Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Centre for Nanotechnology Research

One dimensional nanostructured branched wires of tin dioxide (SnO2) were prepared in an alumina boat by a self catalytic method at different temperatures in a flow of argon and oxygen. The SEM images exhibit the different morphologies of the nanowires with an i.d. of around 40 nm, and presence of core/cluster shell nanowires and of nano/microbelt structures. XRD studies show the product to possess a typical tin dioxide nanowire structure. FTIR and Raman studies revealed the bond information. The sensing properties were studied by monitoring the changes in conductivity on exposure to hydrogen gas. Hydrogen can be detected in the 1000 ppm to 3000 ppm concentration range, and the limit of detection for H2 is 1000 ppm. [Figure not available: see fulltext.]. © 2017, Springer-Verlag Wien.

Department of Information Security

School of Computer Science and Engineering

Vellore Campus

Department of Bio-Sciences

School of Bio Sciences and Technology

Microchimica Acta

Overhead projector sheets as substrate for deposition of one-dimensional tin dioxide nanostructures for use as a chemoresistive sensor for hydrogen

This work reports on the synthesis of nanocomposites from NiO and α-Fe2O3 by a hydrothermal route. The material was characterized in terms of structural and morphological features by X-ray diffraction and scanning electron microscopy. The nanocomposites were synthesized by growing α-Fe2O3 nanoparticles on the surface of flower-like NiO nanosheets, and then characterized by cyclic voltammetry and amperometric techniques. A glassy carbon electrode (GCE) modified with the nanocomposite displayed distinctly improved response to H2O2 compared to a GCE modified with bare NiO. The H2O2 sensor, best operated at a voltage of 0.4 V (vs. Ag/AgCl) has a sensitivity of 146.98 μA·μM−1·cm−2, a 0.05 mM lower detection limit, and a linear working range that extends from 0.5 to 3 mM of H2O2. The sensor is reproducible and long-term stable even in the presence of various interfering molecules such as ascorbic acid and uric acid. [Figure not available: see fulltext.]. © 2017, Springer-Verlag Wien.

VIT Unitversity

World University root node

A non-enzymatic sensor for hydrogen peroxide based on the use of α-Fe2O3 nanoparticles deposited on the surface of NiO nanosheets

This work reports the growth of magnesium oxide (MgO) nanocubes by thermal chemical vapor deposition at various temperatures. The MgO nanocubes were investigated by X-ray diffraction, FESEM, EDAX, TEM and FTIR studies to study its various properties. The material is well-dispersed and has a cubical shape with an average size of 16 nm. XRD shows a face cubic centered structure, and SEM and TEM reveal nanocube morphology. The mechanism of the growth process is briefly detailed. The MgO nanocubes, if deposited on an overhead projector sheet, can be used as a chemoresistive sensor for hydrogen at a constant temperature of typically 200 °C and an applied voltage of 5 V. The sensor can detect hydrogen in the 3000 to 5000 ppm concentration range, and the lowest detectable concentration (at a signal-to-noise ratio of 3) is 3000 ppm. [Figure not available: see fulltext.]. © 2017, Springer-Verlag Wien.

Magnesium oxide nanocubes deposited on an overhead projector sheet: synthesis and resistivity-based hydrogen sensing capability

In this study, magnetic nanocomposites viz. SiO2@CoFe2O4 nanoparticles decorated on graphene oxide were synthesized using solvothermal and sol-gel processes. The prepared nanocomposite materials were used as magnetic adsorbents for the removal of organic and inorganic pollutants (acid black 1 dye and Cr(VI) ions as model pollutants) from aqueous solution. The structure, morphology and other physico-chemical properties of nanocomposites were characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM), X-ray photo spectroscopy (XPS), zeta potential and Fourier transform infrared (FT-IR) spectroscopy. Batch mode adsorption studies were conducted with the prepared nanocomposites to determine the maximum adsorption capacity of acid black 1 dye and Cr(VI) ions as a function of contact time, pH, adsorbent dosage and initial adsorbate concentrations. Different kinetic and isotherm models were tested to describe and elucidate the adsorption mechanisms. Based on the experimental results obtained, the synthesized materials proved to exhibit considerable potential for the removal of acid black 1 and Cr(VI) ions from aqueous solution. © 2017 Elsevier B.V.

Fulltext

Chemical Engineering Journal

Magnetic SiO 2 @CoFe 2 O 4 nanoparticles decorated on graphene oxide as efficient adsorbents for the removal of anionic pollutants from water

In this work, an efficient visible-light active BiFeWO 6 /BiOI nanocomposite was fabricated by mixing various weight percentages (1%, 2% and 3%) of BiFeWO 6 on BiOI via facile one-step wet impregnation method. The synthesized BiFeWO 6 /BiOI nanocomposite were investigated by XRD, FT-IR, FE-SEM, HR-TEM, EDAX, UV–vis DRS and BET. The photocatalytic activity of synthesized BiFeWO 6 /BiOI nanocomposite photocatalysts were assessed for the photodegradation of Rhodamine B (RhB) under visible-light illumination. The optimum 1% BiFeWO 6 /BiOI nanocomposite showed 92% efficiency of RhB after 90 min. The photoluminescence (PL) and photoelectrochemical measurements revealed that the 1% BiFeWO 6 /BiOI nanocomposite greatly enhanced the charge carrier separation and thus by slowing down the recombination rate of the photoinduced charge carriers. The radical trapping experiment inferred the h + and O 2 [rad]− as the important active species responsible for the photodegradation of RhB. The higher photocatalytic activity and recyclability revealed that the BiFeWO 6 /BiOI nanocomposite could be a promising material in wastewater treatment and other environmental remediation applications. © 2017 Elsevier B.V.

Department of Micro and Nanoelectronics

School of Electronics Engineering

Applied Surface Science

A robust visible-light driven BiFeWO 6 /BiOI nanohybrid with efficient photocatalytic and photoelectrochemical performance

An effective and sensitive non-enzymatic electrochemical glucose sensor was fabricated by the use of Ag–CuO nanocomposites, which was synthesised by a simple one step homogeneous co-precipitation route using silver nitrate and copper sulphate as precursor materials. The crystalline nature, optical properties, morphology and chemical composition of the prepared sample was determined using X-ray diffraction, diffuse reflectance ultraviolet spectroscopy, scanning electron microscope and X-ray energy dispersive spectroscopy techniques. Further the prepared composites were tested for its glucose sensing property using electrochemical technique. The electrocatalytic and electrochemical properties of the modified electrode was investigated by cyclic voltammetry. Chronoamperometric behaviour shows that the step-wise increment in current as the concentration of glucose increases from 100 to 1000 μM at a constant oxidation potential of 0.6 V(Ag/AgCl). The results indicated that the sensing properties of developed non-enzymatic biosensor shows excellent sensitivity, fast response (5 s) and good selectivity because the prepared Ag–CuO nanocomposites exhibits enhanced electrocatalytic property, fast electron transfer towards the oxidation of glucose. © 2018, © 2018 Informa UK Limited, trading as Taylor &amp; Francis Group.

Mathematics

School of Advanced Sciences

Chennai Campus

Materials Research Innovations

Electrochemical performance of Ag–CuO nanocomposites towards glucose sensing

Compressed air energy storage (CAES) represents a very attracting option to grid electric energy storage. Although this technology is mature and well established, its overall electricity-to-electricity cycle efficiency is lower with respect to other alternatives such as pumped hydroelectric energy storage. A meager heat management strategy in the CAES technology is among the main reasons of this gap of efficiency. In current CAES plants, during the compression stage, a large amount of thermal energy is produced and wasted. On the other hand, during the electricity generation stage, an extensive heat supply is required, currently provided by burning natural gas. In this work, the coupling of both CAES stages through a thermal energy storage (TES) unit is introduced as an effective solution to achieve a noticeable increase of the overall CAES cycle efficiency. In this frame, the thermal energy produced in the compression stage is stored in a TES unit for its subsequent deployment during the expansion stage, realizing an Adiabatic-CAES plant. The present study addresses the conceptual design of a TES system based on a packed bed of gravel to be integrated in an Adiabatic-CAES plant. With this objective, a complete thermo-fluid dynamics model has been developed, including the implications derived from the TES operating under variable-pressure conditions. The formulation and treatment of the high pressure conditions were found being particularly relevant issues. Finally, the model provided a detailed performance and efficiency analysis of the TES system under charge/discharge cyclic conditions including a realistic operative scenario. Overall, the results show the high potential of integrating this type of TES systems in a CAES plant. © 2017

Applied Energy

Analysis of an integrated packed bed thermal energy storage system for heat recovery in compressed air energy storage technology

We report a catalyst of N-doped graphene CuO nanocomposite, for the non-enzymatic electrocatalytic oxidation of glucose. The hybrid nanocomposite was synthesized by copper sulfate, cetyl ammonium bromide and graphite as starting materials. The synthesized composites were characterized with the techniques like X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope to study the crystalline phase and morphological structure. Based on this composite, a non-enzymatic glucose sensor was constructed. Cyclic voltammetry and chronoamperometry methods were done to investigate the electrocatalytic properties of glucose in alkaline medium. For glucose detection, the fabricated sensor showed a linear response over a wide range of concentration from 3 to 1000 µM, with sensitivity of 2365.7 µA mM−1 cm−2 and a fast response time of 5 s. The designed sensor exhibited negligible current response to the normal concentration of common interferents in the presence of glucose. All these favorable advantages of the fabricated glucose sensor suggest that it may have good potential application in biological samples, food and other related areas. © 2017, Springer-Verlag GmbH Germany.

Applied Physics A: Materials Science and Processing

A novel CuO–N-doped graphene nanocomposite-based hybrid electrode for the electrochemical detection of glucose

The aim of this paper is to study graphene plasmonics for THz applications. The range of absorbance of electromagnetic waves on a graphene monolayer is investigated to understand the plasmonic behaviour of graphene on patterned SiO2 substrate. Simulation results show that absorption range and intensity gets altered according to the graphene doping level, periodicity of grating and dielectric media used on the patterned substrate. These results show the plasmonic effect on graphene has a tuneable behaviour, and it can be utilised for the future plasmonic sensors and optoelectronics devices in the mid-infrared region. © 2017 IEEE.

Electronics

2017 International Conference on Nextgen Electronic Technologies: Silicon to Software (ICNETS2)

Enhanced absorption in graphene on periodic patterned SiO2 substrate

This article presents the thermal stability testing results of five high-temperature phase change materials for their potential use in latent thermal energy storage systems. The tested materials are eutectic metal alloys [Zn84Al8.7Mg7.3, Zn88.7Al11.3, Zn92.2Mg7.8, Zn72Mg28 and Mg70Zn24.9Al5.1 (at.%)] with phase change temperatures in the range of 340–380 °C. The five candidates have been selected not only for their adequate melting temperature and high fusion enthalpy, but also for the availability and appropriate costs [2–3 $/kg (Rodríguez-Aseguinolaza in J Therm Anal Calorim 117:93–99, 2014)] of Zn, Al, and Mg primary metals. As it is well known and demonstrated in previous works, the use of metal alloys presents noticeable benefits on the TES solutions based on their implementation. The particular advantages introduced by the Zn–Mg–Al system in terms of maximization of the storage capacity and appropriate operation temperature justify a deeper analysis of these alloys, previously studied, for a complete thermal performance. In this work, with the aim of reproducing a realistic thermal cycling behaviour in real heat storage applications, the selected candidates have been subjected to short- and long-term thermal cycling tests by 100 and 500 melting/solidification cycles, respectively. These experiments permitted to detect any potential evolution of the thermodynamic and structural properties of the investigated materials that could be sign of an undesirable chemical decomposition or phase segregation. As a conclusion, the Zn84Al8.7Mg7.3, Zn88.7Al11.3, Mg72Zn28 and Mg70Zn24.9Al5.1 alloys have been identified as very promising latent heat storage materials due to their long-term thermal stability. © 2017, Akadémiai Kiadó, Budapest, Hungary.