A. Subramania

Development of Novel Acidizing Inhibitors for Carbon Steel Corrosion in 15% Boiling Hydrochloric Acid

Abstract The inhibitive action of 1-cinnamylidine-3-thiocarbohydrazide (CTCH) and 1,1′-dicinnamylidine-3-thiocarbohydrazide (DCTCH) against the corrosion of carbon steel in 15% hydrochloric acid (HCl) was investigated using nonelectrochemical and electrochemical techniques. Potentiodynamic polarization studies revealed that the compounds were mixed-type inhibitors and exhibited more than 97% inhibition efficiency at 1,500 ppm of inhibitor concentration. The effect of temperature on the corrosion behavior of carbon steel in 15% HCl with 1,500 ppm of inhibitors was studied in the temperature range from 30°C to 110°C. The surface coverage (θ) increased linearly with the logarithm of the inhibitor concentration fitting a Temkin adsorption isotherm. Thermodynamic parameters including the free energy of adsorption, activation energy, enthalpy, entropy, and heat of adsorption were also calculated. The inhibitors reduced the hydrogen permeation current effectively through the steel surface. The protective film fo...

High-Performance Quasi-Solid-State Dye-Sensitized Solar Cell Based on an Electrospun PVdF−HFP Membrane Electrolyte

An electrospun membrane was prepared from a 16 wt % solution of poly(vinylidenefluoride- co-hexafluoropropylene) (PVdF-HFP) in a mixture of acetone/ N, N-dimethylacetamide (7:3 wt %) at an applied voltage of 12 kV. It was then activated by immersing it in 0.6 M 1-hexyl-2,3-dimethylimidazolium iodide, 0.1 M LiI, 0.05 M I 2, and 0.5 M 4- tert-butylpyridine in ethylene carbonate/propylene carbonate (1:1 wt %) to obtain the corresponding membrane electrolyte with an ionic conductivity of 10 (-5) S cm (-1) at 25 degrees C. On the basis of this electrospun membrane electrolyte, quasi-solid-state dye-sensitized solar cells were fabricated, which showed an open-circuit voltage ( V oc) of 0.76 V, a fill factor of 0.62, and a short-circuit current density ( J sc) of 15.57 mA cm (-2) at an incident light intensity of 100 mW cm (-2). This yields a light-to-electricity conversion efficiency of 7.3%. Moreover, this cell possessed better long-term stability than that fabricated with conventional liquid electrolyte.

Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively.

A novel polyaspartate precursor method for the synthesis of LiCayMn2?yO4 nanoparticles for Li-ion batteries

Cubic spinel LiCayMn2?yO4 nanoparticles were synthesized using nitrates of Li+, Ca2+ and acetate of Mn2+ with aspartic acid as a polymerizable combustion fuel. They were dissolved in distilled water and then concentrated by heating to form a viscous resin which was transformed into a foam-like mass by drying at 120??C. Phase pure LiCayMn2?yO4 powders were obtained by combustion of these foams. The decomposition temperature of the polyaspartate precursor was investigated by TG/DTA analysis. The structural property of the synthesized LiCayMn2?yO4 powders was confirmed by x-ray diffraction studies. The average particle size of the synthesized powders was calculated from the x-ray data using the Scherrer equation. TEM analysis was also carried out to confirm the particle size and surface morphology of the synthesized LiCayMn2?yO4 powder. Finally, electrochemical charge?discharge studies were carried out by assembling 2016 type electrochemical button cells using carbon as the anode and the synthesized LiCayMn2?yO4 as the cathode with microporous polymer electrolyte.

Preparation of nanoparticle size LiBiO2 by combustion method and its electrochemical studies for lithium secondary cells

A simple combustion method has been tried for the preparation of nanoparticle-sized LiBiO2 powder with urea as the igniter and glycerol as the binding material. Nitrates of Li+ and Bi3+ were mixed together to form a uniform mixture. Required quantities of urea and glycerol were added to this mixture to form a paste. This paste was carefully heated to 100° C initially and finally heated to 460° C for 5 h. The product obtained was subjected to TG/DTA and XRD analysis. The particle size of the cathode material was roughly calculated from the X-ray data using Scherer equation. However, SEM and EDAX analysis were carried out in detail to confirm the particle size and the composition of LiBiO2 respectively. A 2016 coin type button cell was assembled with LiBiO2 as cathode and graphite as anode containing polypropylene separator and a solution of 1 M LiClO4 dissolved in 1:1 (EC+DEC) mixture as the electrolyte. Charge/discharge studies were conducted to establish viability of the reversible cell

Synthesis of Nanocrystalline LiCdxMn2‐xO4 Cathode Materials by Using a New Combustion Fuel for Li‐ion Polymer Battery

Spinel LiMn2O4 possesses several advantages such as high voltage, wide operating temperature and long self‐life with much lower cost. However it suffers from loss of capacity during cycling. To improve the cycle performance of spinel LiMn2O4, Cd‐doped LiMn2O4 powders were synthesized by combustion route using gelatine as a new combustion fuel that acts as an excellent fuel as well as a very good dispersing agent to obtain nanocrystalline LiCdxMn2‐xO4 powders. The structural phase identification and grain size of the synthesized LiCdxMn2‐xO4 products were characterized by X‐ray diffraction studies and SEM analysis, respectively. Electrochemical discharge characteristics were performed by fabricating a button cell in the configuration of carbon/polymer electrolyte/LiCdxMn2‐xO4.

A new approach to synthesize LiAsF6 and other lithium based fluorochemicals for rechargeable lithium cells

A new method to synthesize inorganic lithium based fluorinated compounds like LiAsF6 (Lithium hexafluoro arsenate) has been developed by a low temperature solid state procedure. LiAsF6 is used extensively in the lithium cells because of its stability to withstand high voltages during cycling. The procedure developed to synthesize lithium based fluorinated compounds is a single step procedure and fluorination is done in-situ. This is an environmentally friendly method and is less expensive than the other known procedures.