bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micelle Mediated Extraction of Neodymium and Electrochemical Characterization of AOT Reverse Micelles
Authors: Anderson Shannon , Kalu Egwu Eric , Clark Clayton , Nilsson Mikael 
Published: February 2020

The extraction and separation of metal ions in the lanthanide series using the liquid-liquid extraction (LLX) technique poses a major challenge due to the chemical similarities of the metals. Hence, interest exists in devising a technique to improve the separation factor. The anionic surfactant, AOT, is proposed to pre-concentrate the metal from an aqueous phase through third phase formation and increasing the conductivity of the organic phase of a LLX experiment so an electric field can be applied to drive the extraction. Surfactants within LLX experiments have been shown to from a third phase and it is theorized that this phase is predominantly the surfactant and target metal, thus pre-concentrating the metal. The use of an imposed external field (electrochemical) to improve the LLX has been explored in the literature with limited success due to conductivity issues. In this work, the use of reverse micelle solutions containing water/AOT/n-dodecane for pre-concentrating Nd and water/AOT-HDEHP/n-dodecane for improved electrical conductivity is explored. The results of a feasibility study of the pre-concentration and electrochemical modulated extraction of neodymium (Nd) using the reverse micelles/microemulsions will be presented.
A concentration of 0.2 M AOT in n-dodecane was used to form a third phase in the extraction/pre-concentration of Nd from an aqueous solution using LLX. At and above an initial Nd concentration of 12 mM, third phase formed. As the initial concentration of the Nd increased, more Nd was extracted from the aqueous phase. Post-extraction washing of the organic phase resulted in approx. 56% of the Nd being accounted for. ICP will be used to determine if there is Nd in the third phase. Below an initial Nd concentration of 10 mM, third phase did not form and Nd was extracted. Post-extraction washing of the organic phase resulted in approx. 90% of the Nd being account for.
Electrochemical impedance (EIS) technique was used to determine the effect of molar content of water, Wo, and temperature on the reverse micelle solution conductivity. Results showed that as Wo increases, conductivity increases until the reverse micelles burst and form a biphasic system. Addition of HDEHP caused a significant drop in solution conductivity. Temperature has a mild effect on increasing the conductivity. Limited to applying 7 V, electrochemical extraction showed small improvement in Nd extraction percent over traditional LLX. The extraction percent of Nd in a liquid-liquid extraction cell containing reverse micelles and the mechanism of electrochemical modulated liquid-liquid metal ion extraction will be discussed.
Electrochemical Reduction of Molybdenium Compounds to Form Molybdenium Powder
Authors: Akpinar Bengisu , Erdogan Metehan , Karakaya Ishak 
Published: February 2020

Molybdenum (Mo) is a refractory metal and mostly used as an alloying agent in cast iron, steels and superalloys to enhance hardenability, strength, toughness and corrosion resistance. It also finds other uses either in the form of a pure metal or an element in, for example, lubricants and catalysts. Traditional metal production methods are not suitable for molybdenum because pure molybdenum has very high melting point and has a tendency to get oxidized at low temperatures. Hydrogen reduction of molybdenum oxide is a very common way for Mo production but, it has two stages during process. At the second stage, the reduction process needs very high temperatures, therefore, high energy consumption and special equipment requirement is essential.
FFC Cambridge process [1] based on electrochemical reduction of solid compounds was considered as an alternative way to produce molybdenum at relatively low temperatures. Similar to reduction of WO3 [2], loss of molybdenum as molybdenum oxychloride from MoO3 in CaCl2 containing molten salts is inevitable [3]. MoS2 powder pressed and sintered at 400oC to form pellets were used as starting material for electrochemical formation of pure Mo in molten CaCl2-NaCl salt mixture under argon gas at 800oC. A constant voltage in the range 1 to 3.0V was applied between MoS2 cathode and graphite anode. When the process was terminated at a prescribed time, the cathode was removed from the molten salt, cooled in argon, washed with water in air to dissolve the solidified salt, and then dried at about 100oC in vacuum before further analysis employing XRD, SEM and EDS.
[1] G.Z. Chen, D. J. Fray, T. W. Farthing, Direct Electrochemical Reduction of Titanium Dioxide to Titanium in Molten Calcium Chloride, Nature, 407 (2000), 361-364.
[2] M. Erdoğan, İ. Karakaya, Electrochemical Reduction of Tungsten Compounds to Produce Tungsten Powder, Metallurgical and Materials Transactions B, 41B (2010), 798-804.
[3] W.T. Thompson, C.W. Bale, and A.D. Pelton: Facility for the Analysis of Chemical Thermodynamics (FACT), McGill University Montreal, Royal Military College of Canada in Kingston, E´cole Polytechnique, Montreal, Canada, 1985.
Molecular Dynamics Simulations of Lithium Ion Transport through Solid Electrolyte Interface Layer
Authors: Muralidharan Ajay , Chaudhari Mangesh , Rempe Susan , Pratt Lawrence R 
Published: February 2020

Lithium ion transport through solid electrode interface (SEI) layer is elusive to molecular simulation studies due to lack of composition information and force field parameters available for organic SEI layer. Last decade, dilithium diethylene carbonate (Li2EDC) was suggested as the primary component of SEI layer using experiments and quantum mechanical simulations. We applied classical, non-polarizable OPLS-AA force field parameters to model SEI layer of Li2EDC molecules. Long time-scale molecular simulations at various temperatures (333, 500, 700K) were performed to calculate structural and transport properties of lithium ion in EDC. Vibrational power spectral analysis suggested two prominent modes of lithium vibrations at frequencies 400 and 650 cm-1 in EDC and pure ethylene carbonate solvents. These vibrational modes were further confirmed in Gaussian electronic structure calculations results. Self part of time dependent correlation function calculated using van Hove function confirm that EDC is crystalline compared to pure ethylene carbonate.
Sandia National Laboratories (SNL) is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's (DOE) National Nuclear Security Administration under Contract DE-AC04-94AL85000.
The Electrochemical Reduction of Organic Acids on Anatase-Type TiO2 Nanoparticles – a Theoretical Approach
Authors: Juhasz Gergely 
Published: February 2020

The electrochemical reduction of organic acids on anatase-type TiO2electrode has been recently reported by Yamauchi [1]. Such an electrochemical reaction has a potential to produce alcohol products with high selectivity and efficiency, which can be used as alternative fuel. However so far the reaction is reported only for oxalic acid, and other acids like acetic acid cannot be reduced.
This reaction raise many questions, including the mechanism or the electrochemical steps as well as the role of the anatase electrode. We used Density Functional Tight Binding (DFTB ) method to study the interaction between organic acids and possible intermediates of the reduction reaction. For the simulation, models of the (101) surface of anatase as well as nanoparticle models were also used.
TiO2 nanoparticles, unlike surface slab models, always have a strong dipole moment, which interfere with absorption of organic acids as well as the solvent water molecules. The morphology of the nanoparticles has also a strong influence on the bandgap of TiO2: calculations showed an approx. 0.5 eV smaller gap for the nanoparticles. The decrease of the gap were mostly due to the significantly lower LUMO energy levels when they are compared to surface models (Figure 1). These low energy LUMO levels are due to edge effects and are expected to play an important role in the electrochemical reduction over these nanoparticles.
Calculations showed very strong absorption of the acids on the anatase models (in order of 150 kJ/mol). Such a strong absorption of the carboxyl group may actually protect it from the reduction. We hypothesized that one of the carboxyl group of oxalic acid acts as an anchor, while the reduction reaction is taking place mostly on the other side of the molecule. This would also explain why ordinary carboxylic acids like acetic acid cannot be reduced under the same conditions.
Reference:
[1] R. Watanabe, M. Yamauchi, M. Sadakiyo, R. Abe and T. Takeguchi, Energy Environ. Sci., 2015, 8, 1456–1462.

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Powder Pulse Electrodeposition for Additive Manufacturing
Authors: Abbott Andrew P , Cihangir Salih , Ryder Karl S 
Published: February 2020

Electrodeposition is commonly used for the deposition of metallic and composite coatings. It is useful as it can coat complex 3D structures and can be used for the deposition of alloys. There are a few disadvantages; it is relatively slow to build up thick coatings and in some cases the current efficiency can be low.
In this study a fundamentally different method for carrying out electrodeposition is demonstrated which can potentially be used for additive manufacturing. Here instead of dissolving metal from the anode and depositing it on the cathode a powder of the coating metal is put in contact with the cathode and pulse plating sequentially dissolves metal from the powder and then deposits it between the powder grains. By this method super-efficient deposition (efficiency >100%) can be achieved and thick layers can quickly be deposited.
This can in principle be carried out in any media but in this study ionic liquids were used to increase the current efficiency of the process. The method is demonstrated using both zinc and copper. It is shown that using these media certain crystal planes can be promoted and ordered deposits are obtained. In addition the same technique was used to deposit composite materials by staring with a mixture of metal powder with ceramic powders, such as alumina, silicon carbide. The morphology of the surfaces was characterized using SEM, X-ray diffraction, and 3D optical microscopy techniques.
(Invited) AlN and ScAlN Contour Mode Resonators for RF Filters
Authors: Henry Michael David , Timon Robert , Young Travis R , Nordquist Chris , Griffin Ben 
Published: February 2020

A very strong technological market pull for wide bandgap semiconductor devices comes from the piezoelectric properties of aluminum nitride (AlN). Portable wireless products are expanding in their use of AlN films as RF devices in bulk acoustic wave (BAW) and surface acoustic wave (SAW) filters with substantial performance properties over other semiconductor materials. To maintain market dominance properties such as size, integration costs, and filter performance metrics continue to improve. Metrics closely coupled to material properties such as piezoelectric coupling coefficient (k2
eff) and quality factor (Q) arising from material sputtering conditions directly impact key filter parameters such as insertion loss, bandwidth, and rejection, and these properties have been intensely investigated as have device and filter architecture. To improve versatility, alternate resonator designs are emerging that combine micromachining and different piezoelectric coefficients such as d31 instead of d33. These contour mode resonators (CMR) differ slightly from BAW and SAW since resonator frequency is determined lithographically and devices are suspended which provides the opportunity to provide multiple frequencies on a single die with reduction of cross talk and integration on top of CMOS.
This work will discuss our efforts in utilizing CMRs to achieve a wide range of operating frequencies on a single die with improved performance. In this presentation we will discuss our RF sputter deposition process for creating high-performance AlN films, as well as plasma etching and integration techniques for fabricating CMRs. Fabricated devices spanning a range of 400 MHz to 3 GHz will be demonstrated with spur modal interaction discussed. Further, early investigations into scandium aluminum nitride (ScAlN) suggest that metrics such as Q and K2
eff can substantially improve simultaneously while still providing a wide frequency range of devices.
Optical Reflectivity of Spin-Coated Multilayered ZnO and Al:ZnO Thin Films
Authors: Buckley Darragh , McCormack Robert , McNulty David , Zubialevich V.Z. , Parbrook Peter J. , O'Dwyer Colm 
Published: February 2020

Zinc oxide (ZnO) and its doped counterparts such as Al:ZnO are extensively investigated as indium-free alternatives for oxide electronics including solar cells, light emitting diodes and also display technologies. For the latter application, thin film transistor (TFT) devices are the building-block structures. High fidelity TFTs require conductive channel materials, with good field effect mobility for majority carriers and tunable optical transparency. Controlling growth, doping, crystallization, and thickness of thin films of these materials is required in order to improve and control physical properties, primarily electronic conductivity and optical transparency. With the advent of flexible electronics and curved TFT-based display panels, low cost, solution-processed methods are important and provide scalable coating methods on a range of substrates.
This work demonstrates the changes to the morphology, crystalline structure, optical reflectivity and electrical conductance of solution-processed ZnO thin films by the inclusion of an aluminium dopant during spin-coating. The is work also determines the compositional chemical state of the Al:ZnO structures compared to ZnO using X-ray photoelectron spectroscopy in conjunction with detailed X-ray diffraction and transmission electron microscopy examination of the film morphology. We also demonstrate a method of determining the optical thickness of multilayer thin films using simple, non-destructive angle-resolved reflectance measurements. Using optical interference, the optical thickness of the multi-layered deposited ZnO and Al:ZnO can be determined and show good agreement with the thicknesses measured by transmission electron microscopy of electron transparent lamellar cross-sections.
We also show the visible and near-infra red (VIS-NIR) light spectroscopy of ZnO and Al:ZnO multi-layered thin film structures grown on oxidized silicon substrates also define the growth conditions and processing to provide tunable antireflection coatings of ZnO and AZO.
(Invited) Surface Plasmon Resonance Sensors for Biomolecular Chirality
Authors: Liu Mingzhao , Lu Fang , Tian Ye , Su Dong , Gang Oleg 
Published: February 2020

Surface Plasmon Resonance Sensors for Biomolecular Chirality

Mingzhao Liu, Fang Lu, Ye Tian, Dong Su, and Oleg Gang

A chiral object, i.e., one that is distinguishable from its mirror image, interacts differently with photons of left-hand (+) and right-hand (-) circular polarizations. The difference in the absorption part is known as circular dichroism (CD), which is usually observed for biomolecules with one or more chiral centers and is widely used to probe their molecular stereometry. Such probing has an increasingly broad importance for biomedical and pharmacological fields due to synthesis/separation/detection of homochiral species, biological role of chiral organization, and structural response to environmental conditions and enantiomeric drugs. Recent theoretical and experimental works demonstrated that the CD signal from chiral organic molecules could appear in the plasmonic band when they are coupled with plasmonic particles. This talk will cover an intriguing case in which non-chiral plasmonic nanoparticles are surrounded by a monolayer of DNA molecules that have chirality arising from its individual nucleobases and helix structure. It is found that the surface plasmon-induced CD is very sensitive to the nonchiral plasmonic nanoparticles’ shape and chemical composition. We identify gold/silver core/shell nanocubes as most effective by providing a giant, 2 orders of magnitude CD enhancement in a near-visible region, while DNA’s native CD signal appears at much higher energy. The discovered phenomenon opens novel opportunities in ultrasensitive probing of biomolecules and for novel optical nanomaterials based on the chiral elements.
Exploration of Novel Magnesium Battery Electrolytes based on Inorganic Salts
Authors: Hou Tianhong , Monroe Charles W 
Published: February 2020

The theoretical volumetric capacity of Mg-ion batteries is far higher than state-of-the-art Li-ion batteries (3833mAh/cm3 for Mg vs. 850 mAh/cm3for Li). The development of suitable Mg-conductive electrolytic solutions has been a major barrier to Mg-ion technology: at present there is a need for liquids with wide anodic stability windows, whose interfaces allow plating and stripping of Mg with high coulombic efficiency and low deposition overpotential.
We have produced a number of Mg-conductive electrolytes by direct reaction of inorganic chloride salts with suspensions of Mg powder in nonaqueous solvents. The Mg-carrying cation in these electrolytes is presumably similar to the one that provides conductivity in the recently discovered magnesium aluminum chloride complex (MACC) electrolyte [1,2], but there is apparently no metal-complex anion, and no need for an auxiliary Lewis acid during synthesis.
The chemically synthesized Mg-conductive electrolyte formed by reacting ZnCl2 with Mg in tetrahydrofuran is stable up to 3.0 V vs. Mg/Mg2+, and produces an ionic conductivity of 0.24 mS/cm at room temperature. Cyclic voltammetry shows reversible Mg plating and stripping on platinum. The deposition overpotential of freshly synthesized electrolyte is below 200mV, and the coulombic efficiency of plating and stripping approaches 100%. Over a period of a week, the coulombic efficiency of plating/stripping only decays by 5%; the deposition overpotential increases more substantially with aging, however. Electrochemical Impedance Spectroscopy (EIS) was used to analyze the transport properties of the solutions. Other properties, such as composition and structure of electrolytic solutions, the morphology of Mg deposits, and thermal stability will be also discussed to explore the precise mechanism by which this and Mg electrolytes formed by other chloride salts form, as well as their feasibility for future magnesium battery applications.

Barile, Christopher J. et al. J. Phys. Chem. C 118.48 (2014): 27623-27630

Vardar, Gulin, et al.
Chem. Mater. 28.21 (2016): 7629-7637

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In Situ Analysis of Solid Electrolyte Interface over Si Based Anodes Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy
Authors: Yohannes Yonas Beyene , Wu Nae-Lih , Lin Shawn D. 
Published: February 2020

In lithium ion battery (LIB), silicon is hopeful electrode having a high theoretical capacity of 3579 mAh/g, which is ten times higher than the currently used graphite anode (1). On the other hand, Si-based electrodes suffer from the poor capacity retention due to the large volume changes during the lithium lithiation and delithiation process. The consequence of the volume change will lead to continuous decomposition of the electrolyte, which results in the formation of solid electrolyte interphase (SEI). Herein, the SEI formed based on fluoroethylene carbonate (FEC) electrolyte additive on a Si-based anode was investigated using in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), which have been also used to analyze SEI species on different electrodes (2, 3). The SEI generated on Si-based anode using 1 M LiPF6 in ethylene carbonate (EC) / ethyl methyl carbonate (EMC), 1/2 (v/v)/ vinylene carbonate (VC), (2 wt%) was started to observe at the onset of 1.1 V in the potential region of 1.0 – 1.3 V due to the decomposition of VC, which preferentially reduce prior to EC and EMC (4). Formation of poly (VC), polycarbonates, and Li2CO3 were identified during first cycle discharging. The incorporation of 10 wt% FEC results with the formation of poly (FEC)/(VC), polycarbonates, Li2CO3, alkoxy species and alkyl phosphorous fluorides. Using FEC as an additive with the onset potetial of 1.4 V the SEI formation started at a higher potential region of 1.3 – 2.5 V. In the course of second discharging, incorporation of FEC also impedes the decomposition of both solvent and salt anion reduction. Notable enough, in-situ DRIFTS spectrum due to the impact of FEC additive after five cycles also show the formation of SEI-film species is in fact increase in the lithiation process. DRIFT spectrum of the SEI-film formed over Si-based anode with and without FEC electrolyte at the onset potential is shown in Fig. 1.
Fig. 1 (a) The first cycle CV results of silicon-based electrodes with EC:EMC:VC/LiPF6 (black) and EC:EMC:VC + FEC/LiPF6 (blue). (b) DRIFT difference spectra obtained at the onset potential of silicon-based electrodes using (I) EC:EMC:VC/LiPF6 and (II) EC:EMC:VC + FEC/LiPF6based electrolytes.
References
1. C. C. Nguyen and B. L. Lucht, J. Electrochem. Soc., 161(2014).
2. A. M. Haregewoin, D. T. Shie, S. D. Lin, J. B. Hwang and M. F. Wang, Ecs Transactions, 53, 23 (2013).
3. M. Teshager, S. D. Lin, B. J. Hwang, F. M. Wang, S. Hy and A. Haregewoin, Chemelectrochem, 3, 337 (2016).
4. K. Tasaki, K. Kanda, T. Kobayashi, S. Nakamura and M. Ue, J. Electrochem. Soc., 153 (2006).

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(Invited) Carbide/Nitride and Bimetallic Catalysts for Water Electrolysis
Authors: Chen Jingguang G 
Published: February 2020

The high cost and impurity tolerance of Pt-group metal electrocatalysts used for HER and OER are significant challenges to overcome in order to achieve wide-spread electrolyzer use. Discovery of active, inexpensive, and impurity tolerant electrocatalysts should be guided by activity trends derived from density functional theory (DFT) calculations and experimental studies on well-characterized thin films. These trends then need to be extended to industrially relevant high surface area catalysts in order to bridge the materials gap.
In this talk we will use three examples to illustrate our efforts in reducing or replacing Pt-group metals for HER and OER. The first example is the utilization of monolayer (ML) Pt-group metals over transition metal carbide (TMC) substrates for HER in acid electrolyte. Metal-modified TMCs are promising inexpensive replacements for Pt-group metals because they have shown the ability to tune hydrogen binding energy, which is a descriptor for predicting the HER activity in acid. We will also use ML Pt-NbC thin films to compare the HER activity in acid and alkaline electrolytes, and to illustrate the impurity tolerance of Pt-NbC in the presence of tap water ions. The second example utilizes non-precious bimetallic catalysts for HER in alkaline electrolyte. The value of hydrogen binding energy appears to be a useful descriptor for predicting monometallic and bimetallic catalysts for HER in alkaline electrolyte. The last example shows the feasibility of coating monolayer coverages of IrO2 on transition metal nitrides for OER in acid electrolyte. All three examples demonstrate the importance of correlating theoretical calculations with experimental measurements for identifying alternative electrocatalysts for water electrolysis.