S. Balakumar

CdO/ZnO nanohybrids: facile synthesis and morphologically enhanced photocatalytic performance

A series of CdO/ZnO nanohybrids of different compositions were synthesized by a wet chemical method and investigated in detail. The nanohybrids were characterized by various techniques such as wide angle X-ray diffraction (XRD), diffuse reflectance UV-vis spectroscopy, transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). The results revealed that the crystal structure and optical properties of the nanohybrids were almost the same for all the compositions. FE-SEM images showed that the morphology of CdO/ZnO was hexagonal like microspheres, and the 0.75 : 1 Cd/Zn sample had a well-proportioned morphology. Three different dyes viz crystal violet, congo red and rhodamineB were used for the photocatalytic studies in a photoreactor and monitored with a UV-visible spectrometer. The nanohybrids showed excellent photocatalytic degradation compared to pure CdO and ZnO. In particular, nanohybrids with 0.75 : 1 (Cd : Zn) composition ratio exhibited better results compared to all other CdO/ZnO nanohybrids, which may be attributed to the improved charge separation at the heterojunction interface.

Effect of nanochitosan on electrochemical, interfacial and thermal properties of composite solid polymer electrolytes

PEO-based solid polymer electrolyte films with various concentrations of nanochitosan as filler and LiCF3SO3 as salt were prepared by membrane hot-press technique. Nanochitosan was prepared from chitosan by conventional chemical cure method. The prepared composite membranes were characterized by FT-IR, XRD, thermal, SEM, AFM analyses, electrochemical impedance spectroscopy, cyclic voltammetry and compatibility studies. The ionic conductivity and thermal stability of the polymer membranes were enhanced significantly by addition of nanofiller. The compatibility studies reveal that filler incorporated membrane is better compatible with lithium interface than filler free electrolyte.

Combined effect of nanochitosan and succinonitrile on structural, mechanical, thermal, and electrochemical properties of plasticized nanocomposite polymer electrolytes (PNCPE) for lithium batteries

A sequence of novel plasticized polymer nanocomposite electrolyte systems based on polyethylene oxide (PEO) as polymer host, LiCF3SO3 as salt, and a variety of concentrations of nanochitosan as inert filler, succinonitrile as a solid non-ionic plasticizer has been prepared. The prepared membranes were subjected to X-ray diffraction, FT-IR, tensile strength, morphological studies, thermal analysis, AC ionic conductivity measurement, and interfacial analyses. The combined effect of succinonitrile and nanochitosan on the electrochemical properties of polymer electrolytes has been studied, and it was confirmed that the ionic conductivity is significantly increased. The maximum ionic conductivity of the plasticized nanocomposite polymer electrolytes are found to be in the range of 10−2.8 S/cm. Besides, the interfacial stability also shows a significant improvement. The tensile measurement and thermal analysis results illustrate that the electrolytes based on that polymer host possess good mechanical and thermal stabilities.

A Review on PEO Based Solid Polymer Electrolytes (SPEs) Complexed with LiX (X=Tf, BOB) for Rechargeable Lithium Ion Batteries

Nanocomposite polymer electrolytes (NCPEs) have been playing a considerable role in the development of alternative clean and sustainable energy technologies. This review article summarizes the recent research progress on the synthesis and characterization of NCPEs and its application in lithium ion battery based energy storage devices. First, an introduction on the properties, synthesis strategies and use of NCPEs is briefly given, followed by a state-of-the-art review on the preparation of NCPEs and their electrochemical properties in lithium ion battery (LIB) applications. Finally, the prospects and future challenges of NCPEs for energy storage are discussed

Ionic Conductivity and Dielectric Studies of Chitin Nanofiber (CNF) Incorporated PMMA Based Polymer Electrolytes

Chitin nanofibers (CNF) are synthesized from shrimp cell chitin by stepwise purification and acid hydrolysis method. PMMA based polymer electrolytes complexed with LIN (CF3SO2)2 and chitin nanofibers as nanofiller have prepared by membrane hot-press technique. The prepared composite electrolytes are subjected to FT-IR, ac impedance, dielectric and modulus analyses. The incorporation of nanofiller in the polymer matrix increases the conductivity by an order of magnitude compared with filler free electrolytes. The complexation behavior of the composite polymer electrolytes are investigated by ATR FT -IR spectroscopy. The electric modulus analysis and dielectric studies of polymer electrolytes revealed that the non Debye dielectric relaxation nature.

Cu(II), Co(II) and Ni(II) Complexes Installed on Functionalized Silica Surface for Hydrogen Peroxide Assisted Cyclohexane Oxidation

In this work, Cu(II), Co(II) and Ni(II) complexes of the Schiff base ((S,E)-2-(3,4-dimethoxybenzylideneamino)-3-(1H-imidazol-4-yl)propionic acid) were synthesized and subsequently anchored onto amine functionalized silica. They were characterized by FT-IR, UV–vis., 29Si NMR, TG-DTG, ESR, FE-SEM and AFM techniques, and employed as catalysts in cyclohexane oxidation using hydrogen peroxide oxidant. Silica supported Cu(II) catalyst was shown the highest catalytic activity (70%) than rest of the catalysts used. On the other hand, all the complexes were selective as they yield only cyclohexanol and cyclohexanone. Silica supported catalysts were maintained their catalytic activity over five successive catalytic run. As these catalysts are selective, reusable and functioning well with hydrogen peroxide, they could design the environment friendly catalytic system for effective cyclohexane oxidation.

Enhancement of CdO/ZnO/PVC Nanocomposites Behavior on Photo-Catalytic Degradation of Congo-Red Dye under UV Light Irradiation

nanoCdO/ZnO/PVC composite thin films were prepared by simple solution cast method, using tetra hydrofuran as solvent. nanoCdO/ZnO/PVC composite thin films were irradiated by UV light at the range of 365 nm, 312 nm, and 254 nm. The photo-catalytic activity of CdO/ZnO/PVC was examined by photo-catalytic decolourization of congo-red in aqueous solution. nanoCdO/ZnO/PVC composite film exhibited higher photo-catalytic activity under UV light radiation at 365 nm rather than 312 nm & 254 nm. After 90 minutes irradiation by UV light almost 95% congo-red got decolorized. FT-IR studies confirm the complexation behavior of polymer with ZnO and CdO present in the composite.

Effect of nanochitosan and succinonitrile on the AC ionic conductivity of plasticized nanocomposite solid polymer electrolytes (PNCSPE)

In the present study, the filler chitosan was converted into nanochitosan by ionotropic gelation method. Plasticized nanocomposite solid polymer electrolytes (PNCSPE) composed of poly ethylene oxide as host polymer, LiBOB (lithium bis(oxalatoborate)) as salt, SN as plasticizer and nanochitosan as filler were prepared by membrane hot-press technique. Succinonitrile and nanochitosan incorporation in PEO-LiBOB matrix enhanced the room temperature ionic conductivity. The highest ionic conductivities were found to be in the order of 10−3.2 S/cm.

Effect of Electron Beam Irradiation on the Mechanical and Electrochemical Properties of Plasticized Polymer Electrolytes Dispersed with Nanoparticles

The effect of electron beam irradiation on electrical, thermal, mechanical and morphological properties of plasticized polymer electrolytes was investigated. A significant improvement in the mechanical strength without reduction in ionic conductivity was observed for the irradiated polymer electrolytes. DSC studies showed that the thermal behavior of the polymer electrolytes was improved by the addition of filler and by irradiation. SEM studies revealed a significant improvement in surface morphology of the polymer electrolyte after irradiation. The results are presented herein.

Characterization of Nanochitosan Incorporated Solid Polymer Composite Electrolytes for Magnesium Batteries

Chitin and chitosan, the most abundant biopolymers possess several excellent advantages such as biodegradability, ecological friendly, biocompatibility, low toxicity, bioactive, antimicrobial activity and low immunogenicity. They occur as ordered crystalline micro fibrils and are useful in applications that require reinforcement and strength. Nanochitosan was prepared from chitosan by oxidation degradation method using H2O2. Nanocomposites polymer electrolyte system composed of polyethylene oxide (PEO) as the host polymer, magnesium perchlorate Mg(ClO4)2 as salt and different concentration of nano-sized chitosan as filler have been studied. The effects of addition of nanochitosan on the ionic conductivity of composite polymer electrolytes are investigated and it is found to rise upon one order (10-3 Scm-1). The complexation behavior of PEO and Mg(ClO4)2 are verified through FT-IR studies. The nanocomposite films possess uniform surface morphology which has been identified by SEM analysis.