@article {46907, title = {2-D to 3-D conversion of WO3 nanostructures using structure directing agent for enhanced NO2 gas sensing performance}, journal = {Sensors and Actuators A-Physical}, volume = {304}, year = {2020}, month = {APR }, pages = {111882}, type = {Article}, abstract = {

An exotic 3-D tungsten oxide (WO3) microflower was synthesized via low-cost and environmental-friendly hydrothermal strategy. The effect of structure-directing agent on the formation of 3-D microflowers from a 2-D nanosheets of WO3 and its gas sensing behavior are investigated. The assynthesized WO3 powder was used in morphological, structural and phase studies by X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The WO3 samples were found to be polycrystalline with monoclinic crystal structure. The SEM micrographs revealed the formation of 3-D microflowers made up of two-dimensional (2-D) multi-directional dendritic nanoplates. The potassium hydroxide (KOH) acts as a structure-directing agent in the formation of 3-D microflowers of WO3 sample. To further understand the formation of 3-D microflowers of WO3 sample, concentration-dependent experiments were carried out by varying KOH concentration and the formation mechanism was investigated. The synthesized WO3 microstructures were subjected to detailed gas sensing tests for different gases at an optimized temperature. A selective, sensitive gas response was obtained for WO3 gas sensor. The lower detection limit is about 1 ppm at 150 degrees C working temperature for an optimized WO3 gas sensor. The gas sensing results indicate that the 3-D microflower-like WO3 nanostructures are highly promising for applications as gas sensors. (C) 2020 Published by Elsevier B.V.

}, keywords = {Microflowers, NO2 detection, WO3}, issn = {0924-4247}, doi = {10.1016/j.sna.2020.111882}, author = {Beknalkar, S. A. and Patil, V. L. and Harale, N. S. and Suryawanshi, M. P. and Patil, A. P. and Patil, V. B. and Kim, J. H. and Patil, P. S.} } @article {47715, title = {Construction of IrO2@Mn3O4 core-shell heterostructured nanocomposites for high performance symmetric supercapacitor device}, journal = {Journal of Alloys and Compounds}, volume = {887}, year = {2021}, month = {DEC }, pages = {161328}, type = {Article}, abstract = {In the present work, we have designed and synthesized nanocomposite of IrO2@Mn3O4 with two-step simple and scalable chemical routes. In this route, nanofibers of IrO2 were synthesized by a single nozzle electrospinning technique onto which Mn3O4 was overlaid by a simple SILAR route. The ratio of Mn3O4 and IrO2 was varied by varying the SILAR cycles onto electrospun IrO2 thin film as 20, 40, 60, and 80 cycles. The structural, morphological, and energy storage performance of IrO2@Mn3O4 composite elec-trodes were investigated. A 2 V kinetic potential with a rectangular-shaped cyclic voltammogram was observed for the IrO2@Mn3O4 electrodes. Moreover, the specific capacitance of 1027 F/g at 1 mA/cm(2) was observed for the optimized electrode which is superior as compared with other electrodes. The opti-mized electrode showed better current and voltage than the individual compounds which might be due to the synergic effect of IrO2 and Mn3O4. Finally, a PVA-LiClO4 gel electrolyte-based solid-state IrO2@ Mn3O4//IrO2@Mn3O4 symmetric device was fabricated. The symmetric device possessed an energy density of 81 Wh/kg with a power delivery of 714 W/kg which was capable to light up a green LED. Hence, the 2D transition metal oxides laminated on 1D metal oxides with high conductivity can be promising electrodes for future research. (C) 2021 Elsevier B.V. All rights reserved.}, keywords = {And nanoflakes, Charge storage kinetics, Electrochemical properties, electrospinning, IrO2@Mn3O4 nanocomposite, nanofibers, SILAR}, issn = {0925-8388}, doi = {10.1016/j.jallcom.2021.161328}, author = {Beknalkar, S. A. and Teli, A. M. and Harale, N. S. and Shin, J. C. and Patil, P. S.} } @article {47030, title = {Fabrication of high energy density supercapacitor device based on hollow iridium oxide nanofibers by single nozzle electrospinning}, journal = {Applied Surface Science}, volume = {546}, year = {2021}, month = {APR }, pages = {149102}, type = {Article}, abstract = {

Herein, we have synthesized iridium oxide (IrO2) nanofibers using electrospinning technique and optimization of annealing temperature is undertaken in order to obtain high quality IrO2 nanofibers. The annealing temperature is varied as 200, 300, 400 and 500 degrees C. The synthesized material has hollow nanofibrous morphology with average diameter similar to 45 nm. The formed nanofibers are amorphous in nature. The X-ray Photoelectron Spectroscopy (XPS) result revealed that synthesized iridium is in +4 oxidation state. The electrochemical performance of IrO2 electrodes showed 2 V potential window in three electrode system using 1 M Sodium sulphate (Na2SO4) aqueous electrolyte. The maximum specific capacitance is obtained for sample annealed at 400 degrees C (705F/g at 1 mA/cm(2)) which is due to the well-developed morphology with complete removal of polymer content. Moreover, a novel solid state symmetric IrO2/IrO2 supercapacitor with a high operating voltage of 2 V is built. The symmetric supercapacitor exhibits an energy density of 59 Wh/kg at a power density of 714 W/kg and an excellent cycling stability. These results demonstrate the potentialities of using IrO2 for symmetric supercapacitor for building high energy and power density devices.

}, keywords = {Aqueous electrolyte, Hollow iridium oxide nanofibers, Symmetric supercapacitor}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2021.149102}, author = {Beknalkar, S. A. and Teli, A. M. and Harale, N. S. and Patil, D. S. and Pawar, S. A. and Shin, J. C. and Patil, P. S.} } @article {47716, title = {Hierarchical ITO nanofibers coated Mn3O(4) nanoplates core-shell nanocomposites for high performance all-solid-state symmetric supercapacitor device}, journal = {Ceramics International}, volume = {47}, year = {2021}, month = {NOV }, pages = {29771-29785}, type = {Article}, abstract = {We have made a first attempt to build a novel Tin doped indium oxide@Manganese oxide (ITO@Mn3O4) nanocomposite electrode to overcome the detriments of Mn3O4 such as low conductivity and small potential window. Herein, we have synthesized the ITO@Mn3O4 nanocomposite by growing Mn3O4 nanoplates over ITO nanofibers synthesized by electrospinning technique. Benefitted from, the high conductivity and negative operating potential window of ITO exceptionally increased in the electrochemical performance of ITO@Mn3O4 was observed. The specific capacitance of optimized ITO@Mn3O4 nanocomposite reached up to 823 F/g at 1 mA/ cm2 in a wide potential window of 2 V using Na2SO4 electrolyte. To determine the practical feasibility an ITO@Mn3O4//ITO@Mn3O4 all-solid-state symmetric device was developed, which operated very well in a 2.2 V voltage window. It was found to deliver a maximum energy density of 88 Wh/kg and a power density of 550 W/ kg. This novel composite inferred the significance of using simple design to build a high-performance device.}, keywords = {electrospinning, ITO@Mn3O4 nanocomposite, PVA-LiClO4, SILAR, Solid-state symmetric device}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2021.07.149}, author = {Beknalkar, S. A. and Teli, A. M. and Harale, N. S. and Pawar, K. K. and Patil, D. S. and Shin, J. C. and Patil, P. S.} } @article {47443, title = {Supercapacitive performance of SILAR grown Mn3O4 nanoclusters: effect of cationic precursor concentration}, journal = {Chinese Journal of Physics}, volume = {72}, year = {2021}, month = {AUG}, pages = {145-158}, type = {Article}, abstract = {

Herein, we have investigated the effect of cationic precursor (manganese chloride tetrahydrate) concentration on the electrochemical performance of successive ionic layer adsorption and reaction (SILAR)-deposited Mn3O4\ thin films. The concentration of the cationic precursor was varied from 0.05 to 0.15 M, and its effect on physicochemical and electrochemical properties was studied. X-ray diffraction and X-ray photoelectron spectroscopy analyses confirmed that Mn3O4\ has a tetragonal structure with Mn2+\ and Mn3+\ oxidation states. SEM micrographs revealed that nanoclusters of Mn3O4\ with an average size of ~200 nm were formed. Moreover, transmission electron microscopy analysis revealed that these nanoclusters were formed from tiny square nanoplates with a size of ~40 nm. Electrochemical studies of the synthesized Mn3O4\ thin films were recorded in a three-electrode system, which suggests that 0.1 M cationic precursor concentration has a good electrochemical signature with a specific capacitance of 470 F/g at 1 mA/cm2\ current density in 1 M Na2SO4\ aqueous electrolyte. The cyclic stability offered was appreciable, with capacitive retention of 75\% up to 10,000 CV cycles scanned at 100 mV/s. The charge storage kinetics of the SILAR-grown Mn3O4\ thin film were investigated. With systematic study we concluded that, the molarity of the cationic precursor plays a vital role in the porosity and microstructure which drastically affects the electrochemical performance.

}, doi = {10.1016/j.cjph.2021.03.028}, author = {Beknalkar, S. A. and Teli, A. M. and Harale, N. S. and Patil, D. S. and Sutar, J. R. and Shin, J. C. and Patil, P. S.} }