Browsing by Author "Moolayadukkam, M."

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Hydrazine sensing properties of microwave synthesized graphene/ZnO composites
(American Institute of Physics Inc. subs@aip.org, 2016) Moolayadukkam, M.; Nagaraja, H.S.; Bhat, K.U.
This paper reports the synthesis of graphene/ ZnO nanocomposite using microwave method and its application in sensing of hydrazine. The morphological characteristics of the samples are studied using Scanning Electron Microscope (SEM). The formation of the composite is further confirmed by the X-ray Diffraction (XRD). Energy Dispersive X-ray Analysis (EDAX) shows the presence of carbon indicating the presence of graphene. The hydrazine sensing property of the electrode is studied using cyclic voltammometry (CV) and Chronoamperometry (CA) studeis. Â© 2016 Author(s).
Hydrothermally synthesized reduced graphene oxide and Sn doped manganese dioxide nanocomposites for supercapacitors and dopamine sensors
(Elsevier Ltd, 2017) Shanbhag, D.; Bindu, K.; Aarathy, A.R.; Ramesh, R.; Moolayadukkam, M.; Nagaraja, H.S.
?-MnO2 nanowires and its nanocomposites (rGO-MnO2 and Sn@rGO-MnO2) were synthesized by a facile hydrothermal technique. Two important electrochemical applications of nanocomposites, viz, electrodes for supercapacitor and sensors for a biomolecule, dopamine are reported. The prepared nanowires have been characterized by XRD, which reveals smaller crystallite size of rGO- MnO2 composites compared to pristine MnO2 and the trend is supported by BET analysis. The wrapping of MnO2 NWs with rGO sheets increases the surface area, as well as, creates more dislocations at the interfaces. The correlation between physicochemical properties leads to an enhancement in the electrochemical performance of the materials. The as-fabricated Sn@rGO-MnO2 supercapacitor electrode reveals superior performance. The specific capacitance of 139.05, 309.7 and 460.9 F/g at a scanning rate of 20 mV/s, in an aqueous Na2SO4 solution (1 M) is obtained for MnO2, rGO-MnO2 and Sn@rGO-MnO2 respectively. Also, the reported nanocomposites show excellent performance towards detection of dopamine. Among ?-MnO2/GCE, rGO-MnO2/GCE and Sn@rGO-MnO2/GCE based sensors for Dopamine detection, rGO-MnO2/GCE sensor exhibits the highest sensitivity of 433.6 ?A/mM and broad linear range, whereas Sn@rGO-MnO2 exhibits lower detection limit of 0.13 ?M. © 2017 Elsevier Ltd
Integrated microchannel cooling for densely packed electronic components using vanadium pentaoxide (V2O5)-xerogel nanoplatelets-based nanofluids
(Springer Science and Business Media B.V., 2023) Narendran, G.; Gnanasekaran, N.; Arumuga Perumal, D.A.; Moolayadukkam, M.; Nagaraja, H.S.
The present study reports the implementation of novel nanoplatelets-based vanadium pent oxide (V2O5)-xerogel for the application of conjugate cooling in densely packed electronic devices. An integrated heat sink is made up of copper with a channel width of 490 µm and is shrink-fitted into aluminium block that acts as a heat spreader. V2O5-xerogel is synthesized by melt quenching process and characterized based on field emission scanning electron microscope, transmission electron microscope, and X-ray diffraction to analyse the surface morphology of the particles. Studies related to the stability of the nanofluids for different concentrations are discussed in this paper. Furthermore, a study on the effect of pulsating flow in microchannel is performed for different flow rates. As a result, a maximum enhancement of 17% in heat transfer coefficient was observed for the concentration of 0.4 mass% with a flow rate of 200 mL min-1 compared to a pure fluid. Finally, the results reveal that the xerogel is a potential working fluid for heat transfer applications involving microscale devices. © 2023, Akadémiai Kiadó, Budapest, Hungary.
Melt quenched vanadium oxide embedded in graphene oxide sheets as composite electrodes for amperometric dopamine sensing and lithium ion battery applications
(Elsevier B.V., 2017) Moolayadukkam, M.; Shenoy, S.; Sridharan, K.; Kufian, D.; Arof, A.K.; Nagaraja, H.S.
Electrochemical sensors and lithium-ion batteries are two important topics in electrochemistry that have attracted much attention owing to their extensive applications in enzyme-free biosensors and portable electronic devices. Herein, we report a simple hydrothermal approach for synthesizing composites of melt quenched vanadium oxide embedded on graphene oxide of equal proportion (MVGO50) for the fabrication of electrodes for nonenzymatic amperometic dopamine sensor and lithium-ion battery applications. The sensing performance of MVGO50 electrodes through chronoamperometry studies in 0.1 M PBS solution (at pH 7) over a wide range of dopamine concentration exhibited a highest sensitivity of 25.02 ?A mM ?1 cm ?2 with the lowest detection limit of 0.07 ?M. In addition, the selective sensing capability of MVGO50 was also tested through chronoamperometry studies by the addition of a very small concentration of dopamine (10 ?M) in the presence of a fairly higher concentration of uric acid (10 mM) as the interfering species. Furthermore, the reversible lithium cycling properties of MVGO50 are evaluated by galvanostatic charge-discharge cycling studies. MVGO50 electrodes exhibited enhanced rate capacity of up to 200 mAhg ?1 at a current of 0.1C rate and remained stable during cycling. These results indicate that MVGO composites are potential candidates for electrochemical device applications. © 2017 Elsevier B.V.
Microwave assisted synthesis of rGO/ZnO composites for non-enzymatic glucose sensing and supercapacitor applications
(Elsevier Ltd, 2017) Moolayadukkam, M.; Dhanush, S.; Rossignol, F.; Nagaraja, H.S.
Zinc oxide (ZnO) and Graphene Oxide (GO) are known to show good electrochemical properties. In this paper, rGO/ZnO nanocomposites have been synthesised using a simple microwave assisted method. The nanocomposites are characterized using XRD, Raman, SEM and TEM. XRD reveals the wurtzite structure of ZnO and TEM shows the heterogeneous nucleation of ZnO nanocrystals anchored onto graphene sheets. The electrochemical properties of the rGO/ZnO nanocomposite enhanced significantly for applications in glucose sensors and supercapacitors. The non-enzymatic glucose sensor of this nanocomposite tested using cyclic voltammetry (CV) and chronoamperometry, exhibits high sensitivity (39.78 mA cm?2 mM?1) and a lower detection limit of 0.2 nM. The supercapacitor electrode of rGO/ZnO nanocomposite exhibits a significant increase in specific capacitance. © 2017 Elsevier Ltd and Techna Group S.r.l.
Solar exfoliated graphene and its application in supercapacitors and electrochemical H2O2 sensing
(Elsevier Ltd, 2015) Moolayadukkam, M.; Huang, N.M.; Nagaraja, H.S.
In the present study, graphene nanosheets are synthesized using sunlight irradiation focussed onto graphite oxide. The morphological characteristics of graphene are examined using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Raman spectroscopy and X-ray diffraction (XRD) are used for the structural characterization of the sample. The electrochemical performance is evaluated using cyclic voltammetry (CV), charge-discharge characteristics and impedance spectroscopy. A high specific capacitance value of 223 F g-1 is obtained using cyclic voltammetry. The electrochemical detection of H2O2, a common biological species using solar graphene is demonstrated. The impedance spectroscopy and CV are used to study the electrocatalytic activity of the material. High sensitivity of 64.79 ?A mM-1 cm-2 is reported. © 2015 Elsevier Ltd. All rights reserved.
Synthesis and electrochemical properties of silver dendrites and silver dendrites/rGO composite for applications in paracetamol sensing
(Elsevier Ltd, 2018) Dhanush, S.; Moolayadukkam, M.; Bindu, K.; Chowdhury, P.; Nagaraja, H.S.
Electrochemical sensors are one of the important applications of electrochemistry. In this paper, synthesis, characterization and application of Silver Dendrites and Silver Dendrites/rGO sensors for simple and fast determination of Paracetamol are described. Silver dendrites and their composite with graphene oxide were synthesized by galvanic replacement method. The synthesized samples were characterized by XRD, SEM and TEM. XRD reveals the FCC structure of silver and TEM images show the formation of dendritic silver wrapped in the graphene sheets. The Electrochemical paracetamol sensing properties of these samples were tested using cyclic voltammetry and chronoamperometry. The silver dendrites exhibit a sensitivity of 2.807 × 105?A/mM/g and a lower detection limit of 2.5 ?M, whereas, the composite with graphene oxide exhibits a high sensitivity of 2.511 × 106?A /mM/g with a lower detection limit of 0.025 ?M. © 2018 Elsevier Ltd