IR@CECRI
Not a member yet
2644 research outputs found
Sort by
Structural, optical, and electrical properties of electron beam evaporated CdSe thin films
No full textCdSe films have been deposited on glass substrates at different substrate temperatures between room
temperature and 300 °C. The films exhibited hexagonal structure with preferential orientation in the (002)
direction. The crystallinity improved and the grain size increased with temperature. Band gap values are
found decreasing from about 1.92 eV to 1.77 eV with increase of the substrate temperature. It is observed that
the resistivity decreases continuously with temperature. Laser Raman studies show the presence of 2 LO and
3 LO peaks at 416 cm-1 and 625 cm-1 respectively
A new class of Sol–gel derived LiM1xM2yMn22x2yO3.8F0.2 (M1 5 Cr, M2 5 V; x 5 y 5 0.2) cathodes for lithium batteries
No full textA series of LiM1xM2yMn2-x-yO3.8F0.2 (M1 =
Cr, M2 = V; x = y = 0.2) cathodes, viz., LiMn2O3.8F0.2,
LiCr0.2Mn1.8O3.8F0.2 and LiCr0.2V0.2Mn1.6O3.8F0.2 along
with native LiMn2O4 have been synthesized by Citric Acid
assisted Modified (CAM) sol–gel method, with a view to
understand the effect of synthesis methodology and the
effect of dual category dopants, viz., anion and/or cation
upon spinel cathodes individually. An acceptable capacity
retention (94%) observed up to 50 cycles for native LiMn2O4
cathodes is attributed to the significance of CAM sol–gel
method. Similarly, the encouraging charge–discharge results
of LiMn2O3.8F0.2 (130 mAh g-1) and LiCr0.2Mn1.8O3.8F0.2
(142 mAh g-1) cathodes revealed a possible augmentation
in the reversible capacity behavior of the spinels upon F-
substitution at 32e site and the simultaneous substitution
of Cr3? and F- at 16d and 32e sites respectively
A comparative evaluation on the voltammetric behavior of boron-doped diamond (BDD) and glassy carbon (GC) electrodes in different electrolyte media
No full textVoltammetric responses of boron-doped diamond (BDD) and glassy carbon (GC) electrodes on the anodic
oxidation of two dissimilar compounds namely 2,6-dimethoxyphenol and 1,3,5-trimethylbenzene in
acidic, neutral and basic media have been explored. Cyclic voltammetric (CV) analysis reveals that the
BDD electrode shows wider cathodic potential window and lower background current in all the media
than the GC. However, in the anodic side, the window is wide only in aqueous acidic medium and the
background limit for both the electrodes is similar in both neutral and alkaline media containing solvents
other than water. Further, the anodic oxidation of 2,6-dimethoxyphenol takes place at less potential on
the GC when compared to the BDD and the oxidation peak current is also higher on the former electrode.
CV results show that no anodic peak appears for the oxidation of 1,3,5-trimethylbenzene on the GC electrode
in any of the above media, whereas in the acidic medium, a broad anodic wave appears on the BDD
Mesoporous Carbon and Poly(3,4-ethylenedioxythiophene) Composite as Catalyst Support for Polymer Electrolyte Fuel Cells
No full textIn situ polymerization of 3,4-ethylenedioxythiophene with sol–gel-derived mesoporous carbon (MC) leading to a new composite
and its subsequent impregnation with Pt nanoparticles for application in polymer electrolyte fuel cells (PEFCs) is reported. The
composite exhibits good dispersion and utilization of platinum nanoparticles akin to other commonly used microporous carbon
materials, such as carbon black. Pt-supported MC–poly(3,4-ethylenedioxythiophene) (PEDOT) composite also exhibits promising
electrocatalytic activity toward oxygen reduction reaction, which is central to PEFCs. The PEFC with Pt-loaded MC-PEDOT
support exhibits 75% of enhancement in its power density in relation to the PEFC with Pt-loaded pristine MC support while
operating under identical conditions. It is conjectured that Pt-supported MC–PEDOT composite ameliorates PEFC performance/
durability on repetitive potential cycling
Preparation and characterization of thermally stable epoxy-titanate coatings
No full textEpoxy-polyamide coatings are used to protect metallic substrates in corrosive atmosphere. Thermal stability
of the coating can be improved by the addition of inorganic cross-linking agent. Epoxy resin is
incorporated with small percentage of silicone resin and cured with two types of hardeners such as
polyamide and butyl titanate. The physical properties, heat resistance properties and electrochemical
impedance behaviour of these coatings on steel in 0.5M NaCl solution have been studied. The result
implies that the heat resistant character of the titanate-cured coating is increased from 260 to 370 ◦C.
The impedance study has shown that the coating resistance exerted by both the systems is in the range
of 105 �cm2 after 6 days of immersion in 0.5M NaCl. FTIR and Raman spectroscopy analysis confirm
the presence of titanate linkage in the cured polymer coating. Thermal stability data indicate that the
epoxy silicone resin cured with titanate hardener possesses higher thermal stability than that cured by
polyamide hardener
Defect engineering and opto electronic property modifications by 1.5MeV Li+ implantation on nano crystalline MgIn2O4 thin films
No full textSpinel MgIn2O4 thin films were deposited on quartz substrates by the chemical spray pyrolysis technique
using metal organic precursors at 450◦C. Energetic 1.5MeV Li+ ions were implanted to various fluences
of 1013, 1014 and 1015 ions/cm2 onto insulating MgIn2O4 films using a 9 SDH-2, NEC, 3MV accelerator
to modify the material properties and surface nature. X-ray diffraction analysis was carried out to identify
the changes in the crystallinity and grain orientations before and after implantations. Before implantation,
the grains of polycrystalline MgIn2O4 were randomly oriented [(222), (311), (442) and (511)], and after
implantation they exhibited a tendency to realign the crystallites along the even (hkl) planes [(222) and
(442)]. On the Li+-implanted sample, one or more grains combine together and form bigger grains along
with shallowpits, as observed through the atomic force micrographs. The as-deposited films have a percentage
transmittance of 70–80% in the wavelength range 400–800 nm and the observed optical transmittance
was less in Li+-implanted MgIn2O4 films. The index of refraction and the extinction co-efficient values
were respectively n = 1.98 and k = 10−2 in the visible region. However, the DC electrical conductivity
of Li+-implanted films to a fluence of 1015 ions/cm2 was nearly 0.7 S/cm at room temperature. The efficiency
of the carrier generation was increased from 13.41% to 26.81% on annealing the implanted sample
to lower fluence (1013 ions/cm2)
Studies Relating to Removal of Arsenate by Electrochemical Coagulation: Optimization, Kinetics, Coagulant Characterization
No full textThe present investigation aims to remove arsenate [As(V)] by
electrochemical coagulation using mild steel as anode and cathode. The results showed that the optimum removal efficiency of 98.6% was achieved at a current density of 0.2Adm-2, at a pH of 7.0. The effect of current density, solution pH, temperature, co-existing ions, adsorption isotherm, and kinetics has been studied. Kinetics reveals that the removal of arsenate by electrochemical coagulation is very rapid in the first 15 min and remains almost constant with the progress of reaction. The adsorption kinetics obeys the second-order rate expression. An equilibrium isotherm was measured experimentally and the results were analyzed by Langmuir, Freundlich, Dubinin- Redushkevich, and Frumkin using the linearized correlation co-efficient. The characteristics parameters for each isotherm were determined. The Langmuir adsorption isotherm was found to fit the equilibrium data for arsenate adsorption. Temperature studies showed that the adsorption was endothermic and spontaneous in nature
Synthesis of fluorine doped tin oxide nanoparticles by sol–gel technique and their characterization
No full textThis article presents novel attempt to synthesis
of fluorine doped tin oxide (FTO) nanoparticles by sol–gel
technique. The synthesized FTO nanoparticles were
obtained after calcination. Temperatures of calcination
were 600 and 700 degree C due to identify changes in the particles size growth. A DG/DTA and FTIR study identifies
the oxide and formation of the nanopowders. The XRD
studies confirm the tetragonal crystallite structure of fluorine doped tin oxide. The TEM image confirms the size of
FTO particles in nanoscale. The electrical studies on FTO
nanopowders results the decrease in resistivity profile with
increasing calcinations. The optical band gap studies for
sol–gel synthesis FTO nanoparticles is found to be in the
range of 4.11–3.84 eV conforming decreasing optical band
gap with increasing calcinating temperatures
Electrochemical Coagulation for Chromium Removal: Process Optimization, Kinetics, Isotherms and Sludge Characterization
No full textThis study presents an electrochemical coagulation process for the removal of chromium
from water using magnesium as the anode and galvanized iron as the cathode.
The effects of pH, current density, concentration, temperature, adsorption kinetics
and adsorption isotherms on chromium removal were investigated. The results
showed that an optimum removal efficiency of 98.6% was achieved at a current density
of 0.2 A/dm2 and a pH of 7.0. The adsorption kinetics showed that the first order
rate expression fitted the adsorption kinetics. The equilibrium isotherm was measured
experimentally. Results were analyzed by Langmuir, Freundlich, Dubinin-
Redushkevich and Frumkin isotherms using linearized correlation coefficients. The
characteristic parameters for each isotherm were determined. The Langmuir adsorption
isotherm was found to fit the equilibrium data best for chromium adsorption.
Temperature studies showed that adsorption was endothermic and spontaneous in
nature
On the Synergistic Effect of Carbonate Anion Directed Shape Controlled Morphology and Super P Carbon in Preparing LiFePO4/C Cathode With Improved Lithium Intercalation Behavior
No full textA simple and carbonic acid directed modified mechano thermal (MMT) method is identified to
produce morphology controlled nano rods of LiFePO4/C composite. The added carbonic acid plays a
vital role in controlling the morphology (CO3
2- inhibition effect) and the formation of rod-like structure
that results from the unidirectional escape of CO2 gas upon calcination. MMT synthesized LiFePO4/C
cathode containing 2 wt.% conducting graphite exhibits a nominal specific capacity of 129 mAhg-1,
while the corresponding LiFePO4/C with 2 wt.% nickel coated graphite delivers 100 mAhg-1 capacity.
On the other hand, MMT synthesized LiFePO4/C composite cathode consisting of 2 wt.% super P
carbon exhibits an appreciable capacity of 160 mAhg-1 with an acceptable rate capability behaviour.
The synergistic effect of shape controlled morphology (resulting from MMT synthesis approach) and
the addition of super P carbon in improving the electrochemical behavior of LiFePO4/C composite
cathode is demonstrated in the present study