bluuebunny/crossref_metadata_2025 huggingface dataset:
(Max Bredig Award Presentation) From Slags to Molten Salts to Ionic Liquids: A 50 Year Joyride
Authors: Angell C. Austen
Published: October 2010

In the 1950's the literature on liquid silicates was mostly concerned with their function as scavengers for unwanted components in the metals extraction process. The slags were described as collections of oxide molecules. Then John Bockris, at Imperial College of Science, London, entered the scene to end this nonsense, and introduced the term "ionic liquids" for the first time. My M.Sc. Advisor in Chemical Metallurgy at Melbourne University, Mervyn Willis, told me this was the way to go, so I dropped the PbO-FeO-Fe2O3 -SiO2 4D phase diagram project I had been working on and joined Bockris' group (now at Penn) in 1956. That started a long journey through liquid silicates, molten salts, concentrated aqueous and non-aqueous solutions and back to ionic liquids, touching many personalities and countries, about which I would like to tell something.We take this opportunity to bring together in the same document, two fundamental energy level diagrams (4 decades apart in their development) that deal with the ionic liquid states of electrons, on the one hand, and protons, on the other.
(Invited) New Functionalized Imidazolium-Based Room-Temperature Ionic Liquids and Composite Materials for Gas Separation and Selective Transport Applications
Authors: Gin Douglas , Noble Richard , Carlisle Trevor , Voss Bret , Bara Jason , LaFrate Andrew , Miller A. Lee , Hudiono Yeny , Wiesenauer Brian , Reynolds Magdalene
Published: October 2010

The design and synthesis of several new types of functionalized, imidazolium-based room-temperature ion liquids (RTILs), ionic polymers based on RTILs, solid-liquid poly(RTIL)-RTIL composites, and gelled RTIL systems for gas separation and selective transport applications are presented. The design principles behind these new functionalized RTIL materials will be discussed in the context of (1) CO2 separation from CH4 and N2 for natural gas purification and greenhouse gas reduction, respectively; and (2) selective blocking or sorption of chemical warfare agent simulants and toxic industrial compounds from water vapor for defense applications. The role of the RTIL components and their unique properties in these two application areas will be highlighted.
Ionic Liquid/Zeolite Composites: Synthesis and Characterization Using Vibrational Spectroscopy Techniques
Authors: Ntais Spyridon , Moschovi Anastasia , Dracopoulos Vassilis , Nikolakis Vladimiros
Published: October 2010

In this work, we studied the synthesis of zeolite (Z) - ionic liquid (ILs) composites with properties of potential interest to fuel cell technology. Such composites might reduce the fuel crossover and enable operation at low humidity levels. In particular, we examined the entrapment of the protic ionic liquid H-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (HMITFSI) into zeolite NaY. The composites were characterized using XRD and FT-Raman spectroscopy. XRD measurements showed no loss of crystallinity after the entrapment procedure. It is also shown that FT-Raman can be used in order to estimate the IL/Z weight ratio of the composites. Moreover, FT-Raman spectra revealed the presence of both ions in the composite after Soxhlet extraction and that the anion tends to adopt the cis instead of the trans conformation which is dominant in pure IL.
Synthesis and Characterization of Choline Chloride Based Binary Mixtures
Authors: Abbas Qamar , Binder Leo
Published: October 2010

Choline chloride based eutectic solvents are of major importance in applied chemistry. They are being used in the fields of Electropolishing, Electrodeposition, Organic synthesis, Biocatalytic reactions and many more. We have synthesized new solvents based on choline chloride, the other component being good hydrogen bond donor (HBD). Binary mixtures based on choline chloride were synthesized with ethylene glycol (EG), glycerol (PG), DMSO, DMF and Urea as HBDs. Further thermogravimeteric analysis (TGA) and differential scanning calorimetry (DSC) measurements of these binary mixtures were carried out. It was noticed that these mixtures are stable liquids at room temperature, cheap and environment friendly solvents. These liquids have low vapor pressure and can be used for various applications in the field of chemistry.
(Invited) Controlled Chemistry of Moisture Sensitive Reagents in Ionic Liquids
Authors: Amigues E. , Hardacre Christopher , Keane G. , Migaud M. , Norman S. , Pitner W.
Published: October 2010

Many reactions involving phosphorus reagents require highly anhydrous and inert conditions for their successful implementation. In particular, the use of PCl3 and its derivatives for synthesis is often hampered by the inherent sensitivity of the materials themselves. Ionic liquids are emerging as green alternative solvents for a range of processes, and in particular have proven to be excellent media for highly sensitive phosphorus reagents without the need for anhydrous or inert conditions. Herein, we report the use of ionic liquids as both storage and reaction media which allows difficult and sensitive chemistry to be achieved in a more accessible manner.
Process Variables that Control Natural Fiber Welding
Authors: Haverhals Luke M. , Sulpizio Hadley M. , Fayos Zane A. , Trulove Matthew A. , Reichert William M. , Foley Matthew P. , De Long H. C. , Trulove P. C.
Published: October 2010

Preliminary data are shown for a systematic study of the variables that control the fiber welding process. Cotton cloth samples are treated with various amounts of 1-ethyl-3-methylimidazolium acetate for a series of times and temperatures. Processed materials are characterized by scanning electron microscopy, infrared spectroscopy, x-ray diffraction, and mechanical (tensile) testing. Chemical and physical properties are shown to be controllably modified with careful management of process variables.
Characterization of Polymer Movement in Fiber Welded Cellulose Composites
Authors: Haverhals Luke M. , Sulpizio Hadley M. , Fayos Zane A. , Trulove Matthew A. , Reichert William M. , Foley Matthew P. , De Long H. C. , Trulove P. C.
Published: October 2010

Several examples of fiber welding were characterized by visible, fluorescent, and scanning electron microscopies to evaluate polymer reorganization. Distinct morphologies were observed that are process dependent. The characterization of process controlled sample morphology is the basis for understanding observed bulk physical properties such as tensile strength and the modulus.
Microencapsulated POSS in Cellulose Using 1-Ethyl-3-Methylimidazolium Acetate
Authors: Fox Douglas M. , Lee Jieun , Jones Jennifer , Zammarano Mauro , Gilman Jeffrey
Published: October 2010

Polyhedral oligomeric silsesquioxane (POSS) and cellulose were reacted in the ionic liquid, 1-ethyl-3-methylimidazolium acetate (EmiAc). Side reactions between the EmiAc and each reactant were prevalent, but use of water as the coagulating solvent produced microencapsulated POSS in cellulose. Effects of cellulose sources, POSS reactive groups, NaOH pretreatment of cellulose, and regenerating solvent were examined using elemental analysis, infrared spectroscopy, nuclear magnetic resonance, and thermogravimetric analysis. POSS - cellulose products had good thermal stability and a high char yield. The high char yield indicates that the cellulose encapsulated POSS may be usable as a carbonization agent in intumescent flame retardant formulations.
Investigation of Fluoroacidity in Molten Fluorides by the Combination of High Temperature NMR and Molecular Dynamics
Authors: Moussaed Georges , Gobet Mallory , Rollet Anne Laure , Sarou-Kanian Vincent , Salanne Mathieu , Simon Christian , Bessada Catherine
Published: October 2010

The acidity of a molten salt will act directly on the formation of complexes involving the cations of the melt. The determination of the speciation with varying overall composition therefore provides an indirect measure of the acidity. This opens a route for building up the acidity scale through the use of some specific in situ spectroscopic approaches. To determine the speciation in the liquid state, Nuclear Magnetic Resonance (NMR) appears as the ideal candidate, as it allows estimating the relative concentration of the various complexes formed in the melt. In parallel, Molecular Dynamics (MD) simulations are the unavoidable complement to this experimental technique. In this work we describe the structure and the dynamics in the LiF-CaF2 system.
Stability of Iridium Anode in Molten Oxide Electrolysis for Ironmaking: Influence of Slag Basicity
Authors: Kim Hojong , Paramore James D. , Allanore Antoine , Sadoway Donald R.
Published: October 2010

Molten oxide electrolysis (MOE) is a carbon-neutral, electrochemical technique to decompose metal oxide directly into liquid metal and oxygen gas upon use of an inert anode. What sets MOE apart from other technologies is its potential environmental advantage of no greenhouse gas emissions. Therefore, the primary challenge for carbon-free molten oxide electrolysis is the development of an inert anode. In the quest for an inert anode that can sustain the aggressive conditions of the process, iridium has been evaluated in two different slags for ironmaking. The basicity of the electrolyte proves to have a dramatic effect on the stability of the iridium anode, where iridium corrosion in an acidic slag with high silica content is less pronounced than the corrosion rate in a basic slag with high calcia content.
Production of Tantalum Fine Powder by Reducing Tantalum Chloride with Zinc in Molten Salt
Authors: Onodera Kiyotaka , Hoshino Yosuke , Takeda Osamu , Sato Yuzuru
Published: October 2010

Production of tantalum (Ta) powder was studied by means of injection of tantalum chloride (TaCl5) vapor into molten LiCl-KCl containing molten metallic zinc (Zn). Production experiments were carried out in the temperature range of 773~973 K, and the feed rate of TaCl5 vapor was set at 42~180 mg•min-1 by precisely controlling the vapor pressure of TaCl5 with an external heater. As a result, purity of Ta powder product increased with increasing experimental temperature. Although the purity of Ta powder obtained is almost independent of the injecting position of TaCl5, the yield was high when TaCl5 was injected inside molten Zn.
Direct Electrolytic Reduction of Powdery SiO2 in Molten CaCl2 with Pellet-Type SiO2 Contacting Electrodes
Authors: Kobayashi Katsutoshi , Nohira Toshiyuki , Hagiwara Rika , Ichitsubo Koki , Yamada Kazuo
Published: October 2010

Direct electrolytic reduction of powdery SiO2 has been investigated in molten CaCl2 at 1123 K aiming at a low-cost production of solar-grade Si. Pellet-type SiO2 contacting electrodes composed of a palletized SiO2 powder and a lead material of a Si rod or a Pt wire were newly contrived, and the impurity levels of the produced Si were evaluated. A two-electrode method was also applied, which considerably lowered impurity levels of metal elements in the produced Si. The concentrations of impurities contained in the original SiO2 powders, the prepared SiO2 pellets and the electrolyzed samples were traced with ICP-AES and GD-MS analyses. It was revealed that B and P concentrations were not significantly increased in the electrolysis. Another pellet-type SiO2 contacting electrode, in which three pellets composed of SiO2 and Si powders were attached to a Si rod, was also devised for the improvement of reduction rate.
Electrochemistry of the Nb(V)/Nb(IV) Redox Couple in the KCl-K2NbF7 Melt
Authors: Popova Anna , Kuznetsov Sergey
Published: October 2010

The electrochemistry of the Nb(V)/Nb(IV) redox couple in the KCl-K2NbF7 melt has been studied at 1073-1173 K on glassy carbon and platinum electrodes by transient electrochemical techniques. The diffusion coefficients of Nb(V) and Nb(IV) were determined by linear sweep voltammetry, chronopotentiometry and chronoamperometry. The values obtained by these methods at the different substrates are also in a good agreement. Diffusion coefficients decreased when niobium oxidation state increased, while the activation energies for diffusion increased. The standard rate constants of charge transfer (ks) on platinum and glassy carbon electrodes for Nb(V)/Nb(IV) redox couple were calculated on the basis of cyclic voltammetry data at a sweep rate 0.75 < v ≤ 2.0 V s-1, where a mixed diffusion and electron-transfer control was observed. It was found that ks increased with increasing temperature and values of ks obtained at platinum electrode were higher than at a glassy carbon electrode. The values of the standard rate constants testify that the redox process Nb(V) + e- ↔ Nb(IV) proceeds quasi-reversibly, mostly under diffusion control.
Cyclic Voltammetry of Solid TiO2 in Molten Alkali Chlorides
Authors: Jiang Kai , Hu Xiaohong , Jin Xianbo , Wang Dihua , Chen George
Published: October 2010

This paper presents the cyclic voltammetric (CV) studies of solid TiO2 in different molten alkali chlorides using "TiO2 powder modified molybdenum electrodes". The results are important for understanding the cathodic electrochemical process of solid metal oxides in molten salts. The constant voltage electrolysis products are also discussed in this paper.
Electronic Absorption Spectra of Vanadium Species in Halide Melts
Authors: Chernyshov Mikhail V. , Polovov Ilya B. , Volkovich Vladimir A. , Vasin Boris D. , Rebrin Oleg I. , Vinogradov Konstantin V. , Griffiths Trevor R.
Published: October 2010

Physico-chemical behavior of vanadium in chloride melts was studied using high temperature electronic absorption spectroscopy and spectroelectrochemistry. Dissolution of VCl3 in molten chloride leads to the formation V(III) species, VCl63-. Vanadium(II) complex ions VCl64- are formed during electroreduction of vanadium(III)-containing melts and vanadium metal anodic dissolution. V(II) chloro-species slowly react with silica to form an oxygen-containing insoluble phase. Due to high volatility of VCl4 oxygen-containing vanadyl species, VOCl42-, is the only stable form of V(IV) in fused chlorides. It is formed when V2O5, V2O4 or V2O3 react with HCl. Electroreduction of vanadyl complexes leads to the formation of insoluble oxygen-containing vanadium(III)species, whereas electrochemical oxidation has no effect on vanadium speciation, VO3+/VO2+ red-ox potential is more positive than Cl2/Cl-. Further oxidation VO2+ species gives vanadate anions. The electronic absorption spectra of soluble vanadium species were measured in 3LiCl-2KCl, NaCl-KCl and NaCl-2CsCl mixtures at 450-750 0C.
Processing of Vanadium and Niobium Electrodeposited from Alkali Chloride Melts
Authors: Chernyshov Mikhail V. , Polovov Ilya B. , Rebrin Oleg I. , Volkovich Vladimir A. , Kamalov Robert V. , Griffiths Trevor R.
Published: October 2010

The methods of hydrometallurgical treatment of cathodic deposits obtained by electrorefining vanadium and niobium metals in chloride melts were studied. The effectiveness of employing nitric acid was demonstrated. The optimal conditions of leaching trapped salt were determined: HNO3 concentration of 2.5 wt. % for vanadium and 5 wt. % for niobium; solid-to-liquid ratio 1:10 for both metals. The effect of increasing duration of a washing cycle on number of process stages was investigated. The methods of final washing and drying metallic powders were considered.
CuO Solubility in Alkali-Chloride Melts
Authors: Skryptun Igor N.
Published: October 2010

Used method of isothermal saturation solubility of copper (II) oxide in alkali and alkaline-salt melts has been investigated at temperature range 673 - 873 K. It was determined that solubility of CuO in the order of melts LiOH < NaOH < KOH are increased. The effect of temperature on the CuO solubility in alkali melts are described of the equation of straight line lnC = A + B/T, where C is concentration of the CuO in the melts, mole fract., A and B are constants. The salt additions of lithium chloride, sodium chloride and potassium chloride to sodium hydroxide melt are decreased the solubility of copper (II) oxide.
Investigation of the Interaction of Components in the System NaF-LiF-LaF3
Authors: Savchuk Ruslan , Faidyuk Natalija
Published: October 2010

The system NaF-LiF-LaF3 has been investigated by differential thermal and X-ray phase analysis, as well as IR spectroscopy. It has been found that the sodium fluoride-lithium fluoride-lanthanum fluoride system consists of one eutectic (mol.%): NaF(44.0)-LiF(42.0)-LaF3(14.0) with a melting point of 580±2°C and one peritectic NaF(45.0)-LiF(39.0)-LaF3(16.0) with a melting point of 595±2°C, which corresponds to the compound NaLaF4 with incongruent character of melting.
Corrosion of Stainless Steel in NaCl-KCl Based Melts
Authors: Polovov Ilya B. , Abramov Alexander V. , Rebrin Oleg I. , Volkovich Vladimir A. , Denisov Eugeniy , Griffiths Trevor R. , May Iain , Kinoshita Hajime
Published: October 2010

Corrosion behavior of stainless steel types AISI 316L, 316Ti and 321 was studied at 750 0C in NaCl-KCl equimolar melts. Iron, chromium and manganese species constitute the major corrosion products. The following mechanism of stainless steel corrosion in molten chlorides was proposed: 1) chemical interaction between the alloy and the salt intensified by the formation of microgalvanic pairs; 2) formation of chromium and molybdenum carbide-containing phases in steel as a result of heating to 750 0C; 3) additional formation of galvanic pairs between the grains of austenitic alloys and the carbide phases at the grain boundaries resulting in enhanced intergranular corrosion.
The Standard Rate Constants of Charge Transfer for the CR(III)/Cr(II) Couple in NaCl-KCl-CrCl3 and NaCl-KCl-K3CrF6 Molten Salts
Authors: Stulov Yuriy , Kuznetsov Sergey
Published: October 2010

Cyclic voltammetry was used to determine standard constants of charge transfer rate at a glassy-carbon electrode for the Cr(III)/Cr(II) redox couple in the NaCl-KCl-CrCl3 and NaCl-KCl-K3CrF6 systems in the temperature range of 973-1173 K. It has been demonstrated that ks increases with temperature increase. The activation energies during the chromium ions recharging have been calculated. The obtained results are explained from the standpoint of complexation in molten salts.
(Invited) Pyrochemical Reprocessing of Used Nuclear Fuels
Authors: Koyama Tadafumi , Sakamura Yoshiharu , Iizuka Masatoshi
Published: October 2010

Pyrochemical reprocessing has potential advantage in proliferation resistance, reduction of waste burden and economy. The authors have been developing pyrochemistry since late 80s with both domestic and international collaborations. In addition to electrochemical properties such as standard potentials in LiCl-KCl eutectic melt, thermodynamic properties necessary for understanding process chemistry have been measured. Flowsheet has been developed through experiments with using active and inactive elements. Demonstration of the technological feasibility for industrialization are being carried out through the development of the engineering-scale equipments.
Effect of Addition of Multi-Component Lanthanides to LiCl-KCl Eutectic on Thermal and Electrochemical Properties
Authors: Misra Mano , Raja Krishnan S. , Jaques Alonso V. , Baral Sudhir
Published: October 2010

Pyrochemical or pyrometallurgical processing using LiCl-KCl molten salt systems is considered one of the alternatives to the PUREX process for safe and proliferation resistant recovery of nuclear fuel elements from the spent fuels. Most of the available thermodynamic data on the molten salt systems pertain to binary or ternary systems. When multiple fission product elements are present in the electrolyte, the reduction behavior of the actinides could be significantly altered because of possible under potential reduction of lanthanides and slower diffusion kinetics of actinides. This presentation reports the variations in melting point and electrochemical behavior of LiCl + KCl eutectic mixture containing multi-components of RECl3 additions. No significant change in the melting temperature was observed with the addition of multiple lanthanide chlorides o the LiCl-KCl eutectic. However, the reduction potential was shifted in the positive direction with the addition of multiple lanthanides, especially when CeCl3 was one of the constituent.
In Situ Experimental Approach of the Speciation in Molten Lanthanide and Actinide Fluorides Combining NMR, EXAFS and Molecular Dynamics
Authors: Bessada Catherine , Pauvert Olivier , Zanghi Didier , Rollet Anne Laure , Sarou-Kanian Vincent , Gobet Mallory , Moussaed Georges , Rakhmatullin Aydar , Salanne Mathieu , Simon Christian , Matsuura Haruaki
Published: October 2010

We study the nature and the distribution of the different anionic species existing in fluoride melts of nuclear interest. Our approach is based on the combination of NMR and EXAFS spectroscopy, both sensitive to the microstructure of the melt, with Molecular Dynamics calculations. Because of its analogy with actinide fluorides, we have studied zirconium fluoride and its mixtures with alkali fluorides. In MF-ZrF4 systems, MD simulations, in agreement with 91Zr and 19F NMR and EXAFS experiments, put in evidence the coexistence of 3 different Zr-based complexes [ZrF6]2-, [ZrF7]3-, and [ZrF8]4- in the melt. Their proportions depend on the amount of ZrF4 and on the nature of the alkali (Li+, Na+ and K+). In the case of lanthanide fluorides, a similar approach performed in the system MF-LaF3 evidences some structural similarity, mainly with the existence of different complexes and upon free fluorine content evolution.
The Effect of Fission Product Elements on the Behavior of Uranyl Species in Alkali Chloride Melts: a Contribution towards Reprocessing Spent Oxide Fuels
Authors: Volkovich Vladimir A. , Aleksandrov Denis E. , Vasin Boris D. , Maltsev Dmitrii S. , Griffiths Trevor R.
Published: October 2010

The reactions of uranyl(VI) containing chloride melts with molybdenum, niobium, zirconium and palladium were studied using high temperature electronic absorption spectroscopy. Depending on the nature of the added element uranium is reduced to uranyl(V) and uranium(IV) chloro-species and UO2. Palladium, niobium and zirconium can all be removed from a uranyl(VI)-containing melt using molybdenum metal and the melt can then be purified from Mo(III) ions by bubbling Cl2 gas. Such approach can be employed for removal a number of fission product elements from molten chloride baths during reprocessing spent oxide fuels.
Electrochemical and Spectroscopic Properties of Technetium in Fused Alkali Metal Chlorides
Authors: Volkovich Vladimir A. , Vasin Boris D. , Griffiths Trevor R.
Published: October 2010

The behavior of metallic technetium in chloride melts was studied for the first time. The experiments were conducted in NaCl-2CsCl eutectic melt at 550 oC using high temperature electronic absorption spectroscopy, cyclic voltammetry and chronopotentiometry. The anodic dissolution of Tc results in the formation of a mixture of Tc(IV) and a lower oxidation state species. Cyclic voltammograms of technetium-containing melts show two cathodic and two associated anodic peaks. One pair is around -0.35 V vs. Ag/AgCl reference electrode and is associated with the deposition of Tc metal.
Behavior of Molybdenum Chloro-Species in Alkali Chloride-Based Melts: Implications for Spent Nuclear Fuel Treatments
Authors: Volkovich Vladimir A. , Polovov Ilya B. , Kamalov Robert V. , Griffiths Trevor R.
Published: October 2010

Chloro-species of molybdenum in oxidation states (III), (IV) and (V) were studied in a range of alkali chloride melts employing high temperature electronic absorption spectroscopy. The reaction rates of disproportionation of MoCl63- complex ions in various melts between 550 and 750 oC were determined. Mo(IV) species MoCl62- were generated and thermodynamic properties of Mo(IV) chloride in NaCl-CsCl eutectic melt estimated. Absorption spectra of molybdenum(V) MoCl6- were measured in a chloride melt for the first time. Speciation and behavior of molybdenum is required for designing processes for molten salt reprocessing of spent nuclear fuel (SNF).
Reaction of Curium(III) Ions with Oxo-Species in Alkali Chloride Melts
Authors: Osipenko Aleksandr G. , Maershin Aleksandr A. , Volkovich Vladimir A. , Kormilitsyn Mikhail V. , Bychkov Aleksandr V.
Published: October 2010

Electronic absorption spectra of curium(III) chloro-species were measured in 3LiCl-2KCl (at 450 oC) and NaCl-2CsCl (at 550, 650 and 750 oC) eutectic melts and the molar absorption coefficients determined. The effect of oxide species addition to the melt on the absorption spectra of curium was studied. A new species, evident from the absorption bands around 360 nm, is formed when barium oxide is dissolved in the melt or O2-Cl2 or Ar-HCl-H2O gas mixtures bubbled through. This species is ascribed to soluble curium oxychloride. It does not react with chlorine bubbled through the melt unless there is carbon present.
Electrodeposition of Crystalline Silicon Films from Alkali Fluoride Mixtures
Authors: Osen Karen S. , Martinez Ana Maria , Rolseth Sverre , Gudbrandsen Henrik , Juel Mari , Haarberg Geir Martin
Published: October 2010

The objective of this work was to study the electrodeposition of silicon in molten KF-LiF (eut)-K2SiF6 (5 mol%) on Ag and Si substrates at 550oC and 800oC. In addition electrochemical studies of the system were performed on silver, tungsten and glassy carbon substrates at 800oC. The electrochemical measurements confirmed that the reduction of Si is diffusion controlled and occurs in two steps. On silver, dense, coherent films with good adhesion and no inclusions of salt were obtained at 800oC at the growth rate 52 µm/hour. On silicon, the microstructure seemed to consist of small "randomly" oriented crystals. At 550oC, the deposit became porous and powderish both on silver and silicon substrates. The low temperature combined with the relatively high current densities applied was believed to hinder crystal growth.
Electrical Conductivity of the Coexisting System Containing Molten Carbonates and Rare-Earth Oxide
Authors: Mizuhata Minoru , Ohashi Toshifumi , Béléké Alexis B.
Published: October 2010

The electrical properties of CeO2/(Li0.52Na0.48)2CO3 coexisting system are investigated by AC impedance, differential thermal analysis and polarized Raman scattering spectroscopy. The system shows a dependence of the electrical conductivity upon the temperature. The transition point varies with the apparent average thickness of the liquid phase, while the activation energy remains constant at any distance from the solid phase. The symmetric stretching mode of the polarized Raman spectra shows that carbonate ion maintains its D3h
symmetry in the presence of ceria. A constant value of the depolarization ratio of the raman band with regard to the apparent average thickness confirms that the symmetry of carbonate ions in the molten state is not altered by the presence of ceria powder. These findings contribute to the understanding of the properties of ceria-based carbonate electrolyte for intermediate temperature fuel cells.
Oxygen Reduction Reaction on LaNiO3 in Li/Na Eutectic Carbonate Melt with La2O3
Authors: Matsuzawa Koichi , Watanabe Kouhei , Mitsushima Shigenori , Ota Ken-ichiro
Published: October 2010

In order to improve the performance of MCFCs, we have investigated the catalytic activity of LaNiO3 for the oxygen reduction reaction (ORR) in Li/Na eutectic carbonates with La oxide. Both LaNiO3 and NiO electrode was performed at meniscus state to compare the ORR activity. In order to obtain the apparent current density (i0) of LaNiO3 electrode and to analyze the reaction mechanism of ORR, the steady state polarization was performed from 0.1 to 0.9 atm of partial pressure of CO2 at 923 K. As a result, the i0 of LaNiO3 was almost same as that of NiO, and the reaction mechanism of ORR on LaNiO3 might be indicated the possibility of the multiple reaction of the superoxide mechanism and the percarbonate mechanism.
Electrowinning of Lithium from Molten Salt Containing LiOH for Hydrogen Storage and Transportation
Authors: Takeda Osamu , Li Mingming , Hoshi Masayoshi , Sato Yuzuru
Published: October 2010

Investigation on electrowinning of lithium from molten salt containing LiOH was conducted in order to develop a system of storage and transportation for hydrogen by using LiH as a storage medium. Electrolysis of LiOH in molten LiOH-42 mol% LiCl was tried, but lithium metal was not obtained. A chemical potential diagram for Li-O-H system was then constructed from thermochemical data for the analysis of side reactions, and a possibility of reaction between lithium metal and LiOH in the bath was revealed. Electrolysis of LiOH in molten LiCl-42 mol% KCl was tried by charging LiOH in an anode compartment comprised of a porous magnesia diaphragm in order to prevent the side reaction of lithium metal with LiOH, and lithium metal was successfully obtained.
(Invited) Amperometric Gas Detection Using Room Temperature Ionic Liquid Solvents
Authors: Rogers Emma I. , O'Mahony Aoife M. , Aldous Leigh , Compton Richard G.
Published: October 2010

The electrochemistry of various gases, including oxygen, carbon dioxide, hydrogen, ammonia, hydrogen sulfi de, sulfur dioxide and nitrogen dioxide, in room temperature ionic liquids (RTILs) is reviewed. The application of RTILs to gas sensor design and development is highlighted.
Photoassisted Anodic Oxidation of Bromide on an n-Type Titanium Dioxide Electrode in an Amide-Type Ionic Liquid
Authors: Katayama Yasushi , Koshizawa Saburo , Miura Takashi
Published: October 2010

Photoassisted anodic oxidation of bromide (Br-) on an n-type titanium dioxide (n-TiO2) electrode has been investigated in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing BMPBr at various concentrations. Photoassisted anodic oxidation of BMPTFSA was confirmed in the absence of BMPBr. A photoanodic current corresponding to the oxidation of Br- was observed under illumination of UV light. The onset potential of the photoanodic current was the function of the concentration of Br-, suggesting the flat band potential of the n-TiO2 electrode in the ionic liquid is related to the potential of zero charge, which is expected to be affected by the specific adsorption of Br- on the n-TiO2 electrode.
Potentiostatic Cu-Zn Alloying for Polymer Metallization Using Medium-Low Temperature Ionic Liquid Baths
Authors: Murase Kuniaki , Yanase Kozo , Ichii Takashi , Sugimura Hiroyuki
Published: October 2010

Cu-Zn alloy metallization of a non-conductive epoxy substrate was demonstrated through successive electrochemical processes: (i) conventional electroless Cu deposition on the substrate using an aqueous bath, and (ii) electrochemical alloying of the resulting Cu layer with Zn by a reduction-diffusion (RD) method using an ionic liquid bath at 150 {degree sign}C. The resulting Cu-Zn alloy layers were adhe-sive and were uniformly grown by maintaining the surface mor-phology of the initial electroless Cu. The Cu-Zn phases, i.e. γ-Cu5Zn8, β′-CuZn, and/or α-Cu(Zn), which define the color of the layers were dependent on applied potential during the RD alloying.
The Group I Alkali Metals in Ionic Liquids: Electrodeposition and Determination of Their Kinetic and Thermodynamic Properties
Authors: Wibowo Rahmat , Aldous Leigh , Ward Jones Sarah E. , Compton Richard G.
Published: October 2010

Cyclic voltammetric experiments were carried out on Li+, Na+, K+, Rb+ and Cs+ in ionic liquids (ILs). Alloy formation was noted at Pt microelectrodes, but not at Ni. A range of ILs was investigated to identify the best IL to study the M/M+ redox couples, and bulk electrodeposition of all metals was observed in at least one IL, N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]). Mathematical simulation of the CVs in this IL was conducted as a function of temperature. The diffusion coefficients, D, of the five metal ions were determined. The formal potential, Ef0 (vs. Fc/Fc+) of the five M/M+ couples was quantified, as well as the electrochemical rate constants, k0, and transfer coefficients, α. The activation energies of diffusion, Ea,dif, of Li+ and Na+ ions, and electron transfer, Ea, of Li/Li+ and Na/Na+ were determined, and ΔS0 (vs. Fc/Fc+) estimated for the Na/Na+ couple. The trends within the group are discussed.
Surface Characterization of High Purity Niobium Electropolished with an Ionic Liquid
Authors: Abdel-Fattah Tarek M. , Crooks Roy
Published: October 2010

We have performed screening tests on candidate solutions to replace hazardous acidic mixtures, such as HF, HNO3 and H3PO4, for the electrochemical polishing of niobium (Nb) superconducting radio frequency (SRF) cavities. The best results, in terms of surface roughness, were found for a relatively environmentally-benign mixture of ionic liquids: vitamin B4 (2-hydroxyethyl-trimethylammonium) chloride, urea, ethylene glycol and ammonium fluoride. Scanning electron microscope (SEM) imaging and atomic force microscopy (AFM) were used to compare the quality of a electrochemical polished surface by ionic liquids (IC) sample and a as-received (AR) sample. The average roughness, Ra, found for one of the (50x50 μm) IC areas examined, was 22 nm. These results suggest the possibility of an effective green process to be used during the production of Nb superconducting radio frequency cavities for the International Linear Collider (ILC).
(Invited) Bulk and Interfacial Behavior of Ionic Liquids from Molecular Dynamics Simulations
Authors: Borodin Oleg , Vatamanu Jenel , Smith Grant
Published: October 2010

Results of molecular dynamics simulations using many-body polarizable APPLE&P force field are presented for 34 ionic liquids covering a broad range of cations and anions. A relation between ionic liquid transport properties (ion self-diffusion coefficient and conductivity), thermodynamic properties (molar volume and heat of vaporization) and cation-anion binding energies are presented. Development of the nonpolarizable united atom force field for alkylpyrrolidinium and tetraalkyl ammonium-based ionic liquids is reported. The nonpolarizable force field yielded higher activation energy for ion transport as a function of temperature and slightly lower heat of vaporization. Interfacial properties of N-methyl-N-propylpyrrolidinium bis(trifluoromethane)sulfonyl imide near a graphite electrode and in nanopores have been studied as a function temperature and electrode potential.
Semi-Empirical Molecular Modeling Methods of Ionic Liquid Tribology: Ionic Liquid-Hydroxylated Silicon Surface Interactions
Authors: Nooruddin Naveed , Wahlbeck Phillip , Carper William R.
Published: October 2010

The interactions between eight ionic liquids and a rolling hydroxylated silicon surface are modeled in this report using various semi-empirical methods. The eight modeled ionic liquids consist of two sets for four ionic liquids from separate tribology studies. The first set of four ionic liquids contain the 1-butyl-3-methyl imidazolium cation (BMIM+) and include BMIM+-BF4-, BMIM+-NO3-, BMIM+-PF6- and BMIM+-ClO4-. The second set of ionic liquids contains the 1-methyl-3-X imidazolium cation and a Cl- anion. The four imidazolium sidechains (X) include -C3H6OH, -C2H4CN, -C3H7 and -C2H4COOH. The individual ionic liquids form complexes with the hydroxylated silicon surface and the enthalpies of complex formation calculated using PM3, PM5 and PM6 semi-empirical methods. The PM3 and PM5 computed ionic liquid-surface complex ΔrH enthalpies of complex formation correlate with the measured frictional coefficients of these ionic liquids. These results allow the investigator to possibly predict the success or failure of other ionic liquids once a baseline is established.
A Neutron Diffraction and Molecular Dynamics Investigation of Acetate-Based Ionic Liquids as Solvents for Glucose
Authors: Mullan Claire L. , Hardacre Christopher , Holbrey John , Lagunas Cristina , Youngs Tristan , Bowron Daniel , Gladden Lynn , Mantle Mick , D'Agostino Carmine
Published: October 2010

The liquid state structure of the ionic liquid, 1-ethyl-3-methylimidazolium acetate, and the solute/solvent structure of glucose dissolved in the ionic liquid at a 1:6 molar ratio have been investigated at 323 K by molecular dynamics simulations and neutron diffraction experiments using H/D isotopically substituted materials. Interactions between hydrogen-bond donating cation sites and polar, directional hydrogen-bond accepting acetate anions are examined. Ion-ion radial distribution functions for the neat ionic liquid, calculated from both MD and derived from the empirical potential structure refinement model to the experimental data, show the alternating shell-structure of anions around the cation, as anticipated. Spatial probability distributions reveal the main anion-to-cation features as in-plane interactions of anions with imidazolium ring hydrogens and cation-cation planar stacking. Interestingly, the presence of the polarised hydrogen-bond acceptor anion leads to increased anion-anion tail-tail structuring within each anion shell, indicating the onset of hydrophobic regions within the anion regions of the liquid.
Vibrational Spectra and Dynamics of Anions and Acids in Ionic Liquids
Authors: Owrutsky Jeff , Houchins Cassidy , Weidinger Daniel , Brown Douglas
Published: October 2010

Vibrational spectra and energy relaxation lifetimes are reported for the protonated acidic species hydrazoic acid (HN3) and the azide (N3-), thiocyanate (NCS-) and dicyanamide (DCA) anions in imidizolium and phosphonium ionic liquids (ILs). The vibrational spectra and dynamics for the anions in phosphonium tetrafluoroborate and dicyanamide ILs are similar to those previously reported for imidizolium ILs, which resemble the behavior in aprotic molecular solvents such as dimethylsulfoxide. The results are different for hydrazoic acid. In water, methanol and other protic solvents the energy relaxation time is shorter for the azide anion than its protonated and neutral counterpart, hydrazoic acid. In ILs, however, the anion relaxation times are faster than the acid, indicating that the intermolecular interactions are different for acids and anions in ILs compared to conventional molecular solvents.
Mechanical and Dynamic Properties of N,N,N,N-Tetramethylammonium Dicyanamide Plastic Crystal
Authors: Hooper Justin B. , Borodin Oleg
Published: October 2010

Elastic constants and relaxation of N,N,N,N-tetramethylammonium (TMA) dicyanamide (DCA) plastic crystal was investigated as a function of temperature using a quantum chemistry based, dipole polarizable force field. Simulations predict the [TMA][DCA] crystal structure and dimensions in good agreement with experiment. Ion-counterion spatial distributions are used to understand the local environment and ion pairing of both ions in crystalline and liquid phases. The rotational dynamics of ions in the crystalline system are thoroughly explored. Arrest of the DCA rotational degrees of freedom is associated with the experimentally observed solid-solid phase transitions.
Exploring the Effect of Structural Modification on the Physical Properties of Various Ionic Liquids
Authors: Lall-Ramnarine Sharon I. , Hatcher Jasmine , Castano Alejandra , Thomas Marie , Wishart James
Published: October 2010

A few classes of ionic liquids were synthesized and investigated for their physical properties as a function of structural variation. Bis(oxalato)borate (BOB) and bis(trifluoromethylsulfonyl)imide (NTf2) ionic liquids (ILs) containing pyridinium, 4-dimethylaminopyridinium (DMAP) and pyrrolidinium cations bearing alkyl, benzyl, hydroxyalkyl and alkoxy substituents, were prepared from the corresponding halide salts. The physical properties of the DMAP based ionic liquids including viscosity, conductivity and thermal profiles were compared to those of their unsubstituted pyridinium analogues. The properties of the BOB and NTf2 salts bearing similar cations were also compared. It was found that the DMAP salts were easier to synthesize and purify and have higher thermal decomposition points compared to their pyridinium and pyrrolidinium analogues. The BOB salts were found to be higher melting and more viscous than the NTf2 salts. The synthesis and physical properties of the various ILs will be discussed.
Effects of Crystal Packing on the Thermal Behavior of N,N'-alkylpiperidinium and N,N'-alkylmorpholinium Iodide Salts
Authors: Reichert William M. , Henderson W. A. , Trulove P. C. , Urban Joseph J. , De Long H. C.
Published: October 2010

The focus of this study was an investigation of the thermal and structural properties of a series of piperidinium (PIPxx) and morpholinium (MORPxx) iodide salts. This study explores the effects changes in the alkyl chain length and ring conformation has in the melting point and crystal packing. As well heteroatom substitution effect on the melting point and conformation of the ionic liquids will be investigated. An evaluation of the structural information and melting point data gave insight into the thermal behavior of these salts. By maintaining the anion and varying the alkyl chain length, we were able to observe the influence that chain length has on cation-anion interactions. The small changes in the cation, such as increasing the alkyl chain length or substituting a heteroatom into the ring, can lead to dramatic changes in the thermal properties.
Transport Properties in Cryolitic Melts: NMR Measurements and Molecular Dynamics Calculations of Self-Diffusion Coefficients
Authors: Gobet Mallory , Sarou-Kanian Vincent , Rollet Anne Laure , Salanne Mathieu , Simon Christian , Bessada Catherine
Published: October 2010

Thanks to the development of a new setup based on Pulsed Field Gradient NMR combined with laser heating, we have studied the dynamics of the different nuclei involved in NaF-AlF3 and LiF-AlF3 cryolitic melts (27Al, 23Na, 7Li and 19F). The self-diffusion coefficients measured in both systems depending on the composition allow a more precise description of the structure and of the nature of the anionic complexes. For LiF-AlF3, these experiments were combined with molecular dynamics simulations. NMR experiments and MD simulations are in good agreement especially concerning the activation energy of diffusion. Such approach is of primary importance for a better understanding of the physico-chemical properties of the cryolitic melts used in aluminum electrolysis.
ALD on High Mobility Channels: Engineering the Proper Gate Stack Passivation
Authors: Sioncke Sonja , Lin Hang-Chun , Adelmann Christoph , Brammertz Guy , Delabie A. , Conard Thierry , Franquet A. , Caymax Matty , Meuris Marc , Struyf Herbert , De Gendt S. , Heyns Marc M. , Fleischmann Claudia , Temst K. , Vantomme A. , Müller Matthias , Kolbe Michael , Beckhoff Burkhard , Schmeisser Dieter , Tallarida Massimo
Published: October 2010

High mobility channels are currently being explored to replace the Si channel in future technology nodes. However, until now the promising bulk properties are very difficult to translate into reality due to a bad passivation of the interface between the gate stack and the substrate. In this paper we want to emphasize that gate stack passivation is the result of a complex interplay between the surface treatment and the ALD deposition. During ALD deposition on GaAs, the removal of surface oxides is observed. However, this effect does not lead to a good passivation. For Ge, the S-passivation of the interface is studied in combination with different high-κ. It is clear that the Ge/S/Al2O3 interface is superior to the Ge/S/ZrO2 interface.
Atomic Layer Deposition for Nanoelectrode Devices
Authors: Willis Brian , Gupta Rahul , Ni Chao-Ying
Published: October 2010

Nanoelectrodes are of interest for a number of emerging nanoelectronics applications where it is desired to measure the electrical signatures of molecular scale devices. These new applications include molecular electronics and biochemical sensing, for example. A key challenge for nanoelectrode applications is the need to control structure and composition for devices where the active elements are on the order of 1 nm. Thus far, there are relatively few options for nanoelectrodes and existing methods do not allow control of nanoelectrode properties. In this paper we present an alternative method for nanoelectrode devices using Atomic Layer Deposition (ALD). ALD provides the subnanometer control required for molecular-scale devices and a means for scale-up. In addition, ALD provides a means to investigate the influence of atomic structure and chemical bonding on molecular scale measurements. Electrical data including tunneling spectroscopy are used to demonstrate the formation and properties of nanoscale devices with ALD.
Atomic Layer Deposition of Al2O3 on Biological Pili Substrate
Authors: Zhu Ye , Cao Binrui , Nicholas Robert , Mao Chuanbin , Kane Matthew
Published: October 2010

This work demonstrates the viability of pilus as a new biological substrate through the growth of Al2O3 by atomic layer deposition. In order to best realize the implementation potential of these new processing capabilities, materials processing by ALD on 3D biological pili templates were explored. The shape and size can be exactly determined by the biological template in a wide variety of shapes and sizes.. In order to get the pili as a substrate, the bacteria E. Coli were cultured and detached using a blending process. The optimal deposition temperature and cycle times were obtained for Al2O3 on the pili by ALD at 25 cycles, 100°C. TEM and electron diffraction were used to characterize the morphology and structure of the nanofibers after ALD deposition.
(Invited) Atomic Layer Deposition for Epitaxial Oxides on Silicon
Authors: Willis Brian , Zhang Changbin B.
Published: October 2010

Thin films of crystalline oxides integrated with silicon are of interest for novel devices that utilize the rich variety of functional properties of oxide materials. Growth of crystalline oxides on silicon requires careful control of a nanometer thin transition region to avoid deleterious side reactions such as oxidation of the substrate. Submonolayer surface reconstructions of alkaline earth metals such as Sr are key to controlling the interface for successful growth. Previously, this has only been accomplished using molecular beam epitaxy growth methods, but there is interest to create an alternative process based on atomic layer deposition. In this work we demonstrate the successful deposition of the critical (2x1) Sr/Si reconstruction using SrO ALD deposition combined with oxide desorption. The results show that ALD based crystalline oxide heteroepitaxy is promising.
Structural and Electrical Analysis of Thin Interface Control Layers of MgO or Al2O3 Deposited by Atomic Layer Deposition and Incorporated at the High-k/III-V Interface of MO2/InxGa1-xAs (M = Hf|Zr, x = 0|0.53) Gate Stacks
Authors: O'Mahony Aileen , Monaghan Scott , Chiodo Rosario , Povey Ian , Cherkaoui Karim , Nagle Roger , O'Connor Eamon , Long Rathnait , Djara Vladimir , O'Connell Dan , Crupi Felice , Pemble Martyn , Hurley Paul K.
Published: October 2010

Control of the high-k/III-V interface by deposition of thin (~1-2 nm) interface control layers (ICLs) of Al2O3 or MgO, as part of an overall bi-layer structure with a high-k metal oxide MO2 (M = Hf|Zr), is explored. An Al2O3 or MgO ICL is deposited on unpassivated InxGa1-xAs (x = 0|0.53) substrates prior to MO2 gate oxide deposition, forming a Pd/high-k/ICL/III-V gate stack. The aim of a bi-layer structure is to enable continued device scaling using a high-k MO2 oxide while improving the high-k/III-V interface quality and interfacial band structure, with an Al2O3 or MgO ICL. Metal-oxide-semiconductor capacitor (MOSCAP) devices with an Al2O3 ICL on p-GaAs display significantly reduced leakage current density, and reduced frequency dispersion of accumulation capacitance when compared to a no-ICL device, indicating an improved high-k/III-V band structure and interface quality, respectively. Further studies on ZrO2/Al2O3/In0.53Ga0.47As devices find a reduced defect response with a post-metal forming gas anneal.