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Exploring non-platinum group metal (n-PGM) based efficient oxygen reduction reaction (ORR) electro-catalysts is highly important for realizing advancement in sustainable next generation-alkaline anion exchange membrane fuel cells (AAEMFCs). Herein, we demonstrate a new “hierarchical shape tuning approach” for the synthesis of controlled sized and shaped non-PGM based Ag ORR electro-catalysts with surface active nano-islands. Hierarchical shapes ranging from spherical (S-AgNs), worm-in-sphere, sphere-in-worm and vermiform (worm-like) Ag nanostructures (V-AgNs) were obtained by precisely varying the ratios of capping agent to dual reducing agents in water at ambient conditions. Compared to S-AgNs, V-AgNs revealed a higher mass normalized ORR Tafel activity (0.303 A mgAg−1 at 0.9 V), onset (1.06 V) and half wave (0.78 V) potentials and higher retention of limiting current density (>88%) after 5000 cycles in 0.5 M potassium hydroxide (KOH) solution attributable to their unique worm like morphology with surface active nano-islands and support free-nature enabled better catalyst utilization. In a fully “non-PGM AAEMFC” (n-PAAEMFC), V-AgNs exhibited the highest fuel cell activity of 115.6 mW cm−2 and stable short-term durability (∼240 h) compared to S-AgNs (41.3 mW cm−2) and previously reported fully n-PAAEMFCs indicating their potential use in next-generation alkaline fuel cells.

A solid-state planar reference electrode (SSPRE) was fabricated and evaluated using polymer membrane, comprising polyvinyl chloride-co-polyvinyl acetate, nitrophenyl octyl ether as plasticizer, and potassium tetraphenylborate as anion blocker, and was used for the fabrication of SSPRE. Screen-printed Ag/AgCl electrode was used as the base electrode for the fabrication of SSPRE and was evaluated in background electrolyte solutions containing KNO3/KCl and was observed that there was no significant potential dependence on anions present in the background electrolyte. Furthermore, SSPRE was tested using a series of cations and anions in solution and varying pH of the background electrolyte with respect to commercial Ag/AgCl with 0.1 M KCl reference electrode. It was noted that the SSPRE provided stable potential by tuning the design of the screen-printed electrodes and the membrane potential. The reference potential does not differ in various background electrolyte solutions, except thiocyanate, which gave a negative shift at high concentration, ca. 0.1 M. Furthermore, the SSPRE was integrated with screen-printed potassium and sodium ion-selective electrodes, and was tested, and the performance was evaluated.

For the first time, we report a facile one pot aqueous method for support-free Pd85Pt15 nano-porous structures (NPoS) synthesis from PdMn nano-alloys at ambient conditions. A hierarchical approach was successfully employed through a simple “self-settlement” process with descending amounts of carbon to carbon-free electro-catalysts to improve catalyst utilization and avoid carbon degradation during fuel cell operating conditions. Pd85Pt15 NPoS exhibits enhanced methanol resistive oxygen reduction reaction (ORR) activity owing to the presence of highly active and unique surface PdPt islands compared to HiSPEC Pt/C catalysts. Accelerated durability tests of the support-free PdPt NPoS show enhanced durability in harsh acidic environment (1.0 N H2SO4) compared to HiSPEC Pt/C and DOE 2017–2020 durability target. Preliminary direct methanol fuel cell studies using hierarchically derived Pd85Pt15 NPoS variants were performed at ultra-low Pt content. The effects of carbon content and catalyst layer thickness on fuel cell activities are well discussed.

Aziridinofullerene-porphyrin (C60-TPP) dyad was synthesized using triethyl phosphite mediated [2+1] cycloaddition reaction. Structural elucidation of the compound was carried out using NMR and FT-IR spectroscopic methods. The synthesized C60-TPP was further characterized using UV-Vis absorption and photoluminescence emission studies. An optical study of the synthesized compound shows absorption maxima at 424 nm, around 516, 550, and 593 nm with small broad absorption peaks at 360 and at 480 nm. Photoluminescence studies of the compound shows emission maxima at around 597, 652 and 717 nm. Electrochemical studies of the compound shows oxidation potentials at 0.30, 0.52, 0.74 V and reduction potentials at−1.69,−2.07 and−2.42 V with respect to internal Fc/Fc+ reference corresponding to porphyrin and fullerene C60 moiety in the compound and the formation of C60-TPP. Furthermore, the absence of obtain XPS peaks corresponding to nitro group in C60-TPP confirms the conversion of nitro group to aziridine group.

Poly(fluorene-alt-benzothiadiazole) having 5 and 10% equivalent meso-tetraphenylporphyrin (m-MTPCC) linked through oxyethylene spacer in carbazole (P2, P3) and the parent poly(9,9-di-hexylfluorene-alt-2,1,3-benzothiadiazole) (P1) were synthesized using Suzuki polymerization reaction. These polymers were characterized using FT-IR, 1H NMR, TGA and gel permeation chromatography. The synthesized polymers are soluble in common organic solvents and are found to be thermally stable. Weight average molecular weights of the polymers were 51.895, 71.224 and 34.789 kDa for P1, P2 and P3, respectively. These copolymers (P2 and P3) shows absorption maxima at around 320, 422, 452 nm and emission maxima at 540 nm in solution, whereas in film state, these polymers (P2 and P3) shows absorption maxima at around 322, 422, 466 and 554 nm and emission at around 539, 654 and 718 nm. The photoluminescence emission at 648 and 720 nm when excited at 320 nm shows that energy transfer from polymer backbone to porphyrin. Surface morphology, optical absorption and emission properties of these polymers with PCBM were also studied. Electrochemical characterization of these polymers shows deep HOMO levels for P2 and P3 when compared with parent polymer and the details are reported.

Herein, we report a simple and elegant aqueous synthesis of Pd100-xPtx (x=5, 10, 15 and 20) nano-porous structures (NPoS) derived from Pd100-xMn2x (x=5, 10, 15 and 20) nano-alloys. Pd100-xPtx/C NPoS exhibit enhanced oxygen reduction reaction (ORR) activity along with higher retention of figure of merit in the presence of methanol compared to HiSPEC Pt/C catalyst. The ORR mass and specific activity values of Pd100-xPtx/C NPoS are high and exceed the U.S. department of energy (DOE) 2017–2020 targets. The enhanced methanol tolerance and ORR activity of Pd100-xPtx/C NPoS is attributed to their unique surface active Pd−Pt islands on nano-porous Pd. Direct methanol fuel cell performance studies employed using Pd85Pt15/C NPoS as cathode material (0.4 mgPt/cm2) and HiSPEC PtRu/C NPs as anode material (0.2 mgPt/cm2) shows improved direct methanol fuel cell (DMFC) single cell activity at low Pt loading and the results are presented.

We demonstrate electrochemical cycling-induced reduction of MoO3 to monoclinic molybdenum dioxide and molybdenum sub-oxides (MoO3-x), which exhibit excellent electrochemical hydrogen evolution reaction (HER) activity. The conversion of MoO3 during cycling was probed; after 250 cycles, the redox peaks were found to diminish with an onset potential shift and increased HER current density. At 400 cycles, the insertion/deinsertion processes observed in the initial cycles are completely absent and the HER current density is enhanced to the maximum. The effect of MoO3 morphology and size on the electrochemical reduction of MoO3 was also studied.

A series of alternate block copolymers of polyphenylene vinylenes that have 1,3-dioctyloxy phenylene in the center of kinked m-terphenyl group as one of the building blocks with either one of the aromatic groups, viz., 1,4-dioctyloxy benzene, 4,6-dioctyloxy benzene and 4,4′-dioctyloxy biphenyl, was synthesized through Heck polymerization. These alternate block copolymers, viz., poly(2,5-bis(octyloxy)phenylene vinylene alt 4′,6′-bis(octyloxy)-1,1′:3′,1″-terphenylene) (P1), poly(2,4-bis(octyloxy)phenylene vinylene alt 4′,6′-bis(octyloxy)-1,1′:3′,1″-terphenylene) (P2) and poly(4,4′-bis(octyloxy-3,3′-biphenylene vinylene alt 4′,6′-bis(octyloxy)-1,1′:3′,1″-terphenylene) (P3), were characterized for their thermal and optical properties. The synthesized polymers had good solubility in organic solvents and were stable up to 350 °C. The molecular weights of the synthesized polymers were in the range 4370–10,900 Da with polydispersity range 1.52–1.65, which were measured by the gel permeation chromatography technique. The optical properties of these polymers showed absorptions in solution at around 400, 329, and 345 nm for P1, P2, and P3 polymers, respectively. The photoluminescence emission maxima of the polymers were at around 461 nm with a shoulder 439 and 424 nm for P1, P2, and P3, respectively. Photoluminescence emission of films of these polymers showed minimum redshift (20 nm) when compared with spectra of their solutions. The optical and photoluminescence emission properties of these polymers were found to vary on the backbone structure.

In the present work, a siloxane based flexible substrate for optoelectronic applications with improved flexibility and high temperature withstanding capacity has been fabricated and the details are reported. The structural and optical properties of the substrate were characterized and the optical transparency is found to be about 90% − 95% in the visible region. The substrate withstands temperatures up to 300 °C without significant degradation and has a low thermal coefficient of expansion. Fourier transform infrared spectral data show the materials in the prepared substrate and SEM studies show the surface and cross-sectional characteristics of the substrate. It has good mechanical strength, can withstand a high breaking load of 7 N, has a average tensile strength of 48.86 MPa and high average tensile modulus of 127.32 and also possesses excellent surface smoothness and resistance to both chemical and moisture with better rigidity; it will be a long lasting alternative for flexible plastic substrates. The optical characteristics such as refractive index (n) and extinction coefficient (k) are also reported. © 2016 Society of Chemical Industry

Cross-linked polymer (CLP) composed of poly(ethylene glycol) methyl ether acrylate and poly(ethylene glycol) diacrylate has been used in synthesizing gel electrolyte. A set of electrolyte samples was synthesized using gel casting method by varying the weight percentage ratio of cross-linked polymers from 2–14 % in an incremental order (2 %) with respect to poly (ethylene oxide) (PEO) and evaluated its performance by employing in the fabrication of dye-sensitized solar cells. The synthesized polymer was subjected to different analytical techniques such as NMR, TGA, DSC, GPC, and FTIR to confirm the materials. The molecular weight of the CLP has been measured using GPC and the obtained value is found to be 3.655 KDa with polydispersity of 1.94. The CLP-PEO gel electrolyte with 10 % weight ratio has obtained the highest ionic conductivity of 3.07 × 10−6 S/cm−1 at room temperature and best photo-conversion efficiency of 5.1 % was achieved for the same.

Fabrication of quasi solid state dye sensitized solar cell with a stable gel electrolyte employing poly(ethylene oxide) (PEO)-poly(ethylene glycol) (PEG) is reported in this paper. PEO-PEG with either one of alkali iodides (LiI or NaI or KI), 1,2-dimethyl-3-propyl imidazolium iodide (DMPI), 4-tertbutylpyridine (TBP) and iodine in acetonitrile were used for the gel electrolyte preparation. The ionic conductivity and the triiodide diffusion coefficient of the gel electrolytes were measured by Electrochemical Impedance Spectroscopy. The photoconversion efficiency of gel state DSSC with NaI was found to be 5.4% at 100 mW/cm 2 with AM 1.5 Gfilter. When nanocrystalline TiO 2 was used as the filler in the gel electrolyte, the photoconversion efficiency was found to be increased up to 6.3%. The quasi solid state DSSC retained its initial value for 600 hours aging under ambient conditions.

A novel terpolymer involving 2-amino-6-nitrobenzothiazole and ethylenediamine with formaldehyde was synthesized by a polycondensation technique using glacial acetic acid as a reaction medium. The resulting chelating terpolymer resin was characterized using elemental analysis, physicochemical parameters, and UV-visible, Fourier transform infrared, 1H NMR and 13C NMR spectral studies. Average molecular weights of the terpolymer were determined using gel permeation chromatography. The surface morphology and the nature of the terpolymer were investigated using scanning electron microscopy and X-ray diffraction. The chelation ion-exchange property of the terpolymer was determined against some common metal ions such as Fe3+, Co2+, Ni2+, Cu2+, Zn2+ and Pb2+ using the batch equilibrium method. Effects of parameters such as the pH, contact time and various electrolyte concentrations were studied. The reusability of the terpolymer was checked in terms of its effective repeated usage. The results of the Langmuir and Freundlich adsorption isotherm models were best fitted with each other and the reaction kinetics followed pseudo second-order kinetics. The terpolymer showed good results against Fe3+, Cu2+ and Ni2+ ions compared to those against the other metal ions. © 2014 Society of Chemical Industry

For the first time, we are reporting the synthesis of Au100-xPtx nanoporous materials in the size range of 7-10 nm through the galvanic replacement of Ag by Pt from Au100-xAg2x spherical nano-alloys (x = 20, 15, 10 and 5) in an aqueous medium. The galvanic replacement reaction follows the 'Volmer-Weber' growth mode, resulting in the formation of surface bound platinum islands on a nanoporous gold surface. The high angle annular dark field image and low angle X-ray diffraction studies confirm the presence of nanoporous Au100-xPtx NPs. The electrochemical studies using the Au85Pt15/C catalyst show excellent methanol tolerance behaviour and better performance towards oxygen reduction reaction (ORR) in terms of high mass activity, mass-specific activity and figure of merit (FOM) when compared to HiSPEC Pt/C commercial catalyst. Preliminary studies on a full cell using nanoporous Au85Pt15/C (loading 1.0 mg cm(-2)) as the cathode material and Pt-Ru/C (loading: 0.5 mg cm(-2)) as the anode material performed better (38 mW cm(-2)) than the HiSPEC Pt/C cathode material (16 mW cm(-2)).

Chelating terpolymer resin was synthesized from anthranilic acid and 2-amino pyridine with formaldehyde to remove the heavy metal ions present in the solutions. The synthesized terpolymer resin was characterized by spectral techniques such as FTIR, NMR (1H and 13C) and elemental analysis to elucidate the structure of the resin. The physico-chemical parameters have also been evaluated for the terpolymer resin. The surface morphology of the terpolymer resin without the metal ion uptake and with the incorporation of the metal ion was examined by scanning electron microscopy. The chelation ion-exchange property of the terpolymer resin was evaluated by batch equilibrium method for specific metal ions viz. Fe3+, Co2+, Ni2+, Cu2+, Zn2+, and Pb2+. The study was extended to three variations such as evaluation of metal ion uptake in presence of various electrolytes in different concentrations, evaluation of the distribution of metal ion uptake at different pH ranges and evaluation of the rate of metal ion uptake at different time intervals. The adsorption isotherm was evaluated by means of Langmuir and Freundlich isotherm models. The order of the kinetics was also determined and the resin follows first order kinetics which shows that physisorption may be involved in the ion-exchange process. From the results, it was observed that the terpolymer resin acts as an excellent cation-exchanger. Compared to the commercially available phenolic and polystyrene resins, the synthesized terpolymer resin showed an excellent ion-exchange capacity with the selected metal ions.

2-Amino-6-nitro-benzothiazole and thiosemicarbazide with formaldehyde (BTF) terpolymer was synthesized by the condensation polymerization technique. The elemental analysis and physico-chemical parameters of the terpolymer were measured. This chelation terpolymer was characterized by infrared, electronic and nuclear magnetic resonance ( 1 H & 13 C NMR) spectral studies. The molecular weight of the terpolymer was determined by gel permeation chromatography (GPC). Surface analysis of the terpolymer was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) method. The thermal stability of the terpolymer was analyzed by thermogravimetric analysis (TGA). The cation-exchange property of the terpolymer was determined by batch equilibrium method with the effect of pH, contact time and electrolytes. The reusability of the resin was also studied to estimate the effectiveness of the terpolymer resin.

Poly(fluorene-alt-carbazole) appended with meso-tetraphenylporphyrin (MTPPC) linked through oxyethylene spacer and the parent poly(N-hexyl-2,7-carbazole-alt-9,9-di-n-hexyl fluorene) (P1) were synthesized and characterized. Optical absorption properties of the polymers containing 5% of MTPPC (P2) and 10% of MTPPC (P3) in the polymer backbone show extended optical absorption toward long wavelength compared to the parent polymer P1. Optical absorption studies of the polymers showed that polymer P1 has absorption at 384 nm in solution, whereas polymers P2 and P3 have absorption at 384 nm corresponding to polymer backbone and soret band at 421 nm with Q bands at around 518 and 554 nm in solution. P1 shows photoluminescence emission around 417 nm, whereas P2 and P3 fall around 656 nm. Thermal, electrochemical, and quenching studies of the polymers have been studied and the details are reported.

Degradation of high-density polyethylene (HDPE) films blended with 0.5, 1.0, and 2.0% metal ions (MIs, chromium = 36%, silicon = 8%, aluminum = 4%, and chlorine = 2%) and 5, 10, and 20% potato starch were studied under two different abiotic treatment conditions (they were either heated to 70�C or exposed to UV at 300-400 nm) for a period of 100 days. The addition of metals did not affect the mechanical strength of the polymer, whereas starch blending did. The latter turned the polymer yellow. HDPE with MIs exhibited higher levels of oxidation than the other samples. UV treatment affected the mechanical strength of the MI-blended HDPE more than the other additive or the thermal treatment. The formation of extractable oxygenated compounds and unoxidized low-molecular-weight hydrocarbons increased with increasing concentration of additives in HDPE. The surface energy in all cases increased, this indicated that the polymers turned hydrophilic. The maximum weight loss (28%) was seen in the 2% MI-blended HDPE exposed to UV followed by the 20% starch-blended polymer exposed to heat (24%). These results indicate a synergy between blending and the treatment strategy, this also suggests an optimal waste-disposal strategy. � 2012 Wiley Periodicals, Inc.

Terpolymer ligand was synthesized from 8-hydroxyquinoline and anthranilic acid with formaldehyde (QAF) by solution condensation in an acid medium. Polychelates of Cu(II), Ni(II), Zn(II), and Pb(II) were prepared using the terpolymer as ligand. The ligand and chelates were characterized by elemental analysis, TGA, DSC, FTIR, electronic absorption, and NMR spectroscopy. The activation energy was calculated for the ligand and its polychelates formation by the Freeman-Carroll method. The ligand and its polychelates possess antimicrobial activity for certain bacteria such as Staphylococcus aureus, Escherichia coli, and fungi Aspergillus niger and Candida albicans. The surface morphology of the ligand and its polychelates was established by SEM.

We are reporting the preparation and characterization of nano-titanium dioxide and silica. The corrosion resistance performance of these nanopigments in silicone as well as silicone–polypyrrole Interpenetrating Polymer Network has been evaluated by impedance spectroscopy. The capacitance and resistance exerted by this nanocomposite coating were compared with the microcomposite coating and found that the nanocomposite coatings has the resistance in the order of 108 Ω cm2 in 3% sodium chloride solution, which is more than the microcomposite coating. The comparison of heat resistance performance of these composite coatings indicates that nanocomposite coatings exhibit higher heat resistance property than the microcomposite coatings.

Polyol mediated synthesis for the preparation of tungsten trioxide and titanium doped tungsten trioxide has been reported. The reaction was carried out using chlorides of tungsten and titanium in diethylene glycol medium and water as the reagent for hydrolysis at 190 deg. C. Formation of a blue coloured dimensionally stable suspension of the precursor materials was observed during the course of the reaction. The particle sizes of the precursor materials were observed to be around 100 nm. The precursor materials were annealed to give tungsten trioxide and titanium doped tungsten trioxide. The precursor materials were characterised using TGA/DTA, FT-IR, optical spectra, SEM, TEM and powder XRD methods. It was observed that the doping of titanium could be effected at least up to 10% of Ti in WO{sub 3}. The TGA/DTA studies indicated that WO{sub 3-x}.H{sub 2}O is the dominant material that formed during the polyol mediated synthesis. The XRD data of the annealed samples revealed that the crystalline phase could be manipulated by varying the extent of titanium doping in the tungsten trioxide matrix.

Electrochemical biosensors have become very important tools in analytical chemistry because of their advantages like accuracy, high sensitivity and easy handling, This article describes electrochemical detection of acetic acid based on the fungus Fusarium solani. The biosensor employed for the study of assimilation of substrates was fabricated by coupling the immobilized membrane with the DO probe using dialysis tubing, A microbial dispersion containing 0.2 g of wet weight of the organisms per mL was used for immobilization upon cellulose nitrate membrane. The membrane retaining the fungus was placed on the Teflon membrane of the oxygen electrode so that the fungus was trapped between the two membranes. The linear range was found to be between 2 and 70 ppm (v/v) of acetic acid. A polypropylene net increases the lifetime of the sensor due to its retention of humidity in the net. By dipping the electrochemical probe onto buffer (pH 7.2), the sensor was found to have an extended lifetime of 120 days with about 800 determinations.

A procedure is developed for the determination of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in water by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after preconcentration on a piperidine dithiocarbamate supported polyurethane foam. The sorbed elements are subsequently eluted with 4 mol L−1 HNO3, and the acid eluates are analysed by ICP-AES. A 20-mL disposable syringe served as a chromatographic preconcentration column. The sorption recoveries of elements except Co and Cr were higher than 97%. The method is also applied for the analysis of natural water samples.

Recent developments in the field of flexible electronics motivated the researchers to start working in verdict of new flexible substrate for replacing the existing rigid glass and flexible plastics. Flexible substrates offer significant rewards in terms of being able to fabricate flexible electronic devices that are robust, thinner, conformable, lighter and can be rolled away when needed. In this work, a new flexible and transparent substrate with the help of organic materials such as Polydimethylsiloxane (PDMS) and tetra ethoxy orthosilicate (TEOS) is synthesized. Transmittance of about 90–95% is acquired in the visible region (400–700[Formula: see text]nm) and the synthesized substrate shows better thermal characteristics and withstands temperature up to 200[Formula: see text]C without any significant degradation. Characteristics such as transmittance ([Formula: see text]), absorption ([Formula: see text]), reflectance ([Formula: see text]), refractive index ([Formula: see text]) and extinction coefficient ([Formula: see text]) are also reported.

Divalent europium-activated alkaline-earth-metal chlorophosphate luminophores (MCAP:Eu 2+ ; M=Ca, Sr, Ba) have been prepared by self-propagating high-temperature (SPHT) synthesis in one pot employing the corresponding nitrates/chlorides, urea and diammonium hydrogen phosphate. The synthesized materials have been characterized by X-ray diffraction, photoluminescent emission spectroscopy, thermogravimetry, scanning electron microscopy and particle size analysis. The formation of chloroapatite depends on the nature of acid used in the combustion mixture. The photoluminescent emission efficiency and particle size distribution are found to depend on the amount of metal chloride used and on the sintering temperature. The results obtained are discussed with respect to the processing method employed.

Environmental issues raise concern on restrict the use of nondegradable polymers and encourage the development of degradable once. This study is carried out was to understand the rate of biodegradation of untreated and pretreated (100 C or UV for 10 days) polypropylene (PP), pro-oxidant blended (MI-PP) and starch blended polypropylenes (ST-PP) with two different fungal strains, Phanerochaete chrysosporium NCIM 1170 (F1) and Engyodontium album MTP091 (F2). About 18.8% and 9.42% gravimetric weight loss and 79% and 57% TGA weight loss (at 400 C) were observed with UV pretreated MI-PP in 1 year with F2 and F1 strains respectively. The amount of lacasse produced by the organism and biomass attached on the polymer surface are correlated with TGA weight loss (0.6–0.93). The formation of extractable oxygenated compounds and unoxidized low-molecular weight hydrocarbons are high in pretreated and blended samples. These results indicate blending and pretreatment strategy leads to an optimal waste-disposal strategy.

Yttrium oxide doped with trivalent europium has been prepared by self-propagating high temperature (SPHT) synthesis, also known as combustion synthesis, with nitrogen-based fuels. The materials synthesized have been characterized by X-ray diffraction, scanning electron microscopy, and luminescent emission spectroscopy. Crystallite size, powder density, and photoluminescent-emission intensity/efficiency are found to depend on the fuels used. The phosphor products were sintered with and without sintering aids. The results obtained are discussed with respect to the processing method employed.

SUMMARYIn conclusion, first time we report that SnCl 2 candope PAni-EB form by producing SnO 2 and HCl.The formed HCl doped the quinoid segments of theE.B structure in a conventional way to form conduct-ing PAni salt and SnO 2 is deposited on the surfaceof the polymer concomitantly to give conductingPAni-SnO 2 composite. In this method of preparation(composite A), tin oxide particles are deposited onPAni fibers. In the case of in situ polymerization(composite B), the composite is a homogeneous mix-ture of some free SnO 2 particles, SnO 2 on PAni andas well as SnO 2 encapsulated/embedded in PAni.The conductivity of the samples A and B increasedsignificantly due to the presence of SnO 2 nanopar-ticles, where the tin oxide particles are crystallizedin tetragonal (t-SnO 2 ) structure. In this study, it isalso established that composite A and B exhibitedimproved electrochemical property compared withpure PAni. The composite B showed enhancedpseudo capacitance as high as 219 F g 1 .The authors thank the directors of IICT and CECRIfor their constant encouragement, unstinted support.References

Large number of biochemical activities and electron behavior have a very close relationship with life forms and living cells [1], which makes the study of physiological and biochemical characteristics an important area in analytical chemistry. In recent years, researchers have developed rapid methods of assessment of cell proliferation [2–3], including reports on methods involving ATP bioluminescence [4], antibody-direct epifluorescent filter technique [5], enzyme immunoassays [6, 7], polymerase chain reaction [8], resonant mirror biosensor [9], quartz crystal microbalance biosensor [10], dielectric measurement [11], electron transfer in protein [12], and the electric impedance sensing systems [13]. The applications of direct voltammetry of cell cultures in the detection of viable microbes in biological samples have been reported [14–16]. Recent research has demonstrated that the live microbes, Tetrahymena shanghaiensis [17] and the Saccharomyces cerevisiae [18], could be monitored using cyclic voltammetry (CV). An attempt has been made here to extend this for fungal strains. The conventional method of the studies on the growth phases of fungi is cumbersome and time consuming because the time period required for the growth of the fungi is in terms of days, while for bacterial strains, all the phases of growth are completed in a few hours. This manuscript discusses the voltammeric behavior of the fungus, Aspergillus niger that was isolated from polyurethane waste scraps.

Anodic oxidation of 1′,8′-dimethyl- and other 1′,8′-disubstituted a.c -biladiene salts affords novel cyclized products. In addition to porphyrin, an unconjugated macrocyclic intermediate product resulting from oxidadve cyclizatfon during porphyrin synthesis is isolated, structurally identified, and characterized with regard to its spectroscopy, electrochemical behavior and chemical reactivity. The formation of a novel homoporphyrin from a 1′-ethoxycarbonylmethy-8′-(2-methoxycarbonylethyl)- a,c -biladiene salt is also briefly discussed.

Several covalently linked bisporphyrin systems, free-base (H 2 P---H 2 P), hybrid bisporphyrins (Zn---H 2 P) and Zn(II) dimers (ZnP---ZnP) and their 1:1 molecular complexes with sym 1,3,5-trinitrobenzene have been investigated by optical absorption and emission, and magnetic resonance spectroscopic methods. In these systems, two porphyrin units are linked singly through one of the meso aryl groups via ether linkages of variable length. The bisporphyrins cooperatively bind a molecule of a π-acceptor; 1,3,5-trinitrobenzene (TNB). The binding constant values vary with interchromophore separation. Maximum binding is observed in the bisporphyrin bearing a two-ether covalent linkage. It is found that TNB quenches the fluorescence of the two porphyrine units in a selective manner. It is suggested that a critical distance between the two porphyrin units is necessary for the observance of maximum cooperative intermolecular binding with an acceptor.

Anodic oxidation of 1′,8′-dimethyl- and other 1′,8′-disubstituted a.c -biladiene salts affords novel cyclized products. In addition to porphyrin, an unconjugated macrocyclic intermediate product resulting from oxidadve cyclizatfon during porphyrin synthesis is isolated, structurally identified, and characterized with regard to its spectroscopy, electrochemical behavior and chemical reactivity. The formation of a novel homoporphyrin from a 1′-ethoxycarbonylmethy-8′-(2-methoxycarbonylethyl)- a,c -biladiene salt is also briefly discussed.

A detailed study using the cyclic voltammogram was done on the live cells of Aspergillus terreus. The peak current values were obtained for different days of growth and plotted against time. The response of cyclic voltammogram showed the phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which assesses the increase of dry weight of the organisms against time. The electrochemical method is more advantageous because it is easy to assess and consumes less time. Further the electrochemical method clearly shows the decline phase which is generally not very defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the biomass. Further work is in progress in order to analyze the metabolite(s) that is/are responsible for the anodic peak.

Recently there has been a considerable focus on the synthesis of nitrogen functionalized graphene for energy storage and conversion. Herein, we report a simple, economical and facile process for the synthesis of nitrogen containing graphene composite which can be scaled up for mass production by using a nitrogen containing organic compound, ethylenediaminetetraacetic acid (EDTA) and graphene oxide as precursors. From the XRD studies, the increase in the interlayer distance between the graphene sheets confirms the functionalization of graphene sheets and the FT-IR spectroscopic analysis revealed the presence of N-containing functional groups in N-doped graphene sheets. XPS analysis confirms the chemical nature of N-containing functional groups, and TG analysis showed the amount of EDTA loaded on the graphene sheets. This composite exhibits a large specific capacitance of 290 F g−1 at 0.1 A g−1 with a capacitance retention of 67% and 58% at high current densities of 10 and 20 A g−1, respectively, thereby showing superior rate capability. In addition, it showed long-term electrochemical stability through 6000 charge–discharge cycles even at a high current density of 5 A g−1 with a specific capacitance loss of 2%.

Mn3O4-reduced graphene oxide (RGO) nanocomposites were prepared by chemical decomposition of the manganese hexacyanoferrate (MnHCF) complex directly on the graphene surface. XRD studies revealed the formation of crystalline hausmannite Mn3O4 nanocubes in the as-prepared nanocomposites without any heat treatment. The FE-SEM images showed the formation of Mn3O4 nanocubes on the graphene surface in the as-prepared nanocomposites. HR-TEM studies confirmed the homogeneous dispersion of ∼25 nm Mn3O4 nanocubes on graphene nanosheets. The amount of Mn3O4 nanocubes and graphene in the nanocomposites was estimated using TGA analysis from room temperature to 800 °C in air. The FT-IR and Raman spectroscopic analysis confirmed the functional groups in the nanocomposites and defects in graphene nanosheets in the nanocomposites. Cyclic voltammetry and galvanostatic charge-discharge experiments demonstrated a high specific capacitance of 131 F g(-1) in 1 M Na2SO4 electrolyte at a current density of 0.5 A g(-1) for the RGM-0.5 nanocomposite. A capacitance retention of 99% was observed for 500 charge-discharge cycles at a current density of 5 A g(-1), which conformed the excellent stability of the RGM electrodes. The prepared Mn3O4-RGO nanocomposites are promising for electrochemical energy storage.

Bulk-synthesized silicon carbide, hitherto considered inactive for electrochemical lithium insertion, is demonstrated as a potential high-capacity, long-cycling anode material for lithium-ion batteries. In this study, we show that cubic (3C polytype) nano SiC, prepared by a chemical vapour deposition (CVD) method, delivers a reversible lithium insertion capacity of about 1200 mA h g−1 over 200 cycles.