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A Pt/Pd/C core–shell-structured catalyst with an extraordinarily high activity of 3625 A g–1-Pt at 0.9 V versus a reversible hydrogen electrode (RHE) for the oxygen reduction reaction (ORR) was cre...

Enhancement of photovoltaic performance due to alkali-metal doping in various thin-film compound solar cells such as chalcogenide Cu(In,Ga)Se2 (CIGS), Cu2ZnSnS4 (CZTS), and organic–inorganic hybrid perovskite, is significant in the development of photovoltaic technologies. In this work, the effects of light Li- and heavy Cs-doping in ternary CuGaSe2 (CGS) and quaternary CIGS thin-films and devices are compared. The new findings are: (i) heavy alkali-metal halide CsF postdeposition treatment (PDT) modifies the CGS film surface morphology and increases the carrier density; however, the beneficial effects of Cs on the CGS photovoltaic performance are low when compared to the results observed from quaternary CIGS devices; (ii) LiF-PDT leads to no significant CGS and CIGS film surface (hetero p-n junction interface) modifications; thus, the use of a thin (approximately 30 nm) CdS buffer layer is not effective in enhancing photovoltaic performance; and (iii) the beneficial effects of either light Li or heavy Cs on ternary CGS devices are modest; nonetheless, Li may be more effective than Cs, unlike quaternary CIGS devices.

A designed two-compartment cell was applied to the degradation analysis of FeF3 having high theoretical energy density. Comparing with the result of the coin cell, the two-compartment cell gave us insight that the elution of Fe was responsible for the degradation of FeF3 and LiDFOB was found as an essentially effective additive for suppressing the degradation of FeF3.

Hierarchical micro-/mesoporous carbons with abundant Fe-N-C sites were prepared through one-step carbonization of a metal-organic framework (MOF) with sodium iron ethylenediaminetetraacetic acid [NaFe(III)EDTA], which can facilitate the nucleation and growth of ultrafine (∼1.4 nm) and highly dispersed palladium nanoparticles (Pd NPs). Interfacing Pd NPs with Fe-N-C sites has been demonstrated for the first time to boost the heterogeneous catalysis of hydrogen production from formic acid, affording an ultrahigh turnover frequency (TOF) value of 7361 h-1 at 323 K. The robust synergistic interactions between Pd NPs and Fe-N-C sites together with the small size effects of Pd NPs are responsible for the enhanced catalytic activity.

Both elemental Rb and Cs are known as effective dopants in enhancing Cu(In,Ga)Se2 (CIGS) thin-film photovoltaic device performance. It is, however, found that there are critical differences in the ...

We investigated the microstructures of Au-deposited PtCo@Pt core-shell nanoparticles (NPs) and discussed enhancement of the oxygen reduction reaction (ORR) properties by Au termination of low-coordination sites of the Pt-shell. The Au-deposited PtCo@Pt NPs showed an improved electrochemical structural stability, together with slight increment in increased initial, pristine area-specific activity relative to the non-Au-deposited PtCo@Pt NPs. Atomic-level microstructural characterization was performed by a back-side illumination fluorescence X-ray absorption fine structure (BI-FXAFS) method and scanning transmission electron microscopy with energy dispersive spectroscopy (STEM-EDS). The BI-FXAFS results indicated that compressive lattice strain in the Pt-shells of the PtCo@Pt NPs was almost unchanged by the subsequent Au deposition. Furthermore, STEM-EDS mapping of Pt, Co, and Au clearly showed that the deposited Au tended to localize at low-coordination sites of the Pt-shell surface, e.g., edges and corners. The atomic-level microstructural characterization conducted in this study demonstrated that effective Au surface terminations of the Pt-shell enhance the ORR durability of Pt-based core-shell type NP catalysts.

Li2MnO3, a layered lithium-rich manganese oxide, is one of the potential high-capacity positive electrode materials among the Li containing transition metal oxide materials but its low electrical conductivity restricts its electrochemical activity. In our previous study, Li–Mn cation disorder in Li2MnO3 resulting in the formation of a NaCl-type structure was found to improve its electrochemical activity, i.e., a high initial discharge capacity of 320 mA h g−1. However, it still suffered from a poor cycling performance probably due to another problem, e.g., its structural instability, i.e., oxygen emission during charging. In this study, we found that the structural stability of NaCl-type Li2MnO3 was significantly improved by forming a composite with spinel-type LiMn2O4 by mechanical milling. The initial discharge capacity of the composite was close to 400 mA h g−1 and its 15th discharge capacity still showed more than 80% of the initial one, while less than 50% for NaCl-type Li2MnO3. The oxide ions in the composite were found to be more stable than those of NaCl-type Li2MnO3 during the electrochemical redox reaction, which was confirmed by O K-edge XAS measurements, resulting in the higher reversible capacity and better cycling performance.

Replacing the scarce metal-based positive electrode materials currently used in rechargeable lithium ion batteries with organic compounds helps address environmental issues and might enhance gravimetric electrochemical capacity. The challenge has been to find organic materials with both high capacity and long-cycle life. Here, we study the naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) skeleton as a high capacity candidate electrode for lithium-ion batteries, showing a multielectron-transfer type redox reaction. We also use electron energy-loss spectroscopy to reveal the reaction stoichiometry during charge/discharge processes. While the lithium salt of naphthazarin itself helped deliver a high initial capacity, its cycle-life was not satisfactory. Instead, a newly synthesized naphthazarin-dimer shows a lengthened cycle-life without sacrificing the initial high capacity of 416 mAh g−1 and energy density of 1.1 Wh g−1. Replacing metal electrodes in lithium-ion batteries with organic materials reduces environmental impact and might lead to high gravimetric capacity. Here, organic electrodes containing a naphthazarin-dimer skeleton achieve an initial capacity of 416 mAh g−1 and energy density of 1.1 Wh g−1 in a lithium-ion battery.

Carbon-supported Pt, Pt-Cu, and Pt-Ru nanoparticles were prepared by an alcohol reduction method in the presence of carboxylates and phosphinate in order to investigate the role of these stabilizers in the nanoparticle formation process and the effect on catalytic properties in 2-propanol oxidation. For the Pt-Cu system, long chain carboxylate gave small dispersed particles even with high metal loading while phosphinate gave aggregated particles. For the Pt and Pt-Ru systems, fewer aggregates were observed and the particle size was independent of the chain length of carboxylate while much smaller and dispersed particles were obtained with phosphinate. Phosphinate mainly prevents metal crystal growth while carboxylates prevent both crystal growth and formation of aggregated particles. Although surface poisoning is severe on small dispersed particles in 2-propanol oxidation, dehydrogenation of 2-propanol at low potential is little affected. Phosphinate-protected catalysts were more tolerant to poisoning promoting 2-propanol electrooxidation at high potential range. The presence of Cu promoted 2-propanol electrooxidation at low potential range. These components made phosphinate-protected PtCu best perform in 2-propanol oxidation at 30 °C.

To develop safe and low-cost Li-ion batteries (LIBs), recently, an aqueous-based electrolyte so-called “hydrate-melt” (HDM) electrolyte is proposed. Li4Ti5O12 is a promising negative electrode material for a LIB with such a HDM electrolyte because of its unexpected reversible Li insertion and extraction properties without usually inevitable water reduction. The solid-electrolyte interphase formation is one of the reasons for this stable reaction, although a detailed analysis is not yet performed. Here, a Li4Ti5O12 electrode surface reacted in a HDM electrolyte is investigated by scanning electron microscopy-based analysis. Surface reaction products are clearly observed on the Li4Ti5O12 surface after the Li insertion reaction in a HDM electrolyte. Energy-dispersive X-ray spectroscopy and Auger electron spectroscopy indicated that the products do not contain any components originated from Li salts, whereas anion-derived passivation films seem to cover a bare surface below the products. Further, the surface ...

International audience; We report a scandium oxyhydride BaScO2H prepared by solid state reaction under high pressure. Rietveld refinements against powder synchrotron X-ray and neutron diffraction data revealed that BaScO2H adopts the ideal cubic perovskite structure (Pm3̅m), where oxide (O(2-)) and hydride (H(-)) anions are disordered. (1)H nuclear magnetic resonance (NMR) spectroscopy provides a positive chemical shift of about +4.4 ppm, which can be understood by the distance to the nearest (and possibly the next nearest) cation from the H nucleus. A further analysis of the NMR data and calculations based on ab initio random structure searches suggest a partial cis preference in ScO4H2 octahedra. The present oxyhydride, if compositionally or structurally tuned, may become a candidate for H(-) conductors.

Confirming the dopant site of In3+-doped SrTiO3 (In-STO) is essential to reveal the mechanism of its photocatalytic activity. In a previous study, x-ray absorption spectroscopic analysis and theoretical investigations were performed to discuss the dopant site, and In3+-Ti4+ substitution was proposed. However, direct confirmation of the In3+ dopant site has not yet been reported. Here, we performed direct atomic-scale imaging of In-STO crystals via analytical transmission electron microscopy and revealed the dopant site based on real-space elemental mapping. The Ti and Sr sites in the SrTiO3 crystal lattice were well identified by atomic column elemental mapping using energy dispersive x-ray spectroscopy (EDS). The EDS signal of indium has a stronger intensity at the Ti site than at the Sr site, based on the total analysis of each Ti and Sr atomic column. By applying principal component analysis on the raw EDS spectral imaging data cube, the indium site was clearly imaged; it completely fit into the Ti atomic column positions. These results provide direct evidence of In-Ti substitution in In-STO photocatalysts.

For large storage batteries, cost performance is more important than energy density. Iron-based conversion-type cathode active materials are promising because this material group satisfies both low-cost and high-capacity requirements. In particular, iron fluoride is notable for its relatively high discharge voltage. However, the electronic conductivity of FeF3 is poor and it has large discharge-charge overvoltage. To solve these issues, xFeF3-V2O5/C (9xFeF3-9V2O5–P2O5) was investigated and the composition with x = 2 was shown to be optimal. Furthermore, the cyclability of 2FeF3–V2O5/C was improved by changing the salt from LiPF6 to LiClO4 and changing the solvent from DMC to EMC. Although the V2O5 glass component showed irreversible capacity due to Li trapping in the glass matrix at the first cycle, the irreversible capacity at the first cycle was successfully compensated by the addition of LiF as a sacrificial salt.

In this study, we synthesized the solid solution system between La2Zr2O7 and La3TaO7 with a fluorite-type structure for the first time by the polymerized complex method and refined its crystal structural parameter using the Rietveld method. Furthermore, we synthesized a garnet-type Li-ion conductor by the precursor method which used a solid solution, La2+xZr2-2xTaxO7 (x = 0.4), as a precursor material. To investigate the reactivity between the Li oxides and the fluorite-type precursor oxide, we performed TG-DTA measurements. As a result, an exothermic peak was observed at 420 °C, indicating the phase formation of the garnet-type Li6.5La3Zr1.5Ta0.5O12 at low-temperature. In addition, we prepared the sintering body of the Li6.5La3Zr1.5Ta0.5O12 using the precursor method. The fabricated sample exhibits a bulk Li-ion conductivity of 9.4 × 10−4 S cm−1 at 25 °C.

The surfaces of LiCoO 2 particles were modified to improve the charge-discharge cycling properties of Li-ion batteries containing LiCoO 2 cathodes. The sol-gel technique was used to modify the surface of LiCoO 2 particles with magnesium oxide. Capacity retention during cycling of the magnesium oxide-coated LiCoO 2 cathode was superior to that of a cathode comprising pristine LiCoO 2 . Moreover, results obtained from TEM measurements indicate that the Li concentration was relatively homogeneous in the magnesium oxide-coated LiCoO 2 particles after cycling tests. The crystallographic planes of the coating were found to be coherently oriented with those of the substrate, MgO(111)[1−10]//LiCoO 2 (003)[100]. Therefore, we believe that a thin cover of Mg on the surface of LiCoO 2 stabilizes the surface, contributing to the homogeneity of charge and discharge reactions.

Au–Ag bimetallic catalysts on SiO2 were prepared using a simultaneous solid grinding (simul-SG) method, in which multiple kinds of organometallic complexes are ground with a support powder. After optimizing the Ag/Au ratio, the obtained catalysts exhibited remarkably high activity for low-temperature CO oxidation compared with that of Au/SiO2 or Ag/SiO2 catalysts. A detailed structural analysis using electron microscopy revealed that a higher ratio of Ag prevents growth of the particles via sintering and induces high densities of active Au–Ag contacts. Our simul-SG method is a promising tool for the easy preparation of multicomponent catalysts on various supports.

Li K-edge analysis obtained by scanning reflection energy loss spectroscopy (REELS) has been used to investigate the positive electrode of a Li-ion battery. Using spectral imaging data, Li mapping of a LiNi1/3Mn1/3Co1/3O2 electrode has been constructed. Inhomogeneous Li distributions are observed in LiNi1/3Mn1/3Co1/3O2 particles after cyclic electrode charging and discharging. The REELS results agree well with those obtained by scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS). Copyright © 2016 John Wiley & Sons, Ltd.

In this study, a new class of contenders for high-voltage and high-capacity positive electrode materials with the composition NaxLi0.7−xNi1−yMnyO2 (0.03 Na0.7Ni1−yMnyO2 (0.5 ≤ y ≤ 0.8) as the precursor exhibited a mixture of layered and spinel structures. The (dis)charge voltage-capacity curve of materials with these compositions significantly varied according to the residual Na and Mn content. Notably, HT-NaxLi0.7−xNi1−yMnyO2 (x = 0.093, y = 0.67) exhibited a maximum discharge capacity of 261 mA h g−1 at an average voltage of 3.36 V at 25 °C (between 2.0 and 4.8 V), which translates to an energy density of 943 W h kg−1. The obtained electrochemical performance is rationalized by the phase fractions of layered and spinel structures, which is triggered by the residual Na and Mn content in NaxLi0.7−xNi1−yMnyO2.

Iron trifluoride (FeF3) has been attracted as one of the promising candidates for the positive electrode material of lithium secondary batteries due to their high theoretical capacity (712 mA g–1) and high energy density (1949 Wh kg–1). However, its poor cyclability and a large hysteresis of the voltage during charge and discharge still remain the problem to solve for the commercialization. The cycling performance of FeF3-based lithium secondary battery has been improved by various strategies, such as the addition of anion receptor, coating by other metals and tuning of electrolyte composition so far [1-3], but the suppression of degradation and the elucidation of its mechanism have not accomplished completely. In the present study, we investigated the charge and discharge behavior of the FeF3 positive electrode using a designed two-compartment type cell which has lithium ion-conducting ceramics as a separator to prevent the cross-talk of the electrolyte between the positive and negative electrode. A charge/discharge test was performed using a coin cell and two-compartment type cell using 1.0 mol dm–3 LiPF6 in 1:1 ratio of ethylene carbonate (EC) and dimethyl carbonate (DMC) as the electrolyte. Disassembling analysis of both cells including SEM observation and X-ray fluorescence analysis revealed that the elution of Fe is more responsible for the degradation of the FeF3 electrode than a thick film formation on the electrode due to the cross-talk in the coin cell. Furthermore, the cyclability was improved using the electrolyte with LiDFOB as an additive for only the positive electrode side of the two-compartment type cell, whereas the improvement of the cyclability was not found when the additive was applied to a coin cell. After the cycling tests, various analyses, such as electrochemical impedance, X-ray photoelectron spectroscopy, and transmission electron microscopy, were also conducted for the electrode with and without additives in the electrolyte to examine the degradation mechanism of FeF3 positive electrode. The obtained results were considered useful for the improvement of the cycling performance of FeF3-based lithium ion batteries. References [1] K. Kumagae, K.-I. Okazaki, K. Matsui, H. Horino, T. Hirai, J.-I. Yamaki and Z. Ogumi, J. Electrochem. Soc., 163, A1633 (2016). [2] Y. Li, X. Zhou, Y. Bai, G. Chen, Z. Wang, H. Li, F. Wu and C. Wu, ACS Appl. Mater. Interfaces, 9, 19852 (2017). [3] H. Senoh, K. Matsui, M. Shikano, T. Okumura, H. Kiuchi, K. Shimoda, K. Yamanaka, T. Ohta, T. Fukunaga, H. Sakaebe and E. Matsubara, ACS Appl. Mater. Interfaces, 11, 30959 (2019). Acknowledgement This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) under the “Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2)”

An electron-conducting mixed oxide, Co-Pt bronze was synthesized and examined as a candidate for a highly durable electrocatalyst for both the polymer electrolyte fuel cells and electrolyzers. The motivation of this study comes from the fact that this material has not been studied as an electrocatalyst in acidic media, although past studies showed a high electronic conductivity and a high corrosion resistance. Co-Pt bronze without metallic Pt was obtained by solid-state synthesis and hot aqua regia rinsing. The OER activity was found to be among the highest as a material without Ir and Ru in acidic media, and it showed extremely high electrochemical stability in the OER potential range. Its oxygen reduction reaction (ORR) was obtained after potential cycles down to the hydrogen region, which formed a thin Pt metallic layer over the oxide. While its specific activity was not more than that of pure platinum nanoparticles, its durability against the potential cycles was much higher.

Analyses of Li has been performed by reflection electron energy-loss spectroscopy (REELS) technique, using a scanning electron microscopy (SEM) apparatus, where Li signals can be detected with high spatial resolution without severe requirements for sample shapes. For Li 4 Ti 5 O 12 and Li 7 Ti 5 O 12 samples as electrode materials of Li-ion batteries, the Li distribution was successfully revealed by the spectrum-imaging scheme. The fine structure of REELS spectra was able to be applied to the chemical analysis of Li-containing compounds.

Composite electrodes composed of amorphous titanium polysulfide (a-TiSx) and titanium disulfide (TiS2) were designed for application in all-solid-state batteries. The conductivity of the a-TiSx/TiS2-based working electrode was higher than that of the amorphous TiS4 (a-TiS4); the reversible capacity of the cell using a-TiSx/TiS2 electrode was higher than that of the cell using a-TiS4. Designing nanocomposite materials such as the a-TiSx/TiS2 described in this paper is an effective way to improve the performance of all-solid-state batteries.

The enhancement of the oxygen reduction reaction (ORR) activity of Pt catalysts by porphyrazines (tetraazaporphyrin and phthalocyanine) is analyzed electrochemically. While tetra(t-butyl)tetraazaporphyrin significantly enhances the ORR activity, the enhancement by dilithium phthalocyanine is limited; this molecule increases the ORR at high potentials but decreases it at low potentials. The cyclic voltammograms (CVs) under an Ar atmosphere and a Tafel analysis reveal that the phthalocyanine promotes the ORR by destabilization of OHad, an intermediate of the ORR, at high potentials. However, this positive effect of the phthalocyanine is counteracted by its inhibitory effects at low potentials. Thus, the tetra(t-butyl)tetraazaporphyrin, which does not have a significant inhibitory effect, would be a better enhancer. The method for preparing tetra(t-butyl)tetraazaporphyrin-adsorbed Pt catalysts was investigated. This molecule is not only mainly adsorbed on a carbon black support, but also adsorbed on the surface of Pt nanoparticles. Tetra(t-butyl)tetraazaporphyrin-adsorbed carbon-supported Pt nanoparticles are prepared by an equilibrium adsorption method and an evaporation-to-dryness method. The optimized preparation method is discussed. Using the evaporation-to-dryness method, we also examined the effects of several porphyrins on the ORR of Pt catalysts.

Lithium metal has been considered as an attractive candidate of the anode material for the next-generation secondary batteries because of its high theoretical capacity and low redox potential. Among a lot of strategies in order to suppress the inhomogeneous or dendritic growth of lithium during deposition have been proposed so far, some reports suggested that the trace-amount of water leads to smooth the morphology of deposited lithium metal. (1, 2) However, the relationship between the morphology of deposited lithium metal and the content of the electrolyte which changes with the time after addition of the water is not clear. In the present study, we investigated the electrodeposition of lithium in LiPF6-based electrolyte with trace-amount of water. Especially, we focused on the change of the morphology and surface state of the deposited lithium metal with the content of the electrolyte. 100 ppm of water was added into 1.0 mol dm–3 LiPF6 in propylene carbonate (PC) in the Ar-filled glove box and temporal change of its water content was checked by Karl-Fischer titration method. The water content was gradually decreased with time due to the reaction of LiPF6 and water. (3) When the electrodeposition of lithium was conducted on the copper electrode in the electrolyte, the morphology of the deposited lithium changed from inhomogeneous to granular and smooth as time passes after addition of water. This result proposed that the decomposed product in the electrolyte was strongly affected to the morphology of the deposit. (4) We also checked the surface state of the deposits by auger electron spectroscopy, X-ray and hard X-ray photoelectron spectroscopy, suggesting that the component of the film greatly influences the morphology of the deposit. Acknowledgement This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) under the “Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2)” References J. Qian, W. Xu, P. Bhattacharya, M. Engelhard, W. A. Henderson, Y. Zhang and J.-G. Zhang, Nano Energy, 15, 135 (2015). H. Koshikawa, S. Matsuda, K. Kamiya, Y. Kubo, K. Uosaki, K. Hashimoto and S. Nakanishi, J. Power Sources, 350, 73 (2017). D. Strmcnik, I. E. Castelli, J. G. Connell, D. Haering, M. Zorko, P. Martins, P. P. Lopes, B. Genorio, T. Østergaard, H. A. Gasteiger, F. Maglia, B. K. Antonopoulos, V. R. Stamenkovic, J. Rossmeisl and N. M. Markovic, Nature Catalysis, 1, 255 (2018). K. Kanamura, S. Shiraishi and Z. Takehara, J. Electrochem. Soc., 143, 2187 (1996).

Composite electrodes based on amorphous titanium polysulfide and acetylene black were mechanically prepared, and their performance was investigated. The amorphous TiS4 and acetylene black composites were discharged and charged with a high reversible capacity of 563 mAh g−1 in the 1.9–3.0 voltage range. The Coulombic efficiency of the composite was higher than that of a sulfur electrode because the dissolution of the polysulfide into electrolytes was suppressed. Amorphization and dispersion of carbon inside the particles were effective in improving the performance of the titanium polysulfide electrodes. Keywords: Lithium batteries, Titanium sulfide, Polysulfide, Lithium–sulfur batteries

Experimental We mechanochemically synthesized the a-NbSx at room tempera- ture. Appropriate amounts of sulfur (S8, 99.9%, Wako Pure Chemical Industries) and niobium disulfide (NbS2, 99%, High Purity Chemi- cals) were weighed and mixed, and the 1.5-g mixture and 500 4-mm- diameter zirconia balls were placed into a 45-mL zirconia pot in a planetary ball mill (P-7, Fritsch GmbH) in an Ar-filled glove box. The mixture was ball-milled at 510 rpm until the amorphous powder was obtained. The X-Ray diffraction (XRD) patterns for the synthesized sam- ples were recorded using an X-ray diffractometer (Rotaflex RU- 200B/RINT, Rigaku). Prior to the measurements, the samples were covered with Kapton film in a glove box to prevent exposure to air. The conductivities of the prepared samples were measured using a two-electrodecell.Thepelletsusedfortheconductivitymeasurements were prepared by pressing powder samples under 360 MPa at 25 ◦ C. A TITAN3 G2 60-300 electron microscope (FEI, Co., Ltd.) was used for the transmission electron microscopy (TEM) measurements. The a-NbS5 powder was directly dispersed on a Cu-mesh-supported carbon film for the TEM measurements. The working electrodes were prepared from a-NbSx (10 mg), acetylene black (1 mg), and polytetrafluoroethylene (PTFE) powder (0.7 mg). A 1 M solution of LiPF6 dissolved in a 1:1 volumet- ric mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) (Tomiyama Pure Chemical Industries, Ltd.) was used as the electrolyte. The counter electrode consisted of a 15-mm-diameter, 0.2-mm-thick Li foil disk. A charge-discharge unit (TOSCAT-3100, Toyo System) was used to perform the electrochemical measurements at 30 ◦ C and 100 μ Ac m −2 between 1.5 and 3.0 V.

We performed first-principles calculations of stable atomic structure and partial density of states (PDOS) analysis of Ethylene (C2H4) adsorption on Pd(100) surface stacked on fcc-Au using the projector augmented-wave (PAW) method. In case of Pd overlayers on the Au(100) substrate, from the analysis of PDOS around surface, highest occupied states become sharpen compared with the case of C2H4 adsorption on Pd monometallic slab surface in both di- and  adsorption model.

Atomic and electronic structures of H-adsorbed Pd overlayers on Au(100) substrates have been studied by first-principles calculations. The geometric strain effects change the electronic structure and local reactivity of the surface. The lattice strained Pd overlayers on Au surfaces have larger adsorption energies for atomic hydrogen than the unstrained Pd slabs. Adsorption energies for several adsorption sites on the models with different numbers of Pd overlayers have been analyzed from the viewpoints of strains and H-Pd and H-substrate interactions.

Binary AuPd nanoparticles were prepared by sonochemical reduction of solutions containing Au3+, Pd2+ ions and surfactant (SDS: sodium dodecyl sulfate and PEG-MS: polyethylene glycol monostearate). When using SDS as an additive, AuPd nanoparticles became a core-shell structure of Au core and Pd shell. AuPd nanoparticle with core-shell structure has catalytic activity superior to alloyed particle or Pd nanoparticles. In order to study the electronic states of AuPd nanoparticles, positron annihilation Doppler broadening measurements by using slow positron beam (energy range of 0.1 to 10 keV) have been performed for AuPd nanoparticles. The size and shape of the nanoparticles are also examined by using transmission electron microscope (TEM). The differences of Doppler broadening parameters between core-shell, alloyed AuPd, pure Au and Pd particles were found. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The purification of raw iron oxide obtained from iron precipitation of the Zinc leach residue using the recrystallization method with Na2B4O7 flux and magnetic properties of Mn0.95Zn0.05Fe2O4 synthesized from resultant iron oxide has been investigated.The main purposes of present study are to decrease the heating temperature as much as possible for reduction of the purifing energy cost, and to examine effects of decrease in heating temperature on iron oxide morphology and removal of Zn, S, As, and effect of iron oxide purity on magnetic properties of Mn0.95Zn0.05Fe2O4 synthesized from resultant iron oxide.The main results obtained as follow:(1) Morphology of purified iron oxide is returned gradually from hexagon crystals pseudoparticles of original raw material as heating temperature is decreased.(2) From removal of Zn, S and As, heating temperature is possible to decrease from 1573K to 1273K.(3) Purity and magnetic properties of iron oxide have nearly no influence on magnetic properties of synthesised Mn0.95Zn0.05Fe2O4 ferrite.

ナホトカ号の事故では,流出オイル防除対策にはリアルタイムでオイル群の挙動を把握する必要があった。そのために船舶や航空機に搭載できて,小型かつ現場で使用できるセンサーが必要なことが分かった。著者らは今までにレーザを使用したリモートセンシングシステム(ライダー)の研究を行い,その技術と蛍光分析法を利用して海上での流出オイル検出システム(蛍光ライダー)を作製し,検証実験を行っている。実験室では,蛍光強度分析よりオイル種を相対的に区別できた。更にフィールドでは,ライダーを船舶に搭載し実船実験を行った。海上でオイルは見つからなかったが,海洋へ紫外光を照射すると蛍光を含んだスポットがその場で検出できた。この蛍光は海洋微生物起源であると考えられる。今回の研究での新たな展開として,オイルや化学物質流出事故後の環境回復状況についても計測できることも分かった。まだ検討の必要はあるが,船舶搭載での観測が可能であることが分かった。

The purification of raw iron oxide obtained from iron precipitation of the zinc leach residue using the recrystallization method with Na2B4O7 flux and their magnetic properties has been investigated. The main purpose of present study are to examine the effect of the prior water washing and decrease of amounts of Na2B4O7 flux on the purification of raw material. As a result, it was recognized that the prior water washing of raw material are undesirable, because of decrease of desulfurization in the purification by the sub-sequent recrystallization method,and the elimination of Zn, S and As in raw material is the best, when raw material/flux ratio is 70/30 and the prior water washing is not carried out. The magnetic properties is similar to that of α-Fe2O3 single crystal. The synthesis and magnetic properties of Mn-Zn ferrite from purified iron oxide were also examined.

Binary Au–Pd nanoparticles were synthesized by ultrasonic irradiation of solutions containing Au3+ and Pd2+ ions (the ion ratio from 0.3:0.7 to 0.9:0.1 mM) and cationic surfactant (SDS: sodium dodecyl sulfate). In each case the core–shell structure (Au core, Pd shell) was confirmed by scanning transmission electron microscopy (STEM). The mean diameters of them were all about 9 nm, and the thickness of the Pd shell depends on the ratio of Pd2+ and Au3+ ions in solution. In order to study the electronic states of core–shell nanoparticles and their dependence on shell thickness, Doppler broadening measurements were performed for Au–Pd core–shell nanoparticles by using slow positron beam technique. The ratio curves of Au–Pd particles did not match with those of pure Pd and pure Au, but a small difference in the low electron momentum region was observed among nanoparticles depending on Pd shell thickness.

In the pyrometallurgical treatment of tin, it is necessary to identify the proper chemical composition of slag based on the thermodynamic behavior and phase diagram for decreasing of tin losses with effective recovery of tin from slag. Although some studies were reported about the phase diagram of SnO-SiO2 binary system, which is basic system of slag in the tin smelting, those results show always disagreement. W hereas it is necessary to consider closely the stability of solid SnO with increasing in temperature when the specimen contains SnO component, because solid SnO decomposes easily by a disproportionation with increasing in temperature.In the present study, firstly, the disproportionation of solid SnO with increasing in temperature was examined, and then the liquidus of SnO-SiO2 binary system was also investigated by SnO or SiO2 saturation method.Furthermore the influence of CaO and FeO addition on the liquidus in SnO-SiO2 system was investigated. The results obtained were summarized as follows:Solid SnO decomposed with increasing in temperature in the following manner: SnO→Sn, SnO, Sn3O4→Sn, Sn3O4→Sn, Sn3O4, SnO2→Sn, SnO2.It was confirmed that the phase diagram of SnO-SiO2 system is an eutectic type and the rising of liquidus at SiO2 side is very sharp. And it was thought to be appropriate that a metasilicate phase, such as SnO·SiO2is existed in this system, and it seemed metastably intermediate product.The melting point of SnO-SiO2 system raised by CaO addition, while it lowered by FeO addition.

In the pyrometallurgical treatment of tin, it has been known that the selectionof optimum slag composition has a significant to promote a smelting efficiency.In order to decide the slag composition, it is essential to investigatethe thermodynamic characteristics of the molten slag, such as the activity of SnO in the slag.In the present study, the activity of SnO in the molten SnO-SiO2 binary systemwhich is the basic system of tin smelting slag was studied by EMF methodusing a zirconia solid electrolyte, and then the influence of addition of CaO, FeO and Al2O3 components on the activity of SnO was also examinated.The results obtained are summarized as follows:1) The activity of SnO in the molten SnO-SiO2 system shifts from positive tonegative compared with Raoult's low as the molar ratio of SiO2 is raised.2) The activity of SnO raises by additing CaO to SnO-SiO2 system, and this effecttend to be remarkable with increase of SiO2 content in the slag.3) The influence of FeO addition on the activity of SnO in SnO-SiO2 system isnot observed remarkably, but the activity of SnO raises slightly only in thecase in which SiO2 content in slag is high.4) The influence of Al2O3 addition on the activity of SnO in the SnO-SiO2 systemis not so observed.

The influences of the immersion of sinter into calcium halide aqueous solutions or suspensions and the subsequent drying of sinter on the reduction degradation index (RDI) and relative reducibility index (RI) were investigated.The immersion treatments of sinters were carried out at a room temperature in air and in vacuum. The calcium halide concentration of aqueous solution or suspension was changed from 1.0 to 10.0 wt%.When sinter was immersed into CaCl2 and CaBr2 aqueous solutions, RI remained at the same value of the original sinter, while the value of RDI decreased, in other words, the degradation during reduction was improved, particularly in case of CaBr2.On the other hand, when sinter was immersed into CaF2 suspension, the effect of the immersion treatment on RI and RDI was scarcely detected.

Treatment of dyspnea in patients with advanced cancer is an important issue. The purpose of the present study was to assess the effect of induced-metabolic alkalosis produced by administration of sodium bicarbonate on dyspneic sensation. In seven healthy subjects, dyspnea was induced by having them breathe with a flow-resistive load (24 cm H2O/L/sec) for 6 min before and after administration of sodium bicarbonate (0.5 mmol/kg, per os + 2 mmol/kg, IV). The intensity of dyspnea was rated using a visual analogue scale (VAS). The VAS scores and minute ventilation during loaded breathing after administration of sodium bicarbonate were significantly lower than those before administration of sodium bicarbonate. These results indicate that induced metabolic alkalosis may alleviate the intensity of dyspneic sensation by a reduction in ventilatory drive.

The structure of Au-Pd nanoparticles prepared by the sonochemical method was observed by an analytical TEM. The core (Au)-shell (Pd) structure was confirmed by ADF-STEM images. The ratio of Au and Pd contents was controlled by adjusting the ratio of precursors, and the Pd-shell thickness was also controlled by the ratio of Au and Pd contents. The electron diffraction patterns showed that the lattice constant of the Pd shell is quite larger than that of bulk Pd and rather similar to that of bulk Au even in the systems with larger ratios of Pd, which supports the pseudomorphic growth of the Pd shell on the Au core.

The immersion of sintered product into CaCl2, CaBr2 aqueous solution and CaF2 suspended solution at room temperature in vacuum and subsequent drying have been carried out. The halide concentration of solution was changed from 0.5 wt% to 10.0 wt%. The effect of immersion treatment on the reducibility index (RI) and reduction degradation index (RDI) of sintered product have been studied.The main results obtained are as follows:(1) On the immersion into CaCl2 aqueous solution, RI was slightly decreased and RDI remarkably im-proved.(2) On the immersion into CaBr2 aqueous solution, RI was maintained in the value of original sintered product and RDI was more improved than in the case of CaCl2 solution.(3) On the immersion into CaF2 and Ca(OH)2 suspended solution, the effect of immersion treatment on RI and RDI was scarcely seen.(4) Improvement of RDI was caused by the delay of the reduction rate due to CaCl2 and CaBr2 layer adhered inside of the pore and resultant decrease of the amount of cracked magnetite particles.