Faculty Publications
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Item Anomalous codeposition and characterization of Zn-Fe alloy(2006) Chitharanjan Hegde, A.; Thangaraj, V.A sulphate bath containing ZnSO4. 7H2O, FeSO 4.VH2O, ascorbic acid and hexamine is proposed for the deposition of bright iron rich Zn-Fe alloy onto mild steel substrate. Due to inherent character of Fe+2 ions to oxidize into Fe+3, the main part of the current applied during electroplating is spent on the reduction of ferric ions into ferrous ions. This results in decrease of cathode current efficiencies and will give instability to the bath. Hence the present work has been carried out with ascorbic acid as antioxidant with hexamine as brightener. Hull cell studies were used to optimize the concentrations of the all constituents in the bath. The influence of bath constituents, current density (c.d.) and pH on the appearance and composition of the deposits were examined. A stable bath has been formulated for deposition of Zn-Fe alloy having about 60% Fe for automobile application, by choosing very less zinc content (8 g/1) in the bath. The bath exhibits the anomalous codeposition with preferential deposition of zinc as characterized by any Zn-Fe group metal alloys. It was found that the due to less Zn+2 ions in the bath, the deposition of more noble iron has not been inhibited resulting in formation of Fe rich alloy. The compositions of the deposit at different conditions were related with their brightness, thickness, hardness and their corrosion behavior. Increase of the bath temperature enhanced the percentage of more readily depositable metal (zinc) in the deposit. Thickness of the deposit increased with c.d. as a characteristic of its iron content. A very thin and bright deposit obtained at about 1 A.dm-2 is found to have about 53% iron and a thick and bright deposit at 4.0 A.dm-2 contains about 80% iron. Photomicrograph observation showed that the phase structures of the deposits are influenced by the applied c.d. and pH of the bath. The proposed bath found to give a smooth and uniform deposit (64% Fe) with good performance against corrosion at about 2.0 A.dm-2. A stable acid sulphate bath has been proposed for iron rich Zn-Fe alloy plating for automobile applications.Item Synthesis of copper nanofluids using ascorbic acid reduction method via one step solution phase approach(ASTM International, 2012) Shenoy, S.U.; Nityananda Shetty, A.N.A simple one step solution phase approach to synthesize copper nanofluids has been developed, involving simultaneous in situ synthesis of nanoparticles and their dispersion in the base fluid. Copper nitrate has been reduced using ascorbic acid in ethylene glycol under thermal as well as microwave conditions. Sodium lauryl sulfate has been used to control the size of the particle as well as to act as a stabilizing agent. The effect of ratio of the reactants, pH, power of microwave, reaction time, and dilution on the size of the particles has been studied using X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. The characterization of the fluids has also been done using Fourier transform infrared spectrometry, ultraviolet-visible spectroscopy, selected area electron diffraction, and energy dispersive X-ray analysis. The thermal conductivity and viscosity of the fluid were also measured at various particle concentrations. The copper particles in the fluid were found to have size less than 50nm and were well dispersed in the fluid. Thus this method was found to preserve the advantages of the polyol process and aqueous chemical reduction method as well. The fluid was stable up to 5 weeks under stationary conditions at room temperature. This method employs fast, inexpensive, extendible process for the synthesis of copper nanofluids and also overcomes the drawbacks of two step process. Copyright © 2012 by ASTM International.Item Effect of dopants on the energy storage performance of reduced graphene oxide/polyaniline nanocomposite(Elsevier Ltd, 2019) Viswanathan, A.; Nityananda Shetty, A.N.The nanocomposites comprising of reduced graphene oxide (rGO) and polyaniline (PANI) were synthesized by facile insitu single step chemical methods, with glacial acetic acid (AA) and methane sulphonic acid (MSA) as dopants for PANI. The rGO/PANI nanocomposites synthesized with the similar weight percentages of constituents exhibited better electrochemical performance in the presence of MSA than in the presence of AA, in the real two-electrode supercapacitor cell system. The nanocomposite of weight percentages of rGO-6.7%, and PANI-93.33% (GP93MSA), with MSA as dopant exhibited a remarkable feature of increase in energy storage when the number of cycles was increased. It exhibited a maximum enhancement of 237.44% in its energy storage performance, after 13600 cycles as compared to the performance before the onset of cyclic test. The high performances obtained with GP93MSA include high specific capacitance of 512.82 F g?1, specific capacity of 615.38 C g?1, energy density of 102.56 W h kg?1 and a power density of 1.8954 kW kg?1 at 1 A g?1. The energy density of the supercapacitor with GP93MSA as the electrode material, is of the same order as that of Li-ion batteries. Also, GP93MSA showcased good cyclic stability up to 23000 cycles. © 2019 Elsevier LtdItem Unveiling the Versatile Applications of Cobalt Oxide-Embedded Nitrogen-Doped Porous Graphene for Enhanced Energy Storage and Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid(Institute of Physics, 2024) Agadi, N.P.; Hegde, S.S.; Teradal, N.L.; Badekai Ramachandra, B.R.; Seetharamappa, J.The advancement of electrode materials is essential for addressing the energy and biomedical challenges. A multi-functional approach was employed to create a new electrode material of cobalt oxide-embedded nitrogen-doped porous graphene (Co3O4@NpG) for sensing and energy storage applications. In the present study, we have fabricated a new electrochemical sensing platform based on Co3O4@NpG. The sensing performance and selective detection capability of the demonstrated sensor was optimized and tested by determining dopamine (DA), uric acid (UA), and ascorbic acid (AA) simultaneously in analyte fortified biological samples. The sensing response is noticed to be linearly dependent upon the concentration of AA, DA, and UA in the range of 0.1-450, 0.1-502, and 0.2-396 μM, respectively. This material also showed good electrochemical energy storage performance when assessed as a supercapacitor electrode. The Co3O4@NpG electrode material showcased a remarkable specific capacitance of 314.58 Fg−1, an energy density of 10.06 Wh kg−1 at a power density of 240 Wkg−1 at 0.5 Ag−1, in a 6 M KOH electrolyte, along with excellent long-term cycling stability. Hence, the material Co3O4@NpG stands out as a promising multifunctional electrode candidate, excelling in the precise simultaneous detection of critical biomolecules besides exhibiting superior energy storage performance. © 2024 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited. All rights, including for text and data mining, AI training, and similar technologies, are reserved.Item An iron(iii) oxide-anchored conductive polymer-graphene ternary nanocomposite decorated disposable paper electrode for non-enzymatic detection of serotonin(Royal Society of Chemistry, 2024) Prashanth, S.; Aziz, R.A.; Raghu, S.V.; Shim, Y.-B.; Prasad, K.; Vasudeva Adhikari, A.V.Serotonin, also known as 5-hydroxytryptamine (5-HT), is an important neurotransmitter that regulates many physiological processes. Both low and high concentrations of 5-HT in the body are associated with several neurological disorders. Hence, there is an urgent need to develop fast, accurate, reliable, and cost-effective disposable sensors for 5-HT detection. Herein, we report the sensing of 5-HT using a disposable paper-based electrode (PPE) modified with a ternary nanocomposite comprising poly(pyrrole) (P(py)), reduced graphene oxide (rGO), and iron oxide (Fe2O3). The sensor material was well characterized in terms of its structural, morphological, and chemical attributes using electron microscopy, spectral techniques, and electrochemical studies to prove the robust formation of the electroactive ternary nanocomposite and its suitability for 5-HT detection. The developed sensor exhibited an impressive limit of detection (LOD) of 22 nM with a wide linear range of 0.01 to 500 ?M, which falls in the recommended clinically relevant range. The analytical recovery, spike sample analysis, and interference studies with ascorbic acid (AA), uric acid (UA), and epinephrine (E) showed satisfactory results, wherein the sensor could detect simultaneously both 5-HT and dopamine (DA). The potential practical utility of the developed sensor was further assessed by quantifying the concentration of 5-HT in the brain samples of Drosophila melanogaster, a versatile genetic model organism employed for modeling different neural disorders in humans, and validated by gold-standard HPLC-UV experiments. The as-fabricated single-run disposable sensor with a ternary nanocomposite exhibits excellent stability with good reproducibility and is a promising platform for identifying clinically relevant concentrations of 5-HT. © 2024 RSC.Item Electrochemical determination of ascorbic acid using carbon paste electrode modified with cobalt oxide nanoparticles(Elsevier Ltd, 2025) G, B.A.; Bhat, R.S.; Hegde, S.S.; Badekai Ramachandra, B.R.The present work introduces a cobalt oxide nanoparticle-modified carbon paste electrode (Co2O3/CPE) as a simple, low-cost, and efficient platform for the electrochemical determination of ascorbic acid. This study shows the excellent selectivity of the electrode against common interferents, linear detection range, low detection limit, and reproducibility, making it a promising substitute to expensive noble-metal-based sensors for real-sample ascorbic acid analysis. An eco-friendly novel electrochemical study is carried out to detect ascorbic acid (ACA) using a Congo red (CR) modified cobalt oxide nanoparticle (Co3O4) composite carbon paste electrode (CRMCCCPE). This CRMCCCPE significantly enhanced the electrochemical performance for the selective and sensitive analysis of ACA. The elemental analysis of the synthesised Co3O4 by EDX (energy-dispersive X-ray spectroscopy), the phase structure through XRD (X-ray diffraction), and the absorbance peaks by Raman spectrometry with 37.41 nm. The surface topography by FESEM (field emission scanning electron microscopy). Voltammetric techniques and EIS (electrochemical impedance spectroscopy) are investigated for the electrochemical redox response of ACA in phosphate buffer (PB) of 0.1 M concentration across the various ranges of pH at a 0.1 V/s scan rate. The ACA detection through the impact of pH, impact of scan rate, concentration, interference, simultaneous detection, and real sample analysis, indicating CV at 0.2 ?M to 2.4?M, DPV at 0.2 ?M to 2.6?M and LSV at 0.2 ?M to 2.4?M, with a lower limit of detection (LOD) were CV is 1.4 ??, DPV is 0.7 ?M, and LSV is 1.5 µ? and quantification (LOQ) was CV is 4.8 ?M, DPV is 2.6 µM, and LSV is 5.0 ?M. The fabricated CRMCCCPE exhibits the novelty of excellent stability, reproducibility, and repeatability, suggesting its potential application for the electrochemical recognition of ACA in complex matrices. The results indicate that CRMCCCPE is a reliable and effective platform for voltammetric sensing of ACA, offering promising applications in food quality control and medicinal diagnostics. © 2025 Elsevier Ltd.