The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

A simple one-step NaCl-assisted microwave-solvothermal method has been developed for the preparation of monodisperse α-Fe2O3 mesoporous microspheres. In this approach, Fe(NO3)3 · 9H2O is used as the iron source, and polyvinylpyrrolidone (PVP) acts as a surfactant in the presence of NaCl in mixed solvents of H2O and ethanol. Under the present experimental conditions, monodisperse α-Fe2O3 mesoporous microspheres can form via oriented attachment of α-Fe2O3 nanocrystals. One of the advantages of this method is that the size of α-Fe2O3 mesoporous microspheres can be adjusted in the range from ca. 170 to ca. 260 nm by changing the experimental parameters. High photocatalytic activities in the degradation of salicylic acid are observed for α-Fe2O3 mesoporous microspheres with different specific surface areas.

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Monodisperse α-Fe2O3 Mesoporous Microspheres: One-Step NaCl-Assisted Microwave-Solvothermal Preparation, Size Control and Photocatalytic Property

This feature article summarizes recent research on and development of semiconductor-based photocatalyst materials that are applicable to environmental remediation and/or chemical synthesis purposes. A wide variety of TiO2 particles and/or films have been studied during the past 30 years because they are the most stable and powerful photocatalysts leading to the degradation of various organic pollutants. The photocatalytic performance of other semiconductor materials such as ZnO, SnO2, WO3, Fe2O3 and CdS has also been intensively investigated. A general limitation in the efficiency of any photocatalytic process is the recombination of the photogenerated charge carriers, i.e., of electrons and holes, following bandgap illumination. Considerable efforts have been made to suppress this recombination and hence to enhance the charge carrier separation and the overall efficiency by means of coupling of different semiconductors with desirable matching of their electronic band structures, or incorporation of noble metal nanoclusters onto the surface of semiconductor photocatalyst particles. Modification of the physicochemical properties, such as particle size, surface area, porosity and/or crystallinity of the semiconductor materials, and optimization of the experimental conditions, such as pH, illumination conditions and/or catalyst loading, during photocatalytic reactions have also been carefully addressed to achieve high reaction rates or yields. To utilize solar energy more efficiently, i.e., to extend the optical absorption of the mostly UV-sensitive photocatalysts into the visible light range, numerous research groups have contributed to the development of novel visible light active photocatalysts. With the application of semiconductors with narrower bandgaps such as CdS, Fe2O3 and WO3 being straightforward choices, doping of wide bandgap semiconductors like TiO2 has been the most popular technique to enhance the catalysts' optical absorption abilities. Research on mixed-oxide-based semiconductor photocatalysts with deliberately modulated band structures has also attracted tremendous attention in the past decade, concentrating on, for example, the generation of H2 and/or O2 from H2O splitting, and the degradation of organic pollutants under visible light irradiation. Both theoretical calculations and experimental results have convincingly shown that the developed materials can serve as highly efficient photocatalysts that are both environmentally and economically significant.

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Photoelectrocatalytic materials for environmental applications

and Perspectives Sophie Carenco,†,‡,§,∥,⊥ David Portehault,*,†,‡,§ Ced́ric Boissier̀e,†,‡,§ Nicolas Meźailles, and Cleḿent Sanchez*,†,‡,§ †Chimie de la Matier̀e Condenseé de Paris, UPMC Univ Paris 06, UMR 7574, Colleg̀e de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France ‡Chimie de la Matier̀e Condenseé de Paris, CNRS, UMR 77574, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Chimie de la Matier̀e Condenseé de Paris, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Laboratory Heteroelements and Coordination, Chemistry Department, Ecole Polytechnique, CNRS-UMR 7653, Palaiseau, France

Nanoscaled metal borides and phosphides: recent developments and perspectives

Semiconductor polymeric graphitic carbon nitride (g-C3N4) photocatalysts have attracted dramatically growing attention in the field of the visible-light-induced hydrogen evolution reaction (HER) because of their facile synthesis, easy functionalization, attractive electronic band structure, high physicochemical stability and photocatalytic activity. This review article presents a panorama of the latest advancements in the rational design and development of g-C3N4 and g-C3N4-based composite photocatalysts for HER application. Concretely, the review starts with the development history, synthetic strategy, electronic structure and physicochemical characteristics of g-C3N4 materials, followed by the rational design and engineering of various nanostructured g-C3N4 (e.g. thinner, highly crystalline, doped, and porous g-C3N4) photocatalysts for HER application. Then a series of highly efficient g-C3N4 (e.g., metal/g-C3N4, semiconductor/g-C3N4, metal organic framework/g-C3N4, carbon/g-C3N4, conducting polymer/g-C3N4, sensitizer/g-C3N4) composite photocatalysts are exemplified. Lastly, this review provides a comprehensive summary and outlook on the major challenges, opportunities, and inspiring perspectives for future research in this hot area on the basis of pioneering works. It is believed that the emerging g-C3N4-based photocatalysts will act as the “holy grail” for highly efficient photocatalytic HER under visible-light irradiation.

Semiconductor polymeric graphitic carbon nitride photocatalysts: the “holy grail” for the photocatalytic hydrogen evolution reaction under visible light

A single‐phase Sr‐based Tb‐123 phase has been synthesized by chemical stabilization. TbSr2Cu2.85Re0.15O7+δ exhibits superconductivity at Tc,zero=22 K. X‐ray diffraction results suggest a relatively small orthorhombicity and neutron diffraction studies indicate an excess oxygen content (≥7.2) in the sample. Tb is present as a trivalent ion in the superconducting phase as derived from x‐ray photoelectron spectroscopy.

Stabilization of a superconducting TbSr2Cu2.85Re0.15O7+δ compound and the valence state of terbium

Being a promising and potential candidate for optoelectronic device applications, zinc selenide thin films were obtained for the first time on the glass microslides using a liquid phase chemical bath deposition. The deposition conditions, such as bath temperature (70 0C), deposition time (210 mins.), reaction pH (10.5± 0.2) and quantity of hydrazine hydrate (reducing agent) were finalized and the possible growth mechanism and reaction kinetics have been suggested. As the ZnSe films grow well in strong reducing atmosphere, the quantity of hydrazine hydrate was varied from 2 ml to 15 ml and ZnSe samples were obtained. The final product ZnSe thin films are physically hard, tightly adherent, relatively uniform and diffusely reflecting with light brown colored tinge in smoky appearance. An EDS analysis showed that the film stoichiometry depends on quantity of the added reducing agent in the bath. Structural studies were carried out on these films by an X-ray diffraction technique using Cukα radiation. It appeared that the ZnSe films are hexagonal wurtzite in structure with preferred orientation along . The calculated d-values, intensities of reflections and lattice parameters matched with that of the JCPD data. The calculated particle size decreased with quantity of hydrazine hydrate added in the bath (decrease in Zn/Se ratio). The optical absorption measurements in the range of wavelength from 300-1100 nm showed direct type of transitions with an optical gap decreased from 2.71 eV to 2.60 eV for the change of Zn/Se ratio from 0.993 to 0.571. The surface features revealed by SEM showed that the crystallites are nonuniformly distributed and spherical in shape. From micrographs it is seen that crystallite size decreased with increasing amount of hydrazine hydrate. Some overgrowth like structures (of the same size and shapes) has also been observed at high concentration of hydrazine hydrate. DOI: http://dx.doi.org/10.3126/jncs.v30i0.9384 Journal of Nepal Chemical Society Vol. 30, 2012 Page: 130-137 Uploaded date: 12/20/2013

Liquid Phase Chemical Deposition of High Tech ZnSe Thin Flims

Naphthyl iso-quinoline alkaloid was extracted from stem of Ancistrocladus heyneanus, in methanol and t hen separated by TLC. It was further assayed by LC/MS a . The alkaloid identified as Yaoundamine was tested for its anti-malarial activity using in vitro metho d and two strains of Plasmodium falciparum a Chloro quinesensitive strain 3D7 and the other Chloroquine-resi stant strain K1. Based on the IC 50 value and SI (Selective Index) of the test samples (Yaoundamine) it was found that the stem extract containing Yaoundamine exhibited promising anti-malarial activity against both 3D7 and K1 stra ins of Plasmodium falciparum along with good SI. I t can be concluded that the extract is active against Chloro quine resistant parasites and efficacy is comparabl e to drug Arteether

Antimalarial Activity of Yaoundamine a Naphthyl Iso-quinoline Alkaloid, Extracted from Stem of Ancistrocladus heyneanus

Effect of various carbon and nitrogen sources, PGRs and their precursors, on the callus growth and L-dopa production by the stem and leaf derived callus of Mucuna pruriens were studied. Five different carbon sources were glucose, fructos e, sucrose, mannose and raffinose. Glucose and sucrose were almost equally effective in both p romoting the growth as well as L-dopa content. The four nitrogen sources were phenylalani ne, tyrosine, glutathione and casein hydrolysate. Tyrosine was found to be most effectiv n trogen source at 25 mgl . Leaf derived callus showed more increase in L-dopa than stem. Ph enylalanine (10 mgl ) along with tyrosine (25 mgl ) could raise the L-dopa content (i.e. % of dry wei ght) from 1.4% of control to 1.7%. Casein hydrolysate was not very effective in L-dopa production. The PGRs tried were BA, Kin, Ad.SO 4; IAA, its precursor shikimic acid and an intermedi ary compound tryptophan; and gibberellic acid and its p recursor mevalonic acid. 1.0 mgl -1 IAA was most effective in promoting both growth and L-dopa content, whereas gibberellic acid and mevalonic acid inhibited both L-dopa content as wel l as growth. Incorporation of best nitrogen source (25 mgl -1 tyrosine) + most effective PGR (1 mgl IAA) to maintenance medium enhanced the L-dopa production t o 1.95%.

Effect of culture conditions on L-dopa accumulation in callus culture of Mucuna pruriens.

The order of kinetics of thermoluminescence of the most prominent glow peak of a single crystal of pure LiCl is investigated by the isothermal decay method. The order of kinetics is found to be 1.25+or-0.05.

Maheshwar Sharon

Papers

Stabilization of a superconducting TbSr2Cu2.85Re0.15O7+δ compound and the valence state of terbium

Liquid Phase Chemical Deposition of High Tech ZnSe Thin Flims

Antimalarial Activity of Yaoundamine a Naphthyl Iso-quinoline Alkaloid, Extracted from Stem of Ancistrocladus heyneanus

Effect of culture conditions on L-dopa accumulation in callus culture of Mucuna pruriens.

The order of kinetics of thermoluminescence of LiCl single crystals