Nidhi Puri; Raj K. Gupta; Akhyaya K. Pattanaik; Navin C. Mehra; Ajit K. Mahapatro; Ram P. Tandon
Abstract
The present paper highlights the synthesis of cobalt antimonide (CoSb3) micro/nanostructures by following solvothermal technique with water as solvent. Recipe is optimized for preparation of refined CoSb3 compounds and demonstrated that a high processing temperature of 500 °C and long duration of ...
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The present paper highlights the synthesis of cobalt antimonide (CoSb3) micro/nanostructures by following solvothermal technique with water as solvent. Recipe is optimized for preparation of refined CoSb3 compounds and demonstrated that a high processing temperature of 500 °C and long duration of 72 hr indicates presence of CoSb3 phase. The microstructures and composition of the as synthesized CoSb3 nanocomposites are characterized to achieve the optimized phase.The morphologies as imaged using field emission scanning electron microscope resemble granules for the as-synthesized CoSb3. The phase purity and crystallographic structure of the as-synthesized CoSb3 nanocomposites as determined by XRD indicates the formation of the cubic phase of CoSb3 and agrees well with the JCPDS data mentioned for the highly pure CoSb3. The EDX estimates the elemental composition of Co and Sb in 1:3 stoichiometric ratio for the as-synthesized CoSb3. The currently prepared nanosized skutterudite CoSb3 material synthesized by solvothermal method could be utilized as active material for the development of highly efficient thermoelectric devices. Copyright © 2018 VBRI Press.
Raj K. Gupta; Ajit K. Mahapatro; Ram P. Tandon
Abstract
This work demonstrates the achievement of high thermopower in the pellets of calcium cobalt oxide (Ca3Co4O9) co-doped with aluminium (Al) and titanium (Ti). The pellets of Ca(3-x)AlxCo(4-y)TiyO9+δ with x, y = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5, oxide ceramics are prepared using a hot-press machine ...
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This work demonstrates the achievement of high thermopower in the pellets of calcium cobalt oxide (Ca3Co4O9) co-doped with aluminium (Al) and titanium (Ti). The pellets of Ca(3-x)AlxCo(4-y)TiyO9+δ with x, y = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5, oxide ceramics are prepared using a hot-press machine by applying an uniaxial pressure of 70 MPa at a dwell temperature of850 ºC. Microstructure imaging reveals compactness of good connectivity among grains with the estimated density using Archimedes principle suggests the formation of near perfect (99%) relative density for the new pelleted ceramics. All theco-doped samples exhibit lower electrical resistivity (r) values compared to pure Ca3Co4O9. The maximum Seebeck coefficient (S) of 177 μV/K at 750 K is achieved for the pure Ca3Co4O9 sample. A significant improvement of 18% in the power factor (S2/r) is realized at 750 K in the co-doped samples containing 0.2 mol% of Al and Ti co-doping. The demonstration of significant thermoelectric properties of Ca(3-x)AlxCo(4-y)TiyO9+δ suggest that these materials could be utilized as promising active material in thermoelectrics. Copyright © 2018 VBRI Press.
Bharti Sharma; Nahar Singh; Ram P. Tandon; Ajit K. Mahapatro
Abstract
This work demonstrates the structural interaction of the as-synthesized zinc peroxide (ZnO2) nanoparticles with fibroblast cells (FBC). The ZnO2 nanoparticles (ZNP) of desired sizes (10-20 nm) are synthesized, and the purity and structural confirmations are studied using various imaging and spectroscopic ...
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This work demonstrates the structural interaction of the as-synthesized zinc peroxide (ZnO2) nanoparticles with fibroblast cells (FBC). The ZnO2 nanoparticles (ZNP) of desired sizes (10-20 nm) are synthesized, and the purity and structural confirmations are studied using various imaging and spectroscopic techniques. FBC (buffalo) lines are cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum and penicillin (100 µg/mL), and with non-essential amino acid and vitamin as additional ingredients, followed by incubation at 37°C with continuous purging of the chamber using 5% CO2. The fluorescent microscopic images are captured for the initial healthy and cultured FBCs, and after pouring the nanoparticles in the cultured FBCs. Healthy cell-growth is noticed during the cell culture process suggesting the formation of ZNP-FBC complexes without contamination and coagulation. After allowing the interaction of ZNPs with the FBCs, the presence of ZNPs only on the cell sites are observed without coagulation of ZNPs in the cell areas, suggesting the selective interference of ZNPs on the surface of the grown cell. The understanding of the interaction process of the ZNPs with the living cell, would provide the practical utilization of the ZNPs in nanomedicine and nano-drug delivery. Copyright © 2017 VBRI Press.
Pooja Saini; Khobaib .; Prikshit Gautam; Manjari Singh; Ram P. Tandon; S. P. Singh; Ajit K. Mahapatro
Abstract
This work explains the functionalization of polyallylamine (PAA) on the graphene oxide (GO) sheets following a chemical route. The resulting GO-PAA complex is characterized by using various imaging and analytical tools. In the Raman spectroscopy for both the GO and GO-PAA, the appearance of D and G characteristic ...
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This work explains the functionalization of polyallylamine (PAA) on the graphene oxide (GO) sheets following a chemical route. The resulting GO-PAA complex is characterized by using various imaging and analytical tools. In the Raman spectroscopy for both the GO and GO-PAA, the appearance of D and G characteristic bands correspond to the sp2 and sp3 contents, respectively, in the carbon sheets. The observation of lowered D/G peak intensity ratio of these peaks from 1.3 for GO to 1.1 for GO-PAA indicates the lowering of the D favored sp2 content in the GO sheet after PAA functionalization. In the Fourier transform infra-red spectroscopy, the disappearance of the vibrational modes for ketone and carboxyl groups, and appearance of the amine (-NH) group confirms the chemical interaction of GO and PAA triggered with the -NH group of PAA interacting with the oxygen contained hydroxyl, epoxy, and carboxylic groups of the GO sheets to form the GO-PAA complex. Scanning electron microscopy imaging indicates opaque layers with no distinction of flakes after PAA functionalization. Copyright © 2017 VBRI Press
