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Characteristics of slurry coated lead selenide films
No full textThin lead selenide films were deposited by the slurry coating technique using the powder
chemically synthesized in the laboratory. The as prepared powder exhibited cubic
structure. This powder was slurry coated onto alumina substrates. The films exhibited
cubic structure with peaks corresponding to single phase PbSe. The films exhibited a
carrier density of 3 ×1018 cm-3 and mobility value of 50 cm2V-1s-1. XPS studies indicated
peaks corresponding to Pb4f5/2 and Se3d. Laser Raman studies exhibited a peak at 135 cm-
1
Studies on the Removal of Iron from Drinking Water by Electrocoagulation – A Clean Process
No full textThe present study describes an electrocoagulation process for the removal of iron
from drinking water using magnesium as the anode and galvanized iron as the cathode.
Experiments were carried out as a function of pH, temperature and current density.
The adsorption capacity was evaluated using both the Langmuir and the Freundlich
isotherm models. The results show that the maximum removal efficiency of
98.4% was achieved at a current density of 0.06 A dm– 2, at a pH of 6.0. The adsorption
of iron was better explained by fitting the Langmuir adsorption isotherm, which suggests
a monolayer coverage of adsorbed molecules. The adsorption process followed a
second-order kinetics model. Temperature studies showed that adsorption was endothermic
and spontaneous in nature
Feasibility studies on newly identified LiCrP2O7 compound for lithium insertion behavior
No full textA new category of lithium intercalating cathode
candidates, namely LiCrP2O7, was synthesized at 800°C using
a citric acid assisted modified (CAM) sol–gel method
and examined for possible lithium insertion behavior. The
formation of a phase pure and monoclinic LiCrP2O7 compound
with finer crystallite size was confirmed from the Xray
diffraction patterns. The presence of nano-sized particles
as observed from a transmittance electron microscope image
of LiCrP2O7 and the presence of a preferred local cation environment,
evidenced from Fourier transform infra-red and
7Li nuclear magnetic resonance studies, are the added advantages
of the present study. Further, cyclic voltametry
study performed on 2016 coin cells consisting of the synthesized
LiCrP2O7 cathode revealed an excellent cycling reversibility
and structural stability. Hence, CAM sol–gel synthesized
LiCrP2O7 is found to possess desirable physical as
well as electrochemical properties, leading one to consider
the same as a possible lithium intercalating cathode material
Determination of migration efficiency of amino alcohol based migrating corrosion inhibitor through concrete
No full textThe migration efficiency of an amino alcohol based migrating corrosion inhibitor (MCI) through
hardened concrete of two different strengths (20 and 30 MPa) with two different thicknesses (25
and 40 mm) has been studied using diffusion test cell arrangement. The corrosion current Icorr
was measured using Tafel extrapolation technique. There is a 20 times reduction in Icorr of steel in
presence of MCI compared to that of bare steel. The migration efficiency decreases with an
increase in thickness as well as strength of concrete. The density of concrete influences the
diffusion rate of MCI. The diffusion rate is two times higher in 20 MPa concrete than that of 30 MPa
concrete. The studies have indicated that the passive layer formed on the rebar surface is not
stable in presence of 1% of chloride in 20 MPa concrete. Because of higher chloride threshold
level the MCI has performed better in 30 MPa concrete. The results conclude that if higher
protection efficiency is needed where structure is exposed to high chloride environments, it is
more appropriate that the MCI shall be added at the rate of 2?45 kg m23 along with concrete/
repair mortar than applied on the concrete surface
Studies on the effect of titanium addition on LiCoO2
No full textThe lithiated transition metal oxide has been used
as the cathode materials for lithium ion rechargeable
batteries. Among the various cathode materials, LiCoO2
has been widely used. There are lot of reports on the
substituted LiCoO2 replacing small amount of Cobalt with
other transition and nontransitional metals. Here, we focus
on to a tetravalent transition metal atom such as titanium, as an addition in LiCoO2 and studied its performance. The
titled cathode material was synthesized by solid-state
reaction method. Thermogravimetric/differential thermal
analysis, X-ray diffraction, X-ray fluorescence, scanning
electron microscopy, and particle size analysis were carried
out to assess the effect of addition of titanium on LiCoO2.
Electrochemical studies were carried out by cyclic voltammetry
and life cycle analyzer
Electrochemical Synthesis and Studies of Polypyrroles Doped by Renewable Dopant Cardanol Azophenylsulfonic Acid Derived from Cashew Nutshells
No full textThe raw material cardanol, a renewable
resource, is industrial waste and a pollutant from the
cashew nut industry. Cardanol is a useful starting material
for synthesizing a new amphiphilic molecule, cardanol azophenylsulfonic
acid (CAPSA). In this study, polypyrroles
were electrochemically synthesized with the renewable
dopant CAPSA. The polymers were characterized with
ultraviolet–visible, Fourier transform infrared, conductivity,
impedance, charge–discharge, and cyclic voltammetry analyses.
The conductivity of the films doped by CAPSA was in
the range of 1.23–3.98 � 10�5 S/cm, and they exhibited
moderate specific capacitance values
Modeling electrowinning process in an expanded bed electrode
No full textA theoretical model has been developed to describe the flow behavior of conducting particles in a fluidized
bed electrode for electro winning of metal ions present in the dilute solution. Model equations have
been developed for potential and current distributions and mass transfer rates. The influence of operating
parameters on particle growth has been critically examined. It has been observed from the present investigation
that the particle size increased with electrolysis time. The present model simulations have been
compared with the experimental data reported in the literature and observed that the model predictions
satisfactorily match with the reported experimental findings
Influence of foreign Fe ions on wet chemical synthesis of Pt nanoparticle thin films at ambient temperature: in situ versus direct addition
No full textNovel Pt nanoparticle thin films have been successfully synthesized on glass surfaces via a wet chemical
method that comprised reduction of aqueous hexachloroplatinic acid solution by ascorbic acid in the
presence of hematite (a-Fe2O3) at room temperature. Scanning electron microscopy (SEM),
transmission electron microscopy (TEM), powder X-ray diffraction (XRD), atomic absorption
spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-Vis absorption spectroscopy and a scratch
testing method have been used to characterize the final and intermediate products of Pt films. It was
found that there existed competition between precipitation of nanoparticles and formation of Pt
nanoparticle thin films, which is controlled by the source of foreign Fe ions i.e. in situ or direct addition
of foreign ions. Besides, the negatively charged glass surface and positively charged hematite surface
under the synthesis condition of pH 3 assisted heterogeneous nucleation of Pt on glass surfaces. The
measured adhesive strength of the film on glass substrate is 106 Mpa and the density of states overlaps
the Fermi energy (Ef ¼ 0), indicating the conducting films are strongly bonded on the glass surface. The
synthetic protocol outlined here shows a new synthetic route to integrate metal nanoparticles directly
on glass substrates
High efficiency quasi-solid-state dye-sensitized solar cell based on polyvinyidene fluoride-co-hexafluoro propylene containing propylene carbonate and acetonitrile as plasticizers
No full textQuasi-solid-state dye-sensitized solar cells (DSSCs) with differentweight ratios of polyvinyidene fluorideco-
hexafluoro propylene (PVDF-HFP) containing two different plasticizers such as propylene carbonate
(PC) and acetonitrile (AN) were fabricated and the effects of TiO2 morphology, light intensities as well
as different organic iodides on the solar cell performance were studied. Two TiO2 photoelectrodes were
designedby the coating of low(P1) and high molecularweight poly(ethylene glycol) (P2) incorporatedinto
the TiO2 suspension. The DSSCs fabricated with the P2 TiO2 electrode showbetter performance in terms of
short-circuit current densities (JSC) and conversion efficiencies than the P1 for all the weight percentages
of PVDF-HFP containing both plasticizers. Further, the maximum current density (JSC) and conversion
efficiency of PVDF-HFP containing different organic iodides follow the order: TBAI > TPAI >NH4I irrespective
of the solvents and light intensity. A good conversion efficiency of 6.74% with JSC of 16.04mA/cm2,
an open-circuit voltage (VOC) of 0.657V and a fill factor of 0.64 under illumination of 100mW/cm2 was
obtained for the DSSC with 10% of PVDF-HFP containing 0.4M of TBAI and 0.04M of I2 in PVDF-HFP/AN
system
Thermal analysis of LixCoO2 cathode material of lithium ion battery
No full textThermal behavior of LixCoO2 cathode material from cells charged to different voltages has been analyzed
using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The mass loss
appearing between 60 and 125 ◦C in TGA and the exothermic peaks with 4.9 and 7.0 J g−1 in DSC around 75
and 85 ◦C for the LixCoO2 cathodes of 4.20 and 4.35V cells has been explained based on solid electrolyte
interface (SEI) film-break down. The SEI film-break down for the highly charged cathode at low temperature
region has been attributed to the conversion of lithium fluoride into hydrofluoric acid in concomitant
with the reaction, Li2CO3 + 2HF→2LiF + CO2 +H2O. Presence of ionic carbonate in the positive electrode
has been identified by ion chromatography (IC). The thermal peaks appearing in different temperature
regions have been explained based on decomposition reaction of LixCoO2 cathodes and the SEI film