission Electron Spectroscopy (TEM), x-ray Diffraction Analysis (XRD) and Fourier-Transform Infrared (FT-IR) spectral and UV-Visible spectral Analysis (UV-Vis) and Raman Spectroscopy and Cyclic Voltammogram (CV) analysis for its morphological, structural, spectral, optical, and the electrochemical properties. The FT-IR spectra show absorption bands around 911 cm−1 and 1416 cm−1 confirms the presence of Mo-S stretching modes. The SEM and TEM analysis reveals that the synthesized MoS2/ZnO nanocomposites are spherical in shape and agglomerated. The UV–Visible spectra reveal the absorption edge is red shifted. The cyclic voltammetry measurement confirms that MoS2/ZnO nanocomposites have cyclic performance as an anode material and have electric double layer capacitance behaviour. These nanocomposites are one of the prominent materials with prospective application in the field of energy storage.
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    DECORATION AND FUNCTIONALIZATION OF GRAPHENE OXIDE NANOCOMPOSITES FOR SENSING APPLICATIONS
    (Elsevier, 2019) Ramalakshmi, V; Balavijayalakshmi, J
    In the present work, β-cyclodextrin functionalized reduced graphene oxide-silver nanocomposites (GO-β-CD-Ag) are effectively synthesized using wet chemical method. The GO-β-CD nanocomposites are initially produced via hydrazine reduction. The various concentrations (0.002 M, 0.004 M, 0.006 M, 0.008 M and 0.01 M) of silver nanoparticles are decorated on the GO-β-CD surface by the reduction of silver nitrate with sodium borohydrate as a reducing agent. The produced GO-β-CD-Ag nanocomposites are well characterized using XRD, SEM and EDAX analysis. The XRD results firmly established that the β-CD molecules are satisfactorily coated on the rGO surface and also the Ag nanoparticles with an average size of 23 nm are evenly decorated on the GO-β-CD surface. The GO-β-CD-Ag nanocomposites modified glassy carbon electrode is captivated for the selective detection of o-Nitrophenol. Cyclic voltammetry test is employed to determine the presence of o-Nitrophenol compound. The result shows the oxidation and reduction potential for o-Nitrophenol at -0.25 V and -0.5 V respectively, indicating the successful determination of o-Nitrophenol by using the GO-CD-Ag nanocomposite modified electrode.
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    IMPACT OF ALUMINIUM ON “STRUCTURAL, OPTICAL AND MORPHOLOGICAL PROPERTIES OF COPPER OXIDE NANOPARTICLES”
    (Elsevier, 2019) Vidhya priya, P; Balavijayalakshmi, J
    Metal-oxide-semiconductors have been widely used for the optoelectronic applications like smart windows, solar cells, light emitting diodes and flat panel displays. Among all the metal oxides, copper oxide nanomaterials have a great attention due to its unique properties. It is mostly used in recent research works because of its low cost, rich availability and used in latent applications like antibacterial activities. Aluminium nanoparticles are a good conductor and it enhances the conductivity. Hence an attempt is made to synthesize CuO and Al doped CuO nanoparticles by hydrothermal method. The prepared samples are characterized by XRD, FT-IR, SEM, UV-Vis and PL analysis.The crystallite structures of CuO and Al doped CuO nanoparticles are identified by XRD analysis. The Fourier transform Infrared spectroscopy is used to determine the functional groups present in the prepared nanoparticles. UV-Vis Spectral analysis is performed to determine the band gap energy of the synthesized nanoparticles. PL spectral studies are used to study the optical properties of the nanoparticles. The morphology of the samples is determined by using scanning electron microscopy analysis. The impact of aluminium on structural, optical and morphological properties is investigated. The antibacterial activities of prepared CuO and Al doped CuO nanoparticles are probed.
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    GRAPHENE BASED NANOCOMPOSITES FOR ELECTROCHEMICAL DETECTION OF H2O2
    (Elsevier, 2019) Yuvashree, S; Balavijayalakshmi, J
    In this study, a novel reduced graphene oxide-based nanocomposite electrochemical biosensor for the reliable detection of H2O2 is developed. Reduced graphene oxide-chitosan nanocomposites are successfully prepared by chemical reduction method. XRD, FT-IR, SEM and EDAX analysis are performed to characterize the structural, spectral, morphology and composition of the prepared nanocomposites. The response of the modified electrode to H2O2 is examined by cyclic voltammetry. Under optimal experimental conditions, the RGO-CS biosensor showed outstanding catalytic activity toward H2O2 reduction. The H2O2 reduction peaks are observed about 0.1V. These results confirm that RGO-CS nanocomposites with the high surface area and electrocatalytic activity offer a promising candidate for the detection of H2O2 in biological environment.
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    CARICA PAPAYA PEEL MEDIATED SYNTHESIS OF SILVER NANOPARTICLES AND ITS ANTIBACTERIAL ACTIVITY AGAINST HUMAN PATHOGENS
    (ScienceDirect, 2017-09-28) Balavijayalakshmi, J; Ramalakshmi, V
    Metallicnanoparticlesaretraditionallysynthesizedbywetchemicaltechniques,inwhichthechemicalsusedarequiteoftentoxicandflammable.Ripecaricapapayapeelisfoundtobeasuitablesourceforgreensynthesisofsilvernanoparticles.Inthepresentwork,acosteffectiveandenvironmentalfriendlytechniqueforthegreensynthesisofsilvernanoparticlesfrom1mMsilvernitrate(AgNO3)solutionthroughtheextractofripeCaricapapayapeelofvariousconcentrations(5ml,10ml,15ml,20ml,25ml)isdescribed.ThesynthesizedsilvernanoparticlesarecharacterizedbyusingtheUV–visabsorptionspectroscopy,FT IR,XRD,SEMandTEM.Theformationofsilvernanoparticlesisconfirmedbysurfaceplasmonresonance,determinedbyUV–visspectraat400–435nm.Theshiftintheabsorptionbandsandvariationinthecalculatedopticalbandgapsforthevariousconcentrationsofpapayapeelsextractsarealsoobserved.TheFT-IRspectrarevealthatanincreaseintheconcentrationofthepapayapeelextractshiftsthebandstohigherwavelengths.TheaveragecrystallitesizeforvariousconcentrationsofpapayapeelextractisobservedfromXRDspectralanalysisandisfoundtobearound16–20nm,whichisingoodagreementwiththeTEManalysis.TheSEManalysisshowsthesphericalstructureofthesilvernanoparticleswithsomeagglomerationforhigherconcentrationsofpapayapeelextract.ThesynthesizedsilvernanoparticlesshowgoodantibacterialactivityagainsthumanpathogenssuchasEscherichiacoliandStaphylococcusaureusandithasmanymedicalapplications
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    EFFECT OF COBALT SUBSTITUTION ON STRUCTURAL AND MAGNETIC PROPERTIES OF MAGNESIUM FERRITE NANOPARTICLES
    (Springer Link, 2017-05-04) Balavijayalakshmi, J; Sudha, T
    Cobalt substituted magnesium ferrite (Mg(1−x)CoxFe2O4, where x = 0.2, 0.4, 0.6 and 0.8) nanoparticles are prepared by co-precipitation method and samples are annealed at 600 °C. The synthesized nanoparticles are characterized using FT-IR spectral analysis, X-ray diffraction (XRD) analysis, Scanning Electron Microscopy (SEM) analysis, Transmission Electron Microscopy (TEM ) analysis and Vibrating Sample Magnetometer (VSM) analysis. The FT-IR spectra show main absorption bands are shifted to higher values as the concentration of cobalt increases. The average nano-crystallite sizes are found to be in the range 7–9 nm. The SEM micrographs show uniformly distributed granular like structure. TEM indicate the presence of rectangular shaped nanoparticles. The magnetic properties of these samples are studied using Vibrating Sample Magnetometer (VSM). As the magnetic properties are enhanced due to the cobalt substitution the synthesized samples can be used as a gas sensor.