Faculty Publications
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Item Microwave synthesized nanostructured TiO 2 -activated carbon composite electrodes for supercapacitor(Elsevier B.V., 2012) Muthu, M.; Bhat, D.K.Electrochemical properties of a supercapacitor based on nanocomposite electrodes of activated carbon with TiO 2 nano particles synthesized by a microwave method have been determined. The TiO 2 /activated carbon nanocomposite electrode with a composition of 1:3 showed a specific capacitance 92 Fg -1 . The specific capacitance of the electrode decreased with increase in titanium dioxide content. The p/p symmetrical supercapacitor fabricated with TiO 2 /activated carbon composite electrodes showed a specific capacitance of 122 Fg -1 . The electrochemical behavior of the neat TiO 2 nanoparticles has also been studied for comparison purpose. The galvanostatic charge-discharge test of the fabricated supercapacitor showed that the device has good coulombic efficiency and cycle life. The specific capacitance of the supercapacitor was stable up to 5000 cycles at current densities of 2, 4, 6 and 7 mA cm -2 . © 2012 Elsevier B.V.Item NiWO4-ZnO-NRGO ternary nanocomposite as an efficient photocatalyst for degradation of methylene blue and reduction of 4-nitro phenol(Elsevier Ltd, 2017) Mohamed, M.; Shenoy, U.S.; Bhat, D.K.A novel NiWO4-ZnO-NRGO ternary nanocomposite has been efficiently synthesized by decorating nitrogen doped reduced graphene oxide (NRGO) with zinc oxide and nickel tungstate nanoparticles via a facile microwave irradiation technique and its capability to catalyze photodegradation of methylene blue (MB) dye in aqueous solution and reduction of 4-nitro phenol (4-NP) to 4-amino phenol (4-AP) using sodium borohydride was explored. The as-synthesized nanocomposite was characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET) analysis, energy dispersive X-ray (EDX) analysis, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and diffuse reflectance spectroscopy (DRS) techniques. The photocatalytic activity of the as-synthesized nanocomposite estimated through the photodegradation of MB under visible light irradiation showed 9 times improvement over pure NiWO4. It also showed excellent catalytic activity in reduction of 4-NP to 4-AP. The material also showed excellent stability and reusability. The entire study revealed that the novel NiWO4-ZnO-NRGO ternary nanocomposite can act as a promising bifunctional photocatalyst for environmental remediation and industrial application. © 2017 Elsevier LtdItem A direct approach towards synthesis of copper nanofluid by one step solution phase method(Elsevier B.V., 2024) Kumar, S.P.; Shenoy, U.S.; Bhat, D.K.We adopted a simple one step approach to synthesize copper nanofluids by reduction of copper sulphate with fructose. The solution phase synthetic technique led to the formation of copper particles whose size was restricted to the nanodimensions by use of sodium lauryl sulphate. We studied the effect of various parameters on the formation and dispersion of the copper nanoparticles in the base fluid containing a 1:1 mixture of water and ethylene glycol. The resulting Newtonian nanofluid was found to be highly stable with increased thermal conductivity. Thus, the applied technique is found to be simple, economic, and extendable to other class of materials to obtain stable dispersions of nanofluids for heat transfer applications. © 2024 Elsevier B.V.Item Design, synthesis, and characterization of stable copper nanofluid with enhanced thermal conductivity(Elsevier Ltd, 2024) Bhat, D.K.; Kumar, S.P.; Shenoy, U.S.Nanofluids, which are liquids that contain small particles with dimensions in the nanometer range, have gained significant attention in recent years due to their enhanced thermal properties in various applications such as thermal management and energy conversion. This article aims to provide insights into the design and optimization of copper nanofluid synthesis and it investigates the thermal and rheological properties at varying concentrations of nanoparticles and temperature. The method involves simultaneous use of fructose as reducing agent and polyvinyl pyrrolidone as stabilizing agent to enable synthesis of copper nanofluid from copper sulphate. The resulting Newtonian nanofluid had a stability of 3 months with enhanced thermal conductivity of up to ∼500 % compared to 1:1 mixture of water and ethylene glycol which served as the base fluid. The approach is suitable for producing large volume of nanofluid using cost effective materials. © 2024 Elsevier LtdItem Exploring the potential of CoAl2O4 nanoflakes in supercapacitor applications(Elsevier B.V., 2025) Ramesh, T.P.; Shenoy, U.S.; Bhat, D.K.Spinel structured nanoparticles with binary and ternary metal oxide combinations have recently been identified as a viable material for use in supercapacitors. Two mixed-valence metal cations provide easy electron transport between various metal cations. High-performance CoAl2O4 spinel nanoflakes were synthesized using a mixed-solvent solvothermal method, followed by calcination. First principles calculations revealed high density of states near the Fermi level indicating its potential for supercapacitor applications. These nanostructured materials were then experimentally explored as promising electrode candidates for supercapacitor applications, using a 2 M KOH aqueous electrolyte. The results were impressive: the material demonstrated a high specific capacitance of 851.9 F/g at a current density of 1 A/g and the fabricated supercapacitor exhibited a power density of 14940.0 W/kg at a current density of 12 A/g. Even under more demanding conditions, the electrode maintained strong durability, in terms of cyclic stability along with high energy and power density values making it a strong contender for next-generation energy storage devices. © 2025 Elsevier B.V.