Qualification: 
Ph.D
k_nikhil@cb.amrita.edu

Dr. Nikhil K. Kothurkar joined Amrita in 2007 after completing postdoctoral work in the USA. 

He received a B. E. in Polymer Engineering from Maharashtra Institute of Technology, University of Pune. In 1999, he moved to Gainesville, Florida, USA, to pursue graduate studies in the University of Florida's Materials Science and Engineering Department where he worked as a graduate research assistant under the guidance of Dr. Anthony B. Brennan developing inorganic-organic particulate nanocomposites for ultrafast infrared optical sensor protection from destructive laser attacks. He graduated with a Ph. D. in 2004, after defending his dissertation entitled, "Solid State Cadmium Sulfide-Polymer Nanocomposites." 

After graduation, he accepted a position as a Postdoctoral Research Associate in the Solar Energy and Energy Conversion Laboratory, University of Florida, for two years. There he developed rugged and crack-free sol-gel photocatalyst coatings on metal and ceramic substrates. He also worked on a project to develop lower cost hydrocarbon polymer electrolyte membranes for fuel cells. He then worked for a year as a Research Scientist at the Clean Energy Research Center, University of South Florida in the fields of photocatalysis and its applications in biomedical devices, and hydrogen production by biomass gasification.

Dr. Kothukar's fields of interest are nanomaterials, photocatalysis, biomedical materials and devices, low cost water treatment and alternative energies. Currently he is teaching Environmental Science and Engineering and Materials Science at Amrita.

Publications

Publication Type: Journal Article

Year of Publication Title

2019

R. Senthilkumar, S Raj, M., Ramakrishnan, S., Dr. Duraisamy Kumaresan, and Dr. Nikhil K. Kothurkar, “Thermally Reduced Graphene Oxide as a Counter Electrode Material for Dye-Sensitized Solar Cells.”, J Nanosci Nanotechnol, vol. 19, no. 4, pp. 2158-2165, 2019.[Abstract]


In this present study, a highly conductive thermally reduced graphene oxide (TRGO) was synthesized by a low temperature thermal reduction method using RF heating, under an argon-hydrogen atmosphere. The crystallinity and morphology were examined by X-ray diffraction, Raman spectroscopy and TEM analysis. The chemical structure including the functional groups present on TRGO was studied using X-ray photoelectron spectroscopy and FTIR analysis. The studies reveal that thermal reduction of graphene oxide was successful under the experimental conditions and that the TRGO had high crystallinity. Further, the performance of the as-prepared TRGO was tested as a counter electrode (CE) in a dye-sensitized solar cell (DSSC). The maximum power conversion efficiency (PCE) obtained was 4.86% for TRGO under one sun illumination, which is comparable to that of a platinum CE-based DSSC (5.24%). The electrocatalytic activity and electron transfer kinetics were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel measurements. The series resistance () and charge transfer resistance () values were found to be 35.4 Ωcm and 56.40 Ωcm for TRGO. The results reveal that the TRGO had an electrocatalytic performance similar to that of Pt, making TRGO-CEs promising alternatives to the conventional Pt-CEs in DSSCs.

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2019

R. Senthilkumar, Balu, M., Ramakrishnan, S., Ramamurthy, P. C., Batabyal Sudip Kumar, Dr. Duraisamy Kumaresan, and Dr. Nikhil K. Kothurkar, “Molybdenum disulfide/reduced graphene oxide hybrids with enhanced electrocatalytic activity: An efficient counter electrode for dye-sensitized solar cells”, Journal of Electroanalytical Chemistry, vol. 847, p. 113236, 2019.[Abstract]


Development of low cost, metal-free electrodes for photovoltaic applications is critical to meet future energy demands. In this work, the one-step hydrothermal synthesis and electrocatalytic activity of molybdenum disulfide/reduced graphene oxide (MoS2-rGO) hybrids are investigated as high-performance counter electrode materials for dye-sensitized solar cells (DSSCs). The crystal structure and morphology analyses of as-prepared MoS2-rGO hybrids indicated the presence of MoS2 nanostructures having a petal-like morphology on rGO sheets. Raman spectroscopy provided evidence for weak Van der Waals interactions between MoS2 and rGO layers along with a low defect density. DSSCs made with counter electrodes (CEs) of MoS2-rGO hybrids, showed an impressive power conversion efficiency of 7.83% surpassing the DSSCs with CEs of pristine MoS2 (5.97%) and the conventional Pt (7.57%). The cyclic voltammetry and electrochemical impedance studies have shown that the incorporation of reduced graphene oxide in the MoS2 nanostructures significantly decreased the charge transfer resistance and improved the electrocatalytic activity of their CEs. This is partly attributed to the morphology of the hybrid in which the petal-like MoS2 nanostructures on the rGO sheets provided numerous catalytic sites, which, in turn, enhanced the charge transfer across the CE providing a synergistically high performance. These results have indicated that the MoS2-rGO hybrids are promising alternatives to the conventional Pt-based CEs in DSSCs.

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2018

M. S. Kumar, Yasoda, K. Y., Batabyal Sudip Kumar, and Dr. Nikhil K. Kothurkar, “Carbon-polyaniline nanocomposites as supercapacitor materials”, Materials Research Express, vol. 5, 2018.[Abstract]


Polyaniline-based nanocomposites containing carbon nanotubes (CNT), reduced graphene oxide (rGO) and mixture of CNTs and rGO were synthesized. UV-visible spectroscopy and FT-IR spectroscopy confirmed the presence of polyaniline (PANi) and carbon nanomaterials. Scanning electron microscopy revealed that the neat PANi had a granular morphology, which can lead to increased electrical resistance to high interfacial resistance between domains of PANi. Cyclic voltammetry of PANi, PANi/CNT, PANi/rGO and PANi/CNT/rGO showed that in general, specific capacitance reduces with increasing scan rate within the range (10-100mVs-1). Also the specific capacitance values at any given scan rate within the above range, for PANi, PANi/CNT, PANi/rGO and PANi/CNT/rGO were found to be in increasing order. The specific capacitance of the PANi/CNT/rGO nanocomposite as measured by galvanostatic charge-discharge measurements, was found to be 312.5 F g-1. The introduction of the carbon nanomaterials (CNTs, rGO) in PANi in general leads to improved specific capacitance, while the addition of CNTs and rGO together leads to synergistic improvement in the specific capacitance, owing to a combination of factors. ©2018 IOP Publishing Ltd. More »»

2016

E. J. Jelmy, Ramakrishnan, S., and Dr. Nikhil K. Kothurkar, “EMI shielding and microwave absorption behavior of Au-MWCNT/polyaniline nanocomposites”, Polymers for Advanced Technologies, 2016.[Abstract]


Electrically conducting Au-multiwalled carbon nanotube/polyaniline (Au-MWCNT/PANi) nanocomposites were synthesized by two different ways: (1) by direct mixing of MWCNT/PANi and Au nanoparticles (Au-MWCNT/PANi-1) and (2) by in situ polymerization of aniline in the presence of both MWCNTs and Au nanoparticles (Au-MWCNT/PANi-2). The higher electrical conductivity of Au-MWCNT/PANi-2 compared with the other samples (PANi, MWCNT/PANi, Au-MWCNT/PANi-1) is supported by the red shifts of the UV-vis bands (polaron/bipolaron), the high value of the -NH+= stretch peak (Fourier transform infrared spectroscopy studies), the high % crystallinity (X-ray diffraction analysis) and more uniform dispersion of the Au NPs in the material. The performance of the samples in electromagnetic interference (EMI) shielding and microwave absorption was studied in the X-band (8-12GHz). For all the samples, absorption was the dominant factor contributing toward the EMI shielding. Au-MWCNT/PANi-2 showed the best performance with a total shielding effectiveness of -16dB [averaged over the X-band (GHz)] and a minimum reflection loss of -56.5dB. The higher dielectric properties resulting from the heterogeneities because of the presence of nanofillers and the high electrical conductivity lead to the increased EMI shielding and microwave absorption. The results show the significance of both Au nanoparticles and method of synthesis on the EMI shielding performance of MWCNT/PANi composites.

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2013

E. J. Jelmy, Ramakrishnan, S., Rangarajan, M., and Dr. Nikhil K. Kothurkar, “Effect of different carbon fillers and dopant acids on electrical properties of polyaniline nanocomposites”, Bulletin of Materials Science, vol. 36, pp. 37-44, 2013.[Abstract]


Electrically conducting nanocomposites of polyaniline (PANI) with carbon-based fillers have evinced considerable interest for various applications such as rechargeable batteries, microelectronics, sensors, electrochromic displays and light-emitting and photovoltaic devices. The nature of both the carbon filler and the dopant acid can significantly influence the conductivity of these nanocomposites. This paper describes the effects of carbon fillers like carbon black (CB), graphite (GR) and muti-walled carbon nanotubes (MWCNT) and of dopant acids like methane sulfonic acid (MSA), camphor sulfonic acid (CSA), hydrochloric acid (HCl) and sulfuric acid (H2SO4) on the electrical conductivity of PANI. The morphological, structural and electrical properties of neat PANI and carbon-PANI nanocomposites were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and the four-point probe technique, respectively. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies were also conducted for different PANI composites. The results show that PANI and carbon-PANI composites with organic acid dopants show good thermal stability and higher electrical conductivity than those with inorganic acid dopants. Also, carbon-PANI composites generally show higher electrical conductivity than neat PANI, with highest conductivities for PANI-CNT composites. Thus, in essence, PANI-CNT composites prepared using organic acid dopants are most suitable for conducting applications. © Indian Academy of Sciences.

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2013

E. J. Jelmy, Ramakrishnan, S., Dr. Sriram Devanathan, Dr. Murali Rangarajan, and Dr. Nikhil K. Kothurkar, “Optimization of the conductivity and yield of chemically synthesized polyaniline using a design of experiments”, Journal of Applied Polymer Science, vol. 130, pp. 1047-1057, 2013.[Abstract]


<p>The electrical conductivity and yield of polyaniline (PANi) were optimized using a design of experiments (DOE). PANi samples were synthesized by the chemical oxidative polymerization of aniline using methane sulfonic acid as the dopant acid and ammonium persulfate as the oxidant. The main factors in the synthesis of PANi that can affect the conductivity were identified as (i) the concentration of dopant acid, (ii) oxidant-to-monomer ratio, and (iii) the addition rate of oxidant to monomer. Using a Box-Behnken DOE method the regression equation, main effects plots, contour plots, and optimization plots for conductivity and yield were generated and analyzed. Under the optimized conditions of dopant acid concentration of 0.9M, an oxidant addition rate of 30 mL/h and an OM ratio of 0.9, PANi with a conductivity of 1.95 S/cm and yield of 95% was obtained. The observed trends in the four-point probe conductivity measurements were correlated with the polymer structure using fourier transform infrared spectroscopy, X-ray diffraction studies, and scanning electron microscopy. © 2013 Wiley Periodicals, Inc.</p>

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Publication Type: Conference Paper

Year of Publication Title

2016

S. O. Wietlisbach, Ram, K., Dr. Nikhil K. Kothurkar, Nair, R., and Harigovind, S., “Performance of a vertical subsurface flow constructed wetland in treating biomethanation effluent”, in GHTC 2016 - IEEE Global Humanitarian Technology Conference: Technology for the Benefit of Humanity, Conference Proceedings, 2016, pp. 847-853.[Abstract]


A system consisting of a biomethanation plant whose effluent is fed to a constructed wetland, can serve as a multipurpose waste-to-wealth system. It can safely treat domestic sewage, and organic solid waste while providing cooking fuel (biogas), reclaimed water and plant biomass. This study evaluates the performance of an outdoor 30 LPD constructed wetland setup in treating the effluent from an existing biomethanation reactor fed with blackwater and organic solid waste. The constructed wetland units contained Vetiver zizanioides and Canna indica and earthworms (Lumbricus terrestris) and the changes in BOD, NH4, NO2, P, total solids (TS) and pH of the effluent were measured. The constructed wetlands were effective in reduction of BOD, N and P. The effect of bed depth and series arrangement of wetland units was studied. The system was modeled using a 1st order differential model assuming plug flow and steady state. The model predictions partly matched the measured values and the trends and the sources of deviations have been discussed. Overall, the performance of vertical subsurface flow constructed wetlands for treating biomethanation effluent was found to be highly encouraging and it warrants further studies to realize the full waste-to-wealth potential of multipurpose biomethanation-constructed wetland systems. © 2016 IEEE.

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