Eco-Materials Processing and Design VIII

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Authors: Minako Nagamori, Yoshihiro Hirata, Soichiro Sameshima
Abstract: Terminal voltage, electric power density and overpotential were measured for the solid oxide fuel cell with gadolinium-doped ceria electrolyte (Ce0.8Gd0.2O1.9, GDC), 30 vol% Ni-GDC anode and Pt cathode using a H2 fuel or biogas (CH4 47, CO2 31, H2 19 vol %) at 1073 K. Addition of 1 ppm H2S in the 3vol % H2O-containing H2 fuel gave no change in the open circuit voltage (0.79 - 0.80 V) and the maximum power density (65 - 72 mW/cm2). Furthermore, no reaction between H2S and Ni in the anode was suggested by the thermodynamic calculation. On the other hand, the terminal voltage and electric power density decreased when 1 ppm H2S gas was mixed with the biogas. After the biogas with 1 ppm H2S flowed into the anode for 8 h, the electric power density decreased from 125 to 90 mW/cm2. The reduced electric power density was also recovered by passing 3 vol % H2O-containing H2 fuel for 2 h.
Authors: Jae Hee Jung, Hyun Cheol Oh, Jun Ho Ji, Sang Soo Kim
Abstract: A generation method of in-situ gold nanoparticles using a small-sized ceramic heater with a local heating area is presented. The heater surface temperature was maintained uniformly. Gold nanoparticles with high concentration (> 107 particles/cm3) were produced and were stably generated for several hours because the heater surface temperature was maintained uniformly. Higher surface temperature yielded higher geometric mean diameter (GMD), geometric standard deviation (GSD), and total number concentration. Using this generator particle size distribution was easily controlled. Spherical and non-agglomerated nanoparticles were observed from TEM images, even at high concentration and high temperature. Although air was used as a carrier gas, the generated gold nanoparticles displayed pure crystallinity of the gold element, as determined by XRD analysis.
Authors: Nitiphong Jirathiwathanakul, Hiroshige Matsumoto, Tatsumi Ishihara
Abstract: Steam electrolysis is attracting much interest method to produce hydrogen and also the new energy recovery process of wasted heat energy. Up to now, Y2O3 stabilized ZrO2 (YSZ) has been used for a solid electrolyte and so the operating temperature is limited down to 1273K. This study is focused on increasing the performance of steam electrolysis by using LaGaO3 based oxide for electrolyte at intermediate temperature of 873 K, which is upper limit of the obtainable wasted heat. It was found that the formation amount of H2 is almost obeyed the Faraday law up to 1.8 V suggesting that the ionic transport number of oxide ion in LaGaO3 was kept to be 1 under the steam electrolysis condition. The electrolyzing current is improved as following order; La0.6Sr0.4CoO3
Authors: Sung Soo Kang, Yutaka Toi
Abstract: The bending deformation of the ionic polymer metal composite (IPMC) upon low electric field is dominated by internal water redistribution. The one-dimensional finite element formulation is conducted for the basic field equations governing electrochemical response of the IPMC. The three-dimensional finite element analysis for the mechanical response of the IPMC beam is also conducted. Some numerical studies are carried out to show the validity of the present formulation.
Authors: Hae Suck Park, Dong Hwan Suh, Dong Hun Lee, Whan Gi Kim
Abstract: Novel bisphenol-based wholly aromatic poly(ether ketone)/poly(ether sulfone) copolymers containing pendant sulfonate groups were prepared by direct aromatic nucleophilic substitution polycondensation of 4,4-difluoro-3,3’-disodiumsulfonylbenzophenone (40mol% of bisphenol), difluorophenylsulfone and bisphenol A. Organic-inorganic composite membranes were obtained by mixing organic polymers with hydrophilic SiO2 (ca. 20nm) obtained by sol-gel process. The physic-chemical properties of these composite membranes were studied by thermogravimetry analysis(TGA), differential scanning calorimetry (DSC) and transform infrared(FTIR) spectroscopy. Scanning electron microscopy (SEM) and atomic Force microscopy (AFM) were used to observe the surface of membrances. The proton conductivity as a function of temperature decreased as SiO2 content increased, but water uptake increased. The membranes were shown all requisite properties; IEC (1.5meq./g), thermal stablity (Tg= 185°C), and low affinity towards methanol (1.5x10-7 - 4.3x10-7 cm2/S).
Authors: Hyun Jung Her, Jung Min Kim, Yun Soo Lim, Jae Wan Kim, Y.J. Choi, C.J. Kang, Yong Sang Kim
Abstract: We produced highly uniform nanoporous thin films of the dense array of titania (TiO2) pores of 70~80 nm in diameter with nanoimprinting method. Titania in HCl and 2-propanol solution was coated on an indium tin oxide (ITO) surface and embossed with an array of PMMA nanopoles which was produced using a nanoporous alumina (Al2O3) template. Two-step anodization was introduced to produce highly uniform and dense nanopores on the aluminum surface. The polymethyl methacrylate (PMMA) was poured onto and infiltrated into the nanoporous alumina surface which was heated at 150 oC. The alumina nanopores and aluminum plate were removed by wet-etching leaving an array of PMMA nanopoles. These highly uniform nanostructured titania films will be very useful for photovoltaic and photocatalytic applications where nanostructuring of surface with controlled dimensions are essential.
Authors: Sang Mock Lee, Jang Hoon Chung
Abstract: Pt-Tm/carbon nanocomposite has been prepared, using a heterobimetallic organometallic complex precursor {(DMF)10Tm2[Pt(CN)4]3} as a source of metals which was obtained in the reaction of TmCl3 with K2Pt(CN)4 in DMF at room temperature. For the electrocatalytic properties of the Pt-Tm catalyst composed with Ketjen Black, the incipient wetness and impregnation method were used. The XRD analysis of this noncomposited half cell materials shows nano size Pt crystalline with no other crystalline phases. Meanwhile, the presence of Tm within cell materials was confirmed by both EDX, and ICP analysis. ICP analysis indicates that the residual carbon from precursor exists as amorphous phase at a given thermal treatment condition. Average Pt particle is slightly bigger than standard Pt catalyst. Even though the particle size of active catalyst is rather similar, the cyclic voltammetry for the oxidation reduction reaction (ORR) shows that the coreduced electrocatalyst, Pt-Tm/carbon nanocomposite has lower catalytic activity compared with the typical Pt/carbon catalyst prepared from H2PtCl6/C. Along with the oxidation reduction reaction (ORR) results, the catalytic activity of methanol oxidation reaction (MOR) was also characterized .
Authors: Dong Seok Seo, Yong Gook Kim, In Ok Hwang, You Bok Park, Jong Kook Lee
Abstract: Effective micro-organisms (EM) increase the natural resistance of soil and plants, and it considerably improves the quality and fertility of soil as well as the growth and quality of crops. In this study, we prepared two types of porous ceramics with high and low porosity, and observed the attaching behavior of micro-organisms to the surface of ceramics. In the case of highly porous ceramics with large pore (80% in porosity), many of micro-organisms were observed in the pores of interior as well as on the ceramic surfaces. However, most of micro-organisms attached on the surface of the low porous ceramics with small pore (45% porosity), and only a few micro-organisms observed in pore inside.
Authors: Taek Rae Kim, Ji Na Lee, Yun Soo Lim, Myung Soo Kim
Abstract: In order to apply to the high-power anode materials of lithium ion battery, various cokes samples were prepared by milling, pitch coating, and following heat treatment. The samples were milled and the larger particles were removed by sieving. Two types of raw cokes and four pitch coated cokes treated at different temperatures were tested as the anode materials for lithium ion battery, and their electrical performance was compared with the cokes without pitch coating. Although the anode materials prepared with cokes showed lower charge-discharge capacity than the graphite anode materials, their power capability was superior to that of graphite. The electrochemical performance of various anodes with the pitch coated cokes was demonstrated as a function of preparation conditions.
Authors: Kengo Oda, Satoko Takase, Youichi Shimizu
Abstract: Lithium ionic conductive solid electrolyte discs based on NASICON-type Li1+xGaxTi2-x(PO4)3 (x = 0.1 - 0.9) were prepared by a wet-chemical route at 1173 - 1273K. Crystalline phase, density, and electrical conductivity of the sintered discs were systematically investigated. Single phase of LiTi2(PO4)3 systems were obtained at the calcination temperatures above 773K. Maximum conductivity 7.3 x 10-4 S/cm at 303K and activation energy of 0.30eV were obtained for the Li1.25Ga0.25Ti1.75(PO4)3 discs sintered at 1223K.

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