Dendrite-Free Electrodeposition and Reoxidation of Lithium-Sodium Alloy for Metal-Anode Battery

DTIC Science & Technology

2011-11-01

Dendrite-Free Electrodeposition and Reoxidation of Lithium-Sodium Alloy for Metal-Anode Battery Johanna K. Star 1 , Yi Ding 2 , and Paul A. Kohl ,1, * 1...Journal Article 3. DATES COVERED 01-11-2011 to 01-11-2011 4. TITLE AND SUBTITLE DENDRITE-FREE ELECTRODEPOSITION AND REOXIDATION OF LITHIUM-SODIUM...Results and Discussion The initial ionic liquid selection was driven by the need to electrodeposit sodium and lithium from the same electrolyte

Synthesis of iron oxides nanoparticles with very high saturation magnetization form TEA-Fe(III) complex via electrochemical deposition for supercapacitor applications

NASA Astrophysics Data System (ADS)

Elrouby, Mahmoud; Abdel-Mawgoud, A. M.; El-Rahman, Rehab Abd

2017-11-01

This work is devoted to the synthesis of magnetic iron oxides nanoparticles with very high saturation magnetization to be qualified for supercapacitor applications using, a simple electrodeposition technique. It is found that the electrochemical reduction process depends on concentration, temperature, deposition potential and the scan rate of potential. The nature of electrodeposition process has been characterized via voltammetric and chronoamperometric techniques. The morphology of the electrodeposits has been investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The structure and phase content of these investigated electrodeposits have been examined and calculated. The obtained iron oxides show a high saturation magnetization (Ms) of about 229 emu g-1. The data exhibited a relation between Ms of electrodeposited iron oxide and specific capacitance. This relation exhibits that the highest Ms value of electrodeposited iron oxides gives also highest specific capacitance of about 725 Fg-1. Moreover, the electrodeposited iron oxides exhibit a very good stability. The new characteristics of the electro synthesized iron oxides at our optimized conditions, strongly qualify them as a valuable material for high-performance supercapacitor applications.

Investigation of Electro-Kinetic Behavior of Cysteine on Electrodeposition of Ni Through the AC and DC Techniques

NASA Astrophysics Data System (ADS)

Ebadi, Mehdi; Basirun, Wan J.; Sim, Yoke-L.; Mahmoudian, Mohammad R.

2013-11-01

Electrodeposition of nickel was studied by the AC (as a novel technique) and DC techniques in nickel chloride aqueous solutions, mixed with various amounts of cysteine (0 to 6 mM). Cyclic voltammetry and chronoamperometry data have shown that the electrodeposition of Ni in the presence of cysteine is not diffusion controlled, but is closer to instantaneous nucleation. However, the current distribution decreased with the addition of further cysteine. The nucleation sites were decreased from 1.72 × 106 to 0.190 × 106 (cm-2) when the concentration of cysteine was increased from 0 to 4 mM. AC impedance during electrodeposition shows that the charge transfer resistance is increased from 0.645 to 5.26 Ω cm2 when the concentration of cysteine is increased from 0.5 to 4 mM. The electro-corrosion tests were done to investigate the corrosion behavior of the electrodeposited layers. X-ray diffraction and scanning electron microscopy containing Energy dispersive X-ray were used to estimate the grain size of the electrodeposited layers and capture the micrograph images and roughness of the Ni-electrodeposited surface.

Electrodeposition of gold particles on aluminum substrates containing copper.

PubMed

Olson, Tim S; Atanassov, Plamen; Brevnov, Dmitri A

2005-01-27

Electrodeposition of adhesive metal films on aluminum is traditionally preceded by the zincate process, which activates the aluminum surface. This paper presents an alternative approach for activation of aluminum by using films containing 99.5% aluminum and 0.5% copper. Aluminum/copper films are made amenable for subsequent electrodeposition by anodization followed by chemical etching of aluminum oxide. The electrodeposition of gold is monitored with electrochemical impedance spectroscopy (EIS). Analysis of EIS data suggests that electrodeposition of gold increases the interfacial capacitance from values typical for electrodes with thin oxide layers to values typical for metal electrodes. Scanning electron microscopy examination of aluminum/copper films following gold electrodeposition shows the presence of gold particles with densities of 10(5)-10(7) particles cm(-2). The relative standard deviation of mean particle diameters is approximately 25%. Evaluation of the micrographs suggests that the electrodeposition occurs by instantaneous nucleation followed by growth of three-dimensional semispherical particles. The gold particles, which are electrically connected to the conductive aluminum/copper film, support a reversible faradaic process for a soluble redox couple. The deposited gold particles are suitable for subsequent metallization of aluminum and fabrication of particle-type films with interesting catalytic, electrical, and optical properties.

ELECTRODEPOSITION OF NEPTUNIUM

DOEpatents

Seaborg, G.T.; Wahl, A.C.

1960-08-30

A process of electrodepositing neptunium from solutions is given which comprises conducting the electrodeposition from an absolute alcohol bath containing a neptunium nitrate and lanthanum nitrate at a potential of approximately 50 volts and a current density of between about 1.8 and 4.7 ma/dm/ sup 2/.

Texture related unusual phenomena in electrodeposition and vapor deposition

NASA Astrophysics Data System (ADS)

Lee, D. N.; Han, H. N.

2015-04-01

The tensile strength of electrodeposits generally decreases with increasing bath temperature because the grain size increases and the dislocation density decreases with increasing bath temperature. Therefore, discontinuities observed in the tensile strength vs. bath temperature curves in electrodeposition of copper are unusual. The tensile strength of electrodeposits generally increases with increasing cathode current density because the rate of nucleation in electrodeposits increases with increasing current density, which in turn gives rise to a decrease in the grain size and in turn an increase in the strength. Therefore, a decrease in the tensile strength of copper electrodeposits at a high current density is unusual. The grain size of vapor deposits is expected to decrease with decreasing substrate temperature. However, rf sputtered Co-Cr deposits showed that deposits formed on water-cooled polyimide substrates had a larger grain size than deposits formed on polyimide substrates at 200 °C. These unusual phenomena can be explained by the preferred growth model for deposition texture evolution.

Electrochemical Study and Applications of Selective Electrodeposition of Silver on Quantum Dots.

PubMed

Martín-Yerga, Daniel; Rama, Estefanía Costa; Costa-García, Agustín

2016-04-05

In this work, selective electrodeposition of silver on quantum dots is described. The particular characteristics of the nanostructured silver thus obtained are studied by electrochemical and microscopic techniques. On one hand, quantum dots were found to catalyze the silver electrodeposition, and on the other hand, a strong adsorption between electrodeposited silver and quantum dots was observed, indicated by two silver stripping processes. Nucleation of silver nanoparticles followed different mechanisms depending on the surface (carbon or quantum dots). Voltammetric and confocal microscopy studies showed the great influence of electrodeposition time on surface coating, and high-resolution transmission electron microscopy (HRTEM) imaging confirmed the initial formation of Janus-like Ag@QD nanoparticles in this process. By use of moderate electrodeposition conditions such as 50 μM silver, -0.1 V, and 60 s, the silver was deposited only on quantum dots, allowing the generation of localized nanostructured electrode surfaces. This methodology can also be employed for sensing applications, showing a promising ultrasensitive electrochemical method for quantum dot detection.

40 CFR 63.3120 - What reports must I submit?

Code of Federal Regulations, 2013 CFR

2013-07-01

... deviation. (8) Deviations: separate electrodeposition primer bake oven capture and control limitations. If you used the separate electrodeposition primer bake oven capture and control limitations in § 63.3092... dates of each month during which there was a deviation from the separate electrodeposition primer bake...

40 CFR 63.3120 - What reports must I submit?

Code of Federal Regulations, 2012 CFR

2012-07-01

... deviation. (8) Deviations: separate electrodeposition primer bake oven capture and control limitations. If you used the separate electrodeposition primer bake oven capture and control limitations in § 63.3092... dates of each month during which there was a deviation from the separate electrodeposition primer bake...

40 CFR 63.3120 - What reports must I submit?

Code of Federal Regulations, 2011 CFR

2011-07-01

... deviation. (8) Deviations: separate electrodeposition primer bake oven capture and control limitations. If you used the separate electrodeposition primer bake oven capture and control limitations in § 63.3092... dates of each month during which there was a deviation from the separate electrodeposition primer bake...

40 CFR 63.3120 - What reports must I submit?

Code of Federal Regulations, 2014 CFR

2014-07-01

... deviation. (8) Deviations: separate electrodeposition primer bake oven capture and control limitations. If you used the separate electrodeposition primer bake oven capture and control limitations in § 63.3092... dates of each month during which there was a deviation from the separate electrodeposition primer bake...

40 CFR 63.3120 - What reports must I submit?

Code of Federal Regulations, 2010 CFR

2010-07-01

... deviation. (8) Deviations: separate electrodeposition primer bake oven capture and control limitations. If you used the separate electrodeposition primer bake oven capture and control limitations in § 63.3092... dates of each month during which there was a deviation from the separate electrodeposition primer bake...

Metal Electrodeposition on an Integrated, Screen-Printed Electrode Assembly

ERIC Educational Resources Information Center

Chyan, Yieu; Chyan, Oliver

2008-01-01

In this lab experiment, screen-printed electrode strips are used to illustrate the essential concepts of electrochemistry, giving students an opportunity to explore metal electrodeposition processes. In the past, metal electrodeposition experiments were seldom included in general chemistry labs because of the difficulty of maintaining separate…

Cationic electrodepositable coating composition comprising lignin

DOEpatents

Fenn, David; Bowman, Mark P; Zawacky, Steven R; Van Buskirk, Ellor J; Kamarchik, Peter

2013-07-30

A cationic electrodepositable coating composition is disclosed. The present invention in directed to a cationic electrodepositable coating composition comprising a lignin-containing cationic salt resin, that comprises (A) the reaction product of: lignin, an amine, and a carbonyl compound; (B) the reaction product of lignin, epichlorohydrin, and an amine; or (C) combinations thereof.

On the electrochemical deposition of metal–organic frameworks

DOE PAGES

Campagnol, Nicolo; Van Assche, Tom R. C.; Li, Minyuan; ...

2016-02-11

In this paper we study and compare the anodic and cathodic electrodeposition of Metal–Organic Frameworks (MOFs) and suggest guidelines for the electrodeposition of new MOFs with this technique. KHUST-1 was electrodeposited both anodically and cathodically and a four step mechanism is proposed to explain the anodic synthesis.

Phase-Change Memory Properties of Electrodeposited Ge-Sb-Te Thin Film.

PubMed

Huang, Ruomeng; Kissling, Gabriela P; Jolleys, Andrew; Bartlett, Philip N; Hector, Andrew L; Levason, William; Reid, Gillian; De Groot, C H 'Kees'

2015-12-01

We report the properties of a series of electrodeposited Ge-Sb-Te alloys with various compositions. It is shown that the Sb/Ge ratio can be varied in a controlled way by changing the electrodeposition potential. This method opens up the prospect of depositing Ge-Sb-Te super-lattice structures by electrodeposition. Material and electrical characteristics of various compositions have been investigated in detail, showing up to three orders of magnitude resistance ratio between the amorphous and crystalline states and endurance up to 1000 cycles.

Phase-Change Memory Properties of Electrodeposited Ge-Sb-Te Thin Film

NASA Astrophysics Data System (ADS)

Huang, Ruomeng; Kissling, Gabriela P.; Jolleys, Andrew; Bartlett, Philip N.; Hector, Andrew L.; Levason, William; Reid, Gillian; De Groot, C. H. `Kees'

2015-11-01

We report the properties of a series of electrodeposited Ge-Sb-Te alloys with various compositions. It is shown that the Sb/Ge ratio can be varied in a controlled way by changing the electrodeposition potential. This method opens up the prospect of depositing Ge-Sb-Te super-lattice structures by electrodeposition. Material and electrical characteristics of various compositions have been investigated in detail, showing up to three orders of magnitude resistance ratio between the amorphous and crystalline states and endurance up to 1000 cycles.

Stability of Electrodeposition at Solid-Solid Interfaces and Implications for Metal Anodes

NASA Astrophysics Data System (ADS)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-08-01

We generalize the conditions for stable electrodeposition at isotropic solid-solid interfaces using a kinetic model which incorporates the effects of stresses and surface tension at the interface. We develop a stability diagram that shows two regimes of stability: a previously known pressure-driven mechanism and a new density-driven stability mechanism that is governed by the relative density of metal in the two phases. We show that inorganic solids and solid polymers generally do not lead to stable electrodeposition, and provide design guidelines for achieving stable electrodeposition.

Process for the electrodeposition of low stress nickel-manganese alloys

DOEpatents

Kelly, James John; Goods, Steven Howard; Yang, Nancy Yuan-Chi; Cadden, Charles Henry

2005-06-07

A process for electrodepositing a low stress nickel-manganese multilayer alloy on an electrically conductive substrate is provided. The process includes the steps of immersing the substrate in an electrodeposition solution containing a nickel salt and a manganese salt and repeatedly passing an electric current through an immersed surface of the substrate. The electric current is alternately pulsed for predetermined durations between a first electrical current that is effective to electrodeposit nickel and a second electrical current that is effective to electrodeposit nickel and manganese. A multilayered alloy having adjacent layers of nickel and a nickel-manganese alloy on the immersed surface of the substrate is thereby produced. The resulting multilayered alloy exhibits low internal stress, high strength and ductility, and high strength retention upon exposure to heat.

Electrodeposition for Electrochemical Energy Conversion and Storage Devices

NASA Astrophysics Data System (ADS)

Shaigan, Nima

Electrodeposition of metals, alloys, metal oxides, conductive polymers, and their composites plays a pivotal role in fabrication processes of some recently developed electrochemical energy devices, most particularly fuel cells, supercapacitors, and batteries. Unique nanoscale architectures of electrocatalysts for low temperature fuel cells, including proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC), can only be obtained through electrodeposition processes. Promising, cost-effective conductive/protective coatings for stainless steel interconnects used in solid oxide fuel cells (SOFCs) have been achieved employing a variety of electrodeposition techniques. In supercapacitors, anodic deposition of metal oxides, conductive polymers, and their composites is a versatile technique for fabrication of electrodes with distinctive morphology and exceptional specific capacitance. Electrodeposition is also very recently employed for preparation of Sn-based anodes for lithium ion batteries.

40 CFR 63.3171 - How do I demonstrate initial compliance?

Code of Federal Regulations, 2013 CFR

2013-07-01

... of electrodeposition bake oven emissions. You must show that the electrodeposition bake oven meets... of the exhaust gases from the bake oven to an add-on control device. For purposes of this showing, an electrodeposition bake oven air seal is not considered a natural draft opening provided you demonstrate that the...

40 CFR 63.3171 - How do I demonstrate initial compliance?

Code of Federal Regulations, 2012 CFR

2012-07-01

... of electrodeposition bake oven emissions. You must show that the electrodeposition bake oven meets... of the exhaust gases from the bake oven to an add-on control device. For purposes of this showing, an electrodeposition bake oven air seal is not considered a natural draft opening provided you demonstrate that the...

40 CFR 63.3171 - How do I demonstrate initial compliance?

Code of Federal Regulations, 2011 CFR

2011-07-01

... of electrodeposition bake oven emissions. You must show that the electrodeposition bake oven meets... of the exhaust gases from the bake oven to an add-on control device. For purposes of this showing, an electrodeposition bake oven air seal is not considered a natural draft opening provided you demonstrate that the...

40 CFR 63.3171 - How do I demonstrate initial compliance?

Code of Federal Regulations, 2014 CFR

2014-07-01

... of electrodeposition bake oven emissions. You must show that the electrodeposition bake oven meets... of the exhaust gases from the bake oven to an add-on control device. For purposes of this showing, an electrodeposition bake oven air seal is not considered a natural draft opening provided you demonstrate that the...

40 CFR 63.3171 - How do I demonstrate initial compliance?

Code of Federal Regulations, 2010 CFR

2010-07-01

... of electrodeposition bake oven emissions. You must show that the electrodeposition bake oven meets... of the exhaust gases from the bake oven to an add-on control device. For purposes of this showing, an electrodeposition bake oven air seal is not considered a natural draft opening provided you demonstrate that the...

Single-step electrodeposition of CIS thin films with the complexing agent triethanolamine

NASA Astrophysics Data System (ADS)

Chiu, Yu-Shuen; Hsieh, Mu-Tao; Chang, Chih-Min; Chen, Chun-Shuo; Whang, Thou-Jen

2014-04-01

Some difficulties have long been encountered by single-step electrodeposition such as the optimization of electrolyte composition, deposition potentials, deposition time, and pH values. The approach of introducing ternary components into single-step electrodeposition is rather challenging especially due to the different values of the equilibrium potential for each constituent. Complexing agents play an important role in single-step electrodeposition of CuInSe2 (CIS), since the equilibrium potential of every constituent can be brought closer to each other when complexing agents are employed. In this work, single-step electrodeposition of CIS was enhanced by adding triethanolamine (TEA) into deposition bath, the CIS thin films were improved consequently in the form of polycrystalline cauliflower structures through the examination of SEM images and XRD patterns. The optimum composition of the solution for single-step electrodeposition of CIS is found to be 5 mM CuCl2, 22 mM InCl3, and 22 mM SeO2 at pH 1.5 with 0.1 M TEA. The structures, compositions, and morphologies of as-deposited and of annealed films were investigated.

Electrodeposition of Nanocrystalline Ni–Fe Alloy Coatings Based on 1-Butyl-3-Methylimidazolium-Hydrogen Sulfate Ionic Liquid.

PubMed

He, Xinkuai; Zhang, Chuang; Zhu, Qingyun; Lu, Haozi; Cai, Youxing; Wu, Luye

2017-02-01

The electrodeposition of nanocrystalline Ni–Fe alloy coatings and associated nucleation/growth processes are investigated on the glassy carbon (GC) electrode in 1-butyl-3-methylimidazolium-hydrogen sulfate ([BMIM]HSO4) ionic liquid (IL). Cyclic voltammetric data suggest that the co-electrodeposition of Ni–Fe alloys is quasi-reversible. Moreover, chronoamperometry results indicate that the electrodeposition proceeds via a simultaneous nucleation and three-dimensional growth mechanism. In addition, the effects of electrodeposition potential and electrolyte temperature on the coating thickness and Fe content are also studied. The microstructure and composition of the Ni–Fe alloy coatings on Cu substrate are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). SEM observations show that these electrodeposits present a dense and compact structure, EDS analysis indicates that the coatings are composed of Ni and Fe, XRD pattern shows the coatings are crystalline with a face-centred cubic (fcc) structure. Tafel plots reveal that the Ni–Fe alloy prepared from [BMIM]HSO4 IL presents better corrosion resistance than that of pure Ni.

Electrodeposition of Copper onto Polypyrrole Films: Application to Proton Reduction

NASA Astrophysics Data System (ADS)

Chikouche, Imene; Sahari, Ali; Zouaoui, Ahmed; Zegadi, Ameur

2016-09-01

In this paper, we have electrodeposited copper on polypyrrole surface. Results show that at high applied cathodic potential (>-1.8V), copper electrodeposition occurs with difficulties. The amount of electrodeposited copper is low (1.32%) and it is limited by the low polypyrrole conductivity. At this potential, poor conductivity is caused by its insulating state. However, at an applied cathodic potential of -1.2V, the polypyrrole exhibits a relatively high conductivity and copper particles are electrodeposited with large amounts (12.44%) on polypyrrole/silicon system. At high applied cathodic potential, the SEM images show clearly dispersed grains of copper, but polypyrrole surface is less occupied. At an applied cathodic potential of -1.2V, the SEM image shows that polypyrrole surface is homogenously more occupied with copper. After copper deposition, the Cu/PPy/Si system is used to catalyze the hydrogen reaction. It was found that, once the deposited copper is present with considerable amounts, the proton reduction occurs easily. As for the polypyrrole conductivity, it was found that electrodeposited copper onto PPy/Si surface affect the total conductivity.

Electrochemical deposition onto self-assembled monolayers: new insights into micro- and nanofabrication.

PubMed

Schilardi, Patricia L; Dip, Patricio; dos Santos Claro, Paula C; Benítez, Guillermo A; Fonticelli, Mariano H; Azzaroni, Omar; Salvarezza, Roberto C

2005-12-16

Pattern transfer with high resolution is a frontier topic in the emerging field of nanotechnologies. Electrochemical molding is a possible route for nanopatterning metal, alloys and oxide surfaces with high resolution in a simple and inexpensive way. This method involves electrodeposition onto a conducting master covered by a self-assembled alkanethiolate monolayer (SAMs). This molecular film enables direct surface-relief pattern transfer from the conducting master to the inner face of the electrodeposit, and also allows an easy release of the electrodeposited film due their excellent anti-adherent properties. Replicas of the original conductive master can be also obtained by a simple two-step procedure. SAM quality and stability under electrodeposition conditions combined with the formation of smooth electrodeposits are crucial to obtain high-quality pattern transfer with sub-50 nm resolution.

Preparation of cuxinygazsen (X=0-2, Y=0-2, Z=0-2, N=0-3) precursor films by electrodeposition for fabricating high efficiency solar cells

DOEpatents

Bhattacharya, Raghu N.; Contreras, Miguel A.; Keane, James; Tennant, Andrew L.; Tuttle, John R.; Ramanathan, Kannan; Noufi, Rommel

1998-03-24

High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

Nucleation and growth mechanism of Co-Pt alloy nanowires electrodeposited within alumina template

NASA Astrophysics Data System (ADS)

Srivastav, Ajeet K.; Shekhar, Rajiv

2015-01-01

Co-Pt alloy nanowires were electrodeposited by direct current electrodeposition within nanoporous alumina templates with varying deposition potentials. The effect of deposition potential on nucleation and growth mechanisms during electrodeposition of Co-Pt alloy nanowires was investigated. The less negative deposition potential (-0.9 V) favours the instantaneous nucleation mechanism. The positive deviation from theoretical instantaneous and progressive nucleation mechanisms occurs at higher negative deposition potentials. The hysteresis behaviour and magnetic properties of electrodeposited Co-Pt alloy nanowires altered with varying deposition potential. The easy magnetization direction was in direction perpendicular to the wire axis. The deposition potential dependent change in hysteresis behaviour with increased coercivity and scattered remanence ratio was observed. This is attributed to better crystallinity with reduced defect density and hydrogen evolution causing structural changes at more negative deposition potentials.

Electrodeposition of thin yttria-stabilized zirconia layers using glow-discharge plasma

NASA Astrophysics Data System (ADS)

Ogumi, Zempachi; Uchimoto, Yoshiharu; Tsuji, Yoichiro; Takehara, Zen-ichiro

1992-08-01

A novel process for preparation of thin yttria-stabilized zirconia (YSZ) layers was developed. This process differs from other vapor-phase deposition methods in that a dc bias circuit, separate from the plasma-generation circuit, is used for the electrodeposition process. The YSZ layer was electrodeposited from ZrCl4 and YCl3 on a nonporous calcia-stabilized zirconia substrate. Scanning electron microscopy, electron probe microanalysis, electron spectroscopy for chemical analysis, and x-ray-diffraction measurements confirmed the electrodeposition of a smooth, pinhole-free yttria-stabilized zirconia film of about 3 μm thickness.

Fabricating Copper Nanotubes by Electrodeposition

NASA Technical Reports Server (NTRS)

Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

2009-01-01

Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

Bringing part of the lab to the field: On-site chromium speciation in seawater by electrodeposition of Cr(III)/Cr(VI) on portable coiled-filament assemblies and measurement in the lab by electrothermal, near-torch vaporization sample introduction and inductively coupled plasma-atomic emission spectrometry

NASA Astrophysics Data System (ADS)

Badiei, Hamid R.; McEnaney, Jennifer; Karanassios, Vassili

2012-12-01

A field-deployable electrochemical approach to preconcentration, matrix clean up and selective electrodeposition of Cr(III) and Cr(III) + Cr(VI) in seawater is described. Using portable, battery-operated electrochemical instrumentation, Cr species in seawater were electrodeposited in the field on portable coiled-filament assemblies made from Re. Assemblies with dried residues of Cr(III) or Cr(III) + Cr(VI) on them were transported to the lab for concentration determination by electrothermal, near-torch vaporization (NTV) sample introduction and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Electrodeposition offers selective species deposition, preconcentration and matrix clean up from seawater samples. For selective deposition, free Cr(VI) was electrodeposited at - 0.3 V and Cr(III) + Cr(VI) at - 1.6 V (both vs Ag/AgCl). Interestingly, at 0 V (vs Ag/AgCl) and in the absence of an electrodeposition potential only Cr(VI) was spontaneously and selectively adsorbed on the coil and reasons for this are given. Due to preconcentration afforded by electrodeposition, the detection limits obtained after a 60 s electrodeposition at the voltages stated above using buffered (pH = 4.7) artificial seawater spiked with either Cr(III) or Cr(VI) were 20 pg/mL for Cr(III) and 10 pg/mL for Cr(VI). For comparison, the detection limit for Cr obtained by pipetting directly on the coil 5 μL of diluted standard solution was 500 pg/mL, thus it was concluded that electrodeposition offered 40 to 60 fold improvements. Matrix clean up is required due to the high salt content of seawater and this was addressed by simply rinsing the coil with 18.2 MΩ water without any loss of Cr species. Reasons for this are provided. The method was validated in the lab using buffered artificial seawater and it was used in the field for the first time by sampling seawater, buffering it and immediately electrodepositing Cr species on portable assemblies on-site. Electrodeposition in the field addressed species transformation during sample pre-treatment. Such transformations occur due to sample acidification and may take place during transport and possibly storage prior to analysis. Thus, electrodeposition in the field is more reflective of Cr species concentration at the environmental conditions (e.g., temperature) at the time of sampling. It also opens up the possibility for shipping to the lab portable assemblies with Cr species on them rather than shipping large volumes of sample to the lab, thus also reducing shipping, handling and storage costs.

Copper-zinc electrodeposition in alkaline-sorbitol medium: Electrochemical studies and structural, morphological and chemical composition characterization

NASA Astrophysics Data System (ADS)

de Almeida, M. R. H.; Barbano, E. P.; de Carvalho, M. F.; Tulio, P. C.; Carlos, I. A.

2015-04-01

The galvanostatic technique was used to analyze the electrodeposition of Cu-Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu-Zn films were whitish golden, light golden, golden/gray depending on the Cu2+/Zn2+ ratios in the electrodeposition bath, deposition current density (jdep) and charge density (qdep). The highest current efficiency was ∼54.0%, at jdep -1.0 mA cm-2 and qdep 0.40 C cm-2 in the Cu70/Zn30 bath. Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower jdep. Also, for same jdep the Cu content increased with qdep. Scanning electron microscopy showed that Cu-Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at jdep -20.0 mA cm-2 and qdep 10.0 C cm-2. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu-Zn electrodeposits obtained at jdep -8.0, -20.0 and -40.0 mA cm-2, in each case, with qdep 2.0 and 10.0 C cm-2, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn5 and Cu5Zn8. Galvanostatic electrodeposits of Cu-Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications, especially for decorative purposes.

Electrodeposited-film electrodes derived from a precursor dinitrosyl iron complex for electrocatalytic water splitting.

PubMed

Li, Wei-Liang; Chiou, Tzung-Wen; Chen, Chien-Hong; Yu, Yi-Ju; Chu, Li-Kang; Liaw, Wen-Feng

2018-05-29

In artificial photosynthesis, water splitting plays an important role for the conversion and storage of renewable energy sources. Here, we report a study on the electrocatalytic properties of the electrodeposited-film electrodes derived from irreversible electro-reduction/-oxidation of a molecular dinitrosyl iron complex (DNIC) {Fe(NO)2}9 [(Me6tren)Fe(NO)2]+ (Me6tren = tris[2-(dimethylamino)ethyl]amine) for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in alkaline solution, individually. For HER, the overpotential and Tafel slope for the electrodeposited-film cathode are lower than those of the equiv.-weight Pt/C electrode. The electrodeposited-film anode for the OER is stable for 139 h. Integration of the electrodeposited-film cathode and anode into a single electrode-pair device for electrocatalytic water splitting exhibits an onset voltage of 1.77 V, achieving a geometrical current density of 10 mA cm-2.

Electrodeposition of metals from supercritical fluids

PubMed Central

Ke, Jie; Su, Wenta; Howdle, Steven M.; George, Michael W.; Cook, David; Perdjon-Abel, Magda; Bartlett, Philip N.; Zhang, Wenjian; Cheng, Fei; Levason, William; Reid, Gillian; Hyde, Jason; Wilson, James; Smith, David C.; Mallik, Kanad; Sazio, Pier

2009-01-01

Electrodeposition is a widely used materials-deposition technology with a number of unique features, in particular, the efficient use of starting materials, conformal, and directed coating. The properties of the solvent medium for electrodeposition are critical to the technique's applicability. Supercritical fluids are unique solvents which give a wide range of advantages for chemistry in general, and materials processing in particular. However, a widely applicable approach to electrodeposition from supercritical fluids has not yet been developed. We present here a method that allows electrodeposition of a range of metals from supercritical carbon dioxide, using acetonitrile as a co-solvent and supercritical difluoromethane. This method is based on a careful selection of reagent and supporting electrolyte. There are no obvious barriers preventing this method being applied to deposit a range of materials from many different supercritical fluids. We present the deposition of 3-nm diameter nanowires in mesoporous silica templates using this methodology. PMID:19706479

Over 95% of large-scale length uniformity in template-assisted electrodeposited nanowires by subzero-temperature electrodeposition.

PubMed

Shin, Sangwoo; Kong, Bo Hyun; Kim, Beom Seok; Kim, Kyung Min; Cho, Hyung Koun; Cho, Hyung Hee

2011-07-23

In this work, we report highly uniform growth of template-assisted electrodeposited copper nanowires on a large area by lowering the deposition temperature down to subzero centigrade. Even with highly disordered commercial porous anodic aluminum oxide template and conventional potentiostatic electrodeposition, length uniformity over 95% can be achieved when the deposition temperature is lowered down to -2.4°C. Decreased diffusion coefficient and ion concentration gradient due to the lowered deposition temperature effectively reduces ion diffusion rate, thereby favors uniform nanowire growth. Moreover, by varying the deposition temperature, we show that also the pore nucleation and the crystallinity can be controlled.

II. Electrodeposition/removal of nickel in a spouted electrochemical reactor.

PubMed

Grimshaw, Pengpeng; Calo, Joseph M; Shirvanian, Pezhman A; Hradil, George

2011-08-17

An investigation is presented of nickel electrodeposition from acidic solutions in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on nickel removal/recovery rate, current efficiency, and corrosion rate of deposited nickel on the cathodic particles were explored under galvanostatic operation. Nitrogen sparging was used to decrease the dissolved oxygen concentration in the electrolyte in order to reduce the nickel corrosion rate, thereby increasing the nickel electrowinning rate and current efficiency. A numerical model of electrodeposition, including corrosion and mass transfer in the particulate cathode moving bed, is presented that describes the behavior of the experimental net nickel electrodeposition data quite well.

Physical and electrochemical properties of ZnO films fabricated from highly cathodic electrodeposition potentials

NASA Astrophysics Data System (ADS)

Ismail, Abdul Hadi; Abdullah, Abdul Halim; Sulaiman, Yusran

2017-03-01

The physical and electrochemical properties of zinc oxide (ZnO) film electrode that were prepared electrochemically were studied. ZnO was electrodeposited on ITO glass substrate by applying three different highly cathodic potentials (-1.3 V, -1.5 V, -1.7 V) in a solution containing 70 mM of Zn(NO3)2.xH2O and 0.1 M KCl with bath temperatures of 70 °C and 80 °C. The presence of ZnO was asserted from XRD analysis where the corresponding peaks in the spectra were assigned. SEM images revealed the plate-like hexagonal morphology of ZnO which is in agreement with the XRD analysis. The areal capacitance of the ZnO was observed to increase when the applied electrodeposition potential is increased from -1.3 V to -1.5 V. However, the areal capacitance is found to decrease when the applied electrodeposition potential is further increased to -1.7 V. The resistance of charge transfer (Rct) of the ZnO decreased when the applied electrodeposition potential varies from -1.3 V to -1.7 V due to the decreased particle size of ZnO when more cathodic electrodeposition potential is applied.

Electrodeposition of reduced graphene oxide with chitosan based on the coordination deposition method

PubMed Central

Liu, Mingyang; Qin, Chaoran; Zhang, Zheng; Ma, Shuai; Cai, Xiuru; Li, Xueqian

2018-01-01

The electrodeposition of graphene has drawn considerable attention due to its appealing applications for sensors, supercapacitors and lithium-ion batteries. However, there are still some limitations in the current electrodeposition methods for graphene. Here, we present a novel electrodeposition method for the direct deposition of reduced graphene oxide (rGO) with chitosan. In this method, a 2-hydroxypropyltrimethylammonium chloride-based chitosan-modified rGO material was prepared. This material disperses homogenously in the chitosan solution, forming a deposition solution with good dispersion stability. Subsequently, the modified rGO material was deposited on an electrode through codeposition with chitosan, based on the coordination deposition method. After electrodeposition, the homogeneous, deposited rGO/chitosan films can be generated on copper or silver electrodes or substrates. The electrodeposition method allows for the convenient and controlled creation of rGO/chitosan nanocomposite coatings and films of different shapes and thickness. It also introduces a new method of creating films, as they can be peeled completely from the electrodes. Moreover, this method allows for a rGO/chitosan film to be deposited directly onto an electrode, which can then be used for electrochemical detection. PMID:29765797

Surface Oxidation of the High-Strength Steels Electrodeposited with Cu or Fe and the Resultant Defect Formation in Their Coating during the Following Galvanizing and Galvannealing Processes

NASA Astrophysics Data System (ADS)

Choi, Yun-Il; Beom, Won-Jin; Park, Chan-Jin; Paik, Doojin; Hong, Moon-Hi

2010-12-01

This study examined the surface oxidation of high-strength steels electrodeposited with Cu or Fe and the resultant defect formation in their coating during the following galvanizing and galvannealing processes. The high-strength steels were coated with an Cu or Fe layer by the electroplating method. Then, the coated steels were annealed in a reducing atmosphere, dipped in a molten zinc, and finally transformed into galvannealed steels through the galvannealing process. The formation of Si and Mn oxides on the surface of the high-strength steel was effectively suppressed, and the density of surface defects on the galvanized steel was significantly reduced by the pre-electrodeposition of Cu and Fe. This effect was more prominent for the steels electrodeposited at higher cathodic current densities. The finer electrodeposit layer formed at higher cathodic current density on the steels enabled the suppression of partial surface oxidation by Mn or Si and better wetting of Zn on the surface of the steels in the following galvanizing process. Furthermore, the pre-electrodeposited steels exhibited a smoother surface without surface cracks after the galvannealing process compared with the untreated steel. The diffusion of Fe and Zn in the Zn coating layer in the pre-electrodeposited steels appears to occur more uniformly during the galvannealing process due to the low density of surface defects induced by oxides.

Preparation of CIGS-based solar cells using a buffered electrodeposition bath

DOEpatents

Bhattacharya, Raghu Nath

2007-11-20

A photovoltaic cell exhibiting an overall conversion efficiency of at least 9.0% is prepared from a copper-indium-gallium-diselenide thin film. The thin film is prepared by simultaneously electroplating copper, indium, gallium, and selenium onto a substrate using a buffered electro-deposition bath. The electrodeposition is followed by adding indium to adjust the final stoichiometry of the thin film.

Electrodeposition of Refractory Carbide Coatings.

DTIC Science & Technology

1982-12-30

refractory carbide coatings from molten salts is described. It consists of the simultaneous reduction of the appropriate metal species dissolved in the...Electrodeposition Molden salts 20. ASSTRACT (Continue an reve.e. 0g.. It necooom wed identify bp block nu.be) A novel method for electrodepositing...respectively. Electrolysis resulted in the formation of millimeter-size crystals on the walls of the graphite crucible which served as the cathode. Analysis of

Development of High ZT Thermoelectric Materials with Nanostructure for Energy Applications

DTIC Science & Technology

2010-03-03

film and nanowires array (embedded in alumina template) were fabricated by potentiostatically electrodeposition . The Seebeck coefficient, electrical...by potentiostatically electrodeposition . The followings are our reports on the synthesis and characterizations of these nano-materials. B1...Synthesis of the nanomaterials Bi2Te3 films were electrodeposited potentiostatically at -150 mV onto an ITO glass substrate from 1 M HNO3 solution

Electrodeposition of Nanocrystalline Cobalt Phosphorous Coatings as a Hard Chrome Alternative

DTIC Science & Technology

2014-11-01

1 ASETSDefense 2014 Electrodeposition of Nanocrystalline Cobalt Phosphorous Coatings as a Hard Chrome Alternative Ruben A. Prado, CEF...COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Electrodeposition of Nanocrystalline Cobalt Phosphorous Coatings as a Hard Chrome Alternative...coatings as a Hard Chrome (EHC) electroplating alternative for DoD manufacturing and repair. – Fully define deposition parameters and properties

Over 95% of large-scale length uniformity in template-assisted electrodeposited nanowires by subzero-temperature electrodeposition

PubMed Central

2011-01-01

In this work, we report highly uniform growth of template-assisted electrodeposited copper nanowires on a large area by lowering the deposition temperature down to subzero centigrade. Even with highly disordered commercial porous anodic aluminum oxide template and conventional potentiostatic electrodeposition, length uniformity over 95% can be achieved when the deposition temperature is lowered down to -2.4°C. Decreased diffusion coefficient and ion concentration gradient due to the lowered deposition temperature effectively reduces ion diffusion rate, thereby favors uniform nanowire growth. Moreover, by varying the deposition temperature, we show that also the pore nucleation and the crystallinity can be controlled. PMID:21781335

Electrodeposition of Manganese-Nickel Oxide Films on a Graphite Sheet for Electrochemical Capacitor Applications.

PubMed

Lee, Hae-Min; Lee, Kangtaek; Kim, Chang-Koo

2014-01-09

Manganese-nickel (Mn-Ni) oxide films were electrodeposited on a graphite sheet in a bath consisting of manganese acetate and nickel chloride, and the structural, morphological, and electrochemical properties of these films were investigated. The electrodeposited Mn-Ni oxide films had porous structures covered with nanofibers. The X-ray diffractometer pattern revealed the presence of separate manganese oxide (g-MnO₂) and nickel oxide (NiO) in the films. The electrodeposited Mn-Ni oxide electrode exhibited a specific capacitance of 424 F/g in Na₂SO₄ electrolyte. This electrode maintained 86% of its initial specific capacitance over 2000 cycles of the charge-discharge operation, showing good cycling stability.

Preparation of copper-indium-gallium-diselenide precursor films by electrodeposition for fabricating high efficiency solar cells

DOEpatents

Bhattacharya, Raghu N.; Hasoon, Falah S.; Wiesner, Holm; Keane, James; Noufi, Rommel; Ramanathan, Kannan

1999-02-16

A photovoltaic cell exhibiting an overall conversion efficiency of 13.6% is prepared from a copper-indium-gallium-diselenide precursor thin film. The film is fabricated by first simultaneously electrodepositing copper, indium, gallium, and selenium onto a glass/molybdenum substrate (12/14). The electrodeposition voltage is a high frequency AC voltage superimposed upon a DC voltage to improve the morphology and growth rate of the film. The electrodeposition is followed by physical vapor deposition to adjust the final stoichiometry of the thin film to approximately Cu(In.sub.1-n Ga.sub.x)Se.sub.2, with the ratio of Ga/(In+Ga) being approximately 0.39.

II. Electrodeposition/removal of nickel in a spouted electrochemical reactor

PubMed Central

Grimshaw, Pengpeng; Calo, Joseph M.; Shirvanian, Pezhman A.; Hradil, George

2011-01-01

An investigation is presented of nickel electrodeposition from acidic solutions in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on nickel removal/recovery rate, current efficiency, and corrosion rate of deposited nickel on the cathodic particles were explored under galvanostatic operation. Nitrogen sparging was used to decrease the dissolved oxygen concentration in the electrolyte in order to reduce the nickel corrosion rate, thereby increasing the nickel electrowinning rate and current efficiency. A numerical model of electrodeposition, including corrosion and mass transfer in the particulate cathode moving bed, is presented that describes the behavior of the experimental net nickel electrodeposition data quite well. PMID:22039317

Electrodeposited styrylquinolinium dye as molecular electrocatalyst for coupled redox reactions.

PubMed

Hubenova, Yolina; Bakalska, Rumyana; Mitov, Mario

2018-05-10

Modification of carbonaceous materials with different conductive coatings is a successful approach to enhance their electrocatalytic activity and thus to increase the electrical outputs when used as electrodes in biofuel cells. In this study, a methodology for electrodeposition of styrylquinolinium dye on carbon felt was developed. The produced dye electrodeposits were characterized by means of AFM, ESI-MS/MS and NMR spectroscopy. The obtained data reveal that the dye forms overlaid layers consisting of monomer molecules most likely with an antiparallel orientation. The UV-VIS spectroscopy, CV and EIS analyses show that the dye molecules preserve their redox activity within the coating and a charge transfer between NADH/NAD + and electrodeposit is possible as a coupled redox reaction. The fabricated nano-modified electrodes were also tested as anodes in batch-mode operating yeast-based biofuel cell. The results indicate that the electrodeposited dye acts as an immobilized exogenous mediator, contributing to enhanced extracellular electron transfer. Copyright © 2018. Published by Elsevier B.V.

Metals Electroprocessing in Molten Salts

NASA Technical Reports Server (NTRS)

Sadoway, D. R.

1985-01-01

The present study seeks to explain the poor quality of solid electrodeposits in molten salts through a consideration of the effects of fluid flow of the electrolyte. Transparent cells allow observation of electrolyte circulation by a laser schlieren optical technique during the electrodeposition of solid zinc from the molten salt electrolyte, ZnCl2 - LiCl-KCl. Experimental variables are current, density, electrolyte composition, and cell geometry. Based on the results of earlier electrodeposition studies as well as reports in the literature, these parameters are identified as having the primary influence on cell performance and deposit quality. Experiments are conducted to measure the fluid flow patterns and the electrochemical cell characteristics, and to correlate this information with the morphology of the solid electrodeposit produced. Specifically, cell voltage, cell current, characteristic time for dendrite evolution, and dendrite growth directions are noted. Their relationship to electrolyte flow patterns and the morphology of the resulting electrodeposit are derived. Results to date indicate that laser schlieren imaging is capable of revealing fluid flow patterns in a molten salt electrolyte.

Electrodeposition of gold nanoparticles on aryl diazonium monolayer functionalized HOPG surfaces.

PubMed

González, M C R; Orive, A G; Salvarezza, R C; Creus, A H

2016-01-21

Gold nanoparticle electrodeposition on a modified HOPG surface with a monolayer organic film based on aryl diazonium chemistry has been studied. This organic monolayer is electrochemically grown with the use of 2,2-diphenyl-1-picrylhydrazyl (DPPH), a radical scavenger. The electrodeposition of gold on this modified surface is highly favored resulting in an AuNP surface density comparable to that found on glassy carbon. AuNPs grow only in the areas covered by the organic monolayer leaving free clean HOPG zones. A progressive mechanism for the nucleation and growth is followed giving hemispherical AuNPs, homogeneously distributed on the surface and their sizes can be well controlled by the applied electrodeposition potential. By using AFM, C-AFM and electrochemical measurements with the aid of two redox probes, namely Fe(CN)6(4-)/Fe(CN)6(3-) and dopamine, relevant results about the electrochemical modified surface as well as the gold nanoparticles electrodeposited on them are obtained.

Surface Modifications of Materials by Electrochemical Methods to Improve the Properties for Industrial and Medical Applications

NASA Astrophysics Data System (ADS)

Benea, Lidia

2018-06-01

There are two applied electrochemical methods in our group in order to obtain advanced functional surfaces on materials: (i) direct electrochemical synthesis by electro-codeposition process and (ii) anodization of materials to form nanoporous oxide layers followed by electrodeposition of hydroxyapatite or other bioactive molecules and compounds into porous film. Electrodeposition is a process of low energy consumption, and therefore very convenient for the surface modification of various types of materials. Electrodeposition is a powerful method compared with other methods, which led her to be adopted and spread rapidly in nanotechnology to obtain nanostructured layers and films. Nanoporous thin oxide layers on titanum alloys as support for hydroxyapatite or other biomolecules electrodeposition in view of biomedical applications could be obtained by electrochemical methods. For surface modification of titanium or titanium alloys to improve the biocompatibility or osseointegration, the two steps must be fulfilled; the first is controlled growth of oxide layer followed by second being biomolecule electrodeposition into nanoporous formed titanium oxide layer.

Cathodic electrodeposition of ceramic and organoceramic materials. Fundamental aspects.

PubMed

Zhitomirsky, I

2002-03-29

Electrodeposition of ceramic materials can be performed by electrophoretic (EPD) or electrolytic (ELD) deposition. Electrophoretic deposition is achieved via motion of charged particles towards an electrode under an applied electric field. Electrolytic deposition produces colloidal particles in cathodic reactions for subsequent deposition. Various electrochemical strategies and deposition mechanisms have been developed for electrodeposition of ceramic and organoceramic films, and are discussed in the present article. Electrode-position of ceramic and organoceramic materials includes mass transport, accumulation of particles near the electrode and their coagulation to form a cathodic deposit. Various types of interparticle forces that govern colloidal stability in the absence and presence of processing additives are discussed. Novel theoretical contributions towards an interpretation of particle coagulation near the electrode surface are reviewed. Background information is given on the methods of particle charging, stabilization of colloids in aqueous and non-aqueous media, electrophoretic mobility of ceramic particles and polyelectrolytes, and electrode reactions. This review also covers recent developments in the electrodeposition of ceramic and organoceramic materials.

Electrochemical mechanism of tin membrane electrodeposition under ultrasonic waves.

PubMed

Nan, Tianxiang; Yang, Jianguang; Chen, Bing

2018-04-01

Tin was electrodeposited from chloride solutions using a membrane cell under ultrasonic waves. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CHR), and chronopotentiometry were applied to investigate the electrochemical mechanism of tin electrodeposition under ultrasonic field. Chronoamperometry curves showed that the initial process of tin electrodeposition followed the diffusion controlled three-dimensional nucleation and grain growth mechanism. The analysis of the cyclic voltammetry and linear sweep voltammetry diagrams showed that the application of ultrasound can change the tin membrane electro-deposition reaction from diffusion to electrochemical control, and the optimum parameters for tin electrodeposition were H + concentration 3.5 mol·L -1 , temperature 35 °C and ultrasonic power 100 W. The coupling ultrasonic field played a role in refining the grain in this process. The growth of tin crystals showed no orientation preferential, and the tin deposition showed a tendency to form a regular network structure after ultrasonic coupling. While in the absence of ultrasonic coupling, the growth of tin crystals has a high preferential orientation, and the tin deposition showed a tendency to form tin whiskers. Ultrasonic coupling was more favorable for obtaining a more compact and smoother cathode tin layer. Copyright © 2017 Elsevier B.V. All rights reserved.

The structure evolution mechanism of electrodeposited porous Ni films on NH4Cl concentration

NASA Astrophysics Data System (ADS)

Yu, Xiangtao; Wang, Mingyong; Wang, Zhi; Gong, Xuzhong; Guo, Zhancheng

2016-01-01

NH4Cl was an important component for the electrodeposition of porous metal films through hydrogen bubble template approach. The effects of NH4Cl concentrations on pore formation and structure evolution of the electrodeposited porous Ni films were studied. It was found that Ni films electrodeposited from solutions with 0.25⿿0.35 M NH4Cl were compact. When NH4Cl concentrations were 0.4⿿0.75 M and 0.85⿿3 M, porous Ni films with dish-like and honeycomb-like pores were electrodeposited, respectively. To form porous structure, the critical amounts of Ni in mass deposited onto the electrode must be achieved. However, at lower NH4Cl concentration, Ni electrodeposition was interrupted after about 15 s due to Ni2+ hydrolysis. The critical amounts of Ni in mass were not reached, and compact Ni films were obtained. When NH4Cl concentrations exceeded 0.4 M, Ni2+ hydrolysis was inhibited due to the enhanced buffer ability of solution and Ni(NH3)n2+ (2 ⿤ n ⿤ 6) complexes became the discharged ions. Ni electrodeposition proceeded continuously and reached the critical amounts of Ni in mass, and porous Ni films were formed. At higher NH4Cl concentration, hydrogen was produced mainly by the electrochemical reduction of NH4+. pH near cathode was hardly changed, and Ni2+ ions with low overpotential were reduced. The rough Ni films were formed, which led to smaller break-off diameter of bubbles. Therefore, the pore sizes of Ni films were decreased.

PROCESS OF SEPARATING PLUTONIUM VALUES BY ELECTRODEPOSITION

DOEpatents

Whal, A.C.

1958-04-15

A process is described of separating plutonium values from an aqueous solution by electrodeposition. The process consists of subjecting an aqueous 0.1 to 1.0 N nitric acid solution containing plutonium ions to electrolysis between inert metallic electrodes. A current density of one milliampere io one ampere per square centimeter of cathode surface and a temperature between 10 and 60 d C are maintained. Plutonium is electrodeposited on the cathode surface and recovered.

Preparation Of Copper Indium Gallium Diselenide Films For Solar Cells

DOEpatents

Bhattacharya, Raghu N.; Contreras, Miguel A.; Keane, James; Tennant, Andrew L. , Tuttle, John R.; Ramanathan, Kannan; Noufi, Rommel

1998-08-08

High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

Electrodeposited gels prepared from protein alloys

PubMed Central

Lin, Yinan; Wang, Siran; Chen, Ying; Wang, Qianrui; Burke, Kelly A; Spedden, Elise M; Staii, Cristian; Weiss, Anthony S; Kaplan, David L

2015-01-01

Aim Silk-tropoelastin alloys, composed of recombinant human tropoelastin and regenerated Bombyx mori silk fibroin, are an emerging, versatile class of biomaterials endowed with tunable combinations of physical and biological properties. Electrodeposition of these alloys provides a programmable means to assemble functional gels with both spatial and temporal controllability. Materials & methods Tropoelastin-modified silk was prepared by enzymatic coupling between tyrosine residues. Hydrogel coatings were electrodeposited using two wire electrodes. Results & discussion Mechanical characterization and in vitro cell culture revealed enhanced adhesive capability and cellular response of these alloy gels as compared with electrogelled silk alone. Conclusion These electro-depositable silk-tropoelastin alloys constitute a suitable coating material for nanoparticle-based drug carriers and offer a novel opportunity for on-demand encapsulation/release of nanomedicine. PMID:25816881

Effects of highly ordered TiO2 nanotube substrates on the nucleation of Cu electrodeposits.

PubMed

Ryu, Won Hee; Park, Chan Jin; Kwon, Hyuk Sang

2010-05-01

We investigated the effects of TiO2 nanotube substrates on the nucleation density of Cu during electrodeposition in a solution of CuSO4 and H2SO4 at 50 degrees C compared with those of pure Ti and micro-porous TiO2 substrates. During electrodeposition, the density of Cu nuclei on the TiO2 nanotube substrate increased and the average size of Cu nuclei decreased with increasing anodizing voltage and time for the synthesis of the substrate. In addition, the nucleation density of Cu electrodeposits on the highly ordered TiO2 nanotube substrate was much higher than that on pure Ti and micro-porous TiO2 substrates.

Electrodeposition of Metal Matrix Composites and Materials Characterization for Thin-Film Solar Cells

DTIC Science & Technology

2017-12-04

34High-Concentration III-V Multijunction Solar Cells," 2017, <http://www.nrel.gov/ pv /high-concentration-iii-v-multijunction- solar - cells.html>. O. K...AFRL-RV-PS- AFRL-RV-PS- TR-2017-0174 TR-2017-0174 ELECTRODEPOSITION OF METAL MATRIX COMPOSITES AND MATERIALS CHARACTERIZATION FOR THIN-FILM SOLAR ...0242 Electrodeposition of Metal Matrix Composites and Materials Characterization for Thin-Film Solar Cells 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

Pulse electro-deposition of copper on molybdenum for Cu(In,Ga)Se2 and Cu2ZnSnSe4 solar cell applications

NASA Astrophysics Data System (ADS)

Bi, Jinlian; Yao, Liyong; Ao, Jianping; Gao, Shoushuai; Sun, Guozhong; He, Qing; Zhou, Zhiqiang; Sun, Yun; Zhang, Yi

2016-09-01

The issues of rough surface morphology and the incorporated additives of the electro-deposited Cu layers, which exists in electrodeposition-based processes, is one of the major obstacles to improve the efficiency of Cu(In,Ga)Se2 (CIGSe) and Cu2ZnSnSe4 (CZTSe) solar cells. In this study, the pulse current electro-deposition method is employed to deposit smooth Cu film on Mo substrate in CuSO4 solution without any additives. Grain size of the deposited Cu film is decreased by high cathode polarization successfully. And the concentration polarization, which results from high pulse current density, is controlled successfully by adjusting the pulse frequency. Flat Cu film with smooth surface and compact structure is deposited as pulse current density @ 62.5 mA cm-2, pulse frequency @100,000 Hz, and duty cycle @ 25%. CIGSe and CZTSe absorber films with flat surface and uniform elemental distribution are prepared by selenizing the stacking metal layers electro-deposited by pulse current method. Finally, the CIGSe and CZTSe solar cells with conversion efficiency of 10.39% and 7.83% respectively are fabricated based on the smooth Cu films, which are better than the solar cells fabricated by the rough Cu film deposited by direct current electro-deposition method.

Plating Repair Of Nickel-Alloy Pressure Vessels

NASA Technical Reports Server (NTRS)

Ricklefs, Steve K.; Chagnon, Kevin M.

1989-01-01

Procedure for localized electrodeposition of nickel enables repair of small damaged nickel-based pressure vessels. Electrodeposition restores weakened areas of vessel wall to at least their former strength.

Toward Cost-Effective Manufacturing of Silicon Solar Cells: Electrodeposition of High-Quality Si Films in a CaCl2 -based Molten Salt.

PubMed

Yang, Xiao; Ji, Li; Zou, Xingli; Lim, Taeho; Zhao, Ji; Yu, Edward T; Bard, Allen J

2017-11-20

Electrodeposition of Si films from a Si-containing electrolyte is a cost-effective approach for the manufacturing of solar cells. Proposals relying on fluoride-based molten salts have suffered from low product quality due to difficulties in impurity control. Here we demonstrate the successful electrodeposition of high-quality Si films from a CaCl 2 -based molten salt. Soluble Si IV -O anions generated from solid SiO 2 are electrodeposited onto a graphite substrate to form a dense film of crystalline Si. Impurities in the deposited Si film are controlled at low concentrations (both B and P are less than 1 ppm). In the photoelectrochemical measurements, the film shows p-type semiconductor character and large photocurrent. A p-n junction fabricated from the deposited Si film exhibits clear photovoltaic effects. This study represents the first step to the ultimate goal of developing a cost-effective manufacturing process for Si solar cells based on electrodeposition. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Preliminary Study on the Synthesis and Characterization of Multilayered Ag/Co Magnetic Nanowires Fabricated via the Electrodeposition Method

PubMed Central

Peng, Cheng-Hsiung; Wu, Tsung-Yung; Hwang, Chyi-Ching

2013-01-01

A single-bath electrodeposition method was developed to integrate multilayer Ag/Co nanowires with a commercial anodic alumina oxide (AAO) template with a pore diameter of 100–200 nm. An electrolyte system containing silver nitride and cobalt sulfide was studied using cyclic voltammetry, and the electrodeposition rate was varied to optimize the electrodeposition conditions. A constant stepwise potential and a variable cation ratio of [Co2+]/[Ag+] were used during electrodeposition. After the dissolution of the template in aqueous NaOH solution, multilayered Ag/Co nanowires were obtained with a composition of [Co]/[Ag80Co20], as identified by XRD and TEM, when [Co2+]/[Ag+] = 150. By annealing at 200°C for 1 h, uniformly structured (Co99.57/Ag100) nanowires were obtained. Compared with pure Co nanowires, the magnetic hysteresis loops showed a greater magnetic anisotropy for (Co99.57/Ag100) nanowires than for pure Co nanowires, corresponding to a change in the easy axis upon magnetization. PMID:24072985

Electrodeposition of uranium and thorium onto small platinum electrodes

NASA Astrophysics Data System (ADS)

Reichenberger, Michael A.; Ito, Takashi; Ugorowski, Philip B.; Montag, Benjamin W.; Stevenson, Sarah R.; Nichols, Daniel M.; McGregor, Douglas S.

2016-03-01

Preparation of thin U- and Th-coated 0.3 mm diameter Pt working electrodes by the cyclic potential sweep method is described. Uranyl- and thorium hydroxide layers were electrodeposited from ethanol solutions containing 0.02 M natural uranyl and 0.02 M natural thorium nitrate, each with 3.6 M ammonium nitrate. The cell for electrodeposition was specially developed in order to accommodate the small working electrodes for this research by including a working electrode probe, 3-D translation stage, and microscope. The source material deposition was analyzed using digital microscopy and scanning electron microscopy, and confirmed using x-ray fluorescence measurements. The appropriate potential range for electrodeposition was determined to be -0.62 V to -0.64 V for a 0.3 mm diameter Pt working electrode placed 1 cm from the counter electrode. Smooth, uniform deposition was observed near the central region of the working electrode, while surface cracking and crystalline formations were found near the edge of the working electrode. The final procedure for sample substrate preparation, electrolytic solution preparation and electrodeposition are described.

Electrodeposition of Al-Ta alloys in NaCl-KCl-AlCl3 molten salt containing TaCl5

NASA Astrophysics Data System (ADS)

Sato, Kazuki; Matsushima, Hisayoshi; Ueda, Mikito

2016-12-01

To form Al-Ta alloys for high temperature oxidation resistance components, molten salt electrolysis was carried out in an AlCl3-NaCl-KCl melt containing TaCl5 at 423 K. The voltammogram showed two cathodic waves at 0.45 V and 0.7 V vs. Al/Al(III), which may correspond to reduction from Ta(V) to Ta(III) and from Ta(III) to tantalum metal, respectively. Electrodeposits of Al and Ta were obtained in the range from -0.05 to 0.3 V and the highest concentration of Ta in the electrodeposit was 72 at% at 0.3 V. With increasing Ta content in the alloy, the morphology of the electrodeposits became powdery and the particle size smaller.

Electrodeposition of Metal on GaAs Nanowires

NASA Astrophysics Data System (ADS)

Liu, Chao; Einabad, Omid; Watkins, Simon; Kavanagh, Karen

2010-10-01

Copper (Cu) electrical contacts to freestanding gallium arsenide (GaAs) nanowires have been fabricated via electrodeposition. The nanowires are zincblende (111) oriented grown epitaxially on n-type Si-doped GaAs (111)B substrates by gold-catalyzed Vapor Liquid Solid (VLS) growth in a metal organic vapour phase epitaxy (MOVPE) reactor. The epitaxial electrodeposition process, based on previous work with bulk GaAs substrates, consists of a substrate oxide pre-etch in dilute ammonium-hydroxide carried out prior to galvanostatic electrodeposition in a pure Cu sulphate aqueous electrolyte at 20-60^oC. For GaAs nanowires, we find that Cu or Fe has a preference for growth on the gold catalyst avoiding the sidewalls. After removing gold, both metals still prefer to grow only on top of the nanowire, which has the largest potential field.

Electrical contact arrangement for a coating process

DOEpatents

Kabagambe, Benjamin; McCamy, James W; Boyd, Donald W

2013-09-17

A protective coating is applied to the electrically conductive surface of a reflective coating of a solar mirror by biasing a conductive member having a layer of a malleable electrically conductive material, e.g. a paste, against a portion of the conductive surface while moving an electrodepositable coating composition over the conductive surface. The moving of the electrodepositable coating composition over the conductive surface includes moving the solar mirror through a flow curtain of the electrodepositable coating composition and submerging the solar mirror in a pool of the electrodepositable coating composition. The use of the layer of a malleable electrically conductive material between the conductive member and the conductive surface compensates for irregularities in the conductive surface being contacted during the coating process thereby reducing the current density at the electrical contact area.

Fabrication of Cu2O/TiO2 Nanotubes Heterojunction Arrays and Investigation of Their Photoelectrochemical Behaviour

DTIC Science & Technology

2012-11-05

investigate phase transformations in TiO2 NTs after annealing and as a consequence of the functionalization. Electrodeposition was performed in a...deposition Cu2O electrodeposition was performed by polarizing the Ti/TiO2 NTs electrodes at UE = - 0.4 V in the CuSO4 containing bath described in...polarization (UE = - 0.4 V) in the electrodeposition solution (see experimental section). As shown in Fig. 6, in spite of the constant polarizing voltage (i.e

Covering Cavities by Electrodeposition

NASA Technical Reports Server (NTRS)

Schmeets, M.; Duesberg, J.

1986-01-01

Reworking technique allows complex surfaces to be reshaped. Contours of large machined parts reworked quickly and inexpensively by electrodeposition and machining, with little risk of damage. Reworking method employs simple, reliable, well-known procedures.

One-step fabrication of nickel nanocones by electrodeposition using CaCl2·2H2O as capping reagent

NASA Astrophysics Data System (ADS)

Lee, Jae Min; Jung, Kyung Kuk; Lee, Sung Ho; Ko, Jong Soo

2016-04-01

In this research, a method for the fabrication of nickel nanocones through the addition of CaCl2·2H2O to an electrodeposition solution was proposed. When electrodeposition was performed after CaCl2·2H2O addition, precipitation of the Ni ions onto the (2 0 0) crystal face was suppressed and anisotropic growth of the nickel electrodeposited structures was promoted. Sharper nanocones were produced with increasing concentration of CaCl2·2H2O added to the solution. Moreover, when temperature of the electrodeposition solutions approached 60 °C, the apex angle of the nanostructures decreased. In addition, the nanocones produced were applied to superhydrophobic surface modification using a plasma-polymerized fluorocarbon (PPFC) coating. When the solution temperature was maintained at 60 °C and the concentration of the added CaCl2·2H2O was 1.2 M or higher, the fabricated samples showed superhydrophobic surface properties. The proposed nickel nanocone formation method can be applied to various industrial fields that require metal nanocones, including superhydrophobic surface modification.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Ke; Wang, Xiaoyun; Liu, Jingjing

Highlights: • Cu/In bilayer was fabricated by BMSMW deposition technique. • High quality CIS film was successfully fabricated. • A preferable ratio of Cu:In:S close to 1:1:2 was approached. • The SPV response as high as 6 mV was achieved. - Abstract: High-quality CuInS{sub 2} (CIS) thin films have been fabricated by sulfurization of electrodeposited copper–indium bilayer. A novel bell-like wave modulated square wave (BWMSW) electrodeposition technique is employed for the deposition of copper thin film. Three independent parameters (current or potential, frequency, duty cycle) are available for the BWMSW electrodeposition, which is different from the traditional electrodeposition technique withmore » only one adjustable parameter (current or potential). The influences of deposition parameters such as frequency, duty cycle and the concentration of complexing agent are investigated. Benefited from the high quality copper film obtained by the BWMSW technique, the indium film is electrodeposited successfully on the copper layer to form a compact copper–indium alloy bilayer. After sulfurized at 600 °C for 60 min, the phase pure CIS film is obtained with better crystallinity. The structures, morphologies and optoelectronic properties of the CIS film are also characterized.« less

Polyamidoamine dendrimers-assisted electrodeposition of gold-platinum bimetallic nanoflowers.

PubMed

Qian, Lei; Yang, Xiurong

2006-08-24

Novel Au-Pt bimetallic flower nanostructures fabricated on a polyamidoamine dendrimers-modified surface by electrodeposition are reported. These polyamidoamine dendrimers were stable, and they assisted the formation of Au-Pt bimetallic nanoflowers during the electrodeposition process. These nanoflowers were characterized by field-emitted scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction, and electrochemical methods. FE-SEM images showed that the bimetallic nanoflower included two parts: the "light" and the "pale" part. The two parts consisted of many small bimetallic nanoparticles, which was attributed to the progressive nucleation process. Moreover, the "light" part contained more bimetallic nanoparticles. The morphologies of bimetallic nanoflowers depended on the electrodeposition time and potential and the layer number of assembled dendrimers. The average size of nanoflowers increased with the increase in electrodeposition time. The layer number of assembled dendrimers obviously affected the size and morphologies of the "pale" parts of deposited nanoflowers. EDS and XPS indicated that the content of Au element was higher than that of Pt element in the nanoflowers. The bimetallic nanoflowers-modified electrode had electrochemical properties similar to those of bare gold and platinum electrodes. It also exhibited significant electrocatalytic activities toward oxygen reduction.

Diameter-dependent optical constants of gold mesoparticles electrodeposited on aluminum films containing copper.

PubMed

Brevnov, Dmitri A; Bungay, Corey

2005-08-04

Electrodeposition of gold mesoparticles on anodized and chemically etched aluminum/copper films deposited on silicon wafers proceeds by instantaneous nucleation and with no diffusion limitations. Both of these phenomena favor the formation of relatively monodispersed gold particles. Under the reported electrodeposition conditions, the relative standard deviation of the particle diameter is 25%. The particle coverage is 7 x 10(8) particles cm(-2). The mean particle diameter varies as a function of electrodeposition time in the range of 40-80 nm. Optical constants of gold mesoparticles are resolved by spectroscopic ellipsometry. A two-layer optical model is constructed to determine both extinction coefficients and refractive indexes of gold mesoparticles as a function of the mean particle diameter. The absorption peak, associated with surface plasmons, is modeled with two Lorentz oscillators. Absorption peak maximums shift from 610 to 675 nm as the mean particle diameter increases from 42 to 74 nm. Electrodeposition of gold particles on technologically relevant substrates, such as aluminum/copper films, is expected to increase the utility of gold particles and facilitate their incorporation in nanostructured materials and a variety of electronic and optical devices.

Low temperature electrodeposition of silicon layers

NASA Astrophysics Data System (ADS)

Pauporté, Thierry; Qi, Shuo; Viana, Bruno

2018-02-01

The electrodeposition of silicon at room temperature in 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide and N-Propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquids containing SiCl4 salt is shown. The electrodeposition window has been determined by cyclic voltammetry. Layers have been deposited in a three electrode cell placed in an inert atmosphere and at constant applied potential. The characterizations by x-ray diffraction and Raman spectroscopy showed the formation of a layer made of amorphous silicon. The scanning electron microscopy examination revealed that the layers were featureless and well-covering.

Organic Solar Cells Based on Electrodeposited Polyaniline Films

NASA Astrophysics Data System (ADS)

Inoue, Kei; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

2012-04-01

Polyaniline thin films as hole transporting layers were fabricated on transparent indium-tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.

Studies of metals electroprocessing in molten salts

NASA Technical Reports Server (NTRS)

Sadoway, D. R.

1982-01-01

Fluid flow patterns in molten salt electrolytes were observed in order to determine how mass transport affects the morphology of the metal deposit. Studies conducted on the same metal, both in aqueous electrolytes in which coherent solid electrodeposits are produced, as well as in transparent molten salt electrolytes are described. Process variables such as current density and composition of the electrolyte are adjusted to change the morphology of the electrodeposit and, thus, to permit the study of the nature of electrolyte flow in relation to the quality of the electrodeposit.

Investigation of Electrodeposited Alloys and Pure Metals as Substitutes for Zinc and Cadmium for Protective Finishes for Steel Parts of Aircraft

DTIC Science & Technology

1949-09-01

ON LOAN FROM 7k a. **+dU fefeÄtüiÄ: .<*-#=« Investigation of Electrodeposited Alloys and Pure Metals as Substitutes for Zinc and Cadmium for...graphs Eight alloys, selected as being superior to pure zinc or cadmium for protecting steel, were evaluated on the basis of static and dynamic... zinc -silver alloy of 25% silver. A tabulated summary of the testing program on all cast and electrodeposited alloys tested is included. * and

Morphology selection for cupric oxide thin films by electrodeposition.

PubMed

Dhanasekaran, V; Mahalingam, T; Chandramohan, R

2011-10-01

Polycrystalline cupric oxide thin films were deposited using alkaline solution bath employing cathodic electrodeposition method. The thin films were electrodeposited at various solution pH. The surface morphology and elemental analyzes of the films were studied using scanning electron microscopy (SEM) and energy dispersive X-ray analysis, respectively. SEM studies revealed that the surface morphology could be tailored suitably by adjusting the pH value during deposition. Mesh average on multiple lattice mode atomic force microscopy image was obtained and reported. Copyright © 2011 Wiley-Liss, Inc.

Electrodeposited non-stoichiometric tungstic acid for electrochromic applications: film growth modes, crystal structure, redox behavior and stability

NASA Astrophysics Data System (ADS)

Pugolovkin, Leonid V.; Cherstiouk, Olga V.; Plyasova, Lyudmila M.; Molina, Irina Yu.; Kardash, Tatyana Yu.; Stonkus, Olga A.; Yatsenko, Dmitriy A.; Kaichev, Vasily V.; Tsirlina, Galina A.

2016-12-01

Bath composition for cathodic electrodeposition of non-stoichiometric hydrated tungstic acid with high electrochromic efficiency is optimized with account for selective electroreduction of certain isopolytungstates. XRD data for thin electrodeposited films and chemically synthesized bulk tungstic acid dihydrate are compared in the context of reversible oxidation and reduction in hydrogen atmosphere, in presence of Pt catalyst. XPS and TEM techniques are attracted to understand the nature of reversible and less reversible transformations of films in the course of their storage and operation.

Controllable electrodeposition of ZnO nanorod arrays on flexible stainless steel mesh substrate for photocatalytic degradation of Rhodamine B

NASA Astrophysics Data System (ADS)

Lu, Hui; Zhang, Mei; Guo, Min

2014-10-01

Well-aligned single-crystalline ZnO nanorod arrays (ZNRAs) were prepared on flexible stainless steel mesh (SSM) substrate in large-scale by using a direct electrodeposition method. The effects of electrochemical parameters, such as applied potential, applied nucleation potential time, substrate pretreatment, electrodeposition duration and times, on the orientation, morphology and density of ZNRAs were systematically studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and the selected area electron diffraction (SAED). The results showed that ZNRAs on SSM substrate with [0 0 1] preferred orientation and well crystallization were obtained by controlling the applied potential in the range of -0.9 to -1.1 V. The density of ZNRAs could be increased obviously by applying a nucleation potential (-1.3 V for more than 10 s before deposition) or by means of substrate pretreatment (the SSM immersed in zinc acetate colloid for more than 10 min before deposition), meanwhile, the deposited ZNRAs also had small average diameter (<46 ± 4 nm), narrow size distribution and good orientation. In addition, it was also found that the average diameter of ZNRAs could be increased from 89 to 201 ± 5 nm by extending the electrodeposition duration from 1800 to 7200 s, and the length of rods was from 0.8 to 2.2 ± 0.1 μm when the times of the electrodeposition from one to six times. Furthermore, the band gap energy (Eg) of as-prepared ZNTAs was not closely related to the electrodeposition times (only changed from 3.30 to 3.32 eV). The ZNRAs prepared with more electrodeposition times showed enhanced photocatalytic performance under the UV-lamp for degradation of Rhodamine B. The degradation efficiency of ZNRAs improved from 89.4% to 98.3% with the deposition times from one to six times.

High adherence copper plating process

DOEpatents

Nignardot, Henry

1993-01-01

A process for applying copper to a substrate of aluminum or steel by electrodeposition and for preparing an aluminum or steel substrate for electrodeposition of copper. Practice of the invention provides good adhesion of the copper layer to the substrate.

Aluminium Electrodeposition from Ionic Liquid: Effect of Deposition Temperature and Sonication †

PubMed Central

Berretti, Enrico; Giaccherini, Andrea; Martinuzzi, Stefano M.; Innocenti, Massimo; Schubert, Thomas J.S.; Stiemke, Frank M.; Caporali, Stefano

2016-01-01

Since their discovery, ionic liquids (ILs) have attracted a wide interest for their potential use as a medium for many chemical processes, in particular electrochemistry. As electrochemical media they allow the electrodeposition of elements that are impossible to reduce in aqueous media. We have investigated the electrodeposition of aluminium from 1-butyl-3-methyl-imidazolium chloride ((Bmim)Cl)/AlCl3 (40/60 mol %) as concerns the effect of deposition parameters on the quality of the deposits. Thick (20 μm) aluminium coatings were electrodeposited on brass substrates at different temperatures and mixing conditions (mechanical stirring and sonication). These coatings were investigated by means of scanning electron microscope, roughness measurements, and X-ray diffraction to assess the morphology and the phase composition. Finally, electrochemical corrosion tests were carried out with the intent to correlate the deposition parameters to the anti-corrosion properties. PMID:28773839

Electrochemical characterization and electrode kinetics for antimony electrodeposition from its oxychloride solution in the presence of tartaric acid

NASA Astrophysics Data System (ADS)

Majidzade, Vusala Asim; Guliyev, Parvin Heydar; Aliyev, Akif Shikhan; Elrouby, Mahmoud; Tagiyev, Dilgam Babir

2017-05-01

This work is devoted to investigate the process of the electrochemical deposition of antimony from antimony oxychloride solution in the presence of tartaric acid in aqueous media. The kinetics and the mechanism of the electrodeposition process at the electrode surface are studied and proposed by the aid of cyclic, linear sweep voltammetric and chronoamperometric characterization methods. It is found that, the process is affected by the presence of tartaric acid and some factors during the electro-reduction process. The results also show that, the temperature, the potential sweep rate and the concentration of antimony have a great influence on the achievement of the electrodeposition process. Some important parameters are calculated such as, the activation energy of the electrochemical reaction, the diffusion coefficient and the number of saturated nucleation sites. The electrodeposited film is examined using X-ray diffraction, scanning electron microscopy and Energy Dispersive Spectroscopy.

Defect structure in electrodeposited nanocrystalline Ni layers with different Mo concentrations

NASA Astrophysics Data System (ADS)

Kapoor, Garima; Péter, László; Fekete, Éva; Gubicza, Jenő

2018-05-01

The effect of molybdenum (Mo) alloying on the lattice defect structure in electrodeposited nanocrystalline nickel (Ni) films was studied. The electrodeposited layers were prepared on copper substrate at room temperature, with a constant current density and pH value. The chemical composition of these layers was determined by EDS. In addition, X-ray diffraction line profile analysis was carried out to study the microstructural parameters such as the crystallite size, the dislocation density and the stacking fault probability. It was found that the higher Mo content yielded more than one order of magnitude larger dislocation density while the crystallite size was only slightly smaller. In addition, the twin boundary formation activity during deposition increased with increasing Mo concentration. The results obtained on electrodeposited layers were compared with previous research carried out on bulk nanocrystalline Ni-Mo materials with similar compositions but processed by severe plastic deformation.

Electrodeposition of Amorphous Molybdenum Chalcogenides from Ionic Liquids and Their Activity for the Hydrogen Evolution Reaction.

PubMed

Redman, Daniel W; Rose, Michael J; Stevenson, Keith J

2017-09-19

This work reports on the general electrodeposition mechanism of tetrachalcogenmetallates from 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Both tetrathio- and tetraselenomolybdate underwent anodic electrodeposition and cathodic corrosion reactions as determined by UV-vis spectroelectrochemistry. Electrodeposition was carried out by cycling the potential between the anodic and cathodic regimes. This resulted in a film of densely packed nanoparticles of amorphous MoS x or MoSe x as determined by SEM, Raman, and XPS. The films were shown to have high activity for the hydrogen evolution reaction. The onset potential (J = 1 mA/cm 2 ) of the MoS x film was E = -0.208 V vs RHE, and that of MoSe x was E = -0.230 V vs RHE. The Tafel slope of MoS x was 42 mV/decade, and that of MoSe x was 59 mV/decade.

Electrodeposited inorganic separators for alkaline batteries

NASA Technical Reports Server (NTRS)

Carson, W. N., Jr.; Consiglio, J. A.; Mc Quade, J. M.

1970-01-01

Coating electrodes of silver-cadmium cells with thermostable electrodeposits of calcium hydroxide or magnesium hydroxide reduces silver migration and increases cell life. Absence of organic matter enables assembled cells to be sterilized without oxidation of the material of the separators.

Methods and electrolytes for electrodeposition of smooth films

DOEpatents

Zhang, Jiguang; Xu, Wu; Graff, Gordon L; Chen, Xilin; Ding, Fei; Shao, Yuyan

2015-03-17

Electrodeposition involving an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and/or film surface. For electrodeposition of a first conductive material (C1) on a substrate from one or more reactants in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second conductive material (C2), wherein cations of C2 have an effective electrochemical reduction potential in the solution lower than that of the reactants.

Electrodeposition of near stoichiometric CuInSe2 thin films for photovoltaic applications

NASA Astrophysics Data System (ADS)

Chandran, Ramkumar; Mallik, Archana

2018-03-01

This work investigates on the single step electrodeposition of quality CuInSe2 (CIS) thin film absorber layer for photovoltaics applications. The electrodeposition was carried using an aqueous acidic solution with a pH of 2.25. The deposition was carried using a three electrode system in potentiostatic conditions for 50 minutes. The as-deposited and nitrogen (N2) annealed films were characterized using XRD, FE-SEM and Raman spectroscopy. It has been observed that the SDS has the tendency to suppress the copper selenide (CuxSe) secondary phase which is detrimental to the device performance.

Electrodeposition of biaxially textured layers on a substrate

DOEpatents

Bhattacharya, Raghu N; Phok, Sovannary; Spagnol, Priscila; Chaudhuri, Tapas

2013-11-19

Methods of producing one or more biaxially textured layer on a substrate, and articles produced by the methods, are disclosed. An exemplary method may comprise electrodepositing on the substrate a precursor material selected from the group consisting of rare earths, transition metals, actinide, lanthanides, and oxides thereof. An exemplary article (150) may comprise a biaxially textured base material (130), and at least one biaxially textured layer (110) selected from the group consisting of rare earths, transition metals, actinides, lanthanides, and oxides thereof. The at least one biaxially textured layer (110) is formed by electrodeposition on the biaxially textured base material (130).

Cyclic voltammetric study of Co-Ni-Fe alloys electrodeposition in sulfate medium

NASA Astrophysics Data System (ADS)

Hanafi, I.; Daud, A. R.; Radiman, S.

2013-11-01

Electrochemical technique has been used to study the electrodeposition of cobalt, nickel, iron and Co-Ni-Fe alloy on indium tin oxide (ITO) coated glass substrate. To obtain the nucleation mechanism, cyclic voltammetry is used to characterize the Co-Ni-Fe system. The scanning rate effect on the deposition process was investigated. Deposition of single metal occurs at potential values more positive than that estimated stability potential. Based on the cyclic voltammetry results, the electrodeposition of cobalt, nickel, iron and Co-Ni-Fe alloy clearly show that the process of diffusion occurs is controlled by the typical nucleation mechanism.

Electrodepositable alginate membranes for enzymatic sensors: An amperometric glucose biosensor for whole blood analysis.

PubMed

Márquez, A; Jiménez-Jorquera, C; Domínguez, C; Muñoz-Berbel, X

2017-11-15

Simple and disposable point of care systems are usually the best solution for chronic patients to get a rapid diagnosis in home care context. However, their main drawback relies on the poor reliability derived from the low stability of the bio-recognition elements and low quality of the transducers. In the current work, we study the use of electrodeposited calcium alginate hydrogels as a biocompatible matrix in the development of enzymatic amperometric biosensors for whole blood analysis, to enhance the enzymes stability and to protect the transducer from biofouling. The alginate electrodeposition involves the controlled Ca 2+ release, so the gel thickness can be modulated. In the biosensor, horseradish peroxidase (HRP) and glucose oxidase (GOD) were electrodeposited within the hydrogel and the activity of the bi-enzymatic system was analyzed chronoamperometrically using 3,3',5,5'-Tetramethylbenzidine (TMB) as the mediator. Besides enzyme entrapment, the obtained gels protected the transducer from biofouling, enabling the reuse of the transducer after hydrogel removal and re-electrodeposition. The biosensors showed good analytical characteristics to glucose determination in whole blood samples, discriminating among healthy and hyperglycemic samples, with good sensitivity (- 0.27µAcm -2 mM -1 ), low limit of detection (126µM) and long lineal range (2-12mM). Copyright © 2017. Published by Elsevier B.V.

Template-assisted fabrication of tin and antimony based nanowire arrays

NASA Astrophysics Data System (ADS)

Zaraska, Leszek; Kurowska, Elżbieta; Sulka, Grzegorz D.; Jaskuła, Marian

2012-10-01

Antimony nanowires with diameters ranging from 35 nm to 320 nm were successfully prepared by simple, galvanostatic electrodeposition inside the pores of anodic alumina membranes from a citrate based electrolyte. The use of the potassium antimonyl tartrate electrolyte for electrodeposition results in the formation of Sb/Sb2O3 nanowires. The structural features of the nanowire arrays were investigated by FE-SEM, and the nanowire composition was confirmed by EDS and XRD measurements. A distinct peak at about 27.5° in the XRD pattern recorded for nanowires formed in the tartrate electrolyte was attributed to the presence of co-deposited Sb2O3. Three types of dense arrays of Sn-SnSb nanowires with diameters ranging from 82 nm to 325 nm were also synthesized by DC galvanostatic electrodeposition into the anodic aluminum oxide (AAO) membranes for the first time. Only Sn and SnSb peaks appeared in the XRD pattern and both phases seem to have a relatively high degree of crystallinity. The influence of current density applied during electrodeposition on the composition of nanowires was investigated. It was found that the Sb content in fabricated nanowires decreases with increasing current density. The diameters of all synthesized nanowires roughly correspond to the dimensions of the nanochannels of AAO templates used for electrodeposition.

Non-enzymatic glucose sensor based on electrodeposited copper on carbon paste electrode (Cu/CPE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nurani, Dita Arifa, E-mail: d.arifa@sci.ui.ac.id; Wibowo, Rahmat; Fajri, Iqbal Farhan El

The development of non-enzymatic glucose sensor has much attention due to their applications in glucose monitoring. In this research, copper oxide is used as a non-enzymatic glucose sensor by oxidizing glucose to gluconolactone. Copper was electrodeposited on Carbon paste electrode (CPE) at constant potential. The experimental condition was varied in electrodeposition of Cu with the following parameters: Electrodeposition time 60 s, 120 s and 180 s and potential reduction -0.166 V, -0.266 V and -0.366 V. The effective performance of these working electrodes in sensing glucose was investigated. The Cu/CPE which used -0.366 V potential reduction and 120 s electrodeposition time shows the bestmore » performance. The amperometric response current in concentration range 1.6-62.5 mM of glucose gives the good linearity R{sup 2} = 0.9988, low detection limit 0.6728 mM and high sensitivity 1183.59 µA mM{sup −1}cm{sup −2}. Furthermore this sensor exhibited a good repeatability with %RSD = 1.31% (n=10) and high stability with %RSD = 1.51% (n=5 days). The homogeneity of Cu particles on CPE was investigated by Scanning Electron Microscope (SEM).« less

III. Co-electrodeposition/removal of copper and nickel in a spouted electrochemical reactor.

PubMed

Grimshaw, Pengpeng; Calo, Joseph M; Hradil, George

2011-07-11

Results are presented of an investigation of co-electrodeposition of copper and nickel from acidic solution mixtures in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on metal removal/recovery rate, current efficiency, and corrosion of the deposited metals from the cathodic particles were examined under galvanostatic operation. The quantitative and qualitative behavior of co-electrodeposition of the two metals from their mixtures differs significantly from that of the individual single metal solutions. This is primarily attributed to the metal displacement reaction between Ni(0) and Cu(2+). This reaction effectively reduces copper corrosion, and amplifies that for nickel (at least at high concentrations). It also amplifies the separation of the deposition regimes of the two metals in time, which indicates that the recovery of each metal as a relatively pure deposit from the mixture is possible. It was also shown that nitrogen sparging considerably increases the observed net electrodeposition rates for both metals - considerably more so than from solutions with just the single metals alone. A numerical model of co-electrodeposition, corrosion, metal displacement, and mass transfer in the cylindrical spouted electrochemical reactor is presented that describes the behavior of the experimental copper and nickel removal data quite well.

III. Co-electrodeposition/removal of copper and nickel in a spouted electrochemical reactor

PubMed Central

Grimshaw, Pengpeng; Calo, Joseph M.; Hradil, George

2011-01-01

Results are presented of an investigation of co-electrodeposition of copper and nickel from acidic solution mixtures in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on metal removal/recovery rate, current efficiency, and corrosion of the deposited metals from the cathodic particles were examined under galvanostatic operation. The quantitative and qualitative behavior of co-electrodeposition of the two metals from their mixtures differs significantly from that of the individual single metal solutions. This is primarily attributed to the metal displacement reaction between Ni0 and Cu2+. This reaction effectively reduces copper corrosion, and amplifies that for nickel (at least at high concentrations). It also amplifies the separation of the deposition regimes of the two metals in time, which indicates that the recovery of each metal as a relatively pure deposit from the mixture is possible. It was also shown that nitrogen sparging considerably increases the observed net electrodeposition rates for both metals – considerably more so than from solutions with just the single metals alone. A numerical model of co-electrodeposition, corrosion, metal displacement, and mass transfer in the cylindrical spouted electrochemical reactor is presented that describes the behavior of the experimental copper and nickel removal data quite well. PMID:21874093

High adherence copper plating process

DOEpatents

Nignardot, H.

1993-09-21

A process is described for applying copper to a substrate of aluminum or steel by electrodeposition and for preparing the surface of an aluminum or steel substrate for the electrodeposition of copper. Practice of the invention provides good adhesion of the copper layer to either substrate.

Sources of stress gradients in electrodeposited Ni MEMS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hearne, Sean Joseph; Floro, Jerrold Anthony; Dyck, Christopher William

2004-06-01

The ability of future integrated metal-semiconductor micro-systems such as RF MEMS to perform highly complex functions will depend on developing freestanding metal structures that offer improved conductivity and reflectivity over polysilicon structures. For example, metal-based RF MEMS technology could replace the bulky RF system presently used in communications, navigation, and avionics systems. However, stress gradients that induce warpage of active components have prevented the implementation of this technology. Figure 1, is an interference micrograph image of a series of cantilever beams fabricated from electrodeposited Ni. The curvature in the beams was the result of stress gradients intrinsic to the electrodepositionmore » process. To study the sources of the stress in electrodeposition of Ni we have incorporated a wafer curvature based stress sensor, the multibeam optical stress sensor, into an electrodeposition cell. We have determined that there are two regions of stress induced by electrodepositing Ni from a sulfamate-based bath (Fig 2). The stress evolution during the first region, 0-1000{angstrom}, was determined to be dependent only on the substrate material (Au vs. Cu), whereas the stress evolution during the second region, >1000{angstrom}, was highly dependent on the deposition conditions. In this region, the stress varied from +0.5 GPa to -0.5GPa, depending solely on the deposition rate. We examined four likely sources for the compressive intrinsic stress, i.e. reduction in tensile stress, and determined that only the adatom diffusion into grain boundaries model of Sheldon, et al. could account for the observed compressive stress. In the presentation, we shall discuss the compressive stress generation mechanisms considered and the ramifications of these results on fabrication of electrodeposited Ni for MEMS applications.« less

DC electrodeposition of NiGa alloy nanowires in AAO template

NASA Astrophysics Data System (ADS)

Maleki, K.; Sanjabi, S.; Alemipour, Z.

2015-12-01

NiGa alloy nanowires were electrodeposited from an acidic sulfate bath into nanoporous anodized alumina oxide (AAO). This template was fabricated by two-step anodizing. The effects of bath composition and current density were explored on the Ga content of electrodeposited nanowires. The Ga content in the deposits was increased by increasing both Ga in the bath composition and electrodepositing current density. The NiGa alloy nanowires were synthesized for Ga content up to 2-4% without significant improving the magnetic properties. Above this threshold Ga clusters were formed and decreased the magnetic properties of the nanowires. For Ga content of the alloy above 30%, the wires were too short and incomplete. X-ray diffraction patterns reveal that the significant increase of Ga content in the nanowires, changes the FCC crystal structure of Ni to an amorphous phase. It also causes a sizeable increase in the Ga cluster size; these both lead to a significant reduction in the coercivity and the magnetization respectively.

Fabrication of cobalt-nickel binary nanowires in a highly ordered alumina template via AC electrodeposition

PubMed Central

2013-01-01

Cobalt-nickel (Co-Ni) binary alloy nanowires of different compositions were co-deposited in the nanopores of highly ordered anodic aluminum oxide (AAO) templates from a single sulfate bath using alternating current (AC) electrodeposition. AC electrodeposition was accomplished without modifying or removing the barrier layer. Field emission scanning electron microscope was used to study the morphology of templates and alloy nanowires. Energy-dispersive X-ray analysis confirmed the deposition of Co-Ni alloy nanowires in the AAO templates. Average diameter of the alloy nanowires was approximately 40 nm which is equal to the diameter of nanopore. X-ray diffraction analysis showed that the alloy nanowires consisted of both hexagonal close-packed and face-centered cubic phases. Magnetic measurements showed that the easy x-axis of magnetization is parallel to the nanowires with coercivity of approximately 706 Oe. AC electrodeposition is very simple, fast, and is useful for the homogenous deposition of various secondary nanostuctured materials into the nanopores of AAO. PMID:23941234

Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

DOE PAGES

Adamic, M. L.; Lister, T. E.; Dufek, E. J.; ...

2015-03-25

This paper presents an evaluation of an alternate method for preparing environmental samples for 129I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Furthermore, precipitated silver iodide samples are usually mixed with niobium or silver powdermore » prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.« less

Electrodeposition of Rhodium Nanowires Arrays and Their Morphology-Dependent Hydrogen Evolution Activity

PubMed Central

Zhang, Liqiu; Liu, Lichun; Wang, Hongdan; Shen, Hongxia; Cheng, Qiong; Yan, Chao; Park, Sungho

2017-01-01

This work reports on the electrodeposition of rhodium (Rh) nanowires with a controlled surface morphology synthesized using an anodic aluminum oxide (AAO) template. Vertically aligned Rh nanowires with a smooth and coarse morphology were successfully deposited by adjusting the electrode potential and the concentration of precursor ions and by involving a complexing reagent in the electrolyte solution. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses were used to follow the morphological evolution of Rh nanowires. As a heterogeneous electrocatalyst for hydrogen evolution reactions (HER), the coarse Rh nanowire array exhibited an enhanced catalytic performance respect to smooth ones due to the larger surface area to mass ratio and the higher density of catalytically active defects, as evidenced by voltammetric measurements and TEM. Results suggest that the morphology of metallic nanomaterials could be readily engineered by electrodeposition. The controlled electrodeposition offers great potential for the development of an effective synthesis tool for heterogeneous catalysts with a superior performance for wide applications. PMID:28467375

Diameter and location control of ZnO nanowires using electrodeposition and sodium citrate

NASA Astrophysics Data System (ADS)

Lifson, Max L.; Levey, Christopher G.; Gibson, Ursula J.

2013-10-01

We report single-step growth of spatially localized ZnO nanowires of controlled diameter to enable improved performance of piezoelectric devices such as nanogenerators. This study is the first to demonstrate the combination of electrodeposition with zinc nitrate and sodium citrate in the growth solution. Electrodeposition through a thermally-grown silicon oxide mask results in localization, while the growth voltage and solution chemistry are tuned to control the nanowire geometry. We observe a competition between lateral (relative to the (0001) axis) citrate-related morphology and voltage-driven vertical growth which enables this control. High aspect ratios result with either pure nitrate or nitrate-citrate mixtures if large voltages are used, but low growth voltages permit the growth of large diameter nanowires in solution with citrate. Measurements of the current density suggest a two-step growth process. An oxide mask blocks the electrodeposition, and suppresses nucleation of thermally driven growth, permitting single-step lithography on low cost p-type silicon substrates.

Characterization of rhenium compounds obtained by electrochemical synthesis after aging process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vargas-Uscategui, Alejandro, E-mail: avargasuscat@ing.uchile.cl; Mosquera, Edgar; López-Encarnación, Juan M.

2014-12-15

The proper identification of the molecular nature of the aged rhenium compound obtained by means of electrodeposition from an alkaline aqueous electrolyte was determined. Chemical, structural and vibrational experimental characterization of the aged Re compound showed agreement with quantum-computations, thereby allowing the unambiguous identification of the Re compound as H(ReO{sub 4})H{sub 2}O. - Graphical abstract: Rhenium oxides were electrodeposited on a copper surface and after environmental aging was formed the H(ReO{sub 4})H{sub 2}O compound. The characterization of the synthesized material was made through the comparison of experimental evidence with quantum mechanical computations carried out by means of density functional theorymore » (DFT). - Highlights: • Aged rhenium compound obtained by means of electrodeposition was studied. • The study was made by combining experimental and DFT-computational information. • The aged electrodeposited material is consistent with the H(ReO{sub 4})H{sub 2}O compound.« less

Mechanisms of Current Transfer in Electrodeposited Layers of Submicron Semiconductor Particles

NASA Astrophysics Data System (ADS)

Zhukov, N. D.; Mosiyash, D. S.; Sinev, I. V.; Khazanov, A. A.; Smirnov, A. V.; Lapshin, I. V.

2017-12-01

Current-voltage ( I- V) characteristics of conductance in multigrain layers of submicron particles of silicon, gallium arsenide, indium arsenide, and indium antimonide have been studied. Nanoparticles of all semiconductors were obtained by processing initial single crystals in a ball mill and applied after sedimentation onto substrates by means of electrodeposition. Detailed analysis of the I- V curves of electrodeposited layers shows that their behavior is determined by the mechanism of intergranular tunneling emission from near-surface electron states of submicron particles. Parameters of this emission process have been determined. The proposed multigrain semiconductor structures can be used in gas sensors, optical detectors, IR imagers, etc.

Electrodeposition of high-density lithium vanadate nanowires for lithium-ion battery

NASA Astrophysics Data System (ADS)

Hua, Kang; Li, Xiujuan; Fang, Dong; Yi, Jianhong; Bao, Rui; Luo, Zhiping

2018-07-01

Lithium vanadate nanowires have been electrodeposited onto a titanium (Ti) foil by a direct current electrodeposition without template. The morphology, crystal structure, and the effects of deposition voltage, temperature and time on the prepared samples were tested and presented. The as-prepared lithium vanadate nanowires/Ti composite can be used as electrode for lithium-ion battery. Electrochemical measurements showed that the electrode displayed a specific discharge capacitance as high as 235.1 mAh g-1 after 100 cycles at a current density of 30 mA g-1. This research provides a new pathway to explore high tap density vanadates nanowires on metals with enhanced electrochemical performance.

Effect of mass density on surface morphology of electrodeposited manganese oxide films

NASA Astrophysics Data System (ADS)

Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder

2018-05-01

This work focus on high surface area morphology of manganese oxide films which are currently required for electrochemical capacitor electrode to enhance their performance. Electrodeposition of manganese oxide films was carried out using Chronoamperometry for different deposition time ranging from 30 to 120 sec. Cronoamperomertic I-T integrated data have been used to analyze active mass of all electrodeposited films. Morphological study of the deposited films with different mass was carried out through scanning electron microscopy. Film deposited for 30 sec time show highest porous morphology than others. Manganese oxide films with high porosity are suitable for electrochemical capacitor electrode.

A Study on the Effect of Electrodeposition Parameters on the Morphology of Porous Nickel Electrodeposits

NASA Astrophysics Data System (ADS)

Sengupta, Srijan; Patra, Arghya; Jena, Sambedan; Das, Karabi; Das, Siddhartha

2018-03-01

In this study, the electrodeposition of nickel foam by dynamic hydrogen bubble-template method is optimized, and the effects of key deposition parameters (applied voltage and deposition time) and bath composition (concentration of Ni2+, pH of the bath, and roles of Cl- and SO4 2- ions) on pore size, distribution, and morphology and crystal structure are studied. Nickel deposit from 0.1 M NiCl2 bath concentration is able to produce the honeycomb-like structure with regular-sized holes. Honeycomb-like structure with cauliflower morphology is deposited at higher applied voltages of 7, 8, and 9 V; and a critical time (>3 minutes) is required for the development of the foamy structure. Compressive residual stresses are developed in the porous electrodeposits after 30 seconds of deposition time (-189.0 MPa), and the nature of the residual stress remains compressive upto 10 minutes of deposition time (-1098.6 MPa). Effect of pH is more pronounced in a chloride bath compared with a sulfate bath. The increasing nature of pore size in nickel electrodeposits plated from a chloride bath (varying from 21 to 48 μm), and the constant pore size (in the range of 22 to 24 μm) in deposits plated from a sulfate bath, can be ascribed to the striking difference in the magnitude of the corresponding current-time profiles.

Copper Electrodeposition on a Magnesium Alloy (AZ80) with a U-Shaped Surface

PubMed Central

Huang, Ching An; Yeh, Yu Hu; Lin, Che Kuan; Hsieh, Chen Yun

2014-01-01

Cu electrodeposition was performed on a cylindrical AZ80 substrate with a U-shaped surface. A uniform deposition of Cu was achieved on an AZ80 electrode via galvanostatic etching, followed by Cu electrodeposition in an eco-friendly alkaline Cu plating bath. Improper wetting and lower rotational speeds of the AZ80 electrode resulted in an uneven Cu deposition at the inner upper site of the U-shaped surface during the Cu electroplating process. This wetting effect could be deduced from the variation in the anodic potential during the galvanostatic etching. The corrosion resistance of the Cu-deposited AZ80 electrode can be considerably improved after Ni electroplating. PMID:28788252

Microgravity effects on electrodeposition of metals and metal-cermet mixtures

NASA Technical Reports Server (NTRS)

Maybee, George W.; Riley, Clyde; Coble, H. Dwain

1987-01-01

An experimental system, designed to investigate the potential advantages of electrodeposition in microgravity, is being developed by the McDonnell Douglas Astronautics Company-Huntsville Division and the University of Alabama in Huntsville. It is intended to fly as an Orbiter payload when NASA resumes STS operations. The system will provide power, thermal conditioning, command and control for the production of electrodeposits; system performance data will be recorded for post-flight analysis. Plated metal surfaces will be created using simple electrolytic cells with pure metal electrodes immersed in aqueous electrolytic solutions. Crystalline structure and other properties will be analyzed to identify differences between samples produced in flight and those obtained from ground-based operations.

Samarium electrodeposited acetate and oxide thin films on stainless steel substrate characterized by XPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myhre, Kristian; Burns, Jonathan; Meyer, Harry

Characterization of a samarium thin film deposited on a stainless steel substrate using molecular electrodeposition was carried out using a Thermo Scientific K-Alpha X-ray photoelectron spectrometer. We studied two types of samarium electrodeposition samples, one as-deposited and one heated to 700 °C in an air flow. Survey scans include peaks coming from the stainless steel substrate, such as Fe and Cr. An X-ray photoelectron spectroscopy (XPS) survey spectrum, Sm 3d, C 1s, and O 1s narrow scans are shown. It was determined that the heating process decomposed the deposited Sm acetate to Sm 2O 3 using XPS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jinlong, Lv, E-mail: ljlbuaa@126.com; State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084; Tongxiang, Liang, E-mail: ljltsinghua@126.com

The nanocrystalline pure nickels with different grain orientations were fabricated by direct current electrodeposition process. The grain size slightly decreased with the increasing of electrodeposition solution temperature. However, grain orientation was affected significantly. Comparing with samples obtained at 50 °C and 80 °C, sample obtained at 20 °C had the strongest (111) orientation plane which increased electrochemical corrosion resistance of this sample. At the same time, the lowest (111) orientation plane deteriorated electrochemical corrosion resistance of sample obtained at 50 °C. - Graphical abstract: The increased electrodeposition temperature promoted slightly grain refinement. The grain orientation was affected significantly by electrodepositionmore » solution temperature. The (111) orientation plane of sample increased significantly corrosion resistance. Display Omitted.« less

Samarium electrodeposited acetate and oxide thin films on stainless steel substrate characterized by XPS

DOE PAGES

Myhre, Kristian; Burns, Jonathan; Meyer, Harry; ...

2016-06-01

Characterization of a samarium thin film deposited on a stainless steel substrate using molecular electrodeposition was carried out using a Thermo Scientific K-Alpha X-ray photoelectron spectrometer. We studied two types of samarium electrodeposition samples, one as-deposited and one heated to 700 °C in an air flow. Survey scans include peaks coming from the stainless steel substrate, such as Fe and Cr. An X-ray photoelectron spectroscopy (XPS) survey spectrum, Sm 3d, C 1s, and O 1s narrow scans are shown. It was determined that the heating process decomposed the deposited Sm acetate to Sm 2O 3 using XPS.

Role of anisotropy in determining stability of electrodeposition at solid-solid interfaces

NASA Astrophysics Data System (ADS)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-10-01

We investigate the stability of electrodeposition at solid-solid interfaces for materials exhibiting an anisotropic mechanical response. The stability of electrodeposition or resistance to the formation of dendrites is studied within a linear stability analysis. The deformation and stress equations are solved using the Stroh formalism and faithfully recover the boundary conditions at the interface. The stability parameter is used to quantify the stability of different solid-solid interfaces incorporating the full anisotropy of the elastic tensor of the two materials. Results show a high degree of variability in the stability parameter depending on the crystallographic orientation of the solids in contact, and point to opportunities for exploiting this effect in developing Li metal anodes.

Electrodeposited Zinc-Nickel as an Alternative to Cadmium Plating for Aerospace Application

NASA Technical Reports Server (NTRS)

Mcmillan, V. C.

1991-01-01

Corrosion evaluation studies were conducted on 4130 alloy steel samples coated with electrodeposited zinc-nickel and samples coated with electrodeposited cadmium. The zinc nickel was deposited by the selection electrochemical metallizing process. These coated samples were exposed to a 5-percent salt fog environment at 35 plus or minus 2 C for a period ranging from 96 to 240 hours. An evaluation of the effect of dichromate coatings on the performance of each plating was conducted. The protection afforded by platings with a dichromate seal was compared to platings without the seal. During the later stages of testing, deposit adhesion and the potential for hydrogen entrapment were also evaluated.

Electrodeposition synthesis of MnO{sub 2}/TiO{sub 2} nanotube arrays nanocomposites and their visible light photocatalytic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Xuyao; Zhou, Xiaosong, E-mail: zxs801213@163.com; Li, Xiaoyu, E-mail: lixiaoyu@iga.ac.cn

2014-11-15

Highlights: • MnO{sub 2}/TiO{sub 2} nanotube arrays nanocomposites are prepared by electrodeposition. • MnO{sub 2}/TiO{sub 2} exhibits high visible light photocatalytic activity. • The results of XRD show the depositions are attributed to α-MnO{sub 2}. • A photocatalytic mechanism is discussed under visible light irradiation. - Abstract: MnO{sub 2}/TiO{sub 2} nanotube arrays nanocomposite photocatalysts have been synthesized through an electrodeposition method. X-ray powder diffraction analysis and X-ray photoelectron spectroscopy measurements reveal that the products of electrodeposition method are MnO{sub 2}. Scanning electron microscopy measurements suggest that the depositions are deposited on the surface or internal of the nanotube. UV–vis lightmore » absorbance spectra demonstrate the excellent adsorption properties of MnO{sub 2}/TiO{sub 2} over the whole region of visible light, which enables this novel photocatalytic material to possess remarkable activity in the photocatalytic degradation of acid Orange II under visible light radiation. Moreover, a possible photocatalytic mechanism is discussed.« less

Embedded vertically aligned cadmium telluride nanorod arrays grown by one-step electrodeposition for enhanced energy conversion efficiency in three-dimensional nanostructured solar cells.

PubMed

Wang, Jun; Liu, Shurong; Mu, Yannan; Liu, Li; A, Runa; Yang, Jiandong; Zhu, Guijie; Meng, Xianwei; Fu, Wuyou; Yang, Haibin

2017-11-01

Vertically aligned CdTe nanorods (NRs) arrays are successfully grown by a simple one-step and template-free electrodeposition method, and then embedded in the CdS window layer to form a novel three-dimensional (3D) heterostructure on flexible substrates. The parameters of electrodeposition such as deposition potential and pH of the solution are varied to analyze their important role in the formation of high quality CdTe NRs arrays. The photovoltaic conversion efficiency of the solar cell based on the 3D heterojunction structure is studied in detail. In comparison with the standard planar heterojunction solar cell, the 3D heterojunction solar cell exhibits better photovoltaic performance, which can be attributed to its enhanced optical absorption ability, increased heterojunction area and improved charge carrier transport. The better photoelectric property of the 3D heterojunction solar cell suggests great application potential in thin film solar cells, and the simple electrodeposition process represents a promising technique for large-scale fabrication of other nanostructured solar energy conversion devices. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Electrodeposition Mode and Deposition Cycle on the Electrochemical Performance of MnO2-NiO Composite Electrodes for High-Energy-Density Supercapacitors.

PubMed

Rusi; Majid, S R

2016-01-01

Nanostructured network-like MnO2-NiO composite electrodes were electrodeposited onto stainless steel substrates via different electrodeposition modes, such as chronopotentiometry, chronoamperometry, and cyclic voltammetry, and then subjected to heat treatment at 300°C for metal oxide conversion. X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy were used to study the crystalline natures and morphologies of the deposited films. The electrochemical properties were investigated using cyclic voltammetry and charge/discharge tests. The results revealed that the electrochemical performance of the as-obtained composite electrodes depended on the electrodeposition mode. The electrochemical properties of MnO2-NiO composite electrodes prepared using cyclic voltammetry exhibited the highest capacitance values and were most influenced by the deposition cycle number. The optimum specific capacitance was 3509 Fg-1 with energy and power densities of 1322 Wh kg-1 and 110.5 kW kg-1, respectively, at a current density of 20 Ag-1 in a mixed KOH/K3Fe(CN)6 electrolyte.

In situ observation of dynamic electrodeposition processes by soft x-ray fluorescence microspectroscopy and keyhole coherent diffractive imaging

NASA Astrophysics Data System (ADS)

Bozzini, Benedetto; Kourousias, George; Gianoncelli, Alessandra

2017-03-01

This paper describes two novel in situ microspectroscopic approaches to the dynamic study of electrodeposition processes: x-ray fluorescence (XRF) mapping with submicrometric space resolution and keyhole coherent diffractive imaging (kCDI) with nanometric lateral resolution. As a case study, we consider the pulse-plating of nanocomposites with polypyrrole matrix and Mn x Co y O z dispersoids, a prospective cathode material for zinc-air batteries. This study is centred on the detailed measurement of the elemental distributions developing in two representative subsequent growth steps, based on the combination of in situ identical-location XRF microspectroscopy—accompanied by soft-x ray absorption microscopy—and kCDI. XRF discloses space and time distributions of the two electrodeposited metals and kCDI on the one hand allows nanometric resolution and on the other hand provides complementary absorption as well as phase contrast modes. The joint information derived from these two microspectroscopies allows measurement of otherwise inaccessible observables that are a prerequisite for electrodeposition modelling and control accounting for dynamic localization processes.

Preparation of alpha sources using magnetohydrodynamic electrodeposition for radionuclide metrology.

PubMed

Panta, Yogendra M; Farmer, Dennis E; Johnson, Paula; Cheney, Marcos A; Qian, Shizhi

2010-02-01

Expanded use of nuclear fuel as an energy resource and terrorist threats to public safety clearly require the development of new state-of-the-art technologies and improvement of safety measures to minimize the exposure of people to radiation and the accidental release of radiation into the environment. The precision in radionuclide metrology is currently limited by the source quality rather than the detector performance. Electrodeposition is a commonly used technique to prepare massless radioactive sources. Unfortunately, the radioactive sources prepared by the conventional electrodeposition method produce poor resolution in alpha spectrometric measurements. Preparing radioactive sources with better resolution and higher yield in the alpha spectrometric range by integrating magnetohydrodynamic convection with the conventional electrodeposition technique was proposed and tested by preparing mixed alpha sources containing uranium isotopes ((238)U, (234)U), plutonium ((239)Pu), and americium ((241)Am) for alpha spectrometric determination. The effects of various parameters such as magnetic flux density, deposition current and time, and pH of the sample solution on the formed massless radioactive sources were also experimentally investigated. Copyright 2009 Elsevier Inc. All rights reserved.

Phase field kinetics of lithium electrodeposits

NASA Astrophysics Data System (ADS)

Ely, David R.; Jana, Aniruddha; García, R. Edwin

2014-12-01

A phase field description is formulated to describe the growth kinetics of an heterogeneously nucleated distribution of lithium electrodeposits. The underlying variational principle includes the bulk electrochemical contributions to the free energy of transformation of the system, the electrolyte-dendrite interfacial energy, and the substrate work of adhesion energetics. Results demonstrate that the rate of electrodeposition at the tip of an isolated dendrite is higher than the rate corresponding to the average overpotential, while the back contact is electrochemically shielded, thus favoring elongated, needle-like shapes. For large populations of electrochemically interacting deposits, two spatially distinct regions of behavior develop: one directly facing the counter-electrode where the local surficial electrodeposition dominates the local kinetics; and a second region, in the vicinity of the substrate-deposit interface, where the electrochemical shielding induced by the tip enables lateral electrochemical lithium exchange dendrite coalescence for small contact angle deposits, and dendrite dewetting and electrodissolution for large contact angle deposits. The underlying physical mechanisms through which some lithium nuclei detach from the depositing substrate, self-induce electrodissolution, while other continue to grow and coalesce are described for different contact angles.

Direct microfabrication of oxide patterns by local electrodeposition of precisely positioned electrolyte: the case of Cu2O

PubMed Central

Wang, P.; Roberts, R. C.; Ngan, A. H. W.

2016-01-01

An efficient technique for writing 2D oxide patterns on conductive substrates is proposed and demonstrated in this paper. The technique concerns a novel concept for selective electrodeposition, in which a minimum quantity of liquid electrolyte, through an extrusion nozzle, is delivered and manipulated into the desired shape on the substrate, meanwhile being electrodeposited into the product by an applied voltage across the nozzle and substrate. Patterns of primarily Cu2O with 80~90% molar fraction are successfully fabricated on stainless steel substrates using this method. A key factor that allows the solid product to be primarily oxide Cu2O instead of metal Cu – the product predicted by the equilibrium Pourbaix diagram given the unusually large absolute deposition voltage used in this method, is the non-equilibrium condition involved in the process due to the short deposition time. Other factors including the motion of the extrusion nozzle relative to the substrate and the surface profile of the substrate that influence the electrodeposition performance are also discussed. PMID:27255188

Atomistic minimal model for estimating profile of electrodeposited nanopatterns

NASA Astrophysics Data System (ADS)

Asgharpour Hassankiadeh, Somayeh; Sadeghi, Ali

2018-06-01

We develop a computationally efficient and methodologically simple approach to realize molecular dynamics simulations of electrodeposition. Our minimal model takes into account the nontrivial electric field due a sharp electrode tip to perform simulations of the controllable coating of a thin layer on a surface with an atomic precision. On the atomic scale a highly site-selective electrodeposition of ions and charged particles by means of the sharp tip of a scanning probe microscope is possible. A better understanding of the microscopic process, obtained mainly from atomistic simulations, helps us to enhance the quality of this nanopatterning technique and to make it applicable in fabrication of nanowires and nanocontacts. In the limit of screened inter-particle interactions, it is feasible to run very fast simulations of the electrodeposition process within the framework of the proposed model and thus to investigate how the shape of the overlayer depends on the tip-sample geometry and dielectric properties, electrolyte viscosity, etc. Our calculation results reveal that the sharpness of the profile of a nano-scale deposited overlayer is dictated by the normal-to-sample surface component of the electric field underneath the tip.

III-V nanowire synthesis by use of electrodeposited gold particles.

PubMed

Jafari Jam, Reza; Heurlin, Magnus; Jain, Vishal; Kvennefors, Anders; Graczyk, Mariusz; Maximov, Ivan; Borgström, Magnus T; Pettersson, Håkan; Samuelson, Lars

2015-01-14

Semiconductor nanowires are great candidates for building novel electronic devices. Considering the cost of fabricating such devices, substrate reuse and gold consumption are the main concerns. Here we report on implementation of high throughput gold electrodeposition for selective deposition of metal seed particles in arrays defined by lithography for nanowire synthesis. By use of this method, a reduction in gold consumption by a factor of at least 300 was achieved, as compared to conventional thermal evaporation for the same pattern. Because this method also facilitates substrate reuse, a significantly reduced cost of the final device is expected. We investigate the morphology, crystallography, and optical properties of InP and GaAs nanowires grown from electrodeposited gold seed particles and compare them with the properties of nanowires grown from seed particles defined by thermal evaporation of gold. We find that nanowire synthesis, as well as the material properties of the grown nanowires are comparable and quite independent of the gold deposition technique. On the basis of these results, electrodeposition is proposed as a key technology for large-scale fabrication of nanowire-based devices.

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion

PubMed Central

Chira, Ana; Bucur, Bogdan; Radu, Gabriel-Lucian

2017-01-01

Copper substrates deposed on a gold screen-printed electrode were covered with different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctyl)aniline, 4-aminoantipyrine, 4-(4-aminophenyl)butyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM). The electrodeposited mass varies between 26 ng/cm2 for 4-fluoroaniline formed during 30 s to 442 ng/cm2 for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN) and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenyl)butyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found. PMID:28772600

Effects of Electrodeposition Mode and Deposition Cycle on the Electrochemical Performance of MnO2-NiO Composite Electrodes for High-Energy-Density Supercapacitors

PubMed Central

Rusi; Majid, S. R.

2016-01-01

Nanostructured network-like MnO2-NiO composite electrodes were electrodeposited onto stainless steel substrates via different electrodeposition modes, such as chronopotentiometry, chronoamperometry, and cyclic voltammetry, and then subjected to heat treatment at 300°C for metal oxide conversion. X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy were used to study the crystalline natures and morphologies of the deposited films. The electrochemical properties were investigated using cyclic voltammetry and charge/discharge tests. The results revealed that the electrochemical performance of the as-obtained composite electrodes depended on the electrodeposition mode. The electrochemical properties of MnO2-NiO composite electrodes prepared using cyclic voltammetry exhibited the highest capacitance values and were most influenced by the deposition cycle number. The optimum specific capacitance was 3509 Fg−1 with energy and power densities of 1322 Wh kg−1 and 110.5 kW kg−1, respectively, at a current density of 20 Ag−1 in a mixed KOH/K3Fe(CN)6 electrolyte. PMID:27182595

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion.

PubMed

Chira, Ana; Bucur, Bogdan; Radu, Gabriel-Lucian

2017-02-28

Copper substrates deposed on a gold screen-printed electrode were covered with different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctyl)aniline, 4-aminoantipyrine, 4-(4-aminophenyl)butyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM). The electrodeposited mass varies between 26 ng/cm² for 4-fluoroaniline formed during 30 s to 442 ng/cm² for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN) and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenyl)butyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found.

Electrodeposition of quaternary alloys in the presence of magnetic field

PubMed Central

2010-01-01

Electrodeposition of Ni-Co-Fe-Zn alloys was done in a chloride ion solution with the presence and absence of a Permanent Parallel Magnetic Field (PPMF). The PPMF was applied parallel to the cathode surface. The deposition profile was monitored chronoamperometrically. It was found that the electrodeposition current was enhanced in the presence of PPMF (9 T) compared to without PPMF. The percentage of current enhancement (Γ%) was increased in the presence of PPMF, with results of Γ% = 11.9%, 16.7% and 18.5% at -1.1, -1.2 and -1.3 V respectively for a 2400 sec duration. In chronoamperometry, the Composition Reference Line (CRL) for Ni was around 57%, although the nobler metals (i.e. Ni, Co) showed anomalous behaviour in the presence of Zn and Fe. The anomalous behaviour of the Ni-Co-Fe-Zn electrodeposition was shown by the Energy Dispersive X-Ray (EDX) results. From Atomic Force Microscopy (AFM) measurements, it was found that the surface roughness of the Ni-Co-Fe-Zn alloy films decreased in the presence of a PPMF. PMID:20604934

Development of Electrodeposited Zn/nano-TiO2 Composite Coatings with Enhanced Corrosion Performance

NASA Astrophysics Data System (ADS)

Benea, L.; Dănăilă, E.

2017-06-01

Pure zinc coatings have been found ineffective when are used in aggressive environments such as those which contain chlorides or industrial pollutants [1]. In this paper, Zn/nano-TiO2 composite coatings with various contents of TiO2 nanoparticles (diameter size of 10 nm) were prepared on low-carbon steel by electro-codeposition technique. The deposition was carried out at different cathodic potentials ranging from -1600 mV to -2100 mV for different deposition times between 5-15 min. Pure Zn coatings were also produced under the same experimental conditions for comparison. Present work aims to investigate the effects of selected electrodeposition parameters (cathodic potential, TiO2 nanoparticle concentration in the plating bath and electrodeposition time) on the corrosion behavior of electrodeposited Zn/nano-TiO2 composite obtained. The corrosion experiments were performed in natural seawater, using electrochemical methods such as open circuit potential, potentiodynamic polarization and linear polarization resistance. The results showed that the inclusion of TiO2 nanoparticles into zinc matrix lead to an improved corrosion resistance comparatively with pure zinc coatings obtained under similar conditions.

Cathodic electrodeposition of amorphous elemental selenium from an air- and water-stable ionic liquid.

PubMed

Redman, Daniel W; Murugesan, Sankaran; Stevenson, Keith J

2014-01-14

Electrodeposition of selenium from 1-propyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide is reported. In situ UV-vis spectroelectrochemistry was used to investigate the reduction of diethyl selenite to form elemental selenium thin films from an ionic liquid-acetonitrile medium. Three reduction peaks of diethyl selenite were observed via cyclic voltammetry and are attributed to the stepwise reduction of the selenium precursor adsorbed on the electrode. The electrodeposition mechanism is influenced by both potential and time. Electrodeposition at -1.7 V vs Pt QRE resulted in the deposition of elemental selenium nanoparticles that with time coalesced to form a continuous film. At reduction potentials more negative than -1.7 V the morphology of the deposit changed significantly due to the reduction of elemental Se to Se(2-). In addition, p-type photoconductivity of the films was observed during the spectroelectrochemical measurements. X-ray diffraction and Raman spectroscopy confirmed that the deposited selenium films were amorphous. X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy confirm the films consisted of pure selenium with minor residual contamination from the precursor and ionic liquid.

One step electrodeposition of Cu2ZnSnS4 thin films in a novel bath with sulfurization free annealing

NASA Astrophysics Data System (ADS)

Tang, Aiyue; Li, Zhilin; Wang, Feng; Dou, Meiling; Pan, Youya; Guan, Jingyu

2017-04-01

Cu2ZnSnS4 (CZTS) is a quaternary kesterite compound with suitable band gap for thin film solar cells. In most electrodeposition-anneal routes, sulfurization is inevitable because the as-deposited film is lack of S. In this work, a novel green electrolyte was designed for synthesizing CZTS thin films with high S content. In the one-step electrodeposition, K4P2O7 and C7H6O6S were added to form complex with metallic ions in the electrolyte, which could attribute to co-deposition. The as-deposited film obtained high S content satisfying stoichiometry. After a sulfurization free annealing, the continuous and uniform CZTS thin film was obtained, which had pure kesterite structure and a suitable band gap of 1.53 eV. Electrodeposition mechanism investigation revealed that the K4P2O7 prevented the excessive deposition of Cu2+ and Sn2+. The C7H6O6S promoted the reduction of Zn2+. So the additives narrowed the co-deposition potentials of the metallic elements through a synergetic effect. They also promoted the reduction of S2O32- to ensure the co-deposition of the four elements and the stoichiometry. The sulfurization free annealing process can promote the commercialization of CZTS films and the successful design principle of environmental friendly electrolytes could be applied in other electrodeposition systems.

Electrodeposited Porous Mn1.5Co1.5O₄/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors.

PubMed

Pan, Guan-Ting; Chong, Siewhui; Yang, Thomas C-K; Huang, Chao-Ming

2017-03-31

Mesoporous Mn 1.5 Co 1.5 O₄ (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO₃) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg -1 and a power density of 1.01 kW·kg -1 at 1 A·g -1 . After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling.

Electrodeposited Porous Mn1.5Co1.5O4/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors

PubMed Central

Pan, Guan-Ting; Chong, Siewhui; Yang, Thomas C.-K.; Huang, Chao-Ming

2017-01-01

Mesoporous Mn1.5Co1.5O4 (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO3) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg−1 and a power density of 1.01 kW·kg−1 at 1 A·g−1. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling. PMID:28772727

Chemical and electrochemical recycling of the nickel, cobalt, zinc and manganese from the positives electrodes of spent Ni-MH batteries from mobile phones

NASA Astrophysics Data System (ADS)

Santos, V. E. O.; Celante, V. G.; Lelis, M. F. F.; Freitas, M. B. J. G.

2012-11-01

Chemical and electrochemical recycling methods for the Ni, Co, Zn and Mn from the positives electrodes of spent Ni-MH batteries were developed. The materials recycled by chemical precipitation have the composition β-Ni(OH)2, Co(OH)2, Zn(OH)2 and Mn3O4. The powder retains sulphate, nitrate and carbonate anions from the mother solution as well as adsorbed water. Studies using cyclic voltammetry show that the current density decreases for scan rates greater than 10 mV s-1 because of the formation of hydroxide films. The amounts of Ni2+, Co2+, Zn2+ and Mn2+ were obtained by analysis of the solution using the inductively coupled plasma with optical emission spectroscopy technique, which demonstrated that the electrodeposition method exhibits anomalous behaviour. The amount of deposited nickel ions is related to the composition of the sulfamate bath. The presence of manganese in the electrodeposits is due to the precipitation of Mn(OH)2, and Zn(OH)42- does not undergo reduction in the investigated potential range. The electrodeposited material contains Ni, Co, CoO, Co(OH)2, and Mn3O4. A charge efficiency of 83.7% was attained for the electrodeposits formed by the application of -1.1 V vs. Ag/AgCl at a charge density of -90 C cm-2. The dissolution of the electrodeposits depends on the applied potential.

Dielectrophoretic alignment of metal and metal oxide nanowires and nanotubes: a universal set of parameters for bridging prepatterned microelectrodes.

PubMed

Maijenburg, A W; Maas, M G; Rodijk, E J B; Ahmed, W; Kooij, E S; Carlen, E T; Blank, D H A; ten Elshof, J E

2011-03-15

Nanowires and nanotubes were synthesized from metals and metal oxides using templated cathodic electrodeposition. With templated electrodeposition, small structures are electrodeposited using a template that is the inverse of the final desired shape. Dielectrophoresis was used for the alignment of the as-formed nanowires and nanotubes between prepatterned electrodes. For reproducible nanowire alignment, a universal set of dielectrophoresis parameters to align any arbitrary nanowire material was determined. The parameters include peak-to-peak potential and frequency, thickness of the silicon oxide layer, grounding of the silicon substrate, and nature of the solvent medium used. It involves applying a field with a frequency >10(5) Hz, an insulating silicon oxide layer with a thickness of 2.5 μm or more, grounding of the underlying silicon substrate, and the use of a solvent medium with a low dielectric constant. In our experiments, we obtained good results by using a peak-to-peak potential of 2.1 V at a frequency of 1.2 × 10(5) Hz. Furthermore, an indirect alignment technique is proposed that prevents short circuiting of nanowires after contacting both electrodes. After alignment, a considerably lower resistivity was found for ZnO nanowires made by templated electrodeposition (2.2-3.4 × 10(-3) Ωm) compared to ZnO nanorods synthesized by electrodeposition (10 Ωm) or molecular beam epitaxy (MBE) (500 Ωm). Copyright © 2010 Elsevier Inc. All rights reserved.

Electrodeposition of crystalline GaAs on liquid gallium electrodes in aqueous electrolytes.

PubMed

Fahrenkrug, Eli; Gu, Junsi; Maldonado, Stephen

2013-01-09

Crystalline GaAs (c-GaAs) has been prepared directly through electroreduction of As(2)O(3) dissolved in an alkaline aqueous solution at a liquid gallium (Ga(l)) electrode at modest temperatures (T ≥ 80 °C). Ga(l) pool electrodes yielded consistent electrochemical behavior, affording repetitive measurements that illustrated the interdependences of applied potential, concentration of dissolved As(2)O(3), and electrodeposition temperature on the quality of the resultant c-GaAs(s). Raman spectra indicated the composition of the resultant film was strongly dependent on both the electrodeposition temperature and dissolved concentration of As(2)O(3) but not to the applied bias. For electrodepositions performed either at room temperature or with high (≥0.01 M) concentrations of dissolved As(2)O(3), Raman spectra of the electrodeposited films were consistent with amorphous As(s). X-ray diffractograms of As(s) films collected after thermal annealing indicated metallurgical alloying occurred only at temperatures in excess of 200 °C. Optical images and Raman spectra separately showed the composition of the as-electrodeposited film in dilute (≤0.001 M) solutions of dissolved As(2)O(3)(aq) was pure c-GaAs(s) at much lower temperatures than 200 °C. Diffractograms and transmission electron microscopy performed on as-prepared films confirmed the identity of c-GaAs(s). The collective results thus provide the first clear demonstration of an electrochemical liquid-liquid-solid (ec-LLS) process involving a liquid metal that serves simultaneously as an electrode, a solvent/medium for crystal growth, and a coreactant for the synthesis of a polycrystalline semiconductor. The presented data serve as impetus for the further development of the ec-LLS process as a controllable, simple, and direct route for technologically important optoelectronic materials such as c-GaAs(s).

Synthesizing the Nanocrytalline Cobalt-Iron Coating Through The Electrodeposition Process With Different Time Deposition

NASA Astrophysics Data System (ADS)

Rozlin Nik Masdek, Nik; Sorfian Hafiz Mansor, Mohd; Salleh, Zuraidah; Hyie, Koay Mei

2018-03-01

In the engineering world, electrodeposition or electroplating has become the most popular method of surface coating in improving corrosion behavior and mechanical properties of material. Therefore in this study, CoFe nanoparticle protective coating has been synthesized on the mild steel washer using electrodeposition method. The electrodeposition was conducted in the acidic environment with the pH value range from 1 to 2 with the controlled temperature of 50°C. The influence of deposition time (30, 60, 90 minutes) towards characteristic and properties such as particle size, surface morphology, corrosion behavior, and microhardness were studied in this investigation. Several results can be obtained by doing this experiment and testing. First, the surface morphology of Cobalt Iron (CoFe) on the electrodeposited mild steel washer are obtained. In addition, the microhardness of the mild steel washer due to the different deposition time are determined. Next, the observation on the difference in the grain size of CoFe that has been electrodeposited on the mild steel plate is made. Last but not least, the corrosion behavior was investigated. CoFe nanoparticles deposited for 30 minutes produced the smallest particle size and the highest microhardness of 86.17 and 236.84 HV respectively. The CoFe nanoparticles also exhibit the slowest corrosion rate at 30 minutes as compared to others. The crystalline size also increases when the time deposition is increased. The sample with 30 minute depositon time indicate the smallest crystalline size which is 15nm. The decrement of deposition time plays an important role in synthesizing CoFe nanoparticles with good corrosion resistance and microhardness. CoFe nanoparticles obtained at 30 minutes shows high corrosion resistance compared to others. In a nutshell, it was observed that the decrement of deposition time improved mechanical and corrosion properties of CoFe nanoparticles.

Hybrid helical magnetic microrobots obtained by 3D template-assisted electrodeposition.

PubMed

Zeeshan, Muhammad A; Grisch, Roman; Pellicer, Eva; Sivaraman, Kartik M; Peyer, Kathrin E; Sort, Jordi; Özkale, Berna; Sakar, Mahmut S; Nelson, Bradley J; Pané, Salvador

2014-04-09

Hybrid helical magnetic microrobots are achieved by sequential electrodeposition of a CoNi alloy and PPy inside a photoresist template patterned by 3D laser lithography. A controlled actuation of the microrobots by a rotating magnetic field is demonstrated in a fluidic environment. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposited nanostructured MnO{sub 2} for non-enzymatic hydrogen peroxide sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saha, B., E-mail: barnamala.saha@gmail.com; Jana, S. K.; Banerjee, S.

2015-06-24

Electrodeposited MnO{sub 2} nanostructure was synthesized on indium tin oxide coated glass electrode by cyclic voltammetry. The as obtained samples were subsequently characterized by atomic force microscopy and their electro-catalytic response towards hydrogen peroxide in alkaline medium of 0.1M NaOH was studied using cyclic voltammetry and amperometry.

High-speed electrodeposition of copper-tin-zinc stacks from liquid metal salts for Cu2ZnSnSe4 solar cells.

PubMed

Steichen, Marc; Malaquias, João C; Arasimowicz, Monika; Djemour, Rabie; Brooks, Neil R; Van Meervelt, Luc; Fransaer, Jan; Binnemans, Koen; Dale, Phillip J

2017-01-16

Cu 2 ZnSnSe 4 -based solar cells with 5.5% power conversion efficiency were fabricated from Cu/Sn/Zn stacks electrodeposited from liquid metal salts. These electrolytes allow metal deposition rates one order of magnitude higher than those of other deposition methods.

Effect of surface etching and electrodeposition of copper on nitinol

NASA Astrophysics Data System (ADS)

Ramos-Moore, E.; Rosenkranz, A.; Matamala, L. F.; Videla, A.; Durán, A.; Ramos-Grez, J.

2017-10-01

Nitinol-based materials are very promising for medical and dental applications since those materials can combine shape memory, corrosion resistance, biocompatibility and antibacterial properties. In particular, surface modifications and coating deposition can be used to tailor and to unify those properties. We report preliminary results on the study of the effect of surface etching and electrodeposition of Copper on Nitinol using optical, chemical and thermal techniques. The results show that surface etching enhances the surface roughness of Nitinol, induces the formation of Copper-based compounds at the Nitinol-Copper interface, reduces the austenitic-martensitic transformations enthalpies and reduces the Copper coating roughness. Further studies are needed in order to highlight the influence of the electrodeposited Copper on the memory shape properties of NiTi.

Electrocatalytic reduction of carbon dioxide on electrodeposited tin-based surfaces

NASA Astrophysics Data System (ADS)

Alba, Bianca Christina S.; Camayang, John Carl A.; Mopon, Marlon L.; del Rosario, Julie Anne D.

2017-08-01

The electrocatalytic reduction of carbon dioxide to small organic molecular compounds provides a means of generating alternative fuel source while suppressing climate change. Suitable catalysts, however, are necessary to optimize its reaction kinetics towards more valuable products. Consequently, in this study, electrodeposited Sn electrodes have been developed as catalysts for CO2 electroreduction. Deposition potential was varied to produce different Sn catalysts. SEM showed varying morphologies and increasing amount as the applied potential becomes more negative. Cyclic voltammetry and chronoamperometry showed that the activity and stability of the catalysts towards CO2 reduction depend on the morphology and presence of tin oxides. These results provide a better understanding on the performance of electrodeposited Sn-based surfaces as catalysts for CO2 reduction.

Electrochemical Study of Cobalt in Urea and Choline Chloride

NASA Astrophysics Data System (ADS)

Li, Min; Shi, Zhongning; Wang, Zhaowen; Reddy, Ramana G.

The nucleation mechanism of Co(II) in urea-choline chloride-CoCl2 melt at 373 K was studied using chronoamperometry. Chronoamperometry experiments confirm that the electrodeposition of cobalt on tungsten electrode is governed by three-dimensional (3D) progressive nucleation and diffusion-controlled growth mechanisms. The average diffusion coefficient of Co(II) in the melt at 373 K is 1.1 × 10-6 cm2 s-1, which is in good agreement with the estimated value obtained from cyclic voltammetry data. Characterization of the Co electrodeposit using scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) techniques indicate that the electrodeposit obtained at -0.75 V and 373 K contain dense and compact surface formed from pure cobalt metal.

Study on electrochemically deposited Mg metal

NASA Astrophysics Data System (ADS)

Matsui, Masaki

An electrodeposition process of magnesium metal from Grignard reagent based electrolyte was studied by comparing with lithium. The electrodeposition of magnesium was performed at various current densities. The obtained magnesium deposits did not show dendritic morphologies while all the lithium deposits showed dendritic products. Two different crystal growth modes in the electrodeposition process of magnesium metal were confirmed by an observation using scanning electron micro scope (SEM) and a crystallographic analysis using X-ray diffraction (XRD). An electrochemical study of the deposition/dissolution process of the magnesium showed a remarkable dependency of the overpotential of magnesium deposition on the electrolyte concentration compared with lithium. This result suggests that the dependency of the overpotential on the electrolyte concentration prevent the locally concentrated current resulting to form very uniform deposits.

Effect of annealing temperature on the PEC performance of electrodeposited copper oxides

NASA Astrophysics Data System (ADS)

Marathey, Priyanka; Pati, Ranjan; Mukhopadhyay, Indrajit; Ray, Abhijit

2018-05-01

In this work, we have deposited Cu2O film on fluorine doped tin oxide (FTO) substrate by electrodeposition. Pure CuO phase has been obtained by annealing the electrodeposited Cu2O film at optimized temperature (500°C) for two hours in air. Copper(I) oxide films showed good photo response with a current density of 0.54mA/cm2 at 0 V vs RHE. It is evident from UV-Visible spectroscopic analysis that the bandgap of Cu(I) and Cu(II) oxides differs from each other resulting in significant change in photo current for these two phases, observed in the PEC study. However CuO film showed better stability as compared to Cu2O film.

Sulfide semiconductor materials prepared by high-speed electrodeposition and discussion of electrochemical reaction mechanism

NASA Astrophysics Data System (ADS)

Okamoto, Naoki; Kataoka, Kentaro; Saito, Takeyasu

2017-07-01

A manufacturing method for SnS using a one-step electrochemical technique was developed. The sulfide semiconductor was formed by electrodeposition using an aqueous bath at low temperatures. The sulfide semiconductor particles produced were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The highest current density at which SnS was formed was 1800 mA/cm2 at a bath temperature of 293 K, which is 36 times larger than that in a previous deposition process. Analysis of the chronoamperometric current-time transients indicated that in the potential range from -1100 to -2000 mV vs saturated calomel electrode (SCE), the electrodeposition of SnS can be explained by an instantaneous nucleation model.

Synthesis of high aspect ratio ZnO nanowires with an inexpensive handcrafted electrochemical setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taheri, Ali, E-mail: at1361@aut.ac.ir, E-mail: atahery@aeoi.org.ir; Saramad, Shahyar; Setayeshi, Saeed

In this work, high aspect ratio zinc oxide nanowires are synthesized using templated one-step electrodeposition technique. Electrodeposition of the nanowires is done using a handcrafted electronic system. Nuclear track-etched polycarbonate membrane is used as a template to form the high aspect ratio nanowires. The result of X-ray diffraction and scanning electron microscopy shows that nanowires with a good crystallinity and an aspect ratio of more than 30 can be achieved in a suitable condition. The height of electrodeposited nanowires reaches to about 11 μm. Based on the obtained results, high aspect ratio ZnO nanowires can be formed using inexpensive electrodepositionmore » setup with an acceptable quality.« less

Role of anisotropy in determining stability of electrodeposition at solid-solid interfaces

DOE PAGES

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-10-24

Here, we investigate the stability of electrodeposition at solid-solid interfaces for materials exhibiting an anisotropic mechanical response. The stability of electrodeposition or resistance to the formation of dendrites is studied within a linear stability analysis. The deformation and stress equations are solved using the Stroh formalism and faithfully recover the boundary conditions at the interface. The stability parameter is used to quantify the stability of different solid-solid interfaces incorporating the full anisotropy of the elastic tensor of the two materials. Our results show a high degree of variability in the stability parameter depending on the crystallographic orientation of the solidsmore » in contact, and point to opportunities for exploiting this effect in developing Li metal anodes.« less

Lithographically patterned electrodeposition of gold, silver, and nickel nanoring arrays with widely tunable near-infrared plasmonic resonances.

PubMed

Halpern, Aaron R; Corn, Robert M

2013-02-26

A novel low-cost nanoring array fabrication method that combines the process of lithographically patterned nanoscale electrodeposition (LPNE) with colloidal lithography is described. Nanoring array fabrication was accomplished in three steps: (i) a thin (70 nm) sacrificial nickel or silver film was first vapor-deposited onto a plasma-etched packed colloidal monolayer; (ii) the polymer colloids were removed from the surface, a thin film of positive photoresist was applied, and a backside exposure of the photoresist was used to create a nanohole electrode array; (iii) this array of nanoscale cylindrical electrodes was then used for the electrodeposition of gold, silver, or nickel nanorings. Removal of the photoresist and sacrificial metal film yielded a nanoring array in which all of the nanoring dimensions were set independently: the inter-ring spacing was fixed by the colloidal radius, the radius of the nanorings was controlled by the plasma etching process, and the width of the nanorings was controlled by the electrodeposition process. A combination of scanning electron microscopy (SEM) measurements and Fourier transform near-infrared (FT-NIR) absorption spectroscopy were used to characterize the nanoring arrays. Nanoring arrays with radii from 200 to 400 nm exhibited a single strong NIR plasmonic resonance with an absorption maximum wavelength that varied linearly from 1.25 to 3.33 μm as predicted by a simple standing wave model linear antenna theory. This simple yet versatile nanoring array fabrication method was also used to electrodeposit concentric double gold nanoring arrays that exhibited multiple NIR plasmonic resonances.

Electrodeposition of CdSe on GaAs and InP substrates

NASA Astrophysics Data System (ADS)

Etcheberry, A.; Cachet, H.; Cortes, R.; Froment, M.

2001-06-01

Epitaxial CdSe layers have been electrodeposited on the (1 0 0) and ( 1¯ 1¯ 1¯) faces of GaAs and InP single crystals. Chemical composition and crystalline quality of CdSe have been studied by X-photoelectron spectroscopy, reflection high energy electron diffraction and X-ray diffraction. Influence of the substrate has been pointed out.

ELECTRODEPOSITION OF NICKEL ON URANIUM

DOEpatents

Gray, A.G.

1958-08-26

A method is described for preparing uranium objects prior to nickel electroplating. The process consiats in treating the surface of the uranium with molten ferric chloride hexahydrate, at a slightiy elevated temperature. This treatment etches the metal surface providing a structure suitable for the application of adherent electrodeposits and at the same time plates the surface with a thin protective film of iron.

A pH Sensor Based on a Stainless Steel Electrode Electrodeposited with Iridium Oxide

ERIC Educational Resources Information Center

Martinez, C. C. M.; Madrid, R. E.; Felice, C. J.

2009-01-01

A simple procedure to make an iridium oxide (IrO[subscript 2]) electrodeposited pH sensor, that can be used in a chemical, biomedical, or materials laboratory, is presented here. Some exercises, based on this sensor, that can be used to teach important concepts in the field of biomedical, biochemical, tissue, or materials engineering, are also…

40 CFR 63.3092 - How must I control emissions from my electrodeposition primer system if I want to comply with the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... electrodeposition primer system if I want to comply with the combined primer-surfacer, topcoat, final repair, glass bonding primer, and glass bonding adhesive emission limit? 63.3092 Section 63.3092 Protection of...-surfacer, topcoat, final repair, glass bonding primer, and glass bonding adhesive emission limit? If your...

40 CFR 63.3092 - How must I control emissions from my electrodeposition primer system if I want to comply with the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... electrodeposition primer system if I want to comply with the combined primer-surfacer, topcoat, final repair, glass bonding primer, and glass bonding adhesive emission limit? 63.3092 Section 63.3092 Protection of...-surfacer, topcoat, final repair, glass bonding primer, and glass bonding adhesive emission limit? If your...

High Pt utilization PEMFC electrode obtained by alternative ion-exchange/electrodeposition.

PubMed

Chen, Siguo; Wei, Zidong; Li, Hua; Li, Li

2010-12-14

High Pt utilization PEMFC electrodes were prepared by an alternative ion-exchange/electrodeposition (AIEE) technique. The results demonstrated that the MEA employing an AIEE electrode with a Pt loading of 0.014 mg Pt cm(-2) exhibits performance approximately 2.2 times larger than that employing a conventional Nafion-bonded Pt/C electrode with a same Pt loading.

The effect of pulsed current electrodeposition parameters of calcium phosphates coating on Ti6Al4V ELI

NASA Astrophysics Data System (ADS)

Sierra-Herrera, D. K.; Sandoval-Amador, A.; Montañez-Supelano, N. D.; Y Peña-Ballesteros, D.

2017-12-01

Pulse current electrodeposition is a technique of special interest, due to the advantages it has, like easy operation, high control in the amount, homogeneity and purity of the deposited material, and low cost. This work studies the influence of the pulsed electrodeposition parameters variation on the characteristics of calcium phosphates coatings, including the composition, crystallinity and morphology. The influence of the current density and pulse on and off time on the physicochemical properties of the obtained coatings were evaluated. The coatings were electrodeposited on Ti6Al4V using Ca(NO3)2·H2O and NH4H2PO4 with a Ca/P molar ratio of 1.67. The coatings were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The analysis of DRX confirmed the formation of HAP. The results revealed that the variation of the current density modified the morphology of the coating. Also, the amount of material deposited increases as the off-time pulse increases, allowing the diffusion of the ions in the solution towards the working electrode.

Influence of support electrolytic in the electrodeposition of CuGaSe thin films

DOE PAGES

Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.; ...

2016-11-02

CuGaSe 2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Because of its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions mustmore » be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. Here, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe 2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. Finally, we present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.« less

Influence of support electrolytic in the electrodeposition of Cusbnd Gasbnd Se thin films

NASA Astrophysics Data System (ADS)

Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.; Deutsch, T. G.

2017-01-01

CuGaSe2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Due to its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions must be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. In this paper, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. We also present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.

Facile fabrication of uniform hierarchical structured (UHS) nanocomposite surface with high water repellency and self-cleaning properties

NASA Astrophysics Data System (ADS)

Bagheri, H.; Aliofkhazraei, M.; Forooshani, H. Mojiri; Rouhaghdam, A. Sabour

2018-04-01

In the present study, two-stage process for the fabrication of superhydrophobic Ni-Cu-TiO2 nanocomposite coatings on the copper substrate has been introduced. Surface modification was performed on the electrodeposited coatings by myristic acid-ethanol solution to achieve superhydrophobicity. Additionally, in order to further study the roughness effect, instead of addition of copper ions in electrodeposition bath, three substrates were roughened by electrochemical etching method. Water repellency properties were studied through measurement of static and dynamic contact angles, and performing bouncing test, self-cleaning and water-jet evaluation. The samples were electrodeposited in various current densities, and the highest corrosion resistance and water repellency properties were obtained for the sample which was electrodeposited in two consecutive steps and modified by a fatty acid called myristic acid (which significantly reduces surface energy of the coating). The highest water contact angle (161°) and the lowest contact angle hysteresis (3°) were obtained for the sample which was coated by 10 mA/cm2 (144 min) and 20 mA/cm2 (18 min), respectively. Since this approach does not require any sophisticated equipment and materials, it shows promising future in the fabrication of superhydrophobic coatings.

Influence of support electrolytic in the electrodeposition of CuGaSe thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, A. M.; Turner, J. A.; Lara-Lara, B.

CuGaSe 2 is an important thin film electronic material that possesses several attributes that make it appealing for solar energy conversion. Because of its properties it can be incorporated in to various devices, among the greatest highlights are photovoltaic cells, as well as its potential use as photocathodes for hydrogen production, via the photoelectrolysis. There are several methods of its preparation, most notably electrodeposition that has the potential for large areas and high volumes. Electrodeposition of ternary and/or quaternary semiconductors generally proceeds via the formation of a binary, which is subsequently reacted to form the ternary compound. Several conditions mustmore » be controlled to form binary compounds that include the use of complexing agents, buffers, temperature, etc. Here, we discuss the effect of anion composition in the electrolytic bath and the type of lithium salts, in order to manipulate the atomic concentration of CuGaSe 2 during the electrodeposition of thin films, yielding copper-rich, gallium-rich or stoichiometric thin films. Finally, we present the results of a study on the morphology and structure obtained using two types of substrates both before and after performing a heat treatment.« less

The use of trivalent chromium bath to obtain a solar selective black chromium coating

NASA Astrophysics Data System (ADS)

Survilienė, S.; Češūnienė, A.; Juškėnas, R.; Selskienė, A.; Bučinskienė, D.; Kalinauskas, P.; Juškevičius, K.; Jurevičiūtė, I.

2014-06-01

Black chromium coatings were electrodeposited from a trivalent chromium bath using a ZnO additive as a second main component. Black chromium was electrodeposited on steel and copper plates and substrates plated with bright nickel prior to black chromium electrodeposition. The black chromium coatings were characterized by XRD and SEM. The XRD data suggest that the phase structure of black chromium may be defined as a zinc solid solution in chromium or a chromium solid solution in zinc depending on the chromium/zinc ratio in the deposit. The role of substrate finish was evaluated through the corrosion resistance and reflectance of black chromium. According to corrosion tests the samples plated with bright nickel prior to black chromium deposition have shown the highest corrosion resistance. The electrodeposited black chromium possesses good optical properties for the absorption of solar energy. The absorption coefficient of black chromium was found to be over 0.99 for the samples obtained without the Ni undercoat and below 0.99 for those obtained with the use of Ni undercoat. However, the use of nickel undercoat before black chromium plating is recommended because it remarkably improves the corrosion resistance of samples.

Modification and properties characterization of heterogeneous anion-exchange membranes by electrodeposition of graphene oxide (GO)

NASA Astrophysics Data System (ADS)

Li, Yujiao; Shi, Shaoyuan; Cao, Hongbin; Zhao, Zhijuan; Wen, Hao

2018-06-01

The heterogeneous anion exchange membranes (AEMs) were modified by electrodeposition of graphene oxide (GO) under different conditions. The physicochemical properties of GO-modified membranes were characterized systemically to obtain the optimized conditions for the electrodeposition of GO on the surface of AEMs. The results indicated that the contact angle and zeta potential of the modified AEMs decreased when increasing the concentration of GO from 0.05 g/L to 0.1 g/L. The higher concentration of NaCl, as the supporting electrolyte, could hinder the electrodeposition of GO on the AEMs for the competitive migration between the GO and Cl- ions. The increase of current density had a positive effect on properties of GO-modified membranes in the range of 1-5 mA/cm2. Compared with the pristine AEM, all the GO-modified AEMs exhibited smoother surface, higher hydrophilicity and negative zeta potential. It was also found that the GO modifying layer did not increase electrical resistance and had only a negligible effect on the desalination performance of AEMs. In the fouling experiments with sodium dodecyl benzene sulfonate (SDBS) as the model foulant, the GO-modified AEMs exhibited improved fouling resistance to SDBS.

Light-addressable electrodeposition of cell-encapsulated alginate hydrogels for a cellular microarray using a digital micromirror device

PubMed Central

Huang, Shih-Hao; Hsueh, Hui-Jung; Jiang, Yeu-Long

2011-01-01

This paper describes a light-addressable electrolytic system used to perform an electrodeposition of calcium alginate hydrogels using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-anode to electrolytically produce protons, which can lead to a decreased pH gradient. The low pH generated at the anode can locally release calcium ions from insoluble calcium carbonate (CaCO3) to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressable electrodeposition of calcium alginate hydrogels with different shapes and sizes, as well as multiplexed micropatterning was performed. The effects of the concentration of the alginate and CaCO3 solutions on the dimensional resolution of alginate hydrogel formation were experimentally examined. A 3 × 3 array of cell-encapsulated alginate hydrogels was also successfully demonstrated through light-addressable electrodeposition. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into cellular microarrays and could have a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery. PMID:22685500

Light-addressable electrodeposition of cell-encapsulated alginate hydrogels for a cellular microarray using a digital micromirror device.

PubMed

Huang, Shih-Hao; Hsueh, Hui-Jung; Jiang, Yeu-Long

2011-09-01

This paper describes a light-addressable electrolytic system used to perform an electrodeposition of calcium alginate hydrogels using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-anode to electrolytically produce protons, which can lead to a decreased pH gradient. The low pH generated at the anode can locally release calcium ions from insoluble calcium carbonate (CaCO(3)) to cause gelation of calcium alginate through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressable electrodeposition of calcium alginate hydrogels with different shapes and sizes, as well as multiplexed micropatterning was performed. The effects of the concentration of the alginate and CaCO(3) solutions on the dimensional resolution of alginate hydrogel formation were experimentally examined. A 3 × 3 array of cell-encapsulated alginate hydrogels was also successfully demonstrated through light-addressable electrodeposition. Our proposed method provides a programmable method for the spatiotemporally controllable assembly of cell populations into cellular microarrays and could have a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery.

Direct in situ observation of ZnO nucleation and growth via transmission X-ray microscopy

NASA Astrophysics Data System (ADS)

Tay, S. E. R.; Goode, A. E.; Nelson Weker, J.; Cruickshank, A. A.; Heutz, S.; Porter, A. E.; Ryan, M. P.; Toney, M. F.

2016-01-01

The nucleation and growth of a nanostructure controls its size and morphology, and ultimately its functional properties. Hence it is crucial to investigate growth mechanisms under relevant growth conditions at the nanometer length scale. Here we image the nucleation and growth of electrodeposited ZnO nanostructures in situ, using a transmission X-ray microscope and specially designed electrochemical cell. We show that this imaging technique leads to new insights into the nucleation and growth mechanisms in electrodeposited ZnO including direct, in situ observations of instantaneous versus delayed nucleation.The nucleation and growth of a nanostructure controls its size and morphology, and ultimately its functional properties. Hence it is crucial to investigate growth mechanisms under relevant growth conditions at the nanometer length scale. Here we image the nucleation and growth of electrodeposited ZnO nanostructures in situ, using a transmission X-ray microscope and specially designed electrochemical cell. We show that this imaging technique leads to new insights into the nucleation and growth mechanisms in electrodeposited ZnO including direct, in situ observations of instantaneous versus delayed nucleation. Electronic supplementary information (ESI) available: Methods and videos of nanoparticle growth. See DOI: 10.1039/c5nr07019h

Tin, Bismuth, and Tin-Bismuth Alloy Electrodeposition from Chlorometalate Salts in Deep Eutectic Solvents.

PubMed

Vieira, Luciana; Burt, Jennifer; Richardson, Peter W; Schloffer, Daniel; Fuchs, David; Moser, Alwin; Bartlett, Philip N; Reid, Gillian; Gollas, Bernhard

2017-06-01

The electrodeposition of tin, bismuth, and tin-bismuth alloys from Sn II and Bi III chlorometalate salts in the choline chloride/ethylene glycol (1:2 molar ratio) deep eutectic solvent was studied on glassy carbon and gold by cyclic voltammetry, rotating disc voltammetry, and chronoamperometry. The Sn II -containing electrolyte showed one voltammetric redox process corresponding to Sn II /Sn 0 . The diffusion coefficient of [SnCl 3 ] - , detected as the dominating species by Raman spectroscopy, was determined from Levich and Cottrell analyses. The Bi III -containing electrolyte showed two voltammetric reduction processes, both attributed to Bi III /Bi 0 . Dimensionless current/time transients revealed that the electrodeposition of both Sn and Bi on glassy carbon proceeded by 3D-progressive nucleation at a low overpotential and changed to instantaneous at higher overpotentials. The nucleation rate of Bi on glassy carbon was considerably smaller than that of Sn. Elemental Sn and Bi were electrodeposited on Au-coated glass slides from their respective salt solutions, as were Sn-Bi alloys from a 2:1 Sn II /Bi III solution. The biphasic Sn-Bi alloys changed from a Bi-rich composition to a Sn-rich composition by making the deposition potential more negative.

Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

NASA Astrophysics Data System (ADS)

Jakupi, P.; Keech, P. G.; Barker, I.; Ramamurthy, S.; Jacklin, R. L.; Shoesmith, D. W.; Moser, D. E.

2015-11-01

Copper coated steel containers are being developed for the disposal of high level nuclear waste using processes such as cold spray and electrodeposition. Electron Back-Scatter Diffraction has been used to determine the microstructural properties and the quality of the steel-copper coating interface. The influence of the nature of the cold-spray carrier gas as well as its temperature and pressure (velocity) on the coating's plastic strain and recrystallization behaviour have been investigated, and one commercially-produced electrodeposited coating characterized. The quality of the coatings was assessed using the coincident site lattice model to analyse the properties of the grain boundaries. For cold spray coatings the grain size and number of coincident site lattice grain boundaries increased, and plastic strain decreased, with carrier gas velocity. In all cases annealing improved the quality of the coatings by increasing texture and coincidence site-lattices, but also increased the number of physical voids, especially when a low temperature cold spray carrier gas was used. Comparatively, the average grain size and number of coincident site-lattices was considerably larger for the strongly textured electrodeposited coating. Tensile testing showed the electrodeposited coating was much more strongly adherent to the steel substrate.

Reducing Bits in Electrodeposition Process of Commercial Vehicle - A Case Study

NASA Astrophysics Data System (ADS)

Rahim, Nabiilah Ab; Hamedon, Zamzuri; Mohd Turan, Faiz; Iskandar, Ismed

2016-02-01

Painting process is critical in commercial vehicle manufacturing process for protection and decorative. The good quality on painted body is important to reduce repair cost and achieve customer satisfaction. In order to achieve the good quality, it is important to reduce the defect at the first process in painting process which is electrodeposition process. The Pareto graph and cause and effect diagram in the seven QC tools is utilized to reduce the electrodeposition defects. The main defects in the electrodeposition process in this case study are the bits. The 55% of the bits are iron filings. The iron filings which come from the metal assembly process at the body shop are minimised by controlling the spot welding parameter, defect control and standard body cleaning process. However the iron filings are still remained on the body and carry over to the paint shop. The remained iron filings on the body are settled inside the dipping tank and removed by filtration system and magnetic separation. The implementation of filtration system and magnetic separation improved 27% of bits and reduced 42% of sanding man hour with a total saving of RM38.00 per unit.

Structure and morphology of CdS thin films electrodeposited in fused salts

NASA Astrophysics Data System (ADS)

Markov, I.; Valova, E.; Ilieva, M.; Kristev, I.

1983-12-01

Thin films of CdS are catholically electrodeposited on copper and silver electrodes in solution of CdCl 2 and Na 2SO 3 in fused LiCl-KCl eutectic. The films consist only of the hexagonal wurtzite phase of CdS. The films grown on Cu substrates are polycrystalline without pronounced fibre texture. The films grown on Ag substrates show practically perfect (000-) texture exposing the Cd face at the film surface. Films deposited at high bath temperatures (450-500°C), low current densities (0.2-0.5 mA/cm 2) or doped with In during the growth are very smooth. From the morphological investigations it is concluded that the CdS films electrodeposited onto Ag substrates have well pronounced laminar structure.

Silver electrodeposition on nanostructured gold: from nanodots to nanoripples.

PubMed

Dos Santos Claro, P C; Fonticelli, M; Benítez, G; Azzaroni, O; Schilardi, P L; Luque, N B; Leiva, E; Salvarezza, R C

2006-07-28

Silver nanodots and nanoripples have been grown on nanocavity-patterned polycrystalline Au templates by controlled electrodeposition. The initial step is the growth of a first continuous Ag monolayer followed by preferential deposition at nanocavities. The Ag-coated nanocavities act as preferred sites for instantaneous nucleation and growth of the three-dimensional metallic centres. By controlling the amount of deposited Ag, dots of approximately 50 nm average size and approximately 4 nm average height can be grown with spatial and size distributions dictated by the template. The dots are in a metastable state. Further Ag deposition drives the dot surface structure to nanoripple formation. Results show that electrodeposition on nanopatterned electrodes can be used to prepare a high density of nanostructures with a narrow size distribution and spatial order.

Electrodeposition of actinide compounds from an aqueous ammonium acetate matrix. Experimental development and optimization

DOE PAGES

Boll, Rose Ann; Matos, Milan; Torrico, Matthew N.

2015-03-27

Electrodeposition is a technique that is routinely employed in nuclear research for the preparation of thin solid films of actinide materials which can be used in accelerator beam bombardments, irradiation studies, or as radioactive sources. The present study investigates the deposition of both lanthanides and actinides from an aqueous ammonium acetate electrolyte matrix. Electrodepositions were performed primarily on stainless steel disks; with yield analysis evaluated using -spectroscopy. Experimental parameters were studied and modified in order to optimize the uniformity and adherence of the deposition while maximizing the yield. The initial development utilized samarium as the plating material, with and withoutmore » a radioactive tracer. As a result, surface characterization studies were performed by scanning electron microscopy, electron microprobe analysis, radiographic imaging, and x-ray diffraction.« less

Surface Engineering of Triboelectric Nanogenerator with an Electrodeposited Gold Nanoflower Structure.

PubMed

Park, Sang-Jae; Seol, Myeong-Lok; Jeon, Seung-Bae; Kim, Daewon; Lee, Dongil; Choi, Yang-Kyu

2015-09-14

A triboelectric nanogenerator composed of gold nanoflowers is demonstrated. The proposed triboelectric nanogenerator creates electricity by contact-separation-based electrification between an anodic metal and a cathodic polymer. For the improvement of output power via the enlargement of the effective surface area in the anodic metal, gold nanoflowers that produce a hierarchical morphology at a micro-to-nano scale by electrodeposition are utilized. The hierarchical morphology is controlled by the applied voltage and deposition time. Even though the triboelectric coefficient of gold is inferior to those of other metals, gold is very attractive to make a flower-like structure by electrodeposition. Moreover, gold is stable against oxidation by oxygen in air. From a reliability and practicality point of view, the aforementioned stability against oxidation is preferred.

Alternate method of source preparation for alpha spectrometry: No electrodeposition, no hydrofluoric acid

DOE PAGES

Kurosaki, Hiromu; Mueller, Rebecca J.; Lambert, Susan B.; ...

2016-07-15

An alternate method of preparing actinide alpha counting sources was developed in place of electrodeposition or lanthanide fluoride micro-precipitation. The method uses lanthanide hydroxide micro-precipitation to avoid the use of hazardous hydrofluoric acid. Lastly, it provides a quicker, simpler, and safer way of preparing actinide alpha counting sources in routine, production-type laboratories that process many samples daily.

Electrodeposition of amorphous ternary nickel-chromium-phosphorus alloy

DOEpatents

Guilinger, Terry R.

1990-01-01

Amorphous ternary nickel-chromium-phosphorus alloys are electrodeposited from a bath comprising a nickel salt, a chromium salt, a phosphorus source such as sodium hypophosphite, a complexing agent for the nickel ions, supporting salts to increase conductivity, and a buffering agent. The process is carried out at about room temperature and requires a current density between about 20 to 40 A/dm.sup.2.

Calcium phosphate deposition rate, structure and osteoconductivity on electrospun poly(l-lactic acid) matrix using electrodeposition or simulated body fluid incubation

PubMed Central

He, Chuanglong; Jin, Xiaobing; Ma, Peter X.

2013-01-01

Mineralized nanofibrous scaffolds have been proposed as promising scaffolds for bone regeneration due to their ability to mimic both nanoscale architecture and chemical composition of natural bone extracellular matrix (ECM). In this study, a novel electrodeposition method was compared with an extensively explored simulated body fluid (SBF) incubation method in terms of the deposition rate, chemical composition, and morphology of calcium phosphate formed on electrospun fibrous thin matrices with a fiber diameter in the range from about 200 nm to about 1400 nm prepared using 6, 8, 10 and 12 wt% poly(l-lactic acid) (PLLA) solutions in a mixture of dichloromethane and acetone (2:1 in volume). The effects of the surface modification using the two mineralization techniques on osteoblastic cell (MC3T3-E1) proliferation and differentiation were also examined. It was found that electrodeposition was two to three orders of magnitude faster than the SBF method in mineralizing the fibrous matrices, reducing the mineralization time from about two weeks to an hour to achieve the same amounts of mineralization. The mineralization rate also varied with the fiber diameter but in opposite directions between the two mineralization methods. As a general trend, the increase of fiber diameter resulted in a faster mineralization rate for the electrodeposition method but a slower mineralization rate for the SBF incubation method. Using the electrodeposition method, one can control the chemical composition and morphology of the calcium phosphate by varying the electric deposition potential and electrolyte temperature to tune the mixture of dicalcium phosphate dihydrate (DCPD) and hydroxy apatite (HAp). Using the SBF method, one can only obtain a low crystallinity HAp. The mineralized electrospun PLLA fibrous matrices from either method similarly facilitate the proliferation and osteogenic differentiation of preosteoblastic MC3T3-E1 cells as compared to neat PLLA matrices. Therefore, the electrodeposition method can be utilized as a fast and versatile technique to fabricate mineralized nanofibrous scaffolds for bone tissue engineering. PMID:24012605

Development of Surface Mechanical Attrition Treatment (SMAT) and Electrodeposition Process for Generating Nanostructured Materials and Study of Their Tensile Properties

NASA Astrophysics Data System (ADS)

Chan, Hoi Lam

This work systematically investigates two of the most promising synthesis methods for producing nanostructured (NS) materials: surface mechanical attrition treatment (SMAT) and the electrodeposition (ED) process, and obtains the proper conditions for fabricating NS materials in bulk form and studies the properties of these materials. SMAT is one of the recently developed processes to form nano-crystallized surface layer and refine grains in the subsurface layers, by actuating a number of spherical projectiles to impact the sample surface. In this work, the detailed measurement of ball impinging velocity is presented, and the resulted strain-rate and strains are theoretically modeled. Consequently the relation between plastic strain history and the observed microstructures is established. The SMAT process with different numbers of balls is explored to manifest that an optimum number of balls exists for the highest efficiency. ED process is widely used in producing NS materials these days. In this work, the relationships among non-metallic substrates, current type, current densities, microstructure and crystallographic textures, and mechanical properties is presented in order to demonstrate the influences of the deposition parameters in obtaining nano-grains and nano-twins microstructures. This work also examines the availability of obtaining bulk NS materials with desirable ductility in production-scale conditions through understanding these relationships. In the last part of the study, the effect of SMAT on the electrodeposits is studied. Tensile properties, microstructures and textures of the SMATed electrodeposits have been examined. The results demonstrate that the NS matrix obtained by the ED process with sufficient thickness retains desirable ductility after employing SMAT technology, and the SMAT process further enhances the strength of the electrodeposits.

Stabilizing electrodeposition in elastic solid electrolytes containing immobilized anions

PubMed Central

Tikekar, Mukul D.; Archer, Lynden A.; Koch, Donald L.

2016-01-01

Ion transport–driven instabilities in electrodeposition of metals that lead to morphological instabilities and dendrites are receiving renewed attention because mitigation strategies are needed for improving rechargeability and safety of lithium batteries. The growth rate of these morphological instabilities can be slowed by immobilizing a fraction of anions within the electrolyte to reduce the electric field at the metal electrode. We analyze the role of elastic deformation of the solid electrolyte with immobilized anions and present theory combining the roles of separator elasticity and modified transport to evaluate the factors affecting the stability of planar deposition over a wide range of current densities. We find that stable electrodeposition can be easily achieved even at relatively high current densities in electrolytes/separators with moderate polymer-like mechanical moduli, provided a small fraction of anions are immobilized in the separator. PMID:27453943

The properties of electrodeposited Zn-Co coatings

NASA Astrophysics Data System (ADS)

Mahieu, J.; de Wit, K.; de Cooman, B. C.; de Boeck, A.

1999-10-01

The possibility of increasing the corrosion resistance of automotive sheet steel by electrodepositing with Zn-Co alloy coatings was investigated. Process variables during electrodeposition such as current density, electrolyte flow rate, and pH were varied in order to examine their influence on the electroplating process. Cobalt contents varying from 0.2 to 7 wt% were easily obtained. The influence of these process parameters on the characteristics of the coating could be related to the hydroxide suppression mechanism for anomalous codeposition. The structure and the morphology of the coatings were determined using SEM and XRD analysis. Application properties important for coating systems used in the automotive industry, such as friction behavior, adhesion, and corrosion behavior, were investigated on coatings with varying cobalt content. The corrosion resistance of the Zn-Co alloy layers was found to be better than that of pure zinc coatings.

High-performance flexible electrode based on electrodeposition of polypyrrole/MnO2 on carbon cloth for supercapacitors

NASA Astrophysics Data System (ADS)

Fan, Xingye; Wang, Xiaolei; Li, Ge; Yu, Aiping; Chen, Zhongwei

2016-09-01

A highly flexible electrodes based on electrodeposited MnO2 and polypyrrole composite on carbon cloth is designed and developed by a facile in-situ electrodeposition technique. Such flexible composite electrodes with multiply layered structure possess a high specific capacitance of 325 F g-1 at a current density of 0.2 A g-1, and an excellent rate capability with a capacitance retention of 70% at a high current density of 5.0 A g-1. The superior electrochemical performance is mainly due to the unique electrode with improved ion- and electron-transportation pathways as well as the efficient utilization of active materials and electrode robustness. The excellent electrochemical performance and the low cost property endow this flexible nanocomposite electrode with great promise in applications of flexible supercapacitors.

Synthesis and electronic properties of nanophase semiconductor materials

NASA Astrophysics Data System (ADS)

Sailor, Michael J.

1993-05-01

The objective of the research effort is to understand and learn to control the morphologic and electronic properties of electrodeposited nanophase semiconductors. The initial work has focused on electrodeposition of nanophase CdSe, using a sequential monolayer deposition technique that we are developing. We are currently extending the synthesis phase of this project into silicon, silicon carbide, and phosphor materials. This work also encompasses studying semiconductor electrodeposition into materials with restricted dimensions, such as microporous alumina and porous silicon membranes. By growing films with very small grain sizes, we hope to produce and study materials that display unusual electronic or luminescent effects. We are primarily interested in the electronic properties of the II-VI and group IV materials, for potential applications in nanoscale electronics and optical detector technologies. The phosphors are being studied for their potential as efficient high-resolution display materials.

Direct fabrication of gas diffusion cathode by pulse electrodeposition for proton exchange membrane water electrolysis

NASA Astrophysics Data System (ADS)

Park, Hyanjoo; Choe, Seunghoe; Kim, Hoyoung; Kim, Dong-Kwon; Cho, GeonHee; Park, YoonSu; Jang, Jong Hyun; Ha, Don-Hyung; Ahn, Sang Hyun; Kim, Soo-Kil

2018-06-01

Pt catalysts for water electrolysis were prepared on carbon paper by using both direct current and pulse electrodeposition. Controlling the mass transfer of Pt precursor in the electrolyte by varying the deposition potential enables the formation of various Pt particle shapes such as flower-like and polyhedral particles. Further control of the deposition parameters for pulse electrodeposition resulted in changes to the particle size and density. In particular, the upper potential of pulse was found to be the critical parameter controlling the morphology of the particles and their catalytic activity. In addition to the typical electrochemical measurements, Pt samples deposited on carbon paper were used as cathodes for a proton exchange membrane water electrolyser. This single cell test revealed that our Pt particle samples have exceptional mass activity while being cost effective.

Semi-empirical equation of limiting current for cobalt electrodeposition in the presence of magnetic field and additive electrolyte

NASA Astrophysics Data System (ADS)

Sudibyo, Aziz, N.

2016-02-01

One of the available methods to solve a roughening in cobalt electrodeposition is magneto electrodeposition (MED) in the presence of additive electrolyte. Semi-empirical equation of limiting current under a magnetic field for cobalt MED in the presence of boric acid as an additive electrolyte was successfully developed. This semi empirical equation shows the effects of the electrode area (A), the concentration of the electro active species (C), the diffusion coefficient of the electro active species (D), the kinematic viscosity of the electrolyte (v), magnetic strength (B) and the number of electrons involved in the redox process (n). The presence of boric acid led to decrease in the limiting current, but the acid was found useful as a buffer to avoid the local pH rise caused by parallel hydrogen evolution reaction (HER).

Fabrication of mesoporous cerium dioxide films by cathodic electrodeposition.

PubMed

Kim, Young-Soo; Lee, Jin-Kyu; Ahn, Jae-Hoon; Park, Eun-Kyung; Kim, Gil-Pyo; Baeck, Sung-Hyeon

2007-11-01

Mesoporous cerium dioxide (Ceria, CeO2) thin films have been successfully electrodeposited onto ITO-coated glass substrates from an aqueous solution of cerium nitrate using CTAB (Cetyltrimethylammonium Bromide) as a templating agent. The synthesized films underwent detailed characterizations. The crystallinity of synthesized CeO2 film was confirmed by XRD analysis and HR-TEM analysis, and surface morphology was investigated by SEM analysis. The presence of mesoporosity in fabricated films was confirmed by TEM and small angle X-ray analysis. As-synthesized film was observed from XRD analysis and HR-TEM image to have well-crystallized structure of cubic phase CeO2. Transmission electron microscopy and small angle X-ray analysis revealed the presence of uniform mesoporosity with a well-ordered lamellar phase in the CeO2 films electrodeposited with CTAB templating.

Magnetic properties of CoNiFe alloys electrodeposited under potential and current control conditions

NASA Astrophysics Data System (ADS)

Perez, L.; Attenborough, K.; De Boeck, J.; Celis, J. P.; Aroca, C.; Sánchez, P.; López, E.; Sánchez, M. C.

2002-04-01

Electrodeposited CoNiFe alloys have been produced under potential and current control conditions. It was found that composition, crystalline structure and magnetic properties are the same irrespective of which plating control is used. Magnetic anisotropy is present in the softest samples. A study of the dependence of magnetic properties and domain structure on the thickness of the films is also reported.

Electrodeposition of Tantalum and Tantalum-Chromium Alloys

DTIC Science & Technology

1980-05-01

Electrochem Soc, 112, 840 (1965). 7Ibid, 113,60 (1966). 8Ibid, 113.66 (1966). J. Wurm, "European Conference on the Development of Molten Salts Applica...Chem. 35, 161-3 (1887). 16. J. Wurm, "European Conference on the Development of Molten Salts Applica- tions," Extended Abstracts and Proceedings, pp...Metals Tantalum Tantalum-Chromium Alloys Chromium Coating Fused Salt Electrolyte Electrodeposition FLINAK 20. ABSTRACT (Continue on reverse

The Role of Dissolved Gas in Ionic Liquid Electrolytes for Secondary Lithium Metal Batteries

DTIC Science & Technology

2013-01-07

devices use lithium-ion batteries comprised of a graphite anode and metal oxide cathode . Lithium, being the third-lightest element, is already synonymous...support shuttling lithium ions (battery cycling) such as the separator, electrolyte, and cathode and anode superstructures contribute most of the...ability of electro-deposit lithium non-dendritically. When lithium is electrodeposited , as during battery charging, it tends to form needle-like

Status of the Electroforming Shield Design (ESD) project

NASA Technical Reports Server (NTRS)

Fletcher, R. E.

1977-01-01

The utilization of a digital computer to augment electrodeposition/electroforming processes in which nonconducting shielding controls local cathodic current distribution is reported. The primary underlying philosophy of the physics of electrodeposition was presented. The technical approach taken to analytically simulate electrolytic tank variables was also included. A FORTRAN computer program has been developed and implemented. The program utilized finite element techniques and electrostatic theory to simulate electropotential fields and ionic transport.

In situ electrochemical SFG/DFG study of CN- and nitrile adsorption at Au from 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl) amide ionic liquid([BMP][TFSA]) containing 4-{2-[1-(2-cyanoethyl)-1,2,3,4-tetrahydroquinolin-6-yl]diazenyl} benzonitrile (CTDB) and K[Au(CN)₂].

PubMed

Bozzini, Benedetto; Busson, Bertrand; Gayral, Audrey; Humbert, Christophe; Mele, Claudio; Six, Catherine; Tadjeddine, Abderrahmane

2012-06-25

In this paper we report an in situ electrochemical Sum-/Difference Frequency Generation (SFG/DFG) spectroscopy investigation of the adsorption of nitrile and CN⁻ from the ionic liquid 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl) amide ([BMP][TFSA]) containing 4-{2-[1-(2-cyanoethyl)-1,2,3,4-tetrahydroquinolin-6-yl]-diazenyl}benzonitrile (CTDB) at Au electrodes in the absence and in the presence of the Au-electrodeposition process from K[Au(CN)₂]. The adsorption of nitrile and its coadsorption with CN⁻ resulting either from the cathodic decomposition of the dye or from ligand release from the Au(I) cyanocomplex yield potential-dependent single or double SFG bands in the range 2,125-2,140 cm⁻¹, exhibiting Stark tuning values of ca. 3 and 1 cm⁻¹ V⁻¹ in the absence and presence of electrodeposition, respectively. The low Stark tuning found during electrodeposition correlates with the cathodic inhibiting effect of CTDB, giving rise to its levelling properties. The essential insensitivity of the other DFG parameters to the electrodeposition process is due to the growth of smooth Au.

Controlling electrodeposited ultrathin amorphous Fe hydroxides film on V-doped nickel sulfide nanowires as efficient electrocatalyst for water oxidation

NASA Astrophysics Data System (ADS)

Shang, Xiao; Yan, Kai-Li; Lu, Shan-Shan; Dong, Bin; Gao, Wen-Kun; Chi, Jing-Qi; Liu, Zi-Zhang; Chai, Yong-Ming; Liu, Chen-Guang

2017-09-01

Developing cost-effective electrocatalysts with both high activity and stability remains challenging for oxygen evolution reaction (OER) in water electrolysis. Herein, based on V-doped nickel sulfide nanowire on nickel foam (NiVS/NF), we further conduct controllable electrodeposition of Fe hydroxides film on NiVS/NF (eFe/NiVS/NF) to further improve OER performance and stability. For comparison, ultrafast chemical deposition of Fe hydroxides on NiVS/NF (uFe/NiVS/NF) is also utilized. V-doping of NiVS/NF may introduce more active sites for OER, and nanowire structure can expose abundant active sites and facilitate mass transport. Both of the two depositions generate amorphous Fe hydroxides film covering on the surface of nanowires and lead to enhanced OER activities. Furthermore, electrodeposition strategy realizes uniform Fe hydroxides film on eFe/NiVS/NF confirmed by superior OER activity of eFe/NiVS/NF than uFe/NiVS/NF with relatively enhanced stability. The OER activity of eFe/NiVS/NF depends on various electrodepositon time, and the optimal time (15 s) is obtained with maximum OER activity. Therefore, the controllable electrodeposition of Fe may provide an efficient and simple strategy to enhance the OER properties of electrocatalysts.

Electrodeposition of Fe{sub 3}O{sub 4} layer from solution of Fe{sub 2}(SO{sub 4}){sub 3} with addition ethylene glycol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahlan, Dahyunir, E-mail: dahyunir@yahoo.com; Asrar, Allan

2016-03-11

The electrodeposition of Fe{sub 3}O{sub 4} layer from the solution Fe{sub 2}(SO{sub 4}){sub 3} with the addition of ethylene glycol on Indium Tin Oxide (ITO) substrate has been performed. The electrodeposition was carried out using a voltage of 5 volts for 120 seconds, with and without the addition of 2% wt ethylene glycol. Significant effects of temperature on the resulting the samples is observed when they are heated at 400 °C. Structural characterization using X-ray diffraction (XRD) shows that all samples produce a layer of Fe{sub 3}O{sub 4} with particle size less than 50 nanometers. The addition of ethylene glycolmore » and the heating of the sample causes a shrinkage in particle size. The scanning electron microscopy (SEM) characterization shows that Fe{sub 3}O{sub 4} layer resulting from the process of electrodeposition of Fe{sub 2}(SO{sub 4}){sub 3} without ethylene glycol, independent of whether the sample is heated or not, is uneven and buildup. Layer produced by the addition of ethylene glycol without heating produces spherical particles. On contrary, when the layer is heated the spherical particles transform to irregularly-shaped particles with smaller size.« less

Melt impregnation as a post processing treatment for performance enhancement in high capacity 3D microporous tin-copper-nickel intermetallic anode for Li-ion battery supported by electrodeposited nickel scaffold: A structural study

NASA Astrophysics Data System (ADS)

Sengupta, Srijan; Patra, Arghya; Mitra, Arijit; Jena, Sambedan; Das, Karabi; Majumder, Subhasish Basu; Das, Siddhartha

2018-05-01

This paper communicates stabilization of a Sn anode by impregnating it within the porous framework of a Ni-scaffold. The impregnation is carried out by electrodeposition Sn on Ni-foam followed by heating at 300 °C for 1 h. The Ni-foam was also electrodeposited on a Cu foil prior to deposition of Sn. The melting step leads to the formation of Nisbnd Sn and Cusbnd Sn intermetallics within pores of the Ni-scaffold. Snsbnd Cu/Ni intermetallics lithiate following the active-inactive strategy in which the inactive Cu/Ni buffers the volume expansion while Sn lithiates. Furthermore, this entire process takes place within Ni-scaffold which resists material pulverization and delamination and provide better electronic pathway for charge transfer. This active-inactive Sn:Snsbnd Cu/Ni intermetallic within a protected Ni-scaffold assembly results in 100th cycle discharge capacity of 587.9 mA h/g at a rate of 500 mA/g (0.5 C), and superior rate capability delivering 463 mAh/g at a rate of 2 A/g (2 C) while retaining structural integrity as compared to pure Sn electrodeposited (without heat-treatment) on the nickel scaffold.

Preparation and characterization of Cu2SnS3 thin films by electrodeposition

NASA Astrophysics Data System (ADS)

Patel, Biren; Narasimman, R.; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit

2018-05-01

Cu2SnS3 thin films were electrodeposited on F:SnO2/Glass substrates at room temperature by using aqueous solution. Copper and tin were first electrodeposited from single bath and post annealed in the presence of sulphur atmosphere to obtain the Cu2SnS3 phase. The Cu2SnS3 phase with preferred orientation along the (112) crystal direction grows to greater extent by the post annealing of the film. Raman analysis confirms the monoclinic crystal structure of Cu2SnS3 with principle mode of vibration as A1 (symmetric breathing mode) corresponding to the band at 291 cm-1. It also reveals the benign coexistence of orthorhombic Cu3SnS4 and Cu2SnS7 phases. Optical properties of the film show direct band gap of 1.25 eV with a high absorption coefficient of the order of 104 cm-1 in the visible region. Photo activity of the electrodeposited film was established in two electrode photoelectro-chemical cell, where an open circuit voltage of 91.6 mV and a short circuit current density of 10.6 µA/cm2 were recorded. Fabrication of Cu2SnS3 thin film heterojunction solar cell is underway.

Controllable Growth of Ga Film Electrodeposited from Aqueous Solution and Cu(In,Ga)Se2 Solar Cells.

PubMed

Bi, Jinlian; Ao, Jianping; Gao, Qing; Zhang, Zhaojing; Sun, Guozhong; He, Qing; Zhou, Zhiqiang; Sun, Yun; Zhang, Yi

2017-06-07

Electrodepositon of Ga film is very challenging due to the high standard reduction potential (-0.53 V vs SHE for Ga 3+ ). In this study, Ga film with compact structure was successfully deposited on the Mo/Cu/In substrate by the pulse current electrodeposition (PCE) method using GaCl 3 aqueous solution. A high deposition rate of Ga 3+ and H + can be achieved by applying a large overpotential induced by high pulse current. In the meanwhile, the concentration polarization induced by cation depletion can be minimized by changing the pulse frequency and duty cycle. Uniform and smooth Ga film was fabricated at high deposition rate with pulse current density 125 mA/cm 2 , pulse frequency 5 Hz, and duty cycle 0.25. Ga film was then selenized together with electrodeposited Cu and In films to make a CIGSe absorber film for solar cells. The solar cell based on the Ga film presents conversion efficiency of 11.04%, fill factor of 63.40%, and V oc of 505 mV, which is much better than those based on the inhomogeneous and rough Ga film prepared by the DCE method, indicating the pulse current electrodeposition process is promising for the fabrication of CIGSe solar cell.

The electrodeposition of multilayers on a polymeric substrate in flexible organic photovoltaic solar cells

NASA Astrophysics Data System (ADS)

Guedes, Andre F. S.; Guedes, Vilmar P.; Souza, Monica L.; Tartari, Simone; Cunha, Idaulo J.

2015-09-01

Flexible organic photovoltaic solar cells have drawn intense attention due to their advantages over competing solar cell technologies. The method utilized to deposit as well as to integrate solutions and processed materials, manufacturing organic solar cells by the Electrodeposition System, has been presented in this research. In addition, we have demonstrated a successful integration of a process for manufacturing the flexible organic solar cell prototype and we have discussed on the factors that make this process possible. The maximum process temperature was 120°C, which corresponds to the baking of the active polymeric layer. Moreover, the new process of the Electrodeposition of complementary active layer is based on the application of voltage versus time in order to obtain a homogeneous layer with thin film. This thin film was not only obtained by the electrodeposition of PANI-X1 on P3HT/PCBM Blend, but also prepared in perchloric acid solution. Furthermore, these flexible organic photovoltaic solar cells presented power conversion efficiency of 12% and the inclusion of the PANI-X1 layer reduced the effects of degradation on these organic photovoltaic panels induced by solar irradiation. Thus, in the Scanning Electron Microscopy (SEM), these studies have revealed that the surface of PANI-X1 layers is strongly conditioned by the dielectric surface morphology.

Lead acid battery recycling for the twenty-first century.

PubMed

Ballantyne, Andrew D; Hallett, Jason P; Riley, D Jason; Shah, Nilay; Payne, David J

2018-05-01

There is a growing need to develop novel processes to recover lead from end-of-life lead-acid batteries, due to increasing energy costs of pyrometallurgical lead recovery, the resulting CO 2 emissions and the catastrophic health implications of lead exposure from lead-to-air emissions. To address these issues, we are developing an iono-metallurgical process, aiming to displace the pyrometallurgical process that has dominated lead production for millennia. The proposed process involves the dissolution of Pb salts into the deep eutectic solvent (DES) Ethaline 200, a liquid formed when a 1 : 2 molar ratio of choline chloride and ethylene glycol are mixed together. Once dissolved, the Pb can be recovered through electrodeposition and the liquid can then be recycled for further Pb recycling. Firstly, DESs are being used to dissolve the lead compounds (PbCO 3 , PbO, PbO 2 and PbSO 4 ) involved and their solubilities measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The resulting Pb 2+ species are then reduced and electrodeposited as elemental lead at the cathode of an electrochemical cell; cyclic voltammetry and chronoamperometry are being used to determine the electrodeposition behaviour and mechanism. The electrodeposited films were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). We discuss the implications and opportunities of such processes.

Light-Addressed Electrodeposition of Enzyme-Entrapped Chitosan Membranes for Multiplexed Enzyme-Based Bioassays Using a Digital Micromirror Device

PubMed Central

Huang, Shih-Hao; Wei, Lu-Shiuan; Chu, Hsiao-Tzu; Jiang, Yeu-Long

2013-01-01

This paper describes a light-addressed electrolytic system used to perform an electrodeposition of enzyme-entrapped chitosan membranes for multiplexed enzyme-based bioassays using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-cathode to electrolytically produce hydroxide ions, which leads to an increased pH gradient. The high pH generated at the cathode can cause a local gelation of chitosan through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressed electrodeposition of chitosan membranes with different shapes and sizes, as well as multiplexed micropatterning, was performed. The effect of the illumination time of the light pattern on the dimensional resolution of chitosan membrane formation was examined experimentally. Moreover, multiplexed enzyme-based bioassay of enzyme-entrapped chitosan membranes was also successfully demonstrated through the electrodeposition of the chitosan membranes with various shapes/sizes and entrapping different enzymes. As a model experiment, glucose and ethanol were simultaneously detected in a single detection chamber without cross-talk using shape-coded chitosan membranes entrapped with glucose oxidase (GOX), peroxidase (POD), and Amplex Red (AmR) or alcohol oxidase (AOX), POD, and AmR by using same fluorescence indicator (AmR). PMID:23959236

Light-addressed electrodeposition of enzyme-entrapped chitosan membranes for multiplexed enzyme-based bioassays using a digital micromirror device.

PubMed

Huang, Shih-Hao; Wei, Lu-Shiuan; Chu, Hsiao-Tzu; Jiang, Yeu-Long

2013-08-16

This paper describes a light-addressed electrolytic system used to perform an electrodeposition of enzyme-entrapped chitosan membranes for multiplexed enzyme-based bioassays using a digital micromirror device (DMD). In this system, a patterned light illumination is projected onto a photoconductive substrate serving as a photo-cathode to electrolytically produce hydroxide ions, which leads to an increased pH gradient. The high pH generated at the cathode can cause a local gelation of chitosan through sol-gel transition. By controlling the illumination pattern on the DMD, a light-addressed electrodeposition of chitosan membranes with different shapes and sizes, as well as multiplexed micropatterning, was performed. The effect of the illumination time of the light pattern on the dimensional resolution of chitosan membrane formation was examined experimentally. Moreover, multiplexed enzyme-based bioassay of enzyme-entrapped chitosan membranes was also successfully demonstrated through the electrodeposition of the chitosan membranes with various shapes/sizes and entrapping different enzymes. As a model experiment, glucose and ethanol were simultaneously detected in a single detection chamber without cross-talk using shape-coded chitosan membranes entrapped with glucose oxidase (GOX), peroxidase (POD), and Amplex Red (AmR) or alcohol oxidase (AOX), POD, and AmR by using same fluorescence indicator (AmR).

Optimization of the electrodeposition of copper on poly-1-naphthylamine for the amperometric detection of carbohydrates in HPLC.

PubMed

D'Eramo, Fabiana; Marioli, Juan M; Arévalo, Alejandro H; Sereno, Leonides E

2003-11-04

A modified electrode consisting of copper dispersed in a poly-1-naphthylamine (p-1-NAP/Cu) film on a glassy carbon electrode was used as an amperometric detector for the on-line analysis of various carbohydrates separated by high performance liquid chromatography. The results obtained with this new sensor were compared to those obtained with a modified electrode based on the same polymer but with copper ions incorporated at open circuit, as described in a previous paper. In this new modified electrode the copper microparticles were electrochemically deposited into the polymeric matrix by single potential step chronoamperometry. A nucleation and growth mechanism was proposed to explain the current transients of copper electrodeposition. The experimental results were fitted to the proposed mechanism by using a mathematical equation that considers three-dimensional growth and progressive nucleation, assuming a no overlap and no diffusion mechanism. Cyclic voltammetric experiments showed that the electrodeposited copper microparticles provided a catalytic surface suited for the oxidation of glucose and several carbohydrates. The sensitivity of the electrode was influenced by the amount of copper electrodeposited, which in turn depended on the applied overpotential used for the deposition of copper. Liquid chromatographic experiments were carried out to test the analytical performance of these electrodes for the determination of various carbohydrates.

Fabrication of vertically aligned Pd nanowire array in AAO template by electrodeposition using neutral electrolyte.

PubMed

Taşaltın, Nevin; Oztürk, Sadullah; Kılınç, Necmettin; Yüzer, Hayrettin; Oztürk, Zaferziya

2010-05-01

A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current-time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction (XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm-2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially.

Tin, Bismuth, and Tin–Bismuth Alloy Electrodeposition from Chlorometalate Salts in Deep Eutectic Solvents

PubMed Central

Vieira, Luciana; Burt, Jennifer; Richardson, Peter W.; Schloffer, Daniel; Fuchs, David; Moser, Alwin; Bartlett, Philip N.; Reid, Gillian

2017-01-01

Abstract The electrodeposition of tin, bismuth, and tin–bismuth alloys from SnII and BiIII chlorometalate salts in the choline chloride/ethylene glycol (1:2 molar ratio) deep eutectic solvent was studied on glassy carbon and gold by cyclic voltammetry, rotating disc voltammetry, and chronoamperometry. The SnII‐containing electrolyte showed one voltammetric redox process corresponding to SnII/Sn0. The diffusion coefficient of [SnCl3]−, detected as the dominating species by Raman spectroscopy, was determined from Levich and Cottrell analyses. The BiIII‐containing electrolyte showed two voltammetric reduction processes, both attributed to BiIII/Bi0. Dimensionless current/time transients revealed that the electrodeposition of both Sn and Bi on glassy carbon proceeded by 3D‐progressive nucleation at a low overpotential and changed to instantaneous at higher overpotentials. The nucleation rate of Bi on glassy carbon was considerably smaller than that of Sn. Elemental Sn and Bi were electrodeposited on Au‐coated glass slides from their respective salt solutions, as were Sn–Bi alloys from a 2:1 SnII/BiIII solution. The biphasic Sn–Bi alloys changed from a Bi‐rich composition to a Sn‐rich composition by making the deposition potential more negative. PMID:28638772

Fabrication of vertically aligned Pd nanowire array in AAO template by electrodeposition using neutral electrolyte

PubMed Central

2010-01-01

A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current–time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction (XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially. PMID:20596417

Super Nonlinear Electrodeposition-Diffusion-Controlled Thin-Film Selector.

PubMed

Ji, Xinglong; Song, Li; He, Wei; Huang, Kejie; Yan, Zhiyuan; Zhong, Shuai; Zhang, Yishu; Zhao, Rong

2018-03-28

Selector elements with high nonlinearity are an indispensable part in constructing high density, large-scale, 3D stackable emerging nonvolatile memory and neuromorphic network. Although significant efforts have been devoted to developing novel thin-film selectors, it remains a great challenge in achieving good switching performance in the selectors to satisfy the stringent electrical criteria of diverse memory elements. In this work, we utilized high-defect-density chalcogenide glass (Ge 2 Sb 2 Te 5 ) in conjunction with high mobility Ag element (Ag-GST) to achieve a super nonlinear selective switching. A novel electrodeposition-diffusion dynamic selector based on Ag-GST exhibits superior selecting performance including excellent nonlinearity (<5 mV/dev), ultra-low leakage (<10 fA), and bidirectional operation. With the solid microstructure evidence and dynamic analyses, we attributed the selective switching to the competition between the electrodeposition and diffusion of Ag atoms in the glassy GST matrix under electric field. A switching model is proposed, and the in-depth understanding of the selective switching mechanism offers an insight of switching dynamics for the electrodeposition-diffusion-controlled thin-film selector. This work opens a new direction of selector designs by combining high mobility elements and high-defect-density chalcogenide glasses, which can be extended to other materials with similar properties.

The effect of acidity of electrolyte on the porosity and the nanostructure morphology of electrolytic manganese dioxide

NASA Astrophysics Data System (ADS)

Adelkhani, H.

2012-06-01

The effects of acidity of electrolyte (pH) on the hysteresis behavior, the specific surface area, and nanostructure morphology of electrolytic manganese dioxides (EMDs) have been studied by using the Barrett-Joyner-Halenda (BJH) analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM) images analysis. EMD samples are electrodeposited at a variable pH (6 to 1) and many fixed pH (2, 3, 4, 5, and 6). Results indicate that pH play key roles in the characteristics of EMD. The samples obtained at low pH (2 and 3) show multi-branched morphology and represent a H4 hysteresis loop. At pH 4 and 5, a uniform and dense structure of MnO2 is obtained without hysteresis behavior. The sample electrodeposited at pH 6 shows a regular reticulate, that its adsorption-desorption isotherm show hysteresis behavior. By electrodeposition at a variable pH, the sample shows a cauliflower-like and multi-branched form. From the viewpoint of classification of isotherm, pH strongly affects on Type of isotherm. The results show that γ-MnO2 is as main-product of electrodeposition and α-MnO2 and β-MnO2 were obtained as side-product at low and high pH, respectively.

Trends in reactivity of electrodeposited 3d transition metals on gold revealed by operando soft x-ray absorption spectroscopy during water splitting

NASA Astrophysics Data System (ADS)

Velasco-Vélez, J. J.; Jones, Travis E.; Pfeifer, Verena; Dong, Chung-Li; Chen, Yu-Xun; Chen, Chieh-Ming; Chen, Hsin-Yu; Lu, Ying-Rui; Chen, Jin-Ming; Schlögl, R.; Knop-Gericke, A.; Chuang, C.-H.

2017-01-01

We activated gold electrodes for their use as electrocatalyst for water splitting by electrodepositing Cu, Ni and Co. A combination of operando x-ray absorption spectroscopy and potentiometric control under aqueous conditions revealed the trends in reactivity yielded by these electrodes, which are directly associated with the cross- and overpotentials as well as the occupancy of the 3d orbitals. It was found that under anodic polarization the materials electrodeposited on gold suffer from a lack of stability, while under cathodic polarization they exhibit stable behavior. The observed activity is strongly related to the lack of stability shown by these composites under anodic polarization revealing a dynamic process ruled by corrosion. By operando x-ray absorption, we established that the overall enhancement of the activity for the oxygen evolution reaction is directly attributable to the cross-potential and corrosion process of the electrodeposited materials. It is associated with the high potential deposition, which is the origin of the incipient oxidation-corrosion resistance of the lattice. We conclude that the observed trends in the total current are directly associated with the loss of oxygen in the metal-oxide lattice and the subsequent dissolution of metallic ions in the electrolyte under anodic polarization.

In Situ Structural Studies of the Underpotential Deposition of Copper onto an Iodine Covered Platinum Surface Using X-Ray Standing Waves

DTIC Science & Technology

1991-01-01

electrocrystallization, catalysis, and surface chemistry. In this process, submonolayer to monolayer(s) amounts of a metal can be electrodeposited on a foreign...mechanisms involving nucleation and growth processes. Although electrochemical methods are invaluable in controlling and measuring thermodynamic...obtain direct atomic structural information about metal deposits on an iodine covered Pt(IIl) surface . They found that electrodeposition occurred in a

Nucleation and growth of metal nanocrystals during electrocrystallization in melts

NASA Astrophysics Data System (ADS)

Isaev, V. A.; Grishenkova, O. V.; Semerikova, O. L.; Kosov, A. V.; Zaykov, Yu. P.

2016-08-01

The initial stages of electrocrystallization in melts are considered. The nucleation and growth rates of metal nanocrystals during electrodeposition are calculated. The diffusion coefficients in the size space in the Fokker-Planck equation, which describes phase formation, are found. The method of calculating the number of nanoclusters formed on an electrode has been proposed. The concentration dependence of the phase formation under potentiostatic and galvanostatic electrodeposition conditions in melts is considered.

Method for producing highly reflective metal surfaces

DOEpatents

Arnold, J.B.; Steger, P.J.; Wright, R.R.

1982-03-04

The invention is a novel method for producing mirror surfaces which are extremely smooth and which have high optical reflectivity. The method includes depositing, by electrolysis, an amorphous layer of nickel on an article and then diamond-machining the resulting nickel surface to increase its smoothness and reflectivity. The machined nickel surface then is passivated with respect to the formation of bonds with electrodeposited nickel. Nickel then is electrodeposited on the passivated surface to form a layer of electroplated nickel whose inside surface is a replica of the passivated surface. The mandrel then may be-re-passivated and provided with a layer of electrodeposited nickel, which is then recovered from the mandrel providing a second replica. The mandrel can be so re-used to provide many such replicas. As compared with producing each mirror-finished article by plating and diamond-machining, the new method is faster and less expensive.

Enantiospecific electrodeposition of chiral CuO films on single-crystal Cu(111).

PubMed

Bohannan, Eric W; Kothari, Hiten M; Nicic, Igor M; Switzer, Jay A

2004-01-21

Epitaxial films of monoclinic CuO have been electrodeposited on single-crystal Cu(111) from solutions containing either (S,S)- or (R,R)-tartrate. X-ray pole figure analysis reveals that the CuO film grown from (S,S)-tartrate exhibits a (1) out-of-plane orientation while the film grown from (R,R)-tartrate has a (11) orientation. Even though CuO does not crystallize within a chiral space group, the orientations obtained exhibit a surface chirality similar to that obtained from high index fcc metal surfaces. The films were shown to be enantioselective toward the catalytic oxidation of tartrate molecules by cyclic voltammetry. The technique should prove to be applicable to the electrodeposition of chiral surfaces of other low-symmetry materials on achiral substrates and should prove to be of use to those interested in the synthesis, separation, and detection of chiral molecules.

Electrodeposition of gold nanoparticles on mesoporous TiO{sub 2} photoelectrode to enhance visible region photocurrent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Supriyono,; Krisnandi, Yuni Krisyuningsih; Gunlazuardi, Jarnuzi, E-mail: jarnuzi@ui.ac.id

2016-04-19

Electrodeposition of gold nanoparticles (Au NPs) on the mesoporous TiO{sub 2} photoelectrode to enchance visible region photocurrent have been investigated. Mesoporous TiO{sub 2} was prepared by a sol gel method and immobilized to the fluorine doped tin oxide (FTO) substrate by dip coating technique. Gold nanoparticles were electrodeposited on the TiO{sub 2} surface and the result FTO/TiO{sub 2}/Au was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), UV-Vis diffuse reflectance spectroscopy (DRS), and X-ray diffraction (XRD). The generated photocurrent was evaluated with an electrochemical workstation (e-DAQ/e-recorder 401) using 60 W wolfram lamp as visible lightmore » source. The photoelectrochemical evaluation indicated that the presence of gold nanoparticles on TiO{sub 2} photoelectrode shall enhance the photocurrent up to 50%.« less

Bipolarly stacked electrolyser for energy and space efficient fabrication of supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Liu, Xiaojuan; Wu, Tao; Dai, Zengxin; Tao, Keran; Shi, Yong; Peng, Chuang; Zhou, Xiaohang; Chen, George Z.

2016-03-01

Stacked electrolysers with titanium bipolar plates are constructed for electrodeposition of polypyrrole electrodes for supercapacitors. The cathode side of the bipolar Ti plates are pre-coated with activated carbon. In this new design, half electrolysis occurs which significantly lowers the deposition voltage. The deposited electrodes are tested in a symmetrical unit cell supercapacitor and an asymmetrical supercapacitor stack. Both devices show excellent energy storage performances and the capacitance values are very close to the design value, suggesting a very high current efficiency during the electrodeposition. The electrolyser stack offers multi-fold benefits for preparation of conducting polymer electrodes, i.e. low energy consumption, facile control of the electrode capacitance and simultaneous preparation of a number of identical electrodes. Therefore, the stacked bipolar electrolyser is a technology advance that offers an engineering solution for mass production of electrodeposited conducting polymer electrodes for supercapacitors.

Electrochemical Deposition of Lanthanum Telluride Thin Films and Nanowires

NASA Astrophysics Data System (ADS)

Chi, Su (Ike); Farias, Stephen; Cammarata, Robert

2013-03-01

Tellurium alloys are characterized by their high performance thermoelectric properties and recent research has shown nanostructured tellurium alloys display even greater performance than bulk equivalents. Increased thermoelectric efficiency of nanostructured materials have led to significant interests in developing thin film and nanowire structures. Here, we report on the first successful electrodeposition of lanthanum telluride thin films and nanowires. The electrodeposition of lanthanum telluride thin films is performed in ionic liquids at room temperature. The synthesis of nanowires involves electrodepositing lanthanum telluride arrays into anodic aluminum oxide (AAO) nanoporous membranes. These novel procedures can serve as an alternative means of simple, inexpensive and laboratory-environment friendly methods to synthesize nanostructured thermoelectric materials. The thermoelectric properties of thin films and nanowires will be presented to compare to current state-of-the-art thermoelectric materials. The morphologies and chemical compositions of the deposited films and nanowires are characterized using SEM and EDAX analysis.

Variation of magnetoimpedance of electrodeposited NiFe/Cu with deposition current density

NASA Astrophysics Data System (ADS)

Mishra, A. C.; Jha, A. K.

2017-12-01

An investigation about influence of deposition current density on electrodeposited magnetic film is reported in this paper. Ferromagnetic NiFe thin films were electrodeposited on copper wires of 100 μm diameter for various electrdepostion current densities ranging from 10 to 60 mA/cm2 maintaining equal thickness in all films. The composition of deposited film varied with deposition current density and in particular, a composition of Ni79Fe21 was achieved for a current density of 20 mA/cm2. The surface microstructure of the film deposited at the current density of 20 mA/cm2 was found to have excellent smoothness. The coercivity of the film was lowest and highest value of magnetoimpedance was measured for this film. The influence of current density on film composition and hence magnetic properties was attributed to the change of deposition mechanism.

Aminosilane-Assisted Electrodeposition of Gold Nanodendrites and Their Catalytic Properties

PubMed Central

Hau, Nga Yu; Yang, Peixian; Liu, Chang; Wang, Jian; Lee, Po-Heng; Feng, Shien-Ping

2017-01-01

A promising alternative route for the synthesis of three-dimensional Au dendrites was developed by direct electrodeposition from a solution of HAuCl4 containing 3-aminopropyltriethoxysilane (APTS). Ultraviolet-visible spectroscopy, fourier transform infrared spectroscopy and isothermal titration calorimetry were used to study the interaction of APTS in electrolyte. The effect of APTS on the formation of the hierarchical structure of Au dendrites was investigated by cyclic voltammetry, rotating disk electrode, electrochemical impedance spectroscopy and quartz crystal microbalance. The growth directions of the trunks and branches of the Au dendrites can be controlled by sweep-potential electrodeposition to obtain more regular structures. The efficacy of as-synthesised Au dendrites was demonstrated in the enhanced electro-catalytic activity to methanol electro-oxidation and the high sensitivity of glucose detection, which have potential applications in direct-methanol fuel cells and non-enzymatic electrochemical glucose biosensors, respectively. PMID:28045064

Effect of Ultrasonic on Copper Electroplating from the Non-Cyanide Alkaline Baths

NASA Astrophysics Data System (ADS)

Li, Minggang; Hu, Shuangshuang; Yang, Yejiong; Xu, Shuhan; Zhao, Xixi; Wei, Guoying

2014-06-01

Effects of the different ultrasonic powers on copper electrodeposition from non-cyanide alkaline baths by using pyrophosphate as complexing agent were investigated by different electrochemical methods. Cyclic voltammetry and current transient measurements were used to characterize the nucleation and growth mechanism. It is very obvious that the reduction potential moves to more positive one as the ultrasonic power increases. The quartz crystal microbalance (QCM) and chronoamperometric method were used to study the relationship between the mass change and the deposition time. It was found that the current efficiency of electrolyte under 0, 60, 80 and 100 W is 91.95%, 92.14%, 89.25% and 96.11%, respectively measured by QCM measurements. The surface morphology of the electrodeposited Cu films is analyzed by scanning electron microscopy (SEM). The morphology of copper films electrodeposited under the power of 60 W and 80 W presents a compact surface and the grains are fine and uniform.

Electrodeposition of Metals in Microgravity Conditions

NASA Technical Reports Server (NTRS)

Nishikawa, K.; Homma, T.; Chassaing, E.; Rosso, M.; Fukunaka, Y.

2012-01-01

Metal electrodeposition may introduce various morphological variations depending on the electrolytic conditions including cell configurations. For liquid electrolytes, a precise study of these deposits may be complicated by convective motion due to buoyancy. Zero-gravity (0-G) condition provided by drop shaft or parabolic flight gives a straightforward mean to avoid this effect: we present here 0-G electrodeposition experiments, which we compare to ground experiments (1-G). Two electrochemical systems were studied by laser interferometry, allowing to measure the concentration variations in the electrolyte: copper deposition from copper sulfate aqueous solution and lithium deposition from an ionic liquid containing LiTFSI. For copper, concentration variations were in good agreement with theory. For lithium, an apparent induction time was observed for the concentration evolution at 1-G: due to this induction time and to the low diffusion coefficient in ionic liquid, the concentration variations were hardly measurable in the parabolic flight 0-G periods of 20 seconds.

Investigation of CuInSe2 nanowire arrays with core-shell structure electrodeposited at various duty cycles into anodic alumina templates

NASA Astrophysics Data System (ADS)

Cheng, Yu-Song; Wang, Na-Fu; Tsai, Yu-Zen; Lin, Jia-Jun; Houng, Mau-Phon

2017-02-01

Copper indium selenide (CuInSe2) nanowire (NW) arrays were prepared at various electrolyte duty cycles by filling anodic alumina templates through the pulsed electrodeposition technique. X-ray diffraction and scanning electron microscopy (SEM) images showed that the nucleation mechanism of CuInSe2 NW arrays was affected by the electrodeposition duty cycle. Moreover, SEM images showed that the diameter and length of the NWs were 80 nm and 2 μm, respectively. Furthermore, PEDOT/CuInSe2 NW core-shell arrays were fabricated using surfactant-modified CuInSe2 NW surfaces showing the lotus effect. Transmission electron microscopy images confirmed that a core-shell structure was achieved. Current-voltage plots revealed that the CuInSe2 NW arrays were p-type semiconductors; moreover, the core-shell structure improved the diode ideality factor from 3.91 to 2.63.

Microstructures of Ni-AlN composite coatings prepared by pulse electrodeposition technology

NASA Astrophysics Data System (ADS)

Xia, Fafeng; Xu, Huibin; Liu, Chao; Wang, Jinwu; Ding, Junjie; Ma, Chunhua

2013-04-01

Ni-AlN composite coating was fabricated onto the surface of steel substrates by using pulse electrodeposition (PED) technique in this work. The effect of pulse current on the nucleation and growth of grains was investigated using transmission electronic microscopy (TEM), X-ray diffraction (XRD), scanning electronic microscopy (SEM) and atomic force microscopy (AFM), respectively. The results show that the contents of AlN nanoparticles increase with density of pulse current and on-duty ratio of pulse current increasing. Whereas the size of nickel grains decreases with density of pulse current increasing and on-duty ratio of pulse current decreasing. Ni-AlN composite coating consists of crystalline nickel (˜68 nm) and AlN particles (˜38 nm). SEM and AFM observations show that the composite coatings obtained by PED showed more compact surfaces and less grain sizes, whereas those obtained by direct current electrodepositing have rougher surfaces and bigger grain sizes.

Method for producing highly reflective metal surfaces

DOEpatents

Arnold, Jones B.; Steger, Philip J.; Wright, Ralph R.

1983-01-01

The invention is a novel method for producing mirror surfaces which are extremely smooth and which have high optical reflectivity. The method includes electrolessly depositing an amorphous layer of nickel on an article and then diamond-machining the resulting nickel surface to increase its smoothness and reflectivity. The machined nickel surface then is passivated with respect to the formation of bonds with electrodeposited nickel. Nickel then is electrodeposited on the passivated surface to form a layer of electroplated nickel whose inside surface is a replica of the passivated surface. The electroplated nickel layer then is separated from the passivated surface. The mandrel then may be re-passivated and provided with a layer of electrodeposited nickel, which is then recovered from the mandrel providing a second replica. The mandrel can be so re-used to provide many such replicas. As compared with producing each mirror-finished article by plating and diamond-machining, the new method is faster and less expensive.

Effect of Magnesium Ion on the Zinc Electrodeposition from Acidic Sulfate Electrolyte

NASA Astrophysics Data System (ADS)

Tian, Lin; Xie, Gang; Yu, Xiao-Hua; Li, Rong-Xing; Zeng, Gui-Sheng

2012-02-01

The effects of Mg2+ ion on the zinc electrodeposition were systematically investigated in sulfuric acid solution through the characterizations of current efficiency (CE), power consumption (PC), deposit morphology, cathodic polarization, and cyclic voltammetry. The results demonstrate that there is no significant influence on CE and PC in the Mg2+ concentration range of 1 to 10 g L-1, but with a drastic decrease of the CE and rapid increase of PC at Mg2+ ion concentration above 15 g L-1. Based on the morphology observation and polarization curves, the presence of Mg2+ ions could also induce the coarse surface on the electrodeposited zinc accompanying the enhancement of the cathodic polarization, which becomes more distinct at a high concentration above 15 g L-1. Furthermore, hydrogen evolution could be promoted with the existence of Mg2+ ions according to cyclic voltammograms.

Aminosilane-Assisted Electrodeposition of Gold Nanodendrites and Their Catalytic Properties

NASA Astrophysics Data System (ADS)

Hau, Nga Yu; Yang, Peixian; Liu, Chang; Wang, Jian; Lee, Po-Heng; Feng, Shien-Ping

2017-01-01

A promising alternative route for the synthesis of three-dimensional Au dendrites was developed by direct electrodeposition from a solution of HAuCl4 containing 3-aminopropyltriethoxysilane (APTS). Ultraviolet-visible spectroscopy, fourier transform infrared spectroscopy and isothermal titration calorimetry were used to study the interaction of APTS in electrolyte. The effect of APTS on the formation of the hierarchical structure of Au dendrites was investigated by cyclic voltammetry, rotating disk electrode, electrochemical impedance spectroscopy and quartz crystal microbalance. The growth directions of the trunks and branches of the Au dendrites can be controlled by sweep-potential electrodeposition to obtain more regular structures. The efficacy of as-synthesised Au dendrites was demonstrated in the enhanced electro-catalytic activity to methanol electro-oxidation and the high sensitivity of glucose detection, which have potential applications in direct-methanol fuel cells and non-enzymatic electrochemical glucose biosensors, respectively.

Surfactant-free electrodeposition of reduced graphene oxide/copper composite coatings with enhanced wear resistance

NASA Astrophysics Data System (ADS)

Mai, Y. J.; Zhou, M. P.; Ling, H. J.; Chen, F. X.; Lian, W. Q.; Jie, X. H.

2018-03-01

How to uniformly disperse graphene sheets into the electrolyte is one of the main challenges to synthesize graphene enhanced nanocomposites by electrodeposition. A surfactant-free colloidal solution comprised of copper (II)-ethylene diamine tetra acetic acid ([CuIIEDTA]2-) complexes and graphene oxide (GO) sheets is proposed to electrodeposit reduced graphene oxide/copper (RGO/Cu) composite coatings. Anionic [CuIIEDTA]2- complexes stably coexist with negatively charged GO sheets due to the electrostatic repulsion between them, facilitating the electrochemical reduction and uniform dispersion of GO sheets into the copper matrix. The RGO/Cu composite coatings are well characterized by XRD, Raman, SEM and XPS. Their tribological behavior as a function of RGO content in composite coatings and normal loads are investigated. Also the chemical composition and topography of the wear tracks for the composite coatings are analyzed to deduce the lubricating and anti-wear mechanism of RGO/Cu composite coatings.

Effect of Carbon Nanotubes on Corrosion and Tribological Properties of Pulse-Electrodeposited Co-W Composite Coatings

NASA Astrophysics Data System (ADS)

Edward Anand, E.; Natarajan, S.

2015-01-01

Cobalt-Tungsten (Co-W) alloy coatings possessing high hardness and wear/corrosion resistance, due to their ecofriendly processing, have been of interest to the researchers owing to its various industrial applications in automobile, aerospace, and machine parts. This technical paper reports Co-W alloy coatings dispersed with multiwalled carbon nanotubes (MWCNTs) produced by pulse electrodeposition from aqueous bath involving cobalt sulfate, sodium tungstate, and citric acid on stainless steel substrate (SS316). Studies on surface morphology through SEM, microhardness by Vickers method, microwear by pin-on-disk method, and corrosion behavior through potentiodynamic polarization method for the Co-W-CNT coatings were reported. Characterization studies were done by SEM and EDX analysis. The results showed that the corrosion and tribological properties of the pulse-electrodeposited Co-W-CNT alloy coatings were greatly influenced by its morphology, microhardness, %W, and MWCNT content in the coatings.

The Cu2ZnSnSe4 thin films solar cells synthesized by electrodeposition route

NASA Astrophysics Data System (ADS)

Li, Ji; Ma, Tuteng; Wei, Ming; Liu, Weifeng; Jiang, Guoshun; Zhu, Changfei

2012-06-01

An electrodeposition route for preparing Cu2ZnSnSe4 thin films for thin film solar cell absorber layers is demonstrated. The Cu2ZnSnSe4 thin films are prepared by co-electrodeposition Cu-Zn-Sn metallic precursor and subsequently annealing in element selenium atmosphere. The structure, composition and optical properties of the films were investigated by X-ray diffraction (XRD), Raman spectrometry, energy dispersive spectrometry (EDS) and UV-VIS absorption spectroscopy. The Cu2ZnSnSe4 thin film with high crystalline quality was obtained, the band gap and absorption coefficient were 1.0 eV and 10-4 cm-1, which is quite suitable for solar cells fabrication. A solar cell with the structure of ZnO:Al/i-ZnO/CdS/Cu2ZnSnSe4/Mo/glass was fabricated and achieved an conversion efficiency of 1.7%.

Maleimide-activated aryl diazonium salts for electrode surface functionalization with biological and redox-active molecules.

PubMed

Harper, Jason C; Polsky, Ronen; Wheeler, David R; Brozik, Susan M

2008-03-04

A versatile and simple method is introduced for formation of maleimide-functionalized surfaces using maleimide-activated aryl diazonium salts. We show for the first time electrodeposition of N-(4-diazophenyl)maleimide tetrafluoroborate on gold and carbon electrodes which was characterized via voltammetry, grazing angle FTIR, and ellipsometry. Electrodeposition conditions were used to control film thickness and yielded submonolayer-to-multilayer grafting. The resulting phenylmaleimide surfaces served as effective coupling agents for electrode functionalization with ferrocene and the redox-active protein cytochrome c. The utility of phenylmaleimide diazonium toward formation of a diazonium-activated conjugate, followed by direct electrodeposition of the diazonium-modified DNA onto the electrode surface, was also demonstrated. Effective electron transfer was obtained between immobilized molecules and the electrodes. This novel application of N-phenylmaleimide diazonium may facilitate the development of bioelectronic devices including biofuel cells, biosensors, and DNA and protein microarrays.

Nucleation and growth in alkaline zinc electrodeposition An Experimental and Theoretical study

NASA Astrophysics Data System (ADS)

Desai, Divyaraj

The current work seeks to investigate the nucleation and growth of zinc electrodeposition in alkaline electrolyte, which is of commercial interest to alkaline zinc batteries for energy storage. The morphology of zinc growth places a severe limitation on the typical cycle life of such batteries. The formation of mossy zinc leads to a progressive deterioration of battery performance while zinc dendrites are responsible for sudden catastrophic battery failure. The problems are identified as the nucleation-controlled formation of mossy zinc and the transport-limited formation of dendritic zinc. Consequently, this thesis work seeks to investigate and accurately simulate the conditions under which such morphologies are formed. The nucleation and early-stage growth of Zn electrodeposits is studied on carbon-coated TEM grids. At low overpotentials, the morphology develops by aggregation at two distinct length scales: ~5 nm diameter monocrystalline nanoclusters form ~50nm diameter polycrystalline aggregates, and second, the aggregates form a branched network. Epitaxial (0002) growth above a critical overpotential leads to the formation of hexagonal single-crystals. A kinetic model is provided using the rate equations of vapor solidification to simulate the evolution of the different morphologies. On solving these equations, we show that aggregation is attributed to cluster impingement and cluster diffusion while single-crystal formation is attributed to direct attachment. The formation of dendritic zinc is investigated using in-operando transmission X-ray microscopy which is a unique technique for imaging metal electrodeposits. The nucleation density of zinc nuclei is lowered using polyaniline films to cover the active nucleation sites. The effect of overpotential is investigated and the morphology shows beautiful in-operando formation of symmetric zinc crystals. A linear perturbation model was developed to predict the growth and formation of these crystals to first-order accuracy. Existing phase-field models of solidification and electrodeposition are used to simulate the growth and formation of individual zinc crystals. The driving force for solidification models (i.e. supersaturation) is reinterpreted in terms of overpotential under the assumption of a conductive electrolyte. The final morphologies are astonishingly similar to those observed in dynamical experiments. Further, the phase-field models obey the predictions of the linear perturbation analysis, which gives good credibility to the phase-field approach to simulate electrodeposition processes.

Electro deposition of cuprous oxide for thin film solar cell applications

NASA Astrophysics Data System (ADS)

Shahrestani, Seyed Mohammad

p and n type copper oxide semiconductor layers were fabricated by electrochemistry using new approaches for photovoltaic applications. Thin films were electroplated by cathodic polarization on a copper foil or indium tin oxide (ITO) substrates. The optimum deposition conditions (composition, pH and temperature of the electrolyte and applied potential) of the layers as thin films have been identified; in particular the conditions that allow getting the n-type layers have been well identified for the first time. The configuration of a photo - electrochemical cell was used to characterize the spectral response of the layers. It was shown that the p type layers exhibit a photocurrent in the cathode potential region and n layers exhibit photo current in the anode potential region. Measurements of electrical resistivity of electro chemically deposited layers of p and n type Cu2O, showed that the resistivity of p-type Cu2O varies from 3.2 x 105 to 2.0 x 108 Ocm. These values depend the electrodepositing conditions such as the pH of the solution, the deposition potential and temperature. The influence of several plating parameters of the p type layers of Cu2O, such as applied potential, pH and temperature of the bath on the chemical composition, degree of crystallinity, grain size and orientation parameters of the sample was systematically studied using X-ray diffraction and scanning electron microscopy. Depending of the electro-deposition potential, two different surface morphologies with various preferential crystal orientations were obtained for the temperatures of the electro-deposition of 30 °C and pH 9. For the same temperature, the layers of p type Cu2O of highly crystalline p type are obtained at pH 12, indicating that the crystallinity depends on the pH of the bath. Also, it has been shown that the morphology of Cu2O layers was changed by varying the potential and the duration of deposition, as well as the temperature of the solution. The conditions for the electro-deposition of Cu2O n-type were identified consistently for the first time. The electro-deposition electrolyte is based 0.01M acetate copper and 0.1 M sodium acetate: it has a pH between 6.3 and 4, a potential of from 0 to -0.25 V vs. Ag / AgCl and a temperature of 60oC. The optimum annealing temperature of the n-type Cu2O layers is between 120-150oC for the annealing time of 30 to 120 minutes. Resistivity of the n-type films varies between 5 x 103 and 5 x 104 at pH 4 to pH 6.4. We have shown for the first time that bubbling nitrogen gas in the electroplating cell improves significantly the spectral response of the electro-deposited n-type thin film. A two steps electro-deposition process was implemented to make the p-n homojunction cuprous oxide. Indium tin oxide (ITO) was used as a transparent conductive oxide substrate. A p-Cu2O was electrodeposited on ITO. After heat treatment a thin film layer of n-Cu 2O was electrodeposited on top of previous layer. The performance of a p-n homojunction photovoltaic solar cell of Cu2O was determined. The short-circuit current and the open circuit voltage were respectively determined to be as 0.35 volts and 235 muA/cm2. The fill factor (FF) and conversion efficiency of light into electricity were respectively measured to be 0.305 and 0.082%.

Mechanism and Kinetics of Li2S Precipitation in Lithium-Sulfur Batteries.

PubMed

Fan, Frank Y; Carter, W Craig; Chiang, Yet-Ming

2015-09-16

The kinetics of Li2 S electrodeposition onto carbon in lithium-sulfur batteries are characterized. Electrodeposition is found to be dominated by a 2D nucleation and growth process with rate constants that depend strongly on the electrolyte solvent. Nucleation is found to require a greater overpotential than growth, which results in a morphology that is dependent on the discharge rate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optical properties of template synthesized nanowalled ZnS microtubules

NASA Astrophysics Data System (ADS)

Kumar, Rajesh; Chakarvarti, S. K.

2007-12-01

Electrodeposition is a versatile technique combining low processing cost with ambient conditions that can be used to prepare metallic, polymeric and semiconducting nano/micro structures. In the present work, track-etch membranes (TEMs) of makrofol (KG) have been used as templates for synthesis of ZnS nanowalled microtubules using electrodeposition technique. The morphology of the microtubules was characterized by scanning electron microscopy. Size effects on the band gap of tubules have also been studied by UV-visible spectrophotometer.

Boron-capped tris(glyoximato) cobalt clathrochelate as a precursor for the electrodeposition of nanoparticles catalyzing H2 evolution in water.

PubMed

Anxolabéhère-Mallart, Elodie; Costentin, Cyrille; Fournier, Maxime; Nowak, Sophie; Robert, Marc; Savéant, Jean-Michel

2012-04-11

Electrochemical investigation of a boron-capped tris(glyoximato)cobalt clathrochelate complex in the presence of acid reveals that the catalytic activity toward hydrogen evolution results from an electrodeposition of cobalt-containing nanoparticles on the electrode surface at a modest cathodic potential. The deposited particles act as remarkably active catalysts for H(2) production in water at pH 7. © 2012 American Chemical Society

Single-step fabrication of electrodes with controlled nanostructured surface roughness using optically-induced electrodeposition

NASA Astrophysics Data System (ADS)

Liu, N.; Li, M.; Liu, L.; Yang, Y.; Mai, J.; Pu, H.; Sun, Y.; Li, W. J.

2018-02-01

The customized fabrication of microelectrodes from gold nanoparticles (AuNPs) has attracted much attention due to their numerous applications in chemistry and biomedical engineering, such as for surface-enhanced Raman spectroscopy (SERS) and as catalyst sites for electrochemistry. Herein, we present a novel optically-induced electrodeposition (OED) method for rapidly fabricating gold electrodes which are also surface-modified with nanoparticles in one single step. The electrodeposition mechanism, with respect to the applied AC voltage signal and the elapsed deposition time, on the resulting morphology and particle sizes was investigated. The results from SEM and AFM analysis demonstrated that 80-200 nm gold particles can be formed on the surface of the gold electrodes. Simultaneously, both the size of the nanoparticles and the roughness of the fabricated electrodes can be regulated by the deposition time. Compared to state-of-the-art methods for fabricating microelectrodes with AuNPs, such as nano-seed-mediated growth and conventional electrodeposition, this OED technique has several advantages including: (1) electrode fabrication and surface modification using nanoparticles are completed in a single step, eliminating the need for prefabricating micro electrodes; (2) the patterning of electrodes is defined using a digitally-customized, projected optical image rather than using fixed physical masks; and (3) both the fabrication and surface modification processes are rapid, and the entire fabrication process only requires less than 6 s.

Electrodeposition of metals and metal/cermet composites in low gravity

NASA Technical Reports Server (NTRS)

Riley, Clyde; Coble, Dwain; Maybee, George

1987-01-01

Electrodeposition experiments were carried out on the bench and a KC-135 aircraft at 0.01 g in anticipation of microgravity flights on NASA's Space Transportation System Shuttle. Experimental results obtained by interferometry compare concentration gradients as a function of time in the vicinity of a reducing electrode (cathode) for Cu(+2) and Co(+2) electrodeposition cells. No difference was found between bench and 0.01 g produced gradients for a .1M CuSO4 cell, but a significant difference was noted between the gradients in a 1M CoSO4 cell even though the bench cells were operated in a nonconvecting shielded (cathode over anode) mode. The gradient for Co(+2) depletion produced at 0.01 g was greater and the entire layer was thicker than found on the bench. Neutral buoyancy/matched density codeposition experiments were performed on the bench in an attempt to physically duplicate the results of metal/cermet codepositions in microgravity. Polystyrene spheres with average diameter 11.8 microns and density approximately matching that of 1M CoSO4 were utilized to emulate nonsedimenting cermets in microgravity. The cells were operated in a shielded convectionless mode. Comparison with literature data on codeposition with stirred cells indicate significant improvement in volume percent neutral occluded in the depositing metal matrix. A multicell electrodeposition flight apparatus that has been designed, constructed and is undergoing testing is discussed.

Lead acid battery recycling for the twenty-first century

PubMed Central

Ballantyne, Andrew D.; Hallett, Jason P.; Riley, D. Jason; Shah, Nilay

2018-01-01

There is a growing need to develop novel processes to recover lead from end-of-life lead-acid batteries, due to increasing energy costs of pyrometallurgical lead recovery, the resulting CO2 emissions and the catastrophic health implications of lead exposure from lead-to-air emissions. To address these issues, we are developing an iono-metallurgical process, aiming to displace the pyrometallurgical process that has dominated lead production for millennia. The proposed process involves the dissolution of Pb salts into the deep eutectic solvent (DES) Ethaline 200, a liquid formed when a 1 : 2 molar ratio of choline chloride and ethylene glycol are mixed together. Once dissolved, the Pb can be recovered through electrodeposition and the liquid can then be recycled for further Pb recycling. Firstly, DESs are being used to dissolve the lead compounds (PbCO3, PbO, PbO2 and PbSO4) involved and their solubilities measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The resulting Pb2+ species are then reduced and electrodeposited as elemental lead at the cathode of an electrochemical cell; cyclic voltammetry and chronoamperometry are being used to determine the electrodeposition behaviour and mechanism. The electrodeposited films were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). We discuss the implications and opportunities of such processes. PMID:29892351

Functionalization of monolithic and porous three-dimensional graphene by one-step chitosan electrodeposition for enzymatic biosensor.

PubMed

Liu, Jiyang; Wang, Xiaohui; Wang, Tianshu; Li, Dan; Xi, Fengna; Wang, Jin; Wang, Erkang

2014-11-26

Biological modification of monolithic and porous 3D graphene is of great significance for extending its application in fabricating highly sensitive biosensors. The present work reports on the first biofunctionalization of monolithic and freestanding 3D graphene foam for one-step preparation of reagentless enzymatic biosensors by controllable chitosan (CS) electrodeposition technology. Using a homogeneous three-component electrodeposition solution containing a ferrocene (Fc) grafted CS hybrid (Fc-CS), glucose oxidase (GOD), and single-walled carbon nanotubes (SWNTs), a homogeneous biocomposite film of Fc-CS/SWNTs/GOD was immobilized on the surface of 3D graphene foam by one-step electrodeposition. The Fc groups grafted on chitosan can be stably immobilized on the 3D graphene surface and keep their original electrochemical activity. The SWNTs doped into the Fc-CS matrix act as a nanowire to facilitate electron transfer and improve the conductivity of the biocomposite film. Combined with the extraordinary properties of 3D graphene foam including large active surface area, high conductivity, and fast mass transport dynamics, the 3D graphene based enzymatic biosensor achieved a large linear range (5.0 μM to 19.8 mM), a low detection limit (1.2 μM), and rapid response (reaching the 95% steady-state response within 8 s) for reagentless detection of glucose in the phosphate buffer solution.

Nucleation, aggregative growth and detachment of metal nanoparticles during electrodeposition at electrode surfaces.

PubMed

Lai, Stanley C S; Lazenby, Robert A; Kirkman, Paul M; Unwin, Patrick R

2015-02-01

The nucleation and growth of metal nanoparticles (NPs) on surfaces is of considerable interest with regard to creating functional interfaces with myriad applications. Yet, key features of these processes remain elusive and are undergoing revision. Here, the mechanism of the electrodeposition of silver on basal plane highly oriented pyrolytic graphite (HOPG) is investigated as a model system at a wide range of length scales, spanning electrochemical measurements from the macroscale to the nanoscale using scanning electrochemical cell microscopy (SECCM), a pipette-based approach. The macroscale measurements show that the nucleation process cannot be modelled as either truly instantaneous or progressive, and that step edge sites of HOPG do not play a dominant role in nucleation events compared to the HOPG basal plane, as has been widely proposed. Moreover, nucleation numbers extracted from electrochemical analysis do not match those determined by atomic force microscopy (AFM). The high time and spatial resolution of the nanoscale pipette set-up reveals individual nucleation and growth events at the graphite basal surface that are resolved and analysed in detail. Based on these results, corroborated with complementary microscopy measurements, we propose that a nucleation-aggregative growth-detachment mechanism is an important feature of the electrodeposition of silver NPs on HOPG. These findings have major implications for NP electrodeposition and for understanding electrochemical processes at graphitic materials generally.

Physical vapor deposition of one-dimensional nanoparticle arrays on graphite: seeding the electrodeposition of gold nanowires.

PubMed

Cross, C E; Hemminger, J C; Penner, R M

2007-09-25

One-dimensional (1D) ensembles of 2-15 nm diameter gold nanoparticles were prepared using physical vapor deposition (PVD) on highly oriented pyrolytic graphite (HOPG) basal plane surfaces. These 1D Au nanoparticle ensembles (NPEs) were prepared by depositing gold (0.2-0.6 nm/s) at an equivalent thickness of 3-4 nm onto HOPG surfaces at 670-690 K. Under these conditions, vapor-deposited gold nucleated selectively at the linear step edge defects present on these HOPG surfaces with virtually no nucleation of gold particles on terraces. The number density of 2-15 nm diameter gold particles at step edges was 30-40 microm-1. These 1D NPEs were up to a millimeter in length and organized into parallel arrays on the HOPG surface, following the organization of step edges. Surprisingly, the deposition of more gold by PVD did not lead to the formation of continuous gold nanowires at step edges under the range of sample temperature or deposition flux we have investigated. Instead, these 1D Au NPEs were used as nucleation templates for the preparation by electrodeposition of gold nanowires. The electrodeposition of gold occurred selectively on PVD gold nanoparticles over the potential range from 700-640 mV vs SCE, and after optimization of the electrodeposition parameters continuous gold nanowires as small as 80-90 nm in diameter and several micrometers in length were obtained.

Enhanced electrocatalytic activity of the Au-electrodeposited Pt nanoparticles-coated conducting oxide for the quantum dot-sensitized solar cells

NASA Astrophysics Data System (ADS)

Yoon, Yeung-Pil; Kim, Jae-Hong; Kang, Soon-Hyung; Kim, Hyunsoo; Choi, Chel-Jong; Kim, Kyong-Kook; Ahn, Kwang-Soon

2014-08-01

Au was electrodeposited potentiostatically at 0.3 V for 5 min on nanoporous Pt nanoparticle-coated F-doped SnO2 (FTO/Pt) substrates. For comparison, Au-electrodeposited FTO (FTO/Au) and Au-uncoated FTO/Pt were prepared. FTO/Au showed large-sized Au clusters dispersed sparsely over FTO, which resulted in lower electrocatalytic activity than FTO/Pt. In contrast, FTO/Pt exhibited poor stability unlike FTO/Au due to poisoning by the adsorption of sulfur species. The Au-electrodeposited FTO/Pt (FTO/Pt/Au) consisted of small Au clusters deposited over the entire area of Pt due to the effective Au nucleation provided by nanoporous metallic Pt. FTO/Pt/Au exhibited enhanced electrocatalytic activity and excellent stability because the small Au particles well-dispersed over the nanoporous metallic Pt network provided numerous electrochemical reaction sites, and the Pt surface was not exposed to the electrolyte. When FTO/Pt/Au was used as the counter electrode (CE) of a quantum dot-sensitized solar cell, the significantly enhanced electrocatalytic activity of the FTO/Pt/Au CE facilitated the reduction reaction of Sn2- + 2e- (CE) → Sn-12- + S2- at the CE/electrolyte interface, resulting in a significantly hindered recombination reaction, Sn2- + 2e- (TiO2 in the photoanode) → Sn-12- + S2-, and significantly improved overall energy conversion efficiency.

A CuNi bimetallic cathode with nanostructured copper array for enhanced hydrodechlorination of trichloroethylene (TCE).

PubMed

Liu, Bo; Zhang, Hao; Lu, Qi; Li, Guanghe; Zhang, Fang

2018-09-01

To address the challenges of low hydrodechlorination efficiency by non-noble metals, a CuNi bimetallic cathode with nanostructured copper array film was fabricated for effective electrochemical dechlorination of trichloroethylene (TCE) in aqueous solution. The CuNi bimetallic cathodes were prepared by a simple one-step electrodeposition of copper onto the Ni foam substrate, with various electrodeposition time of 5/10/15/20 min. The optimum electrodeposition time was 10 min when copper was coated as a uniform nanosheet array on the nickel foam substrate surface. This cathode exhibited the highest TCE removal, which was twice higher compared to that of the nickel foam cathode. At the same passed charge of 1080C, TCE removal increased from 33.9 ± 3.3% to 99.7 ± 0.1% with the increasing operation current from 5 to 20 mA cm -2 , while the normalized energy consumption decreased from 15.1 ± 1.0 to 2.6 ± 0.01 kWh log -1  m -3 . The decreased normalized energy consumption at a higher current density was due to the much higher removal efficiency at a higher current. These results suggest that CuNi cathodes prepared by simple electrodeposition method represent a promising and cost-effective approach for enhanced electrochemical dechlorination. Copyright © 2018 Elsevier B.V. All rights reserved.

Single potential electrodeposition of nanostructured battery materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Mosby, James Matthew

The increasing reliance on portable electronics is continuing to fuel research in the area of low power lithium-ion batteries, while a new surge in research for high power lithium-ion batteries has been sparked by the demand for plug-in hybrid electric vehicles (PHEV) and plug-in electric vehicles (PEV). To compete with current lead-acid battery chemistry, a few of the shortcomings of lithium-ion battery chemistry need to be addressed. The three main drawbacks of lithium-ion batteries for this application are: (1) low power density, (2) safety, and (3) the high cost of manufacturing. This dissertation covers the development of a low cost fabrication technique for an alternative anode material with high surface area geometries. The anode material is safer than the conventional anode material in lithium-ion batteries and the high surface area geometries permit higher power densities to be achieved. Electrodeposition is an inexpensive alternative method for synthesizing materials for electronics, energy conversion and energy storage applications relative to traditional solid state techniques. These techniques led to expensive device fabrication. Unlike most solid state synthesis routes, electrodeposition can usually be performed from common solutions and at moderate conditions. Three other benefits of using electrodeposition are: (1) it allows precise control of composition and crystallinity, (2) it provides the ability to deposit on complex shapes, and (3) it can deposit materials with nanoscale dimensions. The use of electrodeposition for alternative anode materials results in the deposition of the material directly onto the current collector that is used for the battery testing and applications without the need of additional binders and with excellent electrical contact. While this improves the characterization of the material and lowers the weight of the non-active materials within a battery, it also allows the anode to be deposited onto current collectors with different sizes, shapes, and surface areas. This is advantageous because high surface area materials benefit from improved kinetics for solid state transformations and from decreases in mechanical degradation that occurs during the lithiation and delithiation of battery materials. Intermetallic materials are an alternative to conventional anode materials because they have high capacities and react reversibly with lithium at potentials that hinder the dendrite formation of metallic lithium. Unfortunately, the volume expansion associated with the lithiation and delithiation of intermetallic materials is usually large (over 300%). With this in mind a procedure for the electrodeposition of Cu2Sb from aqueous solutions was developed and is presented in this thesis. Cu2Sb is an intermetallic that lithiates at potentials more positive than the potential needed to plate lithium metal, and has a volume expansion less than 100%. Electrodeposition of an intermetallic with a relatively small volume expansion and with high surface area morphology should dramatically reduce material degradation during battery cycling, thus promoting the life of the material. To electrodeposit Cu2Sb from aqueous solutions, soluble salts of Cu2+ and Sb3+ were needed. There are many Cu2+ salts that are highly soluble in water, but most Sb 3+ salts cause formation of Sb2O3 in aqueous solutions. To obtain Sb3+ in aqueous solutions, citric acid was used as a complexing agent. The results presented in this dissertation show that solution speciation plays an important role in the electrochemistry of aqueous citrate solutions of both copper and antimony. The cyclic voltammograms (CVs) presented here show that the reduction potential of Cu2+ shifted in the negative direction and the reduction potential of Sb 3+ shifted in the positive direction with an increase in pH. Also, Cu2Sb films were deposited at a single potential (-1050 mV vs. SSCE) from aqueous solutions at pH 6. We determined that the deposition potential not only affected the crystallinity of the deposited Cu2Sb, but also the ratio of antimony to copper. The temperature of the solution bath, as well as the smoothness of the growth substrate, were found to provide control over the crystallinity of the deposited Cu2Sb. The ability to electrodeposit crystalline Cu2Sb onto a variety of conducting surfaces is uncommon for intermetallics. The ability to deposit Cu2Sb onto transmission electron microscopy (TEM) grids has allowed the investigation of the morphology, composition, and crystallinity of Cu2Sb during the nucleation and growth of the material. This investigation demonstrated that multiple transformations occur during the early stage of the nucleation of Cu2Sb. A deeper understanding of this electrodeposition procedure for this compound will be useful for extending this technique to other crystalline intermetallics. Using the procedure developed for the single potential deposition of Cu2Sb films, the information from the TEM investigation and the results of a qualitative mathematical treatment, a pulse potential deposition procedure for depositing Cu2Sb nanowire arrays was developed. This procedure leads not only to the deposition of crystalline Cu2Sb nanowires, but also to uniform filling of the templates to afford wires of uniform composition and length. After the development of the procedures for the electrodeposition of Cu2Sb films and nanowire arrays from aqueous solutions at a single potential, the battery performance of the deposited Cu2Sb was examined. The ability to directly electrodeposit Cu2Sb onto the current collector has: (1) improved the characterization of the material during the lithiation and delithiation processes, (2) decreased the weight of inactive components, and (3) allowed for the deposition of high surface area Cu2Sb. The preliminary battery testing of electrodeposited Cu2Sb supported the absence of impurities in the deposited material and demonstrated that the electrodeposited Cu2Sb lithiated and delithiated similarly to Cu2Sb synthesized with different techniques. The deposition of Cu2Sb onto TEM grids was used for the first time without binder to characterize the morphology, composition and crystallinity changes that occur during the lithiation and delithiation of Cu2Sb. Superior capacity retention and rate performance was achieved with Cu2Sb electrodeposited onto high surface area copper foil. This superior performance demonstrates the improvement in battery performance that is expected from Cu2Sb nanowires, which have an order of magnitude higher surface area relative to the copper foam.

Characterization and properties of micro- and nanowires of controlled size, composition, and geometry fabricated by electrodeposition and ion-track technology

PubMed Central

2012-01-01

Summary The combination of electrodeposition and polymeric templates created by heavy-ion irradiation followed by chemical track etching provides a large variety of poly- and single-crystalline nanowires of controlled size, geometry, composition, and surface morphology. Recent results obtained by our group on the fabrication, characterization and size-dependent properties of nanowires synthesized by this technique are reviewed, including investigations on electrical resistivity, surface plasmon resonances, and thermal instability. PMID:23365800

On the Formation of Lightweight Nanocrystalline Aluminum Alloys by Electrodeposition

DOE PAGES

Hilty, Robert D.; Masur, Lawrence J.

2017-08-08

New nanocrystalline aluminum alloys have been fabricated by electrodeposition. These are thermodynamically stable alloys of Al-Mn and Al-Zr with grain sizes < 100nm. Al-Mn and Al-Zr alloys are characterized here showing high strength (up to 1350 MPa) and hardness (up to 450 HVN) while maintaining the specific gravity of Al. Smooth and dense deposits plated from ionic liquids, such as EMIM:Cl (1-Ethyl-3-methylimidazolium chloride), can develop to thicknesses of 1mm or more.

Evaluation and Description of Friction between an Electro-Deposited Coating and a Ceramic Ball under Fretting Condition

PubMed Central

Kim, Kyungmok

2015-01-01

This article describes fretting behavior of zirconia and silicon nitride balls on an electro-deposited coating. Fretting tests are performed using a ball-on-flat configuration. The evolution of the kinetic friction coefficient is determined, along with slip ratio. Experimental results show that the steady-state friction coefficient between ceramic balls (Si3N4 and ZrO2) and an electro-deposited coating is about 0.06, lower than the value between AISI 52100 ball and the coating. After a steady-state sliding, the transition of the friction coefficient is varied with a ball. The friction coefficient for ZrO2 balls became a critical value after higher fretting cycles than those for Si3N4 and AISI 52100 balls. In addition, it is identified that two parameters can describe the transition of the friction coefficient. Finally, the evolution of the friction coefficient is expressed as an exponential or a power-law form. PMID:28793471

Epitaxial lift-off of electrodeposited single-crystal gold foils for flexible electronics

NASA Astrophysics Data System (ADS)

Mahenderkar, Naveen K.; Chen, Qingzhi; Liu, Ying-Chau; Duchild, Alexander R.; Hofheins, Seth; Chason, Eric; Switzer, Jay A.

2017-03-01

We introduce a simple and inexpensive procedure for epitaxial lift-off of wafer-size flexible and transparent foils of single-crystal gold using silicon as a template. Lateral electrochemical undergrowth of a sacrificial SiOx layer was achieved by photoelectrochemically oxidizing silicon under light irradiation. A 28-nanometer-thick gold foil with a sheet resistance of 7 ohms per square showed only a 4% increase in resistance after 4000 bending cycles. A flexible organic light-emitting diode based on tris(bipyridyl)ruthenium(II) that was spin-coated on a foil exploited the transmittance and flexibility of the gold foil. Cuprous oxide as an inorganic semiconductor that was epitaxially electrodeposited onto the gold foils exhibited a diode quality factor n of 1.6 (where n = 1.0 for an ideal diode), compared with a value of 3.1 for a polycrystalline deposit. Zinc oxide nanowires electrodeposited epitaxially on a gold foil also showed flexibility, with the nanowires intact up to 500 bending cycles.

Electrodeposition and codeposition under low gravity/nonconvecting conditions

NASA Technical Reports Server (NTRS)

Riley, Clyde; Coble, H. Dwain; Loo, Boon; Benson, Brian; Abi-Akar, Hind

1987-01-01

An experimental electrodeposition system was developed for modeling the behavior of inert particles codepositing in an electroplating matrix under low-gravity conditions. The device consists of a Co-electrodeposition cell operating in a convectionless mode (cathode over anode) and containing polystyrene particles with density approximating that of the electroplating solution. Data were obtained in shielded cells at 1 g, and the experiment was duplicated at 0.01 g on a KC-135 flight. No difference was found between convection-free bench experiments and the 0.01 g KC-135 experiments with 0.0900 M CuSO4. Codeposition experiments using 11.8-micron matched-density polystyrene spheres in 1 M CoSO4 have revealed that a noticeable particle gradient is created as the solution density mismatches in the vicinity of the cathode; gentle stirring was required to maintain a homogeneous particle suspension. Cr3C2 dust, which readily disperses at 1 g, tended to coagulate into spherical globules at 0.01 g, when stirred.

Sensitive electrochemical detection of NADH and ethanol at low potential based on pyrocatechol violet electrodeposited on single walled carbon nanotubes-modified pencil graphite electrode.

PubMed

Zhu, Jun; Wu, Xiao-Yan; Shan, Dan; Yuan, Pei-Xin; Zhang, Xue-Ji

2014-12-01

In this work, the electrodeposition of pyrocatechol violet (PCV) was initially investigated by the electrochemical surface plasmon resonance (ESPR) technique. Subsequently, PCV was used as redox-mediator and was electrodeposited on the surface of pencil graphite electrode (PGE) modified with single-wall carbon nanotubes (SWCNTs). Owing to the remarkable synergistic effect of SWCNTs and PCV, PGE/SWCNTs/PCV exhibited excellent electrocatalytic activity towards dihydronicotinamide adenine dinucleotide (NADH) oxidation at low potential (0.2V vs. SCE) with fast amperometric response (<10s), broad linear range (1.3-280 μM), good sensitivity (146.2 μA mM(-1)cm(-2)) and low detection limit (1.3 μM) at signal-to-noise ratio of 3. Thus, this PGE/SWCNTs/PCV could be further used to fabricate a sensitive and economic ethanol biosensor using alcohol dehydrogenase (ADH) via a glutaraldehyde/BSA cross-linking procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of FeCoNi nanoparticles by galvanostatic technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budi, Setia, E-mail: setiabudi@unj.ac.id; Department of Chemistry, Faculty of Mathematics and Sciences, Universitas Negeri Jakarta, Jl. Pemuda No.10, Rawamangun, Jakarta 13220; Hafizah, Masayu Elita

Soft magnetic nanoparticles of FeCoNi have been becoming interesting objects for many researchers due to its potential application in electronic devices. One of the most promising methods for material preparation is the electrodeposition which capable of growing nanoparticles alloy directly onto the substrate. In this paper, we report our electrodeposition studies on nanoparticles synthesis using galvanostatic electrodeposition technique. Chemical composition of the synthesized FeCoNi was successfully controlled through the adjustment of the applied currents. It is revealed that the content of each element, obtained from quantitative analysis using atomic absorption spectrometer (AAS), could be modified by the adjustment of currentmore » in which Fe and Co content decreased at larger applied currents, while Ni content increased. The nanoparticles of Co-rich FeCoNi and Ni-rich FeCoNi were obtained from sulphate electrolyte at the range of applied current investigated in this work. Broad diffracted peaks in the X-ray diffractograms indicated typical nanostructures of the solid solution of FeCoNi.« less

Nano-micro structured superhydrophobic zinc coating on steel for prevention of corrosion and ice adhesion.

PubMed

Brassard, J D; Sarkar, D K; Perron, J; Audibert-Hayet, A; Melot, D

2015-06-01

Thin films of zinc have been deposited on steel substrates by electrodeposition process and further functionalized with ultra-thin films of commercial silicone rubber, in order to obtain superhydrophobic properties. Morphological feature, by scanning electron microscope (SEM), shows that the electrodeposited zinc films are composed of micro-nano rough patterns. Furthermore, chemical compositions of these films have been analyzed by X-ray diffraction (XRD) and infra-red (IRRAS). An optimum electrodeposition condition, based on electrical potential and deposition time, has been obtained which provides superhydrophobic properties with a water contact angle of 155±1°. The corrosion resistance properties, in artificial seawater, of the superhydrophobic zinc coated steel are found to be superior to bare steel. Similarly, the measured ice adhesion strength on superhydrophobic surfaces, using the centrifugal adhesion test (CAT), is found to be 6.3 times lower as compared to bare steel. This coating has promising applications in offshore environment, to mitigate corrosion and reduce ice adhesion. Copyright © 2014 Elsevier Inc. All rights reserved.

Rapid Obtaining of Nano-Hydroxyapatite Bioactive Films on NiTi Shape Memory Alloy by Electrodeposition Process

NASA Astrophysics Data System (ADS)

Lobo, A. O.; Otubo, J.; Matsushima, J. T.; Corat, E. J.

2011-07-01

Nano-hydroxyapatite (n-HA) crystalline films have been developed in this study by electrodeposition method on NiTi shape memory alloy (SMA). The electrodeposition of the n-HA films was carried out using 0.042 mol/L Ca(NO3)2 · 4H2O + 0.025 mol/L (NH4) · 2HPO4 electrolytes by applying a constant potential of -2.0 V for 120 min and keeping the solution temperature at 70 °C. The characterization of n-HA films is of special importance since bioactive properties related to n-HA have been directly identified with its specific composition and crystalline structure. AFM, XRD, EDX, FEG-SEM and Raman spectroscopy shows a homogeneous film, with high crystallinity, special composition, and bioactivity properties (Ca/P = 1.93) of n-HA on NiTi SMA surfaces. The n-HA coating with special structure would benefit the use of NiTi alloy in orthopedic applications.

Homoepitaxial electrodeposition on reconstructed and unreconstructed Au(100): An in-situ STM study

NASA Astrophysics Data System (ADS)

Al-Shakran, Mohammad; Kibler, Ludwig A.; Jacob, Timo

2015-01-01

A study of homoepitaxial electrodeposition on reconstructed and unreconstructed Au(100) surfaces is presented. The growth behavior has been investigated by in-situ scanning tunneling microscopy for Au(100) in contact with 0.1 M H2SO4 + 5 μM K[AuCl4]. It is shown that the initial surface structure is decisive for the emerging Au structures, giving rise to clearly different surface morphologies for electro-crystallization of Au on the unreconstructed and on the reconstructed Au(100) surface. A layer-by-layer growth is observed at more positive potentials for unreconstructed Au(100). The electrodeposition proceeds initially by the formation of Au islands followed by island coalescence due to the high mobility of surface atoms. Monatomic recessed stripes are formed as a result of the coalescence of deposited Au islands. At more negative potentials, the growth of Au proceeds strongly anisotropic on the reconstructed surface by the formation of reconstructed elongated islands.

Study of the mechanism for electrodeposition of dendrite-free zinc in an alkaline electrolyte modified with 1-ethyl-3-methylimidazolium dicyanamide

NASA Astrophysics Data System (ADS)

Xu, M.; Ivey, D. G.; Qu, W.; Xie, Z.

2015-01-01

Electrodeposition of Zn was conducted in a new electrolyte system composed of an alkaline solution (9 M KOH + 5 wt% ZnO) modified with a small amount (0.5 wt%) of room temperature ionic liquid 1-ethyl-3-methylimidazolium dicyanamide (EMI-DCA). At a high deposition current density of 80 mA cm-2, a porous, dendrite-free Zn film characterized by clusters of small Zn particles was obtained. The mechanism for the modified Zn morphology in the EMI-DCA containing electrolyte was studied by cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy. It was found that the addition of EMI-DCA changed the Zn nucleation process and reduced the potential variation during electrodeposition, which suppressed the uneven growth of Zn deposits and the formation of Zn dendrites. EIS results indicated that there was adsorption of EMI+ cations at the Zn film/electrolyte interface, which may have contributed to suppressed dendritic Zn growth.

Magnetic vortex state and multi-domain pattern in electrodeposited hemispherical nanogranular nickel films

NASA Astrophysics Data System (ADS)

Samardak, Alexander; Sukovatitsina, Ekaterina; Ognev, Alexey; Stebliy, Maksim; Davydenko, Alexander; Chebotkevich, Ludmila; Keun Kim, Young; Nasirpouri, Forough; Janjan, Seyed-Mehdi; Nasirpouri, Farzad

2014-12-01

Magnetic states of nickel nanogranular films were studied in two distinct structures of individual and agglomerated granules electrodeposited on n-type Si(1 1 1) surface from a modified Watts bath at a low pH of 2. Magnetic force microscopy and micromagnetic simulations revealed three-dimensional out-of-plane magnetic vortex states in stand-alone hemispherical granules and their arrays, and multi-domain patterns in large agglomerates and integrated films. Once the granules coalesce into small chains or clusters, the coercivity values increased due to the reduction of inter-granular spacing and strengthening of the magnetostatic interaction. Further growth leads to the formation of a continuous granulated film which strongly affected the coercivity and remanence. This was characterized by the domain wall nucleation and propagation leading to a stripe domain pattern. Magnetoresistance measurements as a function of external magnetic field are indicative of anisotropic magnetoresistance (AMR) for the continuous films electrodeposited on Si substrate.

Nickel recovery from electronic waste II electrodeposition of Ni and Ni-Fe alloys from diluted sulfate solutions.

PubMed

Robotin, B; Ispas, A; Coman, V; Bund, A; Ilea, P

2013-11-01

This study focuses on the electrodeposition of Ni and Ni-Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni(2+)/Fe(2+) ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits' thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni-Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni-Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni-Fe, the obtained data points are best fitted to an instantaneous nucleation model. Copyright © 2013 Elsevier Ltd. All rights reserved.

Electrodeposition of ZnO nanorod arrays on ZnO substrate with tunable orientation and optical properties.

PubMed

Jehl, Z; Rousset, J; Donsanti, F; Renou, G; Naghavi, N; Lincot, D

2010-10-01

The electrodeposition of ZnO nanorods on ZnO:Al films with different orientations is reported. The influence of the total charge exchanged during electrodeposition on the nanorod's geometry (length, diameter, aspect ratio and surface density) and the optical transmission properties of the nanorod arrays is studied on a [0001]-oriented ZnO:Al substrate. The nanorods are highly vertically oriented along the c axis, following the lattice matching with the substrate. The growth on a [1010] and [1120] ZnO:Al-oriented substrate with c axis parallel to the substrate leads to a systematic deviation angle of 55 degrees from the perpendicular direction. This finding has been explained by the occurrence of a minority orientation with the [1011] planes parallel to the surface, with a preferential growth on corresponding [0001] termination. Substrate crystalline orientation is thereby found to be a major parameter in finely tuning the orientation of the nanorod array. This new approach allows us to optimize the light scattering properties of the films.

Facile electrodeposition of reduced graphene oxide hydrogels for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Pham, Viet Hung; Gebre, Tesfaye; Dickerson, James H.

2015-03-01

We report both a facile, scalable method to prepare reduced graphene oxide hydrogels through the electrodeposition of graphene oxide and its use as an electrode for high-performance supercapacitors. Such systems exhibited specific capacitances of 147 and 223 F g-1 at a current density of 10 A g-1 when using H2SO4 and H2SO4 + hydroquinone redox electrolytes, respectively.We report both a facile, scalable method to prepare reduced graphene oxide hydrogels through the electrodeposition of graphene oxide and its use as an electrode for high-performance supercapacitors. Such systems exhibited specific capacitances of 147 and 223 F g-1 at a current density of 10 A g-1 when using H2SO4 and H2SO4 + hydroquinone redox electrolytes, respectively. Electronic supplementary information (ESI) available: GO synthesis, characterization, fabrication of ERGO supercapacitor and electrochemical measurement, elemental composition, TGA and XRD of GO and ERGO. See DOI: 10.1039/c4nr07508k

Spontaneous formation of spiral-like patterns with distinct periodic physical properties by confined electrodeposition of Co-In disks

NASA Astrophysics Data System (ADS)

Golvano-Escobal, Irati; Gonzalez-Rosillo, Juan Carlos; Domingo, Neus; Illa, Xavi; López-Barberá, José Francisco; Fornell, Jordina; Solsona, Pau; Aballe, Lucia; Foerster, Michael; Suriñach, Santiago; Baró, Maria Dolors; Puig, Teresa; Pané, Salvador; Nogués, Josep; Pellicer, Eva; Sort, Jordi

2016-07-01

Spatio-temporal patterns are ubiquitous in different areas of materials science and biological systems. However, typically the motifs in these types of systems present a random distribution with many possible different structures. Herein, we demonstrate that controlled spatio-temporal patterns, with reproducible spiral-like shapes, can be obtained by electrodeposition of Co-In alloys inside a confined circular geometry (i.e., in disks that are commensurate with the typical size of the spatio-temporal features). These patterns are mainly of compositional nature, i.e., with virtually no topographic features. Interestingly, the local changes in composition lead to a periodic modulation of the physical (electric, magnetic and mechanical) properties. Namely, the Co-rich areas show higher saturation magnetization and electrical conductivity and are mechanically harder than the In-rich ones. Thus, this work reveals that confined electrodeposition of this binary system constitutes an effective procedure to attain template-free magnetic, electric and mechanical surface patterning with specific and reproducible shapes.

Ag@Ni core-shell nanowire network for robust transparent electrodes against oxidation and sulfurization.

PubMed

Eom, Hyeonjin; Lee, Jaemin; Pichitpajongkit, Aekachan; Amjadi, Morteza; Jeong, Jun-Ho; Lee, Eungsug; Lee, Jung-Yong; Park, Inkyu

2014-10-29

Silver nanowire (Ag NW) based transparent electrodes are inherently unstable to moist and chemically reactive environment. A remarkable stability improvement of the Ag NW network film against oxidizing and sulfurizing environment by local electrodeposition of Ni along Ag NWs is reported. The optical transmittance and electrical resistance of the Ni deposited Ag NW network film can be easily controlled by adjusting the morphology and thickness of the Ni shell layer. The electrical conductivity of the Ag NW network film is increased by the Ni coating via welding between Ag NWs as well as additional conductive area for the electron transport by electrodeposited Ni layer. Moreover, the chemical resistance of Ag NWs against oxidation and sulfurization can be dramatically enhanced by the Ni shell layer electrodeposited along the Ag NWs, which provides the physical barrier against chemical reaction and diffusion as well as the cathodic protection from galvanic corrosion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Effective Electrodeposition Mode for Porous MnO₂/Ni Foam Composite for Asymmetric Supercapacitors.

PubMed

Tsai, Yi-Chiun; Yang, Wein-Duo; Lee, Kuan-Ching; Huang, Chao-Ming

2016-03-30

Three kinds of MnO₂/Ni foam composite electrode with hierarchical meso-macroporous structures were prepared using potentiodynamic (PD), potentiostatic (PS), and a combination of PS and PD(PS + PD) modes of electrodeposition. The electrodeposition mode markedly influenced the surface morphological, textural, and supercapacitive properties of the MnO₂/Ni electrodes. The supercapacitive performance of the MnO₂/Ni electrode obtained via PS + PD(PS + PD(MnO₂/Ni)) was found to be superior to those of MnO₂/Ni electrodes obtained via PD and PS, respectively. Moreover, an asymmetric supercapacitor device, activated carbon (AC)/PS + PD(MnO₂/Ni), utilizing PS + PD(MnO₂/Ni) as a positive electrode and AC as a negative electrode, was fabricated. The device exhibited an energy density of 7.7 Wh·kg -1 at a power density of 600 W·kg -1 and superior cycling stability, retaining 98% of its initial capacity after 10,000 cycles. The good supercapacitive performance and excellent stability of the AC/PS + PD(MnO₂/Ni) device can be ascribed to its high surface area, hierarchical structure, and interconnected three-dimensional reticular configuration of the nickel metal support, which facilitates electrolyte ion intercalation and deintercalation at the electrode/electrolyte interface and mitigates volume change during repeated charge/discharge cycling. These results demonstrate the great potential of the combination of PS and PD modes for MnO₂ electrodeposition for the development of high-performance electrodes for supercapacitors.

Effect of cobalt content on wear and corrosion behaviors of electrodeposited Ni-Co/WC nano-composite coatings.

PubMed

Amadeh, A; Ebadpour, R

2013-02-01

Metal-ceramic composite coatings are widely used in automotive and aerospace industries as well as micro-electronic systems. Electrodeposition is an economic method for application of these coatings. In this research, nickel-cobalt coatings reinforced by nano WC particles were applied on carbon steel substrate by pulse electrodeposition from modified Watts bath containing different amounts of cobalt sulphate as an additive. Saccharin and sodium dodecyl sulphate (SDS) were also added to electroplating bath as grain refiner and surfactant, respectively. The effect of cobalt content on wear and corrosion behavior of the coatings was investigated. Wear and corrosion properties were assessed by pin-on-disk and potentiodynamic polarization methods, respectively. Phase analysis was performed by X-ray diffraction (XRD) using CuK(alpha) radiation and the worn surfaces were studied by means of Scanning Electron Microscopy (SEM). The results showed that the addition of cobalt improved the wear resistance of the coatings. In the presence of 18 g/L cobalt in electrodeposition bath, the wear rate of the coating decreased to 0.002 mg/m and the coefficient of friction reduced to 0.695 while they were 0.004 mg/m and 0.77 in the absence of cobalt, respectively. This improvement in wear properties can be attributed to the formation of hcp phase in metallic matrix. Meanwhile, the corrosion resistance of the coatings slightly reduced because cobalt is more active metal with respect to nickel.

The influence of poly(ethylene oxide) and illumination on the copper electrodeposition process onto n-Si(100).

PubMed

Muñoz, Eduardo C; Schrebler, Ricardo S; Cury, Paula K; Suarez, Claudio A; Córdova, Ricardo A; Gómez, Carlos H; Marotti, Ricardo E; Dalchiele, Enrique A

2006-10-26

In this study, we examined the influence of illumination and the presence of poly(ethylene oxide) (PEO) as an additive for the copper electrodeposition process onto n-Si(100). The study was carried out by means of cyclic voltammetry (CV) and the potential steps method, from which the corresponding nucleation and growth mechanism (NGM) were determined. Likewise, a morphologic analysis of the deposits obtained at different potential values by means of atomic force microscopy (AFM) was carried out. In a first stage, Mott-Schottky measurements so as to characterize the energetics of the semiconductor/electrolyte interface were made. Also, parallel capacity measurements were carried out in order to determine the surface state density of the substrate. It was found that when PEO concentration is increased, the number of these surface states decreases. The CV results indicated that the presence of PEO inhibits the photoelectrochemical reaction of oxide formation on the surface of the semiconductor. This allows a decrease in the overpotential associated with the electrodeposition process. The analysis of the j/t transients shows that the NGM corresponds to progressive three-dimensional (3D) diffusional controlled (PN3D(Diff)), which was confirmed by the AFM technique. Neither illumination nor the presence of PEO changes the mechanisms. Their influence is in that they diminish the size of the nuclei and the speed with which these are formed, which produces a more homogeneous electrodeposit.

Pulsed Electrodeposition of Ni with Uniform Co-Deposition of Micron Sized Diamond Particles on Copper Substrate

NASA Astrophysics Data System (ADS)

Kumar, Prashant; Mahato, Neelima

Nanocrystalline nickel was deposited on annealed copper substrate of unit surface area (1 cm2) via pulsed electrodeposition technique using potentiostat (model 263A, Princeton Applied Research, USA) from Watts bath containing nickel sulfate, nickel chloride ,boric acid and sodium citrate. Diamond particles of three different dimensions, viz., 1, 3, and 6 micron were added separately (5 g/L) to the watts bath and co-deposited along with nanocrystalline nickel. The temperature was kept constant at 55 °C. The solution was ultrasonicated for 45-60 minutes prior to deposition to disperse the diamond particles uniformly in the bath. Depositions were carried out at different current densities, viz., 50, 100,150 and 200 mA/ cm2 for different durations, i.e.7, 14 and 21 minutes and best results are optimized for 200mA/cm2 so it is used for all process here .Scanning electron micrographs (SEM) show uniform deposition of microstructure of micron diamond on the surface of copper embedded in the nickel matrix. Elemental mapping confirmed uniform deposition of nickel and diamond with almost no cracks or pits. Mechanical properties of the sample such as, Vicker's hardness increased abruptly after the electrodeposition. Improved microstructural and mechanical properties were found in the case of electrodeposited surfaces containing followed by 3 and 6 micron diamond. The properties were also found better than those processed via stirring the solution during deposition.

Electrodeposition of magnesium and magnesium/aluminum alloys

DOEpatents

Mayer, Anton

1988-01-01

Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

Large-scale fabrication of single crystalline tin nanowire arrays

NASA Astrophysics Data System (ADS)

Luo, Bin; Yang, Dachi; Liang, Minghui; Zhi, Linjie

2010-09-01

Large-scale single crystalline tin nanowire arrays with preferred lattice orientation along the [100] direction were fabricated in porous anodic aluminium oxide (AAO) membranes by the electrodeposition method using copper nanorod as a second electrode.Large-scale single crystalline tin nanowire arrays with preferred lattice orientation along the [100] direction were fabricated in porous anodic aluminium oxide (AAO) membranes by the electrodeposition method using copper nanorod as a second electrode. Electronic supplementary information (ESI) available: Experimental details and the information for single crystalline copper nanorods. See DOI: 10.1039/c0nr00206b

Fabrication of submicron metallic grids with interference and phase-mask holography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Joong-Mok; Kim, Tae-Geun; Constant, Kristen

2011-01-25

Complex, submicron Cu metallic mesh nanostructures are made by electrochemical deposition using polymer templates made from photoresist. The polymer templates are fabricated with photoresist using two-beam interference holography and phase mask holography with three diffracted beams. Freestanding metallic mesh structures are made in two separate electrodepositions with perpendicular photoresist grating templates. Cu mesh square nanostructures having large (52.6%) open areas are also made by single electrodeposition with a photoresist template made with a phase mask. These structures have potential as electrodes in photonic devices.

Electrodeposition of magnesium and magnesium/aluminum alloys

DOEpatents

Mayer, A.

1988-01-21

Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

Three model space experiments on chemical reactions. [Gibbs adsorption, equilibrium shift and electrodeposition

NASA Technical Reports Server (NTRS)

Grodzka, P.; Facemire, B.

1977-01-01

Three investigations conducted aboard Skylab IV and Apollo-Soyuz involved phenomena that are of interest to the biochemistry community. The formaldehyde clock reaction and the equilibrium shift reaction experiments conducted aboard Apollo Soyuz demonstrate the effect of low-g foams or air/liquid dispersions on reaction rate and chemical equilibrium. The electrodeposition reaction experiment conducted aboard Skylab IV demonstrate the effect of a low-g environment on an electrochemical displacement reaction. The implications of the three space experiments for various applications are considered.

Electrodeposition of WO3 nanoparticles into surface mounted metal-organic framework HKUST-1 thin films

NASA Astrophysics Data System (ADS)

Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

2017-03-01

We describe a novel procedure to fabricate WO3@surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO3 nanoparticles into HKUST-1, also termed Cu3(BTC)2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

Self Assembled Semiconductor Quantum Dots for Spin Based All Optical and Electronic Quantum Computing

DTIC Science & Technology

2008-04-17

resolution TEM images (see Fig. 10) also show that ZnO nanocrystals nucleate on Fig. 9 SEM images of ZnO nanorods grown on (a) Si(001) and b) GaN/Al2O3... electrodeposition in a non-aqueous solution. The solution consisted of ZnClO4 (10.5 gm), LiClO4 (2.5 gm) and dimethyl sulfoxide (250 ml). The porous...valent Zn atoms which were selectively electrodeposited within the pores since they offered the least impedance path for the ac current

Lead electrowinning in a fluoborate medium. Use of hydrogen diffusion anodes

NASA Astrophysics Data System (ADS)

Expósito, E.; González-García, J.; Bonete, P.; Montiel, V.; Aldaz, A.

The results of an investigation of the electrowinning of lead employing a fluoboric acid bath are reported. The electrodeposition lead reaction was studied by voltammetric methods and scanning electron microscopy (SEM) microphotographs of the electrodeposited lead were taken. The effects of current density, temperature, catholyte flow and H + concentration were investigated on a laboratory scale to optimise operating conditions. Finally, the substitution of the traditionally used Dimensionally Stable Anode (DSA) by a Hydrogen Diffusion Electrode (HDE) was made in order to decrease the energy consumption (EC) of the overall process.

Effect of field deposition and pore size on Co/Cu barcode nanowires by electrodeposition

NASA Astrophysics Data System (ADS)

Cho, Ji Ung; Wu, Jun-Hua; Min, Ji Hyun; Lee, Ju Hun; Liu, Hong-Ling; Kim, Young Keun

2007-03-01

We have studied the effect of an external magnetic field applied during electrodeposition of Co/Cu barcode nanowires in anodic aluminum oxide nanotemplates. The magnetic properties of the barcode nanowires were greatly enhanced for 50 nm pore diameter regardless of segment aspect ratio, but field deposition has little effect on the 200 nm nanowires. The magnetic improvement is correlated with a structural change, attributed to field modification of the growth habit of the barcode nanowires. A mechanism of growth subject to geometric confinement is proposed.

Electrodeposition of WO3 nanoparticles into surface mounted metal-organic framework HKUST-1 thin films.

PubMed

Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

2017-03-17

We describe a novel procedure to fabricate WO 3 @surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO 3 nanoparticles into HKUST-1, also termed Cu 3 (BTC) 2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO 3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

On Controlling the Hydrophobicity of Nanostructured Zinc-Oxide Layers Grown by Pulsed Electrodeposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klochko, N. P., E-mail: klochko-np@mail.ru; Klepikova, K. S.; Kopach, V. R.

The possibility of fabricating highly hydrophobic nanostructured zinc-oxide layers by the inexpensive method of pulsed electrodeposition from aqueous solutions without water-repellent coatings, adapted for large-scale production, is shown. The conditions of the deposition of highly hydrophobic nanostructured zinc-oxide layers exhibiting the “rose-petal” effect with specific morphology, optical properties, crystal structure and texture are determined. The grown ZnO nanostructures are promising for micro- and nanoelectronics as an adaptive material able to reversibly transform to the hydrophilic state upon exposure to ultraviolet radiation.

Simultaneous electropolishing and electrodeposition of aluminum in ionic liquid under ambient conditions

NASA Astrophysics Data System (ADS)

Hou, Yuanyuan; Li, Ruiqian; Liang, Jun

2018-03-01

Electrodeposition and electropolishing of aluminum are achieved simultaneously in the ionic liquid composed of anhydrous aluminum chloride and trimethylamine hydrochloride. With the protection of a hydrocarbon layer, the process can be carried out under ambient atmosphere. As a result, a smooth mirror-like surface with the roughness only several nanometers is obtained on the anode Al and a uniform Al coating with the thickness about 5 μm is covered on the cathode. Importantly, this work presents the recycling of Al resource in a closed system.

2008 Gordon Research Conference on Electrodeposition [Conference summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moffat, Thomas P.; Gray, Nancy Ryan

2009-01-01

Electrodeposition melds key aspects of electrochemistry and materials science. In the last decade the advent of a variety of remarkable in situ characterization methods combined with the ever expanding application of wet chemical processing in high end technological endeavors has transformed the nature of the field. The 'old black magic' is giving way to the rigors of science as the electrodeposition process plays a central role in the fabrication of state-of-the-art ULSI and MEMS devices as well as being a key tool in the fabrication of novel materials and nanostructures. This year the conference will consider several timely issues suchmore » as how electrodeposition can contribute to the effective production of energy conversion devices, ranging from solar collectors to fuel cell electrocatalysts. Likewise, the challenge of building contacts and interconnects for next generation electronics will be examined over length scales ranging from individual atoms or molecules to chip stacking. Electrochemical fabrication of magnetic materials and devices as well as composite materials will also be discussed. Nucleation and growth phenomena underlie all aspect of electrochemical deposition and this year's meeting will consider the effect of both adsorbates and stress state on morphological evolution during thin film growth. A variety of new measurement methods for studying the growing electrode/electrolyte interface will also be detailed. In addition to the scheduled talks a session of short talks on late breaking news will be held Wednesday evening. There will also be at least two lively poster sessions that are essential elements of the conference and to which all attendees are encouraged to contribute. This will be 7th Electrodeposition GRC and based on past experience it is the premier 'mixing bowl' where young investigators and international experts have an extended opportunity to interact in a fun and collegial atmosphere. The afternoons provide free time for discussions coupled with mountain hikes, lake trips, and/or lively soccer, volleyball or tennis matches! We anticipate having some funds available to help graduate students and postdoctoral associates attend the meeting. The attendance of this popular conference is limited so early registration is strongly advised.« less

Capable Copper Electrodeposition Process for Integrated Circuit - substrate Packaging Manufacturing

NASA Astrophysics Data System (ADS)

Ghanbari, Nasrin

This work demonstrates a capable reverse pulse deposition methodology to influence gap fill behavior inside microvia along with a uniform deposit in the fine line patterned regions for substrate packaging applications. Interconnect circuitry in IC substrate packages comprises of stacked microvia that varies in depth from 20microm to 100microm with an aspect ratio of 0.5 to 1.5 and fine line patterns defined by photolithography. Photolithography defined pattern regions incorporate a wide variety of feature sizes including large circular pad structures with diameter of 20microm - 200microm, fine traces with varying widths of 3microm - 30microm and additional planar regions to define a IC substrate package. Electrodeposition of copper is performed to establish the desired circuit. Electrodeposition of copper in IC substrate applications holds certain unique challenges in that they require a low cost manufacturing process that enables a void-free gap fill inside the microvia along with uniform deposition of copper on exposed patterned regions. Deposition time scales to establish the desired metal thickness for such packages could range from several minutes to few hours. This work showcases a reverse pulse electrodeposition methodology that achieves void-free gap fill inside the microvia and uniform plating in FLS (Fine Lines and Spaces) regions with significantly higher deposition rates than traditional approaches. In order to achieve this capability, systematic experimental and simulation studies were performed. A strong correlation of independent parameters that govern the electrodeposition process such as bath temperature, reverse pulse plating parameters and the ratio of electrolyte concentrations is shown to the deposition kinetics and deposition uniformity in fine patterned regions and gap fill rate inside the microvia. Additionally, insight into the physics of via fill process is presented with secondary and tertiary current simulation efforts. Such efforts lead to show "smart" control of deposition rate at the top and bottom of via to avoid void formation. Finally, a parametric effect on grain size and the ensuing copper metallurgical characteristics of bulk copper is also shown to enable high reliability substrate packages for the IC packaging industry.

Multi-dimensional multi-species modeling of transient electrodeposition in LIGA microfabrication.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Gregory Herbert; Chen, Ken Shuang

2004-06-01

This report documents the efforts and accomplishments of the LIGA electrodeposition modeling project which was headed by the ASCI Materials and Physics Modeling Program. A multi-dimensional framework based on GOMA was developed for modeling time-dependent diffusion and migration of multiple charged species in a dilute electrolyte solution with reduction electro-chemical reactions on moving deposition surfaces. By combining the species mass conservation equations with the electroneutrality constraint, a Poisson equation that explicitly describes the electrolyte potential was derived. The set of coupled, nonlinear equations governing species transport, electric potential, velocity, hydrodynamic pressure, and mesh motion were solved in GOMA, using themore » finite-element method and a fully-coupled implicit solution scheme via Newton's method. By treating the finite-element mesh as a pseudo solid with an arbitrary Lagrangian-Eulerian formulation and by repeatedly performing re-meshing with CUBIT and re-mapping with MAPVAR, the moving deposition surfaces were tracked explicitly from start of deposition until the trenches were filled with metal, thus enabling the computation of local current densities that potentially influence the microstructure and frictional/mechanical properties of the deposit. The multi-dimensional, multi-species, transient computational framework was demonstrated in case studies of two-dimensional nickel electrodeposition in single and multiple trenches, without and with bath stirring or forced flow. Effects of buoyancy-induced convection on deposition were also investigated. To further illustrate its utility, the framework was employed to simulate deposition in microscreen-based LIGA molds. Lastly, future needs for modeling LIGA electrodeposition are discussed.« less

In situ electrodeposition of CoP nanoparticles on carbon nanomaterial doped polyphenylene sulfide flexible electrode for electrochemical hydrogen evolution

NASA Astrophysics Data System (ADS)

Wang, Tingxia; Jiang, Yimin; Zhou, Yaxin; Du, Yongling; Wang, Chunming

2018-06-01

Active and durable electrocatalyst for hydrogen evolution reaction (HER) is pivotal to generate molecular hydrogen more energy-efficient, but directly grafting electrocatalyst on electrode material by a single-step method without compromising the catalytic activity and stability remains a challenge. Herein, an intriguing electrode, reduced graphene oxide modified carbon nanotube/reduced graphene oxide/polyphenylene sulfide (RGO-CNT/RGO/PPS) film, is used to replace conventional electrodes. In situ electrodeposition is proposed to fabricate CoP on the RGO-CNT/RGO/PPS (CoP-RGO-CNT/RGO/PPS) electrode and achieves a favorably electrical contact between CoP nanoparticles and RGO-CNT/RGO/PPS electrode due to without any polymer binder. Additionally, the coupling of different electrodeposition stages with scanning electron microscope (SEM) can investigate the nanostructure evolution of CoP nanoparticles, which gives valuable insights into the optimized electrodeposition cycles. The rational integration of RGO onto CNT/RGO/PPS film is an effective approach for enhancing its intrinsic electrical conductivity and favoring the formation of a high density of dispersive CoP nanoparticles. The CoP-RGO-CNT/RGO/PPS film has shown outstanding HER electrocatalytic behaviors performed a current density of 10 mA cm-2 at a relatively low overpotential of 160 mV with a Tafel slope of 60 mV dec-1 in acidic medium, which can be mainly attributed to the synergistic effect between optimized morphology and accelerated kinetics. Additionally, this film electrocatalyst exhibits a good HER activity and stability under both neutral and basic conditions.

An Effective Electrodeposition Mode for Porous MnO2/Ni Foam Composite for Asymmetric Supercapacitors

PubMed Central

Tsai, Yi-Chiun; Yang, Wein-Duo; Lee, Kuan-Ching; Huang, Chao-Ming

2016-01-01

Three kinds of MnO2/Ni foam composite electrode with hierarchical meso-macroporous structures were prepared using potentiodynamic (PD), potentiostatic (PS), and a combination of PS and PD(PS + PD) modes of electrodeposition. The electrodeposition mode markedly influenced the surface morphological, textural, and supercapacitive properties of the MnO2/Ni electrodes. The supercapacitive performance of the MnO2/Ni electrode obtained via PS + PD(PS + PD(MnO2/Ni)) was found to be superior to those of MnO2/Ni electrodes obtained via PD and PS, respectively. Moreover, an asymmetric supercapacitor device, activated carbon (AC)/PS + PD(MnO2/Ni), utilizing PS + PD(MnO2/Ni) as a positive electrode and AC as a negative electrode, was fabricated. The device exhibited an energy density of 7.7 Wh·kg−1 at a power density of 600 W·kg−1 and superior cycling stability, retaining 98% of its initial capacity after 10,000 cycles. The good supercapacitive performance and excellent stability of the AC/PS + PD(MnO2/Ni) device can be ascribed to its high surface area, hierarchical structure, and interconnected three-dimensional reticular configuration of the nickel metal support, which facilitates electrolyte ion intercalation and deintercalation at the electrode/electrolyte interface and mitigates volume change during repeated charge/discharge cycling. These results demonstrate the great potential of the combination of PS and PD modes for MnO2 electrodeposition for the development of high-performance electrodes for supercapacitors. PMID:28773371

Mesoscopic Ni particles and nanowires by pulsed electrodeposition into porous Si

NASA Astrophysics Data System (ADS)

Michelakaki, E.; Valalaki, K.; G. Nassiopoulou, A.

2013-04-01

We report in this article on the formation of mesoscopic Ni particles and filling of continuous Ni nanowires into porous Si layers of thickness in the range of 0.5-4 μm with anisotropic vertical pores of average diameter in the range of 30-45 nm using pulsed electrodeposition from a Ni salt solution. The effect of pulse duration, number of pulses, and total process time on pore filling was investigated for porous Si with different porosities and porous Si layer thicknesses in the above thickness range. Scanning and transmission electron microscopy were used to characterize the samples. It was found that pore filling starts with Ni nucleation and nanoparticle formation at different points of the pore walls along the whole pore length and continues with nanoparticle coalescence to form continuous Ni nanowires that completely fill the pores. The mechanism involved in pore filling is particle nucleation and diffusion-controlled growth of Ni nanoparticles that coalesce to nanowires. From the beginning of the process, a metal film starts to form on the porous Si surface, and its thickness increases with increasing the process time. However, the presence of this film does not impede further pore filling and nanowire formation into the pores. This supports further the diffusion-controlled growth mechanism. Finally, it was demonstrated that full pore filling and continuous Ni nanowire formation were also achieved under direct current electrodeposition, and the results are quite similar to those obtained with pulsed electrodeposition when the same total deposition time is used in both cases.

Influence of a Boron Precursor on the Growth and Optoelectronic Properties of Electrodeposited Zinc Oxide Thin Film.

PubMed

Tsin, Fabien; Thomere, Angélica; Bris, Arthur Le; Collin, Stéphane; Lincot, Daniel; Rousset, Jean

2016-05-18

Highly transparent and conductive materials are required for many industrial applications. One of the interesting features of ZnO is the possibility to dope it using different elements, hence improving its conductivity. Results concerning the zinc oxide thin films electrodeposited in a zinc perchlorate medium containing a boron precursor are presented in this study. The addition of boron to the electrolyte leads to significant effects on the morphology and crystalline structure as well as an evolution of the optical properties of the material. Varying the concentration of boric acid from 0 to 15 mM strongly improves the compactness of the deposit and increases the band gap from 3.33 to 3.45 eV. Investigations were also conducted to estimate and determine the influence of boric acid on the electrical properties of the ZnO layers. As a result, no doping effect effect by boron was demonstrated. However, the role of boric acid on the material quality has also been proven and discussed. Boric acid strongly contributes to the growth of high quality electrodeposited zinc oxide. The high doping level of the film can be attributed to the perchlorate ions introduced in the bath. Finally, a ZnO layer electrodeposited in a boron rich electrolyte was tested as front contact of a Cu(In, Ga)(S, Se)2 based solar cell. An efficiency of 12.5% was measured with a quite high fill factor (>70%) which confirms the high conductivity of the ZnO thin film.

Electrodeposition to construct free-standing chitosan/layered double hydroxides hydro-membrane for electrically triggered protein release.

PubMed

Zhao, Pengkun; Zhao, Yanan; Xiao, Ling; Deng, Hongbing; Du, Yumin; Chen, Yun; Shi, Xiaowen

2017-10-01

In this study, we report the electrodeposition of a chitosan/layered double hydroxides (LDHs) hydro-membrane for protein release triggered by an electrical signal. The electrodeposition was performed in a chitosan and insulin loaded LDHs suspension in the absence of salt. A free-standing chitosan/LDHs hydro-membrane was generated on the electrode with improved mechanical properties, which is dramatically different from the weak hydrogel deposited in the presence of salt. The amount of LDHs in the hydro-membrane affects the optical transmittance and multilayered structure of the hybrid membrane. Compared to the weak chitosan/LDHs hydrogel, the hydro-membrane has a higher insulin loading capacity and the release of insulin is relatively slow. By biasing electrical potentials to the hydro-membrane, the release behavior of insulin can be adjusted accordingly. In addition, the chitosan/LDHs hydro-membrane showed no toxicity to cells. Our results provide a facile method to construct a chitosan/LDHs hybrid multilayered hydro-membrane and suggest the great potential of the hydro-membrane in controlled protein release. Copyright © 2017 Elsevier B.V. All rights reserved.

Microscopic and magnetic properties of template assisted electrodeposited iron nanowires

NASA Astrophysics Data System (ADS)

Irshad, M. I.; Ahmad, F.; Mohamed, N. M.; Abdullah, M. Z.; Yar, A.

2015-07-01

Nanowires of magnetic materials such as Iron, nickel, cobalt, and alloys of them are one of the most widely investigated structures because of their possible applications in high density magnetic recording media, sensor elements, and building blocks in biological transport systems. In this work, Iron nanowires have been prepared by electrodeposition technique using Anodized Aluminium Oxide (AAO) templates. The electrolyte used consisted of FeSO4.6H2O buffered with H3BO3 and acidized by dilute H2SO4. FESEM analysis shows that the asdeposited nanowires are parallel to one another and have high aspect ratio with a reasonably high pore-filing factor. To fabricate the working electrode, a thin film of copper (˜ 220 nm thick) was coated on back side of AAO template by e-beam evaporation system to create electrical contact with the external circuit. The TEM results show that electrodeposited nanowires have diameter around 100 nm and are polycrystalline in structure. Magnetic properties show the existence of anisotropy for in and out of plane configuration. These nanowires have potential applications in magnetic data storage, catalysis and magnetic sensor applications.

Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin.

PubMed

Jiang, Lin; Ding, Yaping; Jiang, Feng; Li, Li; Mo, Fan

2014-06-23

A nitrogen-doped graphene/carbon nanotubes (NGR-NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR-NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR-NCNTs (ENGR-NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR-NCNTs/GCE exhibited a wide linearity of 0.06-50 μM for CAF and 0.01-10 μM for VAN with detection limits of 0.02 μM and 3.3×10(-3) μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR-NCNTs nanocomposite has promising potential in electrocatalytic biosensor application. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of barrier layer conditions on the electrodeposition efficiency and magnetic properties of Fe nanowire arrays

NASA Astrophysics Data System (ADS)

Akhtarianfar, S. F.; Ramazani, A.; Almasi-Kashi, M.; Montazer, A. H.

2018-05-01

Fabrication of different nanostructures based on template-assisted methods has become conventional, due to their numerous potential applications. In this paper, Fe nanowire arrays (NWAs) were fabricated using a pulsed electrodeposition in porous anodic alumina (PAA) templates. The effect of alumina barrier layer conditions such as barrier layer temperature (BLT) and Cu pre-plating at the dendritic sections of pores on the electrodeposition efficiency (EE) and magnetic properties of Fe NWAs in two pH regimes (2.6 and 4.0) has been investigated. At pH 4.0, BLT was changed from 4 to 32 °C, leading to an EE of approximately 60% for BLT 24 °C. Moreover, to overcome the problem of low EE 2% at the pH of 2.6, Cu pre-plating was performed with deposition current densities of 25 and 35 mA/cm2. This procedure increased the EE up to about 40%, providing a promising approach to enhance the EE in the fabrication of Fe NWAs. Furthermore, a nearly constant trend of magnetic properties was observed for highly crystalline Fe NWs.

One-step fabrication of biomimetic superhydrophobic surface by electrodeposition on magnesium alloy and its corrosion inhibition.

PubMed

Liu, Yan; Xue, Jingze; Luo, Dan; Wang, Huiyuan; Gong, Xu; Han, Zhiwu; Ren, Luquan

2017-04-01

A facile, rapid and one-step electrodeposition process has been employed to construct a superhydrophobic surface with micro/nano scale structure on a Mg-Sn-Zn (TZ51) alloy, which is expected to be applied as a biodegradable biomedical implant materials. By changing the electrodeposition time, the maximum contact angle of the droplet was observed as high as 160.4°±0.7°. The characteristics of the as-prepared surface were conducted by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR). Besides, the anti-corrosion performance of the coatings in stimulated body fluid (SBF) solution were investigated by electrochemical measurement. The results demonstrated that the anti-corrosion property of superhydrophobic surface was greatly improved. This method show beneficial effects on the wettability and corrosion behavior, and therefore provides a efficient route to mitigate the undesirable rapid corrosion of magnesium alloy in favor of application for clinical field. Copyright © 2016 Elsevier Inc. All rights reserved.

A Rapid One-Step Process for Fabrication of Biomimetic Superhydrophobic Surfaces by Pulse Electrodeposition.

PubMed

Jiang, Shuzhen; Guo, Zhongning; Liu, Guixian; Gyimah, Glenn Kwabena; Li, Xiaoying; Dong, Hanshan

2017-10-25

Inspired by some typical plants such as lotus leaves, superhydrophobic surfaces are commonly prepared by a combination of low surface energy materials and hierarchical micro/nano structures. In this work, superhydrophobic surfaces on copper substrates were prepared by a rapid, facile one-step pulse electrodepositing process, with different duty ratios in an electrolyte containing lanthanum chloride (LaCl₃·6H₂O), myristic acid (CH₃(CH₂) 12 COOH), and ethanol. The equivalent electrolytic time was only 10 min. The surface morphology, chemical composition and superhydrophobic property of the pulse electrodeposited surfaces were fully investigated with SEM, EDX, XRD, contact angle meter and time-lapse photographs of water droplets bouncing method. The results show that the as-prepared surfaces have micro/nano dual scale structures mainly consisting of La[CH₃(CH₂) 12 COO]₃ crystals. The maximum water contact angle (WCA) is about 160.9°, and the corresponding sliding angle is about 5°. This method is time-saving and can be easily extended to other conductive materials, having a great potential for future applications.

One-step electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on magnesium alloy.

PubMed

Liu, Qin; Chen, Dexin; Kang, Zhixin

2015-01-28

A simple, one-step method has been developed to construct a superhydrophobic surface by electrodepositing Mg-Mn-Ce magnesium plate in an ethanol solution containing cerium nitrate hexahydrate and myristic acid. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were employed to characterize the surfaces. The shortest electrodeposition time to obtain a superhydrophobic surface was about 1 min, and the as-prepared superhydrophobic surfaces had a maximum contact angle of 159.8° and a sliding angle of less than 2°. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements demonstrated that the superhydrophobic surface greatly improved the corrosion properties of magnesium alloy in 3.5 wt % aqueous solutions of NaCl, Na2SO4, NaClO3, and NaNO3. Besides, the chemical stability and mechanical durability of the as-prepared superhydrophobic surface were also examined. The presented method is rapid, low-cost, and environmentally friendly and thus should be of significant value for the industrial fabrication of anticorrosive superhydrophobic surfaces and should have a promising future in expanding the applications of magnesium alloys.

Lithium electrodeposition dynamics in aprotic electrolyte observed in situ via transmission electron microscopy

DOE PAGES

Leenheer, Andrew Jay; Jungjohann, Katherine Leigh; Zavadil, Kevin Robert; ...

2015-03-18

Electrodeposited metallic lithium is an ideal negative battery electrode, but nonuniform microstructure evolution during cycling leads to degradation and safety issues. A better understanding of the Li plating and stripping processes is needed to enable practical Li-metal batteries. Here we use a custom microfabricated, sealed liquid cell for in situ scanning transmission electron microscopy (STEM) to image the first few cycles of lithium electrodeposition/dissolution in liquid aprotic electrolyte at submicron resolution. Cycling at current densities from 1 to 25 mA/cm 2 leads to variations in grain structure, with higher current densities giving a more needle-like, higher surface area deposit. Themore » effect of the electron beam was explored, and it was found that, even with minimal beam exposure, beam-induced surface film formation could alter the Li microstructure. The electrochemical dissolution was seen to initiate from isolated points on grains rather than uniformly across the Li surface, due to the stabilizing solid electrolyte interphase surface film. As a result, we discuss the implications for operando STEM liquid-cell imaging and Li-battery applications.« less

Nanoporous Hybrid Electrolytes for High-Energy Batteries Based on Reactive Metal Anodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tu, Zhengyuan; Zachman, Michael J.; Choudhury, Snehashis

2017-01-06

Successful strategies for stabilizing electrodeposition of reactive metals, including lithium, sodium, and aluminum are a requirement for safe, high-energy electrochemical storage technologies that utilize these metals as anodes. Unstable deposition produces high-surface area dendritic structures at the anode/electrolyte interface, which causes premature cell failure by complex physical and chemical processes that have presented formidable barriers to progress. Here, it is reported that hybrid electrolytes created by infusing conventional liquid electrolytes into nanoporous membranes provide exceptional ability to stabilize Li. Electrochemical cells based on γ-Al2O3 ceramics with pore diameters below a cut-off value above 200 nm exhibit long-term stability even atmore » a current density of 3 mA cm-2. The effect is not limited to ceramics; similar large enhancements in stability are observed for polypropylene membranes with less monodisperse pores below 450 nm. These findings are critically assessed using theories for ion rectification and electrodeposition reactions in porous solids and show that the source of stable electrodeposition in nanoporous electrolytes is fundamental.« less

Composition gradient, structure, stress, roughness and magnetic properties of 5-500 nm thin NiFe films obtained by electrodeposition

NASA Astrophysics Data System (ADS)

Gong, Jie; Riemer, Steve; Kautzky, Michael; Tabakovic, Ibro

2016-01-01

The composition gradients of 5-500 nm thin NiFe films on Cu and NiP substrates obtained by electrodeposition in stirred plating solutions at pH 3.0 on 8 in wafers were studied. It was found that the average elemental composition of the NiFe changes during electrodeposition with steep downturns of Fe-content, from 58 to 50 wt% Fe, in composition gradient zone near the substrate interface in the thickness range 5-250 nm depending on the electrode substrate (Cu and NiP). The increase of Fe-content in the composition gradient zone is accompanied by the increase of coercivity, Hc, magnetic flux saturation, Bs, saturation magnetostriction, λs, increase of dimensionless roughness, ρrms, and change of stress, σ. The coercivity (easy and hard axis) follows the Neel's relation Hc=ct-n (t is thickness and c is a constant). The mechanisms related to the change of coercivity of the NiFe films deposited on different substrates (Cu and NiP) are discussed in terms of material properties of these films.

Recovery of heavy metals from spent Ni-Cd batteries by a potentiostatic electrodeposition technique

NASA Astrophysics Data System (ADS)

Yang, Chun-Chen

Two heavy metals, Cd and Ni, have been separately recovered from spent AA-size Ni-Cd batteries by the potentiostatic electrodeposition and chemical precipitation methods, respectively. Various types and concentrations of HCl, H 2SO 4, and HNO 3 acids had been used as leach extractants. Experimental results indicate that the acid with the best leach capability is 4 M HCl. Three complexing reagents of NH 3, sodium acetate, sodium citrate have been chosen and tested. The most effective buffer is sodium citrate. The optimum mole ratio of metallic ion to citrate ion is 1:1. The recovery process for Cd metal is conducted by the potentiostatic electrodeposition in a leach electrolyte with a sodium citrate complex. The optimum applied potential for Cd recovery is in the range -1100 to -1120 mV (versus saturated calomel electrode (SCE)). The current efficiency for the recovery process is between 70 and 90% and depends strongly on the process parameters, e.g. liquor, concentration, applied potential, temperature, type of complex reagents, mole ratio, mass-transfer rate.

Non-conventional Pt-Cu alloy/carbon paper electrochemical catalyst formed by electrodeposition using hydrogen bubble as template

NASA Astrophysics Data System (ADS)

Kim, Youngkwang; Lee, Hyunjoon; Lim, Taeho; Kim, Hyun-Jong; Kwon, Oh Joong

2017-10-01

With emerging stability issues in fuel cell technology, a non-conventional catalyst not supported on carbon materials has been highlighted because it can avoid negative influences of carbon support materials on the stability, such as carbon corrosion. The nanostructured thin film catalyst is representative of non-conventional catalysts, which shows improved stability, enhanced mass specific activity, and fast mass transfer at high current densities. However, the nanostructured thin film catalyst usually requires multi-step processes for fabrication, making its mass production complex and irreproducible. We introduce a Pt-Cu alloy nanostructured thin film catalyst, which can be simply prepared by electrodeposition. By using hydrogen bubbles as a template, a three-dimensional free-standing foam of Cu was electrodeposited directly on the micro-porous layer/carbon paper and it was then displaced with Pt by simple immersion. The structure characterization revealed that a porous thin Pt-Cu alloy catalyst layer was successfully formed on the micro-porous layer/carbon paper. The synthesized Pt-Cu alloy catalyst exhibited superior durability compared to a conventional Pt/C in single cell test.

Hanle measurements of electrodeposited Fe/GaAs spin tunnel contacts

NASA Astrophysics Data System (ADS)

Majumder, Sarmita; Hohertz, Donna; McNeil, James; SpringThorpe, Anthony; Kavanagh, Karen L.

2014-03-01

We report spin transport in electrodeposited Fe/n-GaAs tunnel diodes via three-terminal Hanle measurements. For temperatures between 20 K and 150 K, the spin resistance was up to 20 times higher than expected from theoretical calculations and 1000 times larger compared to a vacuum-deposited counterpart. This higher spin resistance was correlated with a higher contact resistance, and a higher concentration of oxygen impurities in the electrodeposited Fe film and interface, as detected via x-ray photoelectron and Auger spectroscopies, and inferred from Fe film nucleation rates. These results can be explained via a small effective tunnel-contact area of 5%, but extra spin filtering via interfacial states or magnetic oxide layers cannot be ruled out. The spin diffusion times (8.5 ± 0.4 ns to 1.8 ± 0.4 ns, for 20 K to 150 K) extracted from Lorentzian fits were in good agreement with values obtained from earlier 4-terminal Hanle measurements (7.8 ± 0.4 ns to 3.2 ± 0.4 ns, for 25 K to 77 K), both 10 times slower than reported vacuum-deposited contacts.

Green synthesis of in situ electrodeposited rGO/MnO2 nanocomposite for high energy density supercapacitors.

PubMed

Rusi; Majid, S R

2015-11-05

This paper presents the preparation of in situ electrodeposited rGO/MnO2 nanocomposite as a binder-free electrode for supercapacitor application. The work describes and evaluates the performance of prepared electrode via green and facile electrodeposition technique of in situ rGO/MnO2-glucose carbon nanocomposites. The carbon content in the composite electrode increased after GO and D (+) glucose solution has been added in the deposition electrolyte. This study found that a suitable concentration of D (+) glucose in the deposition electrolyte can slow down the nucleation process of MnO2 particles and lead to uniform and ultrathin nanoflakes structure. The optimize electrode exhibited low transfer resistance and resulted on excellent electrochemical performance in three electrolyte systems viz. Na2SO4, KOH and KOH/K3Fe(CN)6 redox electrolytes. The optimum energy density and power density were 1851 Whkg(-1) and 68 kWkg(-1) at current density of 20 Ag(-1) in mixed KOH/K3Fe(CN)6 electrolyte.

Orienting Periodic Organic-Inorganic Nanoscale Domains Through One-Step Electrodeposition

PubMed Central

Herman, David J.; Goldberger, Joshua E.; Chao, Stephen; Martin, Daniel T.; Stupp, Samuel I

2011-01-01

One of the challenges in the synthesis of hybrid materials with nanoscale structure is to precisely control morphology across length scales. Using a one-step electrodeposition process on indium tin oxide (ITO) substrates followed by annealing, we report here the preparation of materials with preferentially oriented lamellar domains of electron donor surfactants and the semiconductor ZnO. We found that either increasing the concentration of surfactant or the water to dimethyl sulfoxide ratio of solutions used resulted in the suppression of bloom-like morphologies and enhanced the density of periodic domains on ITO substrates. Furthermore, by modifying the surface of the ITO substrate with the conductive polymer blend poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), we were able to alter the orientation of these electrodeposited lamellar domains to be perpendicular to the substrate. The long-range orientation achieved was characterized by 2D grazing incidence small angle X-ray scattering. This high degree of orientation in electronically active hybrids with alternating nanoscale p-type and n-type domains is of potential interest in photovoltaics or thermoelectric materials. PMID:21142087

Direct electrodeposition of porous gold nanowire arrays for biosensing applications.

PubMed

Zhang, Xinyi; Li, Dan; Bourgeois, Laure; Wang, Huanting; Webley, Paul A

2009-02-02

Nanochannel alumina templates are used as templates for fabrication of porous gold nanowire arrays by a direct electrodeposition method. After modification with glucose oxidase, a porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose. The picture shows an SEM image of a nanowire array after removal of the alumina template by acid dissolution. We report the fabrication of porous gold nanowire arrays by means of a one-step electrodeposition method utilizing nanochannel alumina templates. The microstructure of gold nanowires depends strongly on the current density. The formation of porous gold nanowires is attributed to disperse crystallization under conditions of low nucleation rate. Interfacial electron transport through the porous gold nanowires is studied by electrochemical impedance spectroscopy. Cyclic voltammetric studies on the porous gold nanowire arrays reveal a low-potential electrocatalytic response towards hydrogen peroxide. The properties of the glucose oxidase modified porous gold nanowire array electrode are elucidated and compared with those of nonporous enzyme electrodes. The glucose oxidase modified porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose.

Green synthesis of in situ electrodeposited rGO/MnO2 nanocomposite for high energy density supercapacitors

NASA Astrophysics Data System (ADS)

Rusi; Majid, S. R.

2015-11-01

This paper presents the preparation of in situ electrodeposited rGO/MnO2 nanocomposite as a binder-free electrode for supercapacitor application. The work describes and evaluates the performance of prepared electrode via green and facile electrodeposition technique of in situ rGO/MnO2-glucose carbon nanocomposites. The carbon content in the composite electrode increased after GO and D (+) glucose solution has been added in the deposition electrolyte. This study found that a suitable concentration of D (+) glucose in the deposition electrolyte can slow down the nucleation process of MnO2 particles and lead to uniform and ultrathin nanoflakes structure. The optimize electrode exhibited low transfer resistance and resulted on excellent electrochemical performance in three electrolyte systems viz. Na2SO4, KOH and KOH/K3Fe(CN)6 redox electrolytes. The optimum energy density and power density were 1851 Whkg-1 and 68 kWkg-1 at current density of 20 Ag-1 in mixed KOH/K3Fe(CN)6 electrolyte.

Morphology-controlled preparation of lead powders by electrodeposition from different PbO-containing choline chloride-urea deep eutectic solvent

NASA Astrophysics Data System (ADS)

Ru, Juanjian; Hua, Yixin; Xu, Cunying; Li, Jian; Li, Yan; Wang, Ding; Qi, Cancan; Jie, Yafei

2015-04-01

Lead powders with different morphologies, including corals, rods, wires, needles, ferns and dendritic forms, are prepared by electrodeposition onto a stainless steel substrate from different PbO-containing (10-60 mM) choline chloride-urea deep eutectic solvent at cell voltage 2.5 V and 343 K for 2 h. The electrochemical behavior of the PbO dissolved in this solvent is investigated with cyclic voltammetry. It is demonstrated that the increasing of PbO concentration makes the reduction potential EPb(II)/Pb shift positively and facilitates the electrodeposition of lead from PbO in the deep eutectic solvent. According to the analysis of the morphological and crystallographic characteristics of lead powders, the predominant origin of the growth layers is turned away from centre type towards the edge and corner types with the increase in PbO concentration. Due to the large number of growth centres at higher PbO concentration, fine and irregular grains are observed on the surface of formed particles which results in the development of primary and secondary branches in dendrites.

A Rapid One-Step Process for Fabrication of Biomimetic Superhydrophobic Surfaces by Pulse Electrodeposition

PubMed Central

Jiang, Shuzhen; Guo, Zhongning; Liu, Guixian; Gyimah, Glenn Kwabena; Li, Xiaoying; Dong, Hanshan

2017-01-01

Inspired by some typical plants such as lotus leaves, superhydrophobic surfaces are commonly prepared by a combination of low surface energy materials and hierarchical micro/nano structures. In this work, superhydrophobic surfaces on copper substrates were prepared by a rapid, facile one-step pulse electrodepositing process, with different duty ratios in an electrolyte containing lanthanum chloride (LaCl3·6H2O), myristic acid (CH3(CH2)12COOH), and ethanol. The equivalent electrolytic time was only 10 min. The surface morphology, chemical composition and superhydrophobic property of the pulse electrodeposited surfaces were fully investigated with SEM, EDX, XRD, contact angle meter and time-lapse photographs of water droplets bouncing method. The results show that the as-prepared surfaces have micro/nano dual scale structures mainly consisting of La[CH3(CH2)12COO]3 crystals. The maximum water contact angle (WCA) is about 160.9°, and the corresponding sliding angle is about 5°. This method is time-saving and can be easily extended to other conductive materials, having a great potential for future applications. PMID:29068427

Green synthesis of in situ electrodeposited rGO/MnO2 nanocomposite for high energy density supercapacitors

PubMed Central

Rusi; Majid, S. R.

2015-01-01

This paper presents the preparation of in situ electrodeposited rGO/MnO2 nanocomposite as a binder-free electrode for supercapacitor application. The work describes and evaluates the performance of prepared electrode via green and facile electrodeposition technique of in situ rGO/MnO2-glucose carbon nanocomposites. The carbon content in the composite electrode increased after GO and D (+) glucose solution has been added in the deposition electrolyte. This study found that a suitable concentration of D (+) glucose in the deposition electrolyte can slow down the nucleation process of MnO2 particles and lead to uniform and ultrathin nanoflakes structure. The optimize electrode exhibited low transfer resistance and resulted on excellent electrochemical performance in three electrolyte systems viz. Na2SO4, KOH and KOH/K3Fe(CN)6 redox electrolytes. The optimum energy density and power density were 1851 Whkg−1 and 68 kWkg−1 at current density of 20 Ag−1 in mixed KOH/K3Fe(CN)6 electrolyte. PMID:26537363

Electrodeposition of organic-inorganic tri-halide perovskites solar cell

NASA Astrophysics Data System (ADS)

Charles, U. A.; Ibrahim, M. A.; Teridi, M. A. M.

2018-02-01

Perovskite (CH3NH3PbI3) semiconductor materials are promising high-performance light energy absorber for solar cell application. However, the power conversion efficiency of perovskite solar cell is severely affected by the surface quality of the deposited thin film. Spin coating is a low-cost and widely used deposition technique for perovskite solar cell. Notably, film deposited by spin coating evolves surface hydroxide and defeats from uncontrolled precipitation and inter-diffusion reaction. Alternatively, vapor deposition (VD) method produces uniform thin film but requires precise control of complex thermodynamic parameters which makes the technique unsuitable for large scale production. Most deposition techniques for perovskite require tedious surface optimization to improve the surface quality of deposits. Optimization of perovskite surface is necessary to significantly improve device structure and electrical output. In this review, electrodeposition of perovskite solar cell is demonstrated as a scalable and reproducible technique to fabricate uniform and smooth thin film surface that circumvents the need for high vacuum environment. Electrodeposition is achieved at low temperatures, supports precise control and optimization of deposits for efficient charge transfer.

Emerging materials for solar cell applications: Electrodeposited CdTe

NASA Astrophysics Data System (ADS)

Rod, R. L.; Basol, B. M.; Stafsudd, O.

1980-09-01

Work was centered about improving electroplating processes and cell fabrication techniques, with emphasis being given to three differing n-CdTe/Au Schottky configurations. The highest values of efficiency related parameters achieved with a simulated solar irradiation of 100 mW/sq cm were 0.57V for open circuit voltage, 0.6 for fill factor, and 6 mA/sq cm for short circuit current. Four important parameters are known to control the quality of the Monosolar electrodeposition process and resultant solar cells. They are electrolyte temperature, Te concentration in the solution at a specific pH, deposition or quasi-rest potential, and flow pattern of the electrolyte (stirring). The first three considerations are believed to be fully understood and optimized. Work is underway to further understand the effects of stirring on the diffusion of ionic components and the effects on CdTe film performance. Work was accelerated during the quarter to increase the short circuit current. Parallel programs using laser irradiation of finished CdTe films, heat treatment, and changes in the electrodeposition process itself to recrystallize films were started.

Use of Electrodeposition for Sample Preparation and Rejection Rate Prediction for Assay of Electroformed Ultra High Purity Copper for 232Th and 238U Prior to Inductively Coupled Plasma Mass Spectrometry (ICP/MS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoppe, Eric W.; Aalseth, Craig E.; Brodzinski, Ronald L.

The search for neutrinoless double beta decay in 76Ge has driven the need for ultra-low background Ge detectors shielded by electroformed copper of ultra-high radiopurity (<0.1µBq/kg). Although electrodeposition processes are almost sophisticated enough to produce copper of this purity, to date there are no methods sensitive enough to assay it. Inductively-coupled plasma mass spectrometry (ICP/MS) can detect thorium and uranium at femtogram levels, but in the past, this assay has been hindered by high copper concentrations in the sample. Electrodeposition of copper samples removes copper from the solution while selectively concentrating thorium and uranium contaminants to be assayed by ICP/MS.more » Spiking 232Th and 238U into the plating bath simulates low purity copper and allows for the calculation of the electrochemical rejection rate of thorium and uranium in the electroplating system. This rejection value will help to model plating bath chemistry.« less

Lithographically Patterned Nanoscale Electrodeposition of Plasmonic, Bimetallic, Semiconductor, Magnetic, and Polymer Nanoring Arrays

PubMed Central

2015-01-01

Large area arrays of magnetic, semiconducting, and insulating nanorings were created by coupling colloidal lithography with nanoscale electrodeposition. This versatile nanoscale fabrication process allows for the independent tuning of the spacing, diameter, and width of the nanorings with typical values of 1.0 μm, 750 nm, and 100 nm, respectively, and was used to form nanorings from a host of materials: Ni, Co, bimetallic Ni/Au, CdSe, and polydopamine. These nanoring arrays have potential applications in memory storage, optical materials, and biosensing. A modified version of this nanoscale electrodeposition process was also used to create arrays of split gold nanorings. The size of the split nanoring opening was controlled by the angle of photoresist exposure during the fabrication process and could be varied from 50% down to 10% of the ring circumference. The large area (cm2 scale) gold split nanoring array surfaces exhibited strong polarization-dependent plasmonic absorption bands for wavelengths from 1 to 5 μm. Plasmonic nanoscale split ring arrays are potentially useful as tunable dichroic materials throughout the infrared and near-infrared spectral regions. PMID:25553204

Electrodeposition of catalytic and magnetic gold nanoparticles on dendrimer-carbon nanotube layer-by-layer films.

PubMed

Siqueira, José R; Gabriel, Rayla C; Zucolotto, Valtencir; Silva, Anielle C A; Dantas, Noelio O; Gasparotto, Luiz H S

2012-11-07

Magnetic and catalytic gold nanoparticles were electrodeposited through potential pulse on dendrimer-carbon nanotube layer-by-layer (LbL) films. A plasmon absorption band at about 550 nm revealed the presence of nanoscale gold in the film. The location of the Au nanoparticles in the film was clearly observed by selecting the magnetic force microscopy mode. To our knowledge, this is the first report on the electrochemical synthesis of magnetic Au nanoparticles. In addition to the magnetic properties, the Au nanoparticles also exhibited high catalytic activity towards ethanol and glycerol oxidation in alkaline medium.

Electrodeposition on nanofibrous polymer scaffolds: Rapid mineralization, tunable calcium phosphate composition and topography

PubMed Central

He, Chuanglong; Xiao, Guiyong; Jin, Xiaobing; Sun, Chenghui; Ma, Peter X.

2011-01-01

We developed a straightforward, fast, and versatile technique to fabricate mineralized nanofibrous polymer scaffolds for bone regeneration in this work. Nanofibrous poly(l-lactic acid) scaffolds were fabricated using both electrospinning and phase separation techniques. An electrodeposition process was designed to deposit calcium phosphate on the nanofibrous scaffolds. Such scaffolds contain a high quality mineral coating on the fiber surface with tunable surface topography and chemical composition by varying the processing parameters, which can mimic the composition and structure of natural bone extracellular matrix and provide a more biocompatible interface for bone regeneration. PMID:21673827

A phase-field simulation of uranium dendrite growth on the cathode in the electrorefining process

NASA Astrophysics Data System (ADS)

Shibuta, Yasushi; Unoura, Seiji; Sato, Takumi; Shibata, Hiroki; Kurata, Masaki; Suzuki, Toshio

2011-07-01

The uranium dendrite growth on the cathode during the pyroprocessing of uranium is investigated using a novel phase-field model, in which electrodeposition of uranium and zirconium from the molten-salt is taken into account. The threshold concentration of zirconium in the molten salt demarcating the dendritic and planar growth is then estimated as a function of the current density. Moreover, the growth process of both the dendritic and planar electrodeposits has been demonstrated by way of varying the mobility of the phase field, which consists of the effect of attachment kinetics and diffusion.

An Investigation of Electrodeposited Alloys and Pure Metals as Substitutes for Zinc and Cadmium for Protective Finishes for Steel Parts of Aircraft

DTIC Science & Technology

1947-11-30

t » 35 Electropolishing Bath . .... 4 ... • »»«.»•» 35 Operating Conditions . ... ....«.»«•» 4 » . 35 Operating Details...electrodeposited or cast (Figure 6 , Appendix II, Table 4 , Appendix III). =trr 11. ’i. "•i Zinc - Tin Alloys The static potentials of the zinc - tin alloys...UJ Ul 8 J o < X-4130 ALLOY S2 ’I -O -o 4 O- o- 6 POTENTI- OMETER Q UJ CO UJ < o A FIGURE 2 ~ SCHEMATIC REPRESENTATION OF

Long-range ordering effect in electrodeposition of zinc and zinc oxide.

PubMed

Liu, Tao; Wang, Sheng; Shi, Zi-Liang; Ma, Guo-Bin; Wang, Mu; Peng, Ru-Wen; Hao, Xi-Ping; Ming, Nai-Ben

2007-05-01

In this paper, we report the long-range ordering effect observed in the electro-crystallization of Zn and ZnO from an ultrathin aqueous electrolyte layer of ZnSO4 . The deposition branches are regularly angled, covered with random-looking, scalelike crystalline platelets of ZnO. Although the orientation of each crystalline platelet of ZnO appears random, transmission electron microscopy shows that they essentially possess the same crystallographic orientation as the single-crystalline zinc electrodeposit underneath. Based on the experimental observations, we suggest that this unique long-range ordering effect results from an epitaxial nucleation effect in electrocrystallization.

Kinetic Monte Carlo simulations of nucleation and growth in electrodeposition.

PubMed

Guo, Lian; Radisic, Aleksandar; Searson, Peter C

2005-12-22

Nucleation and growth during bulk electrodeposition is studied using kinetic Monte Carlo (KMC) simulations. Ion transport in solution is modeled using Brownian dynamics, and the kinetics of nucleation and growth are dependent on the probabilities of metal-on-substrate and metal-on-metal deposition. Using this approach, we make no assumptions about the nucleation rate, island density, or island distribution. The influence of the attachment probabilities and concentration on the time-dependent island density and current transients is reported. Various models have been assessed by recovering the nucleation rate and island density from the current-time transients.

Detection of sub-femtomolar DNA based on double potential electrodeposition of electrocatalytic platinum nanoparticles.

PubMed

Spain, Elaine; McArdle, Hazel; Keyes, Tia E; Forster, Robert J

2013-08-07

Suspensions of electrocatalytic platinum nanoparticles with radii as small as 78.9 ± 3.5 nm that are functionalised with DNA only in one region have been created using templated electrodeposition. The integrity of the bound DNA following nanoparticle desorption from the electrode is demonstrated by detecting attomolar concentrations of DNA without the need for molecular, e.g., PCR or NASBA, amplification. Double potential step approaches coupled with interface engineering via nucleation sites allows PtNPs to be created with controlled particle size and density in a facile and reproducible manner.

Electrodeposition of Gold to Conformally Fill High Aspect Ratio Nanometric Silicon Grating Trenches: A Comparison of Pulsed and Direct Current Protocols

PubMed Central

Znati, Sami A.; Chedid, Nicholas; Miao, Houxun; Chen, Lei; Bennett, Eric E.; Wen, Han

2016-01-01

Filling high-aspect-ratio trenches with gold is a frequent requirement in the fabrication of x-ray optics as well as micro-electronic components and other fabrication processes. Conformal electrodeposition of gold in sub-micron-width silicon trenches with an aspect ratio greater than 35 over a grating area of several square centimeters is challenging and has not been described in the literature previously. A comparison of pulsed plating and constant current plating led to a gold electroplating protocol that reliably filled trenches for such structures. PMID:27042384

Spalling of a Thin Si Layer by Electrodeposit-Assisted Stripping

NASA Astrophysics Data System (ADS)

Kwon, Youngim; Yang, Changyol; Yoon, Sang-Hwa; Um, Han-Don; Lee, Jung-Ho; Yoo, Bongyoung

2013-11-01

A major goal in solar cell research is to reduce the cost of the final module. Reducing the thickness of the crystalline silicon substrate to several tens of micrometers can reduce material costs. In this work, we describe the electrodeposition of a Ni-P alloy, which induces high stress in the silicon substrate at room temperature. The induced stress enables lift-off of the thin-film silicon substrate. After lift-off of the thin Si film, the mother substrate can be reused, reducing material costs. Moreover, the low-temperature process expected to be improved Si substrate quality.

High-temperature ductility of electro-deposited nickel

NASA Technical Reports Server (NTRS)

Dini, J. W.; Johnson, H. R.

1977-01-01

Work done during the past several months on high temperature ductility of electrodeposited nickel is summarized. Data are presented which show that earlier measurements made at NASA-Langley erred on the low side, that strain rate has a marked influence on high temperature ductility, and that codeposition of a small amount of manganese helps to improve high temperature ductility. Influences of a number of other factors on nickel properties were also investigated. They included plating solution temperature, current density, agitation, and elimination of the wetting agent from the plating solution. Repair of a large nozzle section by nickel plating is described.

Structure and properties of nanostructured ZnO arrays and ZnO/Ag nanocomposites fabricated by pulsed electrodeposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopach, V. R.; Klepikova, K. S.; Klochko, N. P., E-mail: klochko-np@mail.ru

We investigate the structure, surface morphology, and optical properties of nanostructured ZnO arrays fabricated by pulsed electrodeposition, Ag nanoparticles precipitated from colloidal solutions, and a ZnO/Ag nanocomposite based on them. The electronic and electrical parameters of the ZnO arrays and ZnO/Ag nanocomposites are analyzed by studying the I–V and C–V characteristics. Optimal modes for fabricating the ZnO/Ag heterostructures with the high stability and sensitivity to ultraviolet radiation as promising materials for use in photodetectors, gas sensors, and photocatalysts are determined.

Synthesis of tin oxide nanoparticle film by cathodic electrodeposition.

PubMed

Kim, Seok; Lee, Hochun; Park, Chang Min; Jung, Yongju

2012-02-01

Three-dimensional SnO2 nanoparticle films were deposited onto a copper substrate by cathodic electrodeposition in a nitric acid solution. A new formation mechanism for SnO2 films is proposed based on the oxidation of Sn2+ ion to Sn4+ ion by NO+ ion and the hydrolysis of Sn4+. The particle size of SnO2 was controlled by deposition potential. The SnO2 showed excellent charge capacity (729 mAh/g) at a 0.2 C rate and high rate capability (460 mAh/g) at a 5 C rate.

A Nose for Hydrogen Gas: Fast, Sensitive H2 Sensors Using Electrodeposited Nanomaterials.

PubMed

Penner, Reginald M

2017-08-15

Hydrogen gas (H 2 ) is odorless and flammable at concentrations above 4% (v/v) in air. Sensors capable of detecting it rapidly at lower concentrations are needed to "sniff" for leaked H 2 wherever it is used. Electrical H 2 sensors are attractive because of their simplicity and low cost: Such sensors consist of a metal (usually palladium, Pd) resistor. Exposure to H 2 causes a resistance increase, as Pd metal is converted into more resistive palladium hydride (PdH x ). Sensors based upon Pd alloy films, developed in the early 1990s, were both too slow and too insensitive to meet the requirements of H 2 safety sensing. In this Account, we describe the development of H 2 sensors that are based upon electrodeposited nanomaterials. This story begins with the rise to prominence of nanowire-based sensors in 2001 and our demonstration that year of the first nanowire-based H 2 sensor. The Pd nanowires used in these experiments were prepared by electrodepositing Pd at linear step-edge defects on a graphite electrode surface. In 2005, lithographically patterned nanowire electrodeposition (LPNE) provided the capability to pattern single Pd nanowires on dielectrics using electrodeposition. LPNE also provided control over the nanowire thickness (±1 nm) and width (±10-15%). Using single Pd nanowires, it was demonstrated in 2010 that smaller nanowires responded more rapidly to H 2 exposure. Heating the nanowire using Joule self-heating (2010) also dramatically accelerated sensor response and recovery, leading to the conclusion that thermally activated H 2 chemisorption and desorption of H 2 were rate-limiting steps in sensor response to and recovery from H 2 exposure. Platinum (Pt) nanowires, studied in 2012, showed an inverted resistance response to H 2 exposure, that is, the resistance of Pt nanowires decreased instead of increased upon H 2 exposure. H 2 dissociatively chemisorbs at a Pt surface to form Pt-H, but in contrast to Pd, it stays on the Pt surface. Pt nanowires showed a faster response to H 2 exposure than Pd nanowires operating at the same elevated temperature, but they had a surprising disadvantage: The resistance change observed for Pt nanowires was exactly the same for all H 2 concentrations. Electron surface scattering was implicated in the mechanism for these sensors. Work on Pt nanowires lead in 2015 to the preparation of Pd nanowires that were electrochemically modified with thin Pt layers (Pd@Pt nanowires). Relative to Pd nanowires, Pt@Pd nanowires showed accelerated response and recovery to H 2 while retaining the same high sensitivity to H 2 concentration seen for sensors based upon pure Pd nanowires. A new chapter in H 2 sensing (2017) involves the replacement of metal nanowires with carbon nanotube ropes decorated with electrodeposited Pd nanoparticles (NPs). Even higher sensitivity and faster sensor response and recovery are enabled by this sensor architecture. Sensor properties are strongly dependent on the size and size monodispersity of the Pd NPs, with smaller NPs yielding higher sensitivity and more rapid response/recovery. We hope the lessons learned from this science over 15 years will catalyze the development of sensors based upon electrodeposited nanomaterials for gases other than H 2 .

Numerical insights into the early stages of nanoscale electrodeposition: nanocluster surface diffusion and aggregative growth.

PubMed

Mamme, Mesfin Haile; Köhn, Christoph; Deconinck, Johan; Ustarroz, Jon

2018-04-19

Fundamental understanding of the early stages of electrodeposition at the nanoscale is key to address the challenges in a wide range of applications. Despite having been studied for decades, a comprehensive understanding of the whole process is still out of reach. In this work, we introduce a novel modelling approach that couples a finite element method (FEM) with a random walk algorithm, to study the early stages of nanocluster formation, aggregation and growth, during electrochemical deposition. This approach takes into account not only electrochemical kinetics and transport of active species, but also the surface diffusion and aggregation of adatoms and small nanoclusters. The simulation results reveal that the relative surface mobility of the nanoclusters compared to that of the adatoms plays a crucial role in the early growth stages. The number of clusters, their size and their size dispersion are influenced more significantly by nanocluster mobility than by the applied overpotential itself. Increasing the overpotential results in shorter induction times and leads to aggregation prevalence at shorter times. A higher mobility results in longer induction times, a delayed transition from nucleation to aggregation prevalence, and as a consequence, a larger surface coverage of smaller clusters with a smaller size dispersion. As a consequence, it is shown that a classical first-order nucleation kinetics equation cannot describe the evolution of the number of clusters with time, N(t), in potentiostatic electrodeposition. Instead, a more accurate representation of N(t) is provided. We show that an evaluation of N(t), which neglects the effect of nanocluster mobility and aggregation, can induce errors of several orders of magnitude in the determination of nucleation rate constants. These findings are extremely important towards evaluating the elementary electrodeposition processes, considering not only adatoms, but also nanoclusters as building blocks.

Californium Electrodepositions at Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boll, Rose Ann

2015-01-01

Electrodepositions of californium isotopes were successfully performed at Oak Ridge National Laboratory (ORNL) during the past year involving two different types of deposition solutions, ammonium acetate (NH 4C 2H 3O 2) and isobutanol ((CH 3) 2CHCH 2OH). A californium product that was decay enriched in 251Cf was recovered for use in super-heavy element (SHE) research. This neutron-rich isotope, 251Cf, provides target material for SHE research for the potential discovery of heavier isotopes of Z=118. The californium material was recovered from aged 252Cf neutron sources in storage at ORNL. These sources have decayed for over 30 years, thus providing material withmore » a very high 251Cf-to- 252Cf ratio. After the source capsules were opened, the californium was purified and then electrodeposited using the isobutanol method onto thin titanium foils for use in an accelerator at the Joint Institute for Nuclear Research in Dubna, Russia. Another deposition method, ammonium acetate, was used to produce a deposition containing 1.7 0.1 Ci of 252Cf onto a stainless steel substrate. This was the largest single electrodeposition of 252Cf ever prepared. The 252Cf material was initially purified using traditional ion exchange media, such as AG50-AHIB and AG50-HCl, and further purified using a TEVA-NH 4SCN system to remove any lanthanides, resulting in the recovery of 3.6 0.1 mg of purified 252Cf. The ammonium acetate deposition was run with a current of 1.0 amp, resulting in a 91.5% deposition yield. Purification and handling of the highly radioactive californium material created additional challenges in the production of these sources.« less

Controlled electrodeposition of Cu-Ga from a deep eutectic solvent for low cost fabrication of CuGaSe2 thin film solar cells.

PubMed

Steichen, Marc; Thomassey, Matthieu; Siebentritt, Susanne; Dale, Phillip J

2011-03-14

The electrochemical deposition of Ga and Cu-Ga alloys from the deep eutectic solvent choline chloride/urea (Reline) is investigated to prepare CuGaSe(2) (CGS) semiconductors for their use in thin film solar cells. Ga electrodeposition is difficult from aqueous solution due to its low standard potential and the interfering hydrogen evolution reaction (HER). Ionic liquid electrolytes offer a better thermal stability and larger potential window and thus eliminate the interference of solvent breakdown reactions during Ga deposition. We demonstrate that metallic Ga can be electrodeposited from Reline without HER interference with high plating efficiency on Mo and Cu electrodes. A new low cost synthetic route for the preparation of CuGaSe(2) absorber thin films is presented and involves the one-step electrodeposition of Cu-Ga precursors from Reline followed by thermal annealing. Rotating disk electrode (RDE) cyclic voltammetry (CV) is used in combination with viscosity measurements to determine the diffusion coefficients of gallium and copper ions in Reline. The composition of the codeposited Cu-Ga precursor layers can be controlled to form Cu/Ga thin films with precise stoichiometry, which is important for achieving good optoelectronic properties of the final CuGaSe(2) absorbers. The morphology, the chemical composition and the crystal structure of the deposited thin films are analysed by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). Annealing of the Cu-Ga films in a selenium atmosphere allowed the formation of high quality CuGaSe(2) absorber layers. Completed CGS solar cells achieved a 4.1% total area power conversion efficiency.

PdNi- and Pd-coated electrodes prepared by electrodeposition from ionic liquid for nonenzymatic electrochemical determination of ethanol and glucose in alkaline media.

PubMed

Huang, Hsin-Yi; Chen, Po-Yu

2010-12-15

Nonenzymatic electrochemical determination of ethanol and glucose was respectively achieved using PdNi- and Pd-coated electrodes prepared by electrodeposition from the novel metal-free ionic liquid (IL); N-butyl-N-methylpyrrolidinium dicyanamide (BMP-DCA). BMP-DCA provided an excellent environment and wide cathodic limit for electrodeposition of metals and alloys because many metal chlorides could dissolve in this IL where the reduction potentials of Pd(II) and Ni(II) indeed overlapped, leading to the convenience of potentiostatic codeposition. In aqueous solutions, the reduction potentials of Pd(II) and Ni(II) are considerably separated. The bimetallic PdNi coatings with atomic ratios of ∼ 80/20 showed the highest current for ethanol oxidation reaction (EOR). Ethanol was detected by either cyclic voltammetry (CV) or hydrodynamic amperometry (HA). Using CV, the dependence of EOR peak current on concentration was linear from 4.92 to 962 μM with a detection limit of 2.26 μM (σ=3), and a linearity was observed from 4.92 to 988 μM using HA (detection limit 0.83 μM (σ=3)). The Pd-coated electrodes prepared by electrodeposition from BMP-DCA showed electrocatalytic activity to glucose oxidation and CV, HA, and square-wave voltammetry (SWV) were employed to determine glucose. SWV showed the best sensitivity and linearity was observed from 2.86 μM to 107 μM, and from 2.99 mM to 10.88 mM with detection limits of 0.78 μM and 25.9 μM (σ=3), respectively. For glucose detection, the interference produced from ascorbic acid, uric acid, and acetaminophen was significantly suppressed, compared with a regular Pt disk electrode. Copyright © 2010 Elsevier B.V. All rights reserved.

Morphology, structure, and magnetism of FeCo thin films electrodeposited on hydrogen-terminated Si(111) surfaces.

PubMed

Zarpellon, J; Jurca, H F; Mattoso, N; Klein, J J; Schreiner, W H; Ardisson, J D; Macedo, W A A; Mosca, D H

2007-12-15

In this work we describe the fabrication of FeCo alloy (less than 10 at% Co) thin films from aqueous ammonium sulfate solutions onto n-type Si(111) substrates using potentiostatic electrodeposition at room temperature. The incorporation of Co into the deposits tends to inhibit Fe silicide formation and to protect deposits against oxidation under air exposure. As the incorporation of Co was progressively increased, the sizes of nuclei consisting of FeCo alloy increased, leading to films with a highly oriented body-centered cubic structure with crystalline texture, where (110) planes remain preferentially oriented parallel to the film surface.

Seed defective reduction in automotive Electro-Deposition Coating Process of truck cabin

NASA Astrophysics Data System (ADS)

Sonthilug, Aekkalag; Chutima, Parames

2018-02-01

The case study company is one of players in Thailand’s Automotive Industry who manufacturing truck and bus for both domestic and international market. This research focuses on a product quality problem about seed defects occurred in the Electro-Deposition Coating Process of truck cabin. The 5-phase of Six Sigma methodology including D-Define, M-Measure, A-Analyze, I-Improve, and C-Control is applied to this research to identify root causes of problem for setting new parameters of each significant factor. After the improvement, seed defects in this process is reduced from 9,178 defects per unit to 876 defects per unit (90% improvement)

Electrodeposited highly-ordered manganese oxide nanowire arrays for supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Haifeng; Lu, Bingqiang; Wei, Shuiqiang; Bao, Mi; Wen, Yanxuan; Wang, Fan

2012-07-01

Large arrays of well-aligned Mn oxide nanowires were prepared by electrodeposition using anodic aluminum oxide templates. The sizes of nanowires were tuned by varying the electrotype solution involved and the MnO2 nanowires with 10 μm in length were obtained in a neutral KMnO4 bath for 1 h. MnO2 nanowire arrays grown on conductor substance save the tedious electrode-making process, and electrochemical characterization demonstrates that the MnO2 nanowire arrays electrode has good capacitive behavior. Due to the limited mass transportation in narrow spacing, the spacing effects between the neighbor nanowires have show great influence to the electrochemical performance.

Anisotropic Effects on the Thermoelectric Properties of Highly Oriented Electrodeposited Bi2Te3 Films

PubMed Central

Manzano, Cristina V.; Abad, Begoña; Muñoz Rojo, Miguel; Koh, Yee Rui; Hodson, Stephen L.; Lopez Martinez, Antonio M.; Xu, Xianfan; Shakouri, Ali; Sands, Timothy D.; Borca-Tasciuc, Theodorian; Martin-Gonzalez, Marisol

2016-01-01

Highly oriented [1 1 0] Bi2Te3 films were obtained by pulsed electrodeposition. The structure, composition, and morphology of these films were characterized. The thermoelectric figure of merit (zT), both parallel and perpendicular to the substrate surface, were determined by measuring the Seebeck coefficient, electrical conductivity, and thermal conductivity in each direction. At 300 K, the in-plane and out-of-plane figure of merits of these Bi2Te3 films were (5.6 ± 1.2)·10−2 and (10.4 ± 2.6)·10−2, respectively. PMID:26776726

Methods and energy storage devices utilizing electrolytes having surface-smoothing additives

DOEpatents

Xu, Wu; Zhang, Jiguang; Graff, Gordon L; Chen, Xilin; Ding, Fei

2015-11-12

Electrodeposition and energy storage devices utilizing an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and anode surface. For electrodeposition of a first metal (M1) on a substrate or anode from one or more cations of M1 in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second metal (M2), wherein cations of M2 have an effective electrochemical reduction potential in the solution lower than that of the cations of M1.

Annealing temperature dependence of magnetoimpedance effect in electrodeposited [Ni80fe20/Cu]3 multilayers

NASA Astrophysics Data System (ADS)

Maulana, Frendi; Eko Prastyo, W.; Nuryani; Purnama, B.

2017-11-01

We have conducted an experiment of magnetoimpedance with a variation of annealing temperature of [Ni80Fe20/Cu)]3 multilayers. The multilayer is electrodeposited on Cu-PCB substrate. Magnetoimpedance effect is impedance measure on account of external magnetic field. The found MI (magnetoimpedance) ratio is 7,63 % (without annealing) and 4,75 % (using annealing) of 100 ºC. We find that MI ratio depends on to annealing temperature and current frequence. MI ratio decreases due to rising temperature and identified increase due to the frequency. The highest MI ratio is on a sample without annealing temperature and measurement at 100 kHz frequence.

Insights into semiconductor nanowire conductivity using electrodeposition

NASA Astrophysics Data System (ADS)

Liu, C.; Salehzadeh, O.; Poole, P. J.; Watkins, S. P.; Kavanagh, K. L.

2012-10-01

Copper (Cu) and iron (Fe) electrical contacts to gallium arsenide (GaAs) and indium arsenide (InAs) nanowires (NWs) have been fabricated via electrodeposition. For undoped or low carbon-doped (1017/cm-3), p-type GaAs NWs, Cu or Fe nucleate and grow only on the gold catalyst at the NW tip, avoiding the sidewalls. Metal growth is limited by the Au contact resistance due to thick sidewall depletion layers. For InAs NWs and heavier-doped, core-shell (undoped core-C-doped shell) GaAs NWs, metal nucleation and growth occurs on the sidewalls as well as on the gold catalyst limited now by the ion electrolyte diffusivity.

Enhanced magnetic performance of metal-organic nanowire arrays by FeCo/polypyrrole co-electrodeposition

NASA Astrophysics Data System (ADS)

Luo, X. J.; Xia, W. B.; Gao, J. L.; Zhang, S. Y.; Li, Y. L.; Tang, S. L.; Du, Y. W.

2013-05-01

FeCo/polypyrrole (PPy) composite nanowire array, which shows enhanced magnetic remanence and coercivity along the nanowires, was fabricated by AC electrodeposition using anodic aluminum oxide templates. High resolution transmission electron microscopy shows that PPy grows on the surface of FeCo nanowires forming a coaxial nanowire structure, with a coating layer of about 4 nm. It suggests that the decreased dipolar interaction due to the reduced nanowire diameters is responsible for the enhancement of magnetic performance. The possible mechanism of this coating may be that PPy is inclined to nucleate along the pore wall of the templates.

ELECTRO-DEPOSITION OF NICKEL ALLOYS FROM THE PYROPHOSPHATE BATH: NICKEL- ZINC AND NICKEL-MOLYBDENUM ALLOYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panikkar, S.K.; Char, T.L.R.

1958-02-01

Results of studies on the electrodeposition of nickel-zinc and nickel-- molybdenum alloys in a pyrophosphate bath using platinium electrodes are presented. The fects of varying current density and metal contents of the electrolyte on alloy deposit composition, cathode efficiency, and cathode potential are presented in tabular form. (J.R.D.) l2432 A study was made of the effect of homogenization on the mechanical properties of solution-treated and aged aluminum and the quantitative effects of several variables on hardness. The effect of alloying elements on the increase in hardness of aluminum is shown. (J.E.D.)

Systems and Methods for the Electrodeposition of a Nickel-cobalt Alloy

NASA Technical Reports Server (NTRS)

Ogozalek, Nance Jo (Inventor); Wistrand, Richard E. (Inventor)

2013-01-01

Systems and methods for electrodepositing a nickel-cobalt alloy using a rotating cylinder electrode assembly with a plating surface and an electrical contact. The assembly is placed within a plating bath and rotated while running a plating cycle. Nickel-cobalt alloy deposition is selectively controlled by controlling current density distribution and/or cobalt content in the plating bath while running the plating cycle to deposit an alloy of a desired yield strength onto the plating surface in a single plating cycle. In various embodiments, the rotating cylinder may be used as an insitu monitoring method to assist in obtaining the properties desired.

The microstructure and magnetic properties of Cu/CuO/Ni core/multi-shell nanowire arrays

NASA Astrophysics Data System (ADS)

Yang, Feng; Shi, Jie; Zhang, Xiaofeng; Hao, Shijie; Liu, Yinong; Feng, Chun; Cui, Lishan

2018-04-01

Multifunctional metal/oxide/metal core/multi-shell nanowire arrays were prepared mostly by physical or chemical vapor deposition. In our study, the Cu/CuO/Ni core/multi-shell nanowire arrays were prepared by AAO template-electrodeposition and oxidation processes. The Cu/Ni core/shell nanowire arrays were prepared by AAO template-electrodeposition method. The microstructure and chemical compositions of the core/multi-shell nanowires and core/shell nanowires have been characterized using transmission electron microscopy with HADDF-STEM and X-ray diffraction. Magnetization measurements revealed that the Cu/CuO/Ni and Cu/Ni nanowire arrays have high coercivity and remanence ratio.

PROCESS OF COATING METALS WITH BISMUTH OR BISMUTH-BASE ALLOYS

DOEpatents

Beach, J.G.

1958-01-28

A method is described for producing coatings of bismuth or bismuth alloys on a metal base. This is accomplished by electrodepositing the bismuth from an aqueous solution of BiCl/sub 3/, and by making the metal base alternately the cathode and the anode, the cathode periods being twice as long as the anode periods. In one embodiment a nickel coating is first electrodeposited in a known way, and this nickel plated piece is tae base upon which tae bismuth is deposited by the process of this patent. The coated piece is then heat treated to produce a homogeneous Ni--Bi alloy by diffusion.

Target and method for the production of fission product molybdenum-99

DOEpatents

Vandegrift, George F.; Vissers, Donald R.; Marshall, Simon L.; Varma, Ravi

1989-01-01

A target for the reduction of fission product Mo-99 is prepared from uranium of low U-235 enrichment by coating a structural support member with a preparatory coating of a substantially oxide-free substrate metal. Uranium metal is electrodeposited from a molten halide electrolytic bath onto a substrate metal. The electrodeposition is performed at a predetermined direct current rate or by using pulsed plating techniques which permit relaxation of accumulated uranium ion concentrations within the melt. Layers of as much as to 600 mg/cm.sup.2 of uranium can be prepared to provide a sufficient density to produce acceptable concentrations of fission product Mo-99.

Electrodeposition of polymer electrolyte in nanostructured electrodes for enhanced electrochemical performance of thin-film Li-ion microbatteries

NASA Astrophysics Data System (ADS)

Salian, Girish D.; Lebouin, Chrystelle; Demoulin, A.; Lepihin, M. S.; Maria, S.; Galeyeva, A. K.; Kurbatov, A. P.; Djenizian, Thierry

2017-02-01

We report that electrodeposition of polymer electrolyte in nanostructured electrodes has a strong influence on the electrochemical properties of thin-film Li-ion microbatteries. Electropolymerization of PMMA-PEG (polymethyl methacrylate-polyethylene glycol) was carried out on both the anode (self-supported titania nanotubes) and the cathode (porous LiNi0.5Mn1.5O4) by cyclic voltammetry and the resulting electrode-electrolyte interface was examined by scanning electron microscopy. The electrochemical characterizations performed by galvanostatic experiments reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte.

Selective high-resolution electrodeposition on semiconductor defect patterns.

PubMed

Schmuki, P; Erickson, L E

2000-10-02

We report a new principle and technique that allows one to electrodeposit material patterns of arbitrary shape down to the submicrometer scale. We demonstrate that an electrochemical metal deposition reaction can be initiated selectively at surface defects created in a p-type Si(100) substrate by Si (++) focused ion beam bombardment. The key principle is that, for cathodic electrochemical polarization of p-type material in the dark, breakdown of the blocking Schottky barrier at the semiconductor/electrolyte interface occurs at significantly lower voltages at implanted locations than for an unimplanted surface. This difference in the threshold voltages is exploited to achieve selective electrochemical deposition.

Atomically resolved calcium phosphate coating on a gold substrate.

PubMed

Metoki, Noah; Baik, Sung-Il; Isheim, Dieter; Mandler, Daniel; Seidman, David N; Eliaz, Noam

2018-05-10

Some articles have revealed that the electrodeposition of calcium phosphate (CaP) coatings entails a precursor phase, similarly to biomineralization in vivo. The chemical composition of the initial layer and its thickness are, however, still arguable, to the best of our knowledge. Moreover, while CaP and electrodeposition of metal coatings have been studied utilizing atom-probe tomography (APT), the electrodeposition of CaP ceramics has not been heretofore studied. Herein, we present an investigation of the CaP deposition on a gold substrate. Using APT and transmission electron microscopy (TEM) it is found that a mixture of phases, which could serve as transient precursor phases to hydroxyapatite (HAp), can be detected. The thickness of these phases is tens of nanometers, and they consist of amorphous CaP (ACP), dibasic calcium phosphate dihydrate (DCPD), and octacalcium phosphate (OCP). This demonstrates the value of using atomic-resolved characterization techniques for identifying the precursor phases. It also indicates that the kinetics of their transformation into the more stable HAp is not too fast to enable their observation. The coating gradually displays higher Ca/P atomic ratios, a porous nature, and concomitantly a change in its density.

Synthesis and Performance Evaluation of Pulse Electrodeposited Ni-AlN Nanocomposite Coatings

PubMed Central

Ali, Kamran; Narayana, Sivaprasad; Okonkwo, Paul C.; Yusuf, Moinuddin M.; Alashraf, Abdullah

2018-01-01

This research work presents the microscopic analysis of pulse electrodeposited Ni-AlN nanocomposite coatings using SEM and AFM techniques and their performance evaluation (mechanical and electrochemical) by employing nanoindentation and electrochemical methods. The Ni-AlN nanocomposite coatings were developed by pulse electrodeposition. The nickel matrix was reinforced with various amounts of AlN nanoparticles (3, 6, and 9 g/L) to develop Ni-AlN nanocomposite coatings. The effect of reinforcement concentration on structure, surface morphology, and mechanical and anticorrosion properties was studied. SEM and AFM analyses indicate that Ni-AlN nanocomposite coatings have dense, homogenous, and well-defined pyramid structure containing uniformly distributed AlN particles. A decent improvement in the corrosion protection performance is also observed by the addition of AlN particles to the nickel matrix. Corrosion current was reduced from 2.15 to 1.29 μA cm−2 by increasing the AlN particles concentration from 3 to 9 g/L. It has been observed that the properties of Ni-AlN nanocomposite coating are sensitive to the concentration of AlN nanoparticles used as reinforcement. PMID:29619143

The Interplay of Al and Mg Speciation in Advanced Mg Battery Electrolyte Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

See, Kimberly A.; Chapman, Karena W.; Zhu, Lingyang

2016-01-13

Mg batteries are an attractive alternative to Li-based energy storage due to the possibility of higher volumetric capacities with the added advantage of using sustainable materials. A promising emerging electrolyte for Mg batteries is the magnesium aluminum chloride complex (MACC) which shows high Mg electrodeposition and stripping efficiencies and relatively high anodic stabilities. As prepared, MACC is inactive with respect to Mg deposition; however, efficient Mg electrodeposition can be achieved following an electrolytic conditioning process. Through the use of Raman spectroscopy, surface enhanced Raman spectroscopy, 27Al and 35Cl nuclear magnetic resonance spectroscopy, and pair distribution function analysis, we explore themore » active vs inactive complexes in the MACC electrolyte and demonstrate the codependence of Al and Mg speciation. These techniques report on significant changes occurring in the bulk speciation of the conditioned electrolyte relative to the as-prepared solution. Analysis shows that the active Mg complex in conditioned MACC is very likely the [Mg2(μ–Cl)3·6THF]+ complex that is observed in the solid state structure. Additionally, conditioning creates free Cl– in the electrolyte solution, and we suggest the free Cl– adsorbs at the electrode surface to enhance Mg electrodeposition.« less

Salvinia-Effect-Inspired "Sticky" Superhydrophobic Surfaces by Meniscus-Confined Electrodeposition.

PubMed

Zheng, Deyin; Jiang, Youhua; Yu, Wentao; Jiang, Xiufen; Zhao, Xin; Choi, Chang-Hwan; Sun, Guangyi

2017-11-28

Inspired by the Salvinia effect, we report the fabrication and characterization of a novel "sticky" superhydrophobic surface sustaining a Cassie-Baxter wetting state for water droplets with high contact angles but strong solid-liquid retention. Unlike superhydrophobic surfaces mimicking the lotus or petal effect, whose hydrophobicity and droplet retention are typically regulated by hierarchical micro- and nanostructures made of a homogeneous material with the same surface energy, our superhydrophobic surface merely requires singular microstructures covered with a hydrophobic coating but creatively coupled with hydrophilic tips with different surface energy. Hydrophilic tips are selectively formed by meniscus-confined electrodeposition of a metal (e.g., nickel) layer on top of hydrophobic microstructures. During the electrodeposition process, the superhydrophobic surface retains its plastron so that the electrolyte cannot penetrate into the cavity of hydrophobic microstructures, consequently making the electrochemical reaction between solid and electrolyte occur only on the tip. In contrast to typical superhydrophobic surfaces where droplets are highly mobile, the "sticky" superhydrophobic surface allows a water droplet to have strong local pinning and solid-liquid retention on the hydrophilic tips, which is of great significance in many droplet behaviors such as evaporation.

Effect of platinum nanoparticle deposition parameters on hydrogen peroxide transduction for applications in wearable electrochemical glucose biosensors

NASA Astrophysics Data System (ADS)

Cargill, Allison A.; Neil, Kathrine M.; Hondred, John A.; McLamore, Eric S.; Claussen, Jonathan C.

2016-05-01

Enhanced interest in wearable biosensor technology over the past decade is directly related to the increasing prevalence of diabetes and the associated requirement of daily blood glucose monitoring. In this work we investigate the platinum-carbon transduction element used in traditional first-generation glucose biosensors which rely on the concentration of hydrogen peroxide produced by the glucose-glucose oxidase binding scheme. We electrodeposit platinum nanoparticles on a commercially-available screen printed carbon electrode by stepping an applied current between 0 and 7.12 mA/cm2 for a varying number of cycles. Next, we examine the trends in deposition and the effect that the number of deposition cycles has on the sensitivity of electrochemical glucose sensing. Results from this work indicate that applying platinum nanoparticles to screen printed carbon via electrodeposition from a metal salt solution improves overall biosensor sensitivity. This work also pinpoints the amount of platinum (i.e., number of deposition cycles) that maximizes biosensor sensitivity in an effort to minimize the use of the precious metals, viz., platinum, in electrode fabrication. In summary, this work quantifies the relationship between platinum electrodeposition and sensor performance, which is crucial in designing and producing cost-effective sensors.

High performance nano-Ni/Graphite electrode for electro-oxidation in direct alkaline ethanol fuel cells

NASA Astrophysics Data System (ADS)

Soliman, Ahmed B.; Abdel-Samad, Hesham S.; Abdel Rehim, Sayed S.; Ahmed, Mohamed A.; Hassan, Hamdy H.

2016-09-01

Ni/Graphite electrocatalysts (Ni/G) are successfully prepared through electrodeposition of Ni from acidic (pH = 0.8) and feebly acidic (pH = 5.5) aqueous Ni (II) baths. The efficiencies of such electrodes are investigated as anodes for direct alkaline ethanol fuel cells through their ethanol electrooxidation cyclic voltammetric (CV) response in alkaline medium. A direct proportionality between the amount of the electrodeposited Ni and its CV response is found. The amounts of the deposited Ni from the two baths are recorded using the Electrochemical Quartz Crystal Microbalance (eQCM). The Ni/G electrodes prepared from the feebly acidic bath show a higher electrocatalytic response than those prepared from the acidic bath. Surface morphology of the Ni particles electrodeposited from feebly acidic bath appears in a nano-scale dimension. Various electrochemical experiments are conducted to confirm that the Ni/G ethanol electrooxidation CV response greatly depends on the pH rather than nickel ion concentration of the deposition bath. The eQCM technique is used to detect the crystalline phases of nickel as α-Ni(OH)2/γ-NiOOH and β-Ni(OH)2/β-NiOOH and their in-situ inter-transformations during the potentiodynamic polarization.

Electrochemical preparation of vertically aligned, hollow CdSe nanotubes and their p-n junction hybrids with electrodeposited Cu2O.

PubMed

Debgupta, Joyashish; Devarapalli, Ramireddy; Rahman, Shakeelur; Shelke, Manjusha V; Pillai, Vijayamohanan K

2014-08-07

Vertically aligned, hollow nanotubes of CdSe are grown on fluorine doped tin oxide (FTO) coated glass substrates by ZnO nanowire template-assisted electrodeposition technique, followed by selective removal of the ZnO core using NH4OH. A detailed mechanism of nucleation and anisotropic growth kinetics of nanotubes have been studied by a combination of characterization tools such as chronoamperometry, SEM and TEM. Interestingly, "as grown" CdSe nanotubes (CdSe NTs) on FTO coated glass plates behave as n-type semiconductors exhibiting an excellent photo-response (with a generated photocurrent density value of ∼ 470 μA cm(-2)) while in contact with p-type Cu2O (p-type semiconductor, grown separately on FTO plates) because of the formation of a n-p heterojunction (type II). The observed photoresponse is 3 times higher than that of a similar device prepared with electrodeposited CdSe films (not nanotubes) and Cu2O on FTO. This has been attributed to the hollow 1-D nature of CdSe NTs, which provides enhanced inner and outer surface areas for better absorption of light and also assists faster transport of photogenerated charge carriers.

Preparation and Characterization of Cu-Ga-Se Thin Films Synthesized by Electrodeposition: Effect of Complexing Agent and Supporting Electrolyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, John A; Deutsch, Todd G; Fernandez, A. M.

CuGaSe2 (CGS) is a semiconductor that has potential use as a photo electrode for solar water splitting. Its wide band gap and high absorption coefficient make it an ideal candidate for the top absorber in tandem structures. CGS can be synthesized by several techniques, being electrodeposition the most advantageous from a technical standpoint. Many reports show that electrodeposition of these films for producing the desired precursor atomic composition can be aided by using a complexing agent. However, the use of supporting electrolyte and the type of the electrolyte to improve the atomic composition in the films has never been reported.more » Using cyclic voltammetry, with complexing agents and deposition potentials between -0.5 and -0.9 V vs. Ag/AgCl reference electrode atomic ratios close to the ideal values ([Cu]/[Ga] = 1 and [Se]/[Cu + Ga] = 1), based on atomic composition and morphology analysis are reported in this work. From the X-ray diffraction (XRD), the as-deposited films exhibit poor crystallinity; however, the XRD patterns evidence the formation CuGaSe2 after annealing of the samples.« less

Characterization of Nanocrystalline Nickel-Cobalt Alloys Synthesized by Direct and Pulse Electrodeposition

NASA Astrophysics Data System (ADS)

Salehi, M.; Saidi, A.; Ahmadian, M.; Raeissi, K.

2014-01-01

Nanocrystalline Ni-Co alloys are electrodeposited by direct (DC) and pulse current (PC) in an electrolyte solution which consisted of nickel sulfate, cobalt sulfate and boric acid. Electrodeposition parameters including current density, electrolyte pH and pulse times in a single electrolyte bath were changed. XRD pattern showed that the structure of the alloys depends on Co content and the synthesis parameter and changed from single phase structure (fcc) to dual phase structure (fcc + hcp). The Co content in the deposited alloys declined from 70 at.% to 50 at.% by increasing in direct current from 70 mA/cm2 to 115 mA/cm2 and also decreased from 75 at.% to 33 at.% with decrease in pH values from 4 to 2. By applying PC the Co content changed from 76 at.% to 41 at.%. Magnetic properties measurements showed the saturation magnetization (Ms) increased with increasing the Co content. There was no significant effect on coercivity values (Hc) with change in Co content and about 40 Oe was obtained for all samples. The grain size of deposited alloys obtained between 24-58 nm and 15-21 nm by applying DC and PC, respectively.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang

Graphical abstract: CuO nanotube array electrodes prepared by electrodeposition method exhibit an excellent lithium ion storage ability as anode of Li-ion battery. - Highlights: • CuO nanotube arrays are synthesized by an electrodeposition method. • CuO nanotube shows a high-rate performance. • CuO nanotube shows an excellent cycling performance. - Abstract: We report a facile strategy to prepared CuO nanotube arrays directly grown on Cu plate through the electrodeposition method. The as-prepared CuO nanotubes show a quasi-cylinder nanostructure with internal diameters of ca. ∼100 nm, external diameters of ca. ∼120 nm, and average length of ∼3 μm. As an anodemore » for lithium ion batteries, the electrochemical properties of the CuO nanotube arrays are investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests. Due to the unique nanotube nanostructure, the as-prepared CuO electrodes exhibit good rate performance (550 mAh g{sup −1} at 0.1 C and 464 mAh g{sup −1} at 1 C) and cycling performance (581 mAh g{sup −1} at 0.1 C and 538 mAh g{sup −1} at 0.5 C)« less

Ohmic model for electrodeposition of metallic ions

NASA Astrophysics Data System (ADS)

Gliozzi, A. S.; Alexe-Ionescu, A. L.; Barbero, G.

2015-10-01

An ohmic model to describe the electrodeposition of metallic ions on the electrodes is proposed. We assume that the ionic distribution is homogeneous across the electrolytic cell, and that the ionic current is due to the bulk electric field. The nucleation in the electrodeposition is supposed to be well described by a kinetic equation at the electrode, taking into account the neutralization of metallic ions on the electrodes. Two cases are considered. In the first case the characteristic time describing the neutralization of the ions is supposed to be negligible with respect to the flight time of the ions across the cell. In this framework the bulk electric field coincides with the external electric field, and our analysis gives analytical formulae for the surface density of deposited ions and for the electric current in the external circuit. The case where the two characteristic times are comparable, and the effective electric field in the bulk depends on the surface deposition, is considered too. In this case the ordinary differential equations describing the ionic distribution and the adsorption phenomenon have to be solved numerically. The agreement between the presented model and the experimental results published by several groups is reasonably good.

Electrochemical preparation of nanostructured lanthanum using lanthanum chloride as a precursor in 1-butyl-3-methylimidazolium dicyanamide ionic liquid.

PubMed

Zhang, Q B; Yang, C; Hua, Y X; Li, Y; Dong, P

2015-02-14

Nanostructured lanthanum was electrochemically prepared on a platinum (Pt) substrate in the room temperature ionic liquid 1-butyl-3-methylimidazolium dicyanamide (BMI-DCA) containing anhydrous LaCl3 at 333 K. The electrochemical reduction behavior of La(iii) was investigated using cyclic voltammetry and chronoamperometry techniques. Cyclic voltammogram revealed that the reduction of La(iii) in BMI-DCA involved an irreversible process controlled by diffusion. Chronoamperometric transient analysis confirmed the diffusion controlled electrodeposition process with the diffusion coefficient of La(iii) species in the range of 10(-10) cm(2) s(-1). The strong complexing capability of DCA(-) anions facilitated the displacement of chloride ligands and induced the solubility of LaCl3. The subsequent coordination of La(iii) and DCA(-) anions forming [La(DCA)4](-) complex anions was monitored by designing amperometric titration experiments. Potentiostatically deposited La-deposits with different nanostructures were characterized by SEM, XRD and XPS analyses. The electrodeposition potential was found to play an important role in controlling the nucleation and growth kinetics of the nanocrystal during the electrodeposition process. Depending on the deposition potential, metallic lanthanum with either nanoparticles or nanoporous structures was obtained.

Electrodeposition of MWNT/Bi2Te3 Composite Thermoelectric Films

NASA Astrophysics Data System (ADS)

Xu, Han; Wang, Wei

2013-07-01

The effect of multiwalled carbon nanotubes (MWNTs) on the electrochemical behavior of the Bi-Te binary system in nitric acid baths was investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy. Based on the results, MWNT/Bi2Te3 composite thermoelectric films were prepared by potentiostatic electrodeposition at room temperature. The morphology, composition, and structure of the MWNT/Bi2Te3 composite films were analyzed by environmental scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction. The results show that addition of MWNTs to the electrolyte did not change the electrochemical reduction mechanisms of Bi3+, HTeO{2/+} or their mixture, but the reduction processes of Bi3+, HTeO{2/+}, and their mixture become easier. MWNT/Bi2Te3 composite thermoelectric films can be obtained by potentiostatic electrodeposition at a wide range of potentials with subsequent annealing. The MWNTs in the films act as nucleation sites for Bi2Te3 compound and thereby elevate the film deposition rate. The content of Bi element and MWNTs in the films increased as the potential was shifted negatively. In addition, the MWNTs can enhance the crystallization of Bi2Te3 film.

Designing solid-liquid interphases for sodium batteries.

PubMed

Choudhury, Snehashis; Wei, Shuya; Ozhabes, Yalcin; Gunceler, Deniz; Zachman, Michael J; Tu, Zhengyuan; Shin, Jung Hwan; Nath, Pooja; Agrawal, Akanksha; Kourkoutis, Lena F; Arias, Tomas A; Archer, Lynden A

2017-10-12

Secondary batteries based on earth-abundant sodium metal anodes are desirable for both stationary and portable electrical energy storage. Room-temperature sodium metal batteries are impractical today because morphological instability during recharge drives rough, dendritic electrodeposition. Chemical instability of liquid electrolytes also leads to premature cell failure as a result of parasitic reactions with the anode. Here we use joint density-functional theoretical analysis to show that the surface diffusion barrier for sodium ion transport is a sensitive function of the chemistry of solid-electrolyte interphase. In particular, we find that a sodium bromide interphase presents an exceptionally low energy barrier to ion transport, comparable to that of metallic magnesium. We evaluate this prediction by means of electrochemical measurements and direct visualization studies. These experiments reveal an approximately three-fold reduction in activation energy for ion transport at a sodium bromide interphase. Direct visualization of sodium electrodeposition confirms large improvements in stability of sodium deposition at sodium bromide-rich interphases.The chemistry at the interface between electrolyte and electrode plays a critical role in determining battery performance. Here, the authors show that a NaBr enriched solid-electrolyte interphase can lower the surface diffusion barrier for sodium ions, enabling stable electrodeposition.

Electrodeposition of hierarchical ZnO/Cu{sub 2}O nanorod films for highly efficient visible-light-driven photocatalytic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, S. T.; Fan, G. H.; Liang, M. L.

2014-02-14

The development of high-performance visible-light-responsive photocatalytic materials has attracted widespread interest due to their potential applications in the environmental and energy industries. In this work, hierarchical ZnO nanorods films were successfully prepared on the stainless steel mesh substrates via a simple two-step seed-assisted electrodeposition route. Cu{sub 2}O nanoparticles were then electrodeposited on the surface of ZnO nanorods to form the core-shell heterostructure. The synthesized ZnO/Cu{sub 2}O nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, and UV-visible spectrophotometer. Due to the branched hierarchical morphologies and core-shell structure, ZnO/Cu{sub 2}O nanomaterials show a prominent visible-light-driven photocatalytic performance under the low-intensitymore » light irradiation (40 mW/cm{sup 2}). The influence of some experimental parameters, such as Cu{sub 2}O loading amount, ZnO morphologies, the substrate type, and the PH of the Cu{sub 2}O precursor solution on ZnO/Cu{sub 2}O photocatalytic performance was evaluated.« less

Non-gassing nickel-cadmium battery electrodes and cells

NASA Technical Reports Server (NTRS)

Luksha, E.; Gordy, D. J.

1972-01-01

The concept of a negative limited nongassing nickel-cadmium battery was demonstrated by constructing and testing practical size experimental cells of approximately 25 Ah capacity. These batteries operated in a gas-free manner and had measured energy densities of 10-11 Wh/lb. Thirty cells were constructed for extensive testing. Some small cells were tested for over 200 cycles at 100% depth. For example, a small cell with an electrodeposited cadmium active mass on a silver screen still had 55% of its theoretical capacity (initial efficiency was 85%). There was no evidence of deterioration of gassing properties with cycling of the nickel electrodes. The charge temperature was observed to be the most critical variable governing nickel electrode gassing. This variable was shown to be age dependent. Four types of cadmium electrodes were tested: an electrodeposited cadmium active mass on a cadmium or silver substrate, a porous sintered silver substrate based electrode, and a Teflon bonded pressed cadmium electrode. The electrodeposited cadmium mass on a silver screen was found to be the best all-around electrode from a performance point of view and from the point of view of manufacturing them in a size required for a 25 Ah size battery.

Californium purification and electrodeposition

DOE PAGES

Burns, Jonathan D.; Van Cleve, Shelley M.; Smith, Edward Hamilton; ...

2014-11-30

The staff at the Radiochemical Engineering Development Center, located at Oak Ridge National Laboratory, produced a 6.3 ± 0.4 GBq (1.7 ± 0.1 Ci) 252Cf source for the Californium Rare Isotope Breeder Upgrade (CARIBU) project at Argonne National Laboratory’s Argonne Tandem Linac Accelerator System. The source was produced by electrodeposition of a 252Cf sample onto a stainless steel substrate, which required material free from excess mass for efficient deposition. The resulting deposition was the largest reported 252Cf electrodeposition source ever produced. Several different chromatographic purification methods were investigated to determine which would be most effective for final purification of themore » feed material used for the CARIBU source. The separation of lanthanides from the Cf was of special concern. Furthermore, the separation, using 145Sm, 153Gd, and 249Cf as tracers, was investigated using BioRad AG 50X8 in α-hydroxyisobutyric acid, Eichrom LN resin in both HNO 3 and HCl, and Eichrom TEVA resin in NH 4SCN. The TEVA NH 4SCN system was found to completely separate 145Sm and 153Gd from 249Cf and was adopted into the purification process used in purifying the 252Cf.« less

Mass transfer study on the electrochemical removal of copper ions from synthetic effluents using reticulated vitreous carbon.

PubMed

Britto-Costa, Pedro H; Ruotolo, Luís Augusto M

2013-01-01

Porous electrodes have been successfully used for metal electrodeposition from diluted aqueous solution due to their high porosity and specific surface area, which lead to high mass transfer rates. This work studies the mass transfer of copper electrodeposition on reticulated vitreous carbon in a flow reactor without membrane. The flow configuration, otherwise the filter-press electrochemical reactors, was designed in order to minimize the pressure drop. The mass transfer coefficient was determined by voltammetric and galvanostatic electrodeposition. In the voltammetric experiments a Luggin capillary was used to measure the current-potential curves and to determine the limiting current (and, consequently, the mass transfer coefficient). In the galvanostatic experiments the concentration-time curves were obtained and considering a limiting current kinetics model, the mass transfer coefficient (k(m)) was determined for different flow velocities. The results showed that both methods give similar values of k(m), thus the voltammetric method can be recommended because it is faster and simpler. Finally, the reactor performance was compared with others from literature, and it was observed that the proposed reactor design has high Sherwood numbers similar to other reactor configurations using membranes and reticulated vitreous carbon electrodes.

Uniaxial Magnetization Performance of Textured Fe Nanowire Arrays Electrodeposited by a Pulsed Potential Deposition Technique

NASA Astrophysics Data System (ADS)

Neetzel, C.; Ohgai, T.; Yanai, T.; Nakano, M.; Fukunaga, H.

2017-11-01

Textured ferromagnetic Fe nanowire arrays were electrodeposited using a rectangular-pulsed potential deposition technique into anodized aluminum oxide nanochannels. During the electrodeposition of Fe nanowire arrays at a cathodic potential of - 1.2 V, the growth rate of the nanowires was ca. 200 nm s-1. The aspect ratio of Fe nanowires with a diameter of 30 ± 5 nm reached ca. 2000. The long axis of Fe nanowires corresponded with the <200> direction when a large overpotential during the on-time pulse was applied, whereas it orientated to the <110> direction under the potentiostatic condition with a small overpotential. By shifting the on-time cathode potential up to - 1.8 V, the texture coefficient for the (200) plane, TC200, reached up to 1.94. Perpendicular magnetization performance was observed in Fe nanowire arrays. With increasing TC200, the squareness of Fe nanowire arrays increased up to 0.95 with the coercivity maintained at 1.4 kOe at room temperature. This research result has opened a novel possibility of Fe nanowire arrays that can be applied for a new permanent magnetic material without rare-earth metals.

Effect of iron content on the catalytic activity of Fe-MnOx electrodeposited films in water oxidation

NASA Astrophysics Data System (ADS)

Selinger, Elizabeth; Ryczko, Kevin; Lopinski, Gregory; Armandi, Marco; Bonelli, Barbara; Tamblyn, Isaac

We report on the experimental and computational optimization and characterization of an MnOx structure containing a small amount of Fe, used as a catalyst for the water oxidation reaction (WOR), the key limiting reaction in water splitting. MnOx materials are earth-abundant and known to be efficient for WOR, and the method of cathodically electrodepositing catalysts allows for quick synthesis and a homogeneous coverage of the substrate. We present an increase in WOR activity due to the presence of Fe in this MnOx catalyst structure. First, we explored the optimal range for Fe(NO3)3 concentration in an KMnO4 solution for electrodeposition and tested for WOR activity. The catalyst structure was then analyzed using FESEM, XPS, and a Kelvin probe. We then developed a computational model of this structure, using density functional theory to obtain adsorption energies, work functions, projected density of states, and Born-Oppenheimer molecular dynamics. In this theoretical framework, we explore how these observables change with respect to concentration of Fe, and compare the theoretical model with experiment. special acknowledgement to the Italian Cultural Centre of Durham scholarship program.

Protein addressing on patterned microchip by coupling chitosan electrodeposition and 'electro-click' chemistry.

PubMed

Shi, Xiao-Wen; Qiu, Ling; Nie, Zhen; Xiao, Ling; Payne, Gregory F; Du, Yumin

2013-12-01

Many applications in proteomics and lab-on-chip analysis require methods that guide proteins to assemble at surfaces with high spatial and temporal control. Electrical inputs are particularly convenient to control, and there has been considerable effort to discover simple and generic mechanisms that allow electrical inputs to trigger protein assembly on-demand. Here, we report the electroaddressing of a protein to a patterned surface by coupling two generic electroaddressing mechanisms. First, we electrodeposit the stimuli-responsive film-forming aminopolysaccharide chitosan to form a hydrogel matrix at the electrode surface. After deposition, the matrix is chemically functionalized with alkyne groups. Second, we ''electro-click' an azide-tagged protein to the functionalized matrix using electrical signals to trigger conjugation by Huisgen 1,3-dipolar cycloadditions. Specifically, a cathodic potential is applied to the matrix-coated electrode to reduce Cu(II) to Cu(I) which is required for the click reaction. Using fluorescently-labeled bovine serum albumin as our model, we demonstrate that protein conjugation can be controlled spatially and temporally. We anticipate that the coupling of polysaccharide electrodeposition and electro-click chemistry will provide a simple and generic approach to electroaddress proteins within compatible hydrogel matrices.

Effect of ZnO core electrodeposition conditions on electrochemical and photocatalytic properties of polypyrrole-graphene oxide shelled nanoarrays

NASA Astrophysics Data System (ADS)

Pruna, A.; Shao, Q.; Kamruzzaman, M.; Li, Y. Y.; Zapien, J. A.; Pullini, D.; Busquets Mataix, D.; Ruotolo, A.

2017-01-01

Novel hybrid core-shell nanoarchitectures were fabricated by a simple two-step electrochemical approach: first ZnO nanorod core was electrodeposited from Zn(NO3)2 solution; further, the core nanoarray was coated with a shell based on polypyrrole hybridized with graphene oxide by electropolymerization. The properties of the core/shell nanoarchitectures were studied as a function of the core properties induced by electrodeposition parameters. The ZnO nanostructures showed improved crystallinity and c-axis preferred orientation with increasing cathodic deposition potential while the increased deposition duration resulted in a morphology transition from nanorod to pyramidal shape. The electrochemical activity of the core/shell arrays was found to increase with the deposition potential of ZnO core but decreased when morphology changed from nanorod to pyramid shape. The photocatalytic results showed improved activity for the core/hybrid shell nanoarrays with respect to ZnO and ZnO/PPy ones. The degradation rate for methylene blue decreased with prolonged deposition duration of the core. The obtained results highlight the importance of electrochemical tuning of ZnO-based core/shell nanoarrays for improved performance in electrochemical and photocatalytic applications.

Electrically erasable non-volatile memory via electrochemical deposition of multifractal aggregates

NASA Astrophysics Data System (ADS)

West, William Clark

An electrically erasable non-volatile memory system based on the electrochemical deposition of Ag or Cu from a solid electrolyte is presented. This memory system, referred to as Metal Dendrite Memory, is characterized by its simplicity of design and operation, low power consumption, and potentially high cell density. By applying a small DC voltage (2.5-5V) across a Cu or Ag doped As-S amorphous chalcogenide film sandwiched between two metal electrodes, a metal filament can be electrodeposited, shorting the large impedance solid electrolyte ("on" state). Application of smaller amplitude voltage pulses (1-1.5V) across the metal filament ruptures the short, returning the cell to the high impedance state ("off" state). The state of the cell is read by applying very small amplitude voltage pulses (0.25V). These "read" voltage pulses do not disturb the state of the cell even after 10sp7 pulses. Due to difficulties in characterizing this solid electrolyte system via conventional techniques, the MDM cells have been examined using low excitation characterization methods such as Impedance Spectroscopy (IS) and polarization measurements. These studies have yielded a self-consistent equivalent circuit model as well as parameters such as ionic diffusivity and conductivity, double layer and geometric capacitances. In addition to materials characterization, the speed at which the MDM cells operate has been systematically studied using a series of statistically designed experiments, demonstrating the importance of photodoping time and applied voltage on device speed. These results were further examined using IS and Rutherford Backscattering Spectrometry (RBS). The morphology of the growing electrodeposit was studied in several different electrode arrangements and excitation conditions. Under migrationally limited conditions, the electrodeposit grew in multifractal patterns, as measured using lacunarity analysis. If a conducting film was deposited parallel to the growth direction, the electrodeposition could be driven from Diffusion Limited Aggregation (DLA) to Densely Branched Morphology (DBM) modes by changing the voltage applied to the cell. In summary, this study has laid the groundwork for future research and development of MDM memory systems by identifying many important characteristics of the MDM cell. These findings include quantitative measurement of ionic transport values, identification of the electrochemical mechanisms involved in MDM data storage, determination of parameters that are statistically significant in affecting data storage speed, and determination of the effect of cell geometry and bias on electrodeposit morphology.

Electrodeposition of titania and barium titanate thin films for high dielectric applications

NASA Astrophysics Data System (ADS)

Roy, Biplab Kumar

In order to address the requirement of a low-temperature low-cost cost processing for depositing high dielectric constant ceramic films for applications in embedded capacitor and flexible electronics technology, two different chemical bath processes, namely, thermohydrolytic deposition (TD) and cathodic electrodeposition (ED) have been exploited to generate titania thin films. In thermohydrolytic deposition technique, titania films were generated from acidic aqueous solution of titanium chloride on F: SnO2 coated glass and Si substrates by temperature assisted hydrolysis mechanism. On the other hand, in cathodic electrodeposition, in-situ electro-generation of hydroxyl ions triggered a fast deposition of titania on conductive substrates such as copper and F: SnO2 coated glass from peroxotitanium solution at low temperatures (˜0°C). In both techniques, solution compositions affected the morphology and crystallinity of the films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques have been employed to perform such characterization. As both processes utilized water as solvent, the as-deposited films contained hydroxyl ligand or physically adsorbed water molecules in the titania layer. Besides that, electrodeposited films contained peroxotitanium bonds which were characterized by FTIR studies. Although as-electrodeposited titania films were X-ray amorphous, considerable crystallinity could be generated by heat treatment. The films obtained from both the processes showed v moderately high dielectric constant (ranging from 9-30 at 100 kHz) and high breakdown voltage (0.09-0.15 MV/cm) in electrical measurements. To further improve the dielectric constant, electrodeposited titania films were converted to barium titanate films in high pH barium ion containing solution at 80-90°C. The resultant film contained cubic crystalline barium titanate verified by XRD analysis. Simple low-temperature hydrothermal technique of conversion worked perfect for F:SnO2 coated glass substrates, but in this process, high pH precursor caused corrosion in copper substrates and deposition of copper oxide in the final films. To overcome this, an innovative technique, which incorporates an electrochemical protection of substrates by application of cathodic potential in addition to common hydrothermal conversion, has been adopted. Films generated by common hydrothermal technique on F:SnO 2/glass substrates and via electrochemical-hydrothermal technique on Cu substrates showed promising dielectric behavior. Apart from the experimental studies, this report also includes various thermodynamic studies related to hydrolysis and precipitation of titanium ion, protection of copper during titania deposition and barium titanate conversion. Gibbs free energy based model and speciation studies were used to understand supersaturation which is a controlling factor in thermohydrolytic deposition. Similar approaches were utilized to understand the possibilities of barium titanate formation at different Ba2+ concentrations with different pH conditions. Possibilities of atmospheric carbon dioxide incorporation to generate barium carbonate instead of barium titanate formation were also determined by mathematical calculations. Whenever relevant, results of such theoretical analysis were utilized to design the experiment or to explain the experimental observations.

Enhanced interface perpendicular magnetic anisotropy in electrodeposited Co/Au(111) layers

NASA Astrophysics Data System (ADS)

Cagnon, L.; Devolder, T.; Cortes, R.; Morrone, A.; Schmidt, J. E.; Chappert, C.; Allongue, P.

2001-03-01

This work investigates the structure and interface perpendicular magnetic anisotropy (PMA) of electrodeposited Cu/Co/Au(111) sandwiches with variable Co thickness [2-20 monolayers (ML's)]. In optimum deposition conditions, polar magneto-optical Kerr effect measurements show that the axis of easy magnetization is perpendicular to the layers for thicknesses below ca. 7.2 ML's. This value is among the best ever reported for the Cu/Co/Au(111) structure. While extended x-ray-absorption fine structure indicates that layers are hcp, in situ STM imaging suggests that magnetoelastic effects contribute significantly to PMA. The correlation observed between the strength of PMA and film structure is discussed in details.

Surface plasmon effect in electrodeposited diamond-like carbon films for photovoltaic application

NASA Astrophysics Data System (ADS)

Ghosh, B.; Ray, Sekhar C.; Espinoza-González, Rodrigo; Villarroel, Roberto; Hevia, Samuel A.; Alvarez-Vega, Pedro

2018-04-01

Diamond-like carbon (DLC) films and nanocrystalline silver particles containing diamond-like carbon (DLC:Ag) films were electrodeposited on n-type silicon substrate (n-Si) to prepare n-Si/DLC and n-Si/DLC:Ag heterostructures for photovoltaic (PV) applications. Surface plasmon resonance (SPR) effect in this cell structure and its overall performance have been studied in terms of morphology, optical absorption, current-voltage characteristics, capacitance-voltage characteristics, band diagram and external quantum efficiency measurements. Localized surface plasmon resonance effect of silver nanoparticles (Ag NPs) in n-Si/DLC:Ag PV structure exhibited an enhancement of ∼28% in short circuit current density (JSC), which improved the overall efficiency of the heterostructures.

Electro Processing Research

NASA Technical Reports Server (NTRS)

1982-01-01

Electroprocessing which is concerned with fluid dynamics of the electroreduction process to determine how it may be modified to improve the quality of the deposit was studied. Experimental techniques are used in this research. These techniques include laser Schlieren photography, laser Doppler velocimetry, and frequency spectrum analysis. Projects involve fluid flow studies of zinc plating in aqueous and molten salt electrolytes, study of cell design for magnesium chlorides electrolysis, digital signal analysis of manganese electrodeposition in molten chlorides, and electroplating of molybdenum from low melting salts. It is anticipated that the use of refractory metals as constructed materials in engineering will increase. Their electrodeposition from molten salt electrolytes is important in the extraction metallurgy of refractory metals.

Metal-insulator transition in nanocomposite VOx films formed by anodic electrodeposition

NASA Astrophysics Data System (ADS)

Tsui, Lok-kun; Hildebrand, Helga; Lu, Jiwei; Schmuki, Patrik; Zangari, Giovanni

2013-11-01

The ability to grow VO2 films by electrochemical methods would open a low-cost, easily scalable production route to a number of electronic devices. We have synthesized VOx films by anodic electrodeposition of V2O5, followed by partial reduction by annealing in Ar. The resulting films are heterogeneous, consisting of various metallic/oxide phases and including regions with VO2 stoichiometry. A gradual metal insulator transition with a nearly two order of magnitude change in film resistance is observed between room temperature and 140 °C. In addition, the films exhibit a temperature coefficient of resistance of ˜ -2.4%/ °C from 20 to 140 °C.

Chalcogenide Nanoionic-based Radio Frequency Switch

NASA Technical Reports Server (NTRS)

Nessel, James (Inventor); Lee, Richard (Inventor)

2013-01-01

A nonvolatile nanoionic switch is disclosed. A thin layer of chalcogenide glass engages a substrate and a metal selected from the group of silver and copper photo-dissolved in the chalcogenide glass. A first oxidizable electrode and a second inert electrode engage the chalcogenide glass and are spaced apart from each other forming a gap therebetween. A direct current voltage source is applied with positive polarity applied to the oxidizable electrode and negative polarity applied to the inert electrode which electrodeposits silver or copper across the gap closing the switch. Reversing the polarity of the switch dissolves the electrodeposited metal and returns it to the oxidizable electrode. A capacitor arrangement may be formed with the same structure and process.

Target and method for the production of fission product molybdenum-99

DOEpatents

Vandegrift, G.F.; Vissers, D.R.; Marshall, S.L.; Varma, R.

1987-10-26

A target for the reduction of fission product Mo-99 is prepared from uranium of low U-235 enrichment by coating a structural support member with a preparatory coating of a substantially oxide-free substrate metal. Uranium metal is electrodeposited from a molten halide electrolytic bath onto a substrate metal. The electrodeposition is performed at a predetermined direct current rate or by using pulsed plating techniques which permit relaxation of accumulated uranium ion concentrations within the melt. Layers of as much as to 600 mg/cm/sup 2/ of uranium can be prepared to provide a sufficient density to produce acceptable concentrations of fission product Mo-99. 2 figs.

Platinum Electrodeposition for Supported ALD Templated Foam Hohlraum Liners

DOE PAGES

Horwood, Corie; Stadermann, Michael; Biener, Monika; ...

2017-12-20

Two commercially available platinum plating solutions (Platanex III and Platanex Luna) were evaluated for the electrodeposition of platinum layers on gold hohlraums and cylindrically shaped silver-gold ingots. The successful deposition of thin Pt layers on gold hohlraums as well as thick Pt layers on silver-gold alloys will allow for the integration of atomic layer deposition templated foam inside a hohlraum. We found that when the manufacturer’s recommendations for the Pt plating solutions were used, the coatings obtained were unacceptable because of cracking, poor adhesion, or thin and powdery Pt deposits. Therefore, alternative plating parameters were investigated, and the conditions resultingmore » in acceptable coatings are reported here.« less

Platinum Electrodeposition for Supported ALD Templated Foam Hohlraum Liners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horwood, Corie; Stadermann, Michael; Biener, Monika

Two commercially available platinum plating solutions (Platanex III and Platanex Luna) were evaluated for the electrodeposition of platinum layers on gold hohlraums and cylindrically shaped silver-gold ingots. The successful deposition of thin Pt layers on gold hohlraums as well as thick Pt layers on silver-gold alloys will allow for the integration of atomic layer deposition templated foam inside a hohlraum. We found that when the manufacturer’s recommendations for the Pt plating solutions were used, the coatings obtained were unacceptable because of cracking, poor adhesion, or thin and powdery Pt deposits. Therefore, alternative plating parameters were investigated, and the conditions resultingmore » in acceptable coatings are reported here.« less

Auger electron and characteristic energy loss spectra for electro-deposited americium-241

NASA Astrophysics Data System (ADS)

Varma, Matesh N.; Baum, John W.

1983-07-01

Auger electron energy spectra for electro-deposited americium-241 on platinum substrate were obtained using a cylindrical mirror analyzer. Characteristic energy loss spectra for this sample were also obtained at primary electron beam energies of 990 and 390 eV. From these measurements PI, PII, and PIII energy levels for americium-241 are determined. Auger electron energies are compared with theoretically calculated values. Minimum detectability under the present condition of sample preparation and equipment was estimated at approximately 1.2×10-8 g/cm2 or 3.9×10-8 Ci/cm2. Minimum detectability for plutonium-239 under similar conditions was estimated at about 7.2×10-10 Ci/cm2.

Stable room temperature magnetocurrent in electrodeposited permeable n-type metal base transistor

NASA Astrophysics Data System (ADS)

Silva, G. V. O.; Teixeira, H. A.; Mello, S. L. A.; de Araujo, C. I. L.

2018-02-01

We investigated a permeable metal base transistor consisting of a ZnO/NiFe/Si heterostructure. Both ZnO and NiFe layers were grown by electrodeposition techniques, using only adhesive tape masks to define deposition regions. The base permeability can thus be controlled by varying the NiFe deposition time. We report here our best results obtained for the permeable NiFe base close to the electrical percolation threshold, which gives reasonable sensitivity to the device. Magnetocurrent measurements carried out at room temperature show that this permeable metal base transistor is stable and sensitive under applied magnetic fields of low intensities, ˜100 Oe, required for electronics integration.

Effect of thiourea on electrochemical nucleation and electrochemical impedance spectroscopy of electrodeposited tin on a copper substrate in a sulfate bath.

PubMed

Lee, Mi-Ri; Na, Seong-Hun; Park, Hwa-Sun; Suh, Su-Jeong

2014-12-01

The effect of thiourea on the electrochemical nucleation of tin on a copper substrate from a sulfate bath was studied using voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and scanning electron microscopy. Without thiourea, electrodeposition of tin showed very poor surface coverage. However, re-nucleation and growth of tin occurred after the addition of thiourea. In particular, very rapid re-nucleation and growth behavior of tin were observed when up to 6 g/L of thiourea was added. Furthermore, impedance analysis allowed the estimation of the change in the growth behavior of tin when up to 6 g/L of thiourea was added.

Chalcogenide Nanoionic-Based Radio Frequency Switch

NASA Technical Reports Server (NTRS)

Nessel, James (Inventor); Lee, Richard (Inventor)

2011-01-01

A nonvolatile nanoionic switch is disclosed. A thin layer of chalcogenide glass engages a substrate and a metal selected from the group of silver and copper photo-dissolved in the chalcogenide glass. A first oxidizable electrode and a second inert electrode engage the chalcogenide glass and are spaced apart from each other forming a gap there between. A direct current voltage source is applied with positive polarity applied to the oxidizable electrode and negative polarity applied to the inert electrode which electrodeposits silver or copper across the gap closing the switch. Reversing the polarity of the switch dissolves the electrodeposited metal and returns it to the oxidizable electrode. A capacitor arrangement may be formed with the same structure and process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

Here, we investigate the stability of electrodeposition at solid-solid interfaces for materials exhibiting an anisotropic mechanical response. The stability of electrodeposition or resistance to the formation of dendrites is studied within a linear stability analysis. The deformation and stress equations are solved using the Stroh formalism and faithfully recover the boundary conditions at the interface. The stability parameter is used to quantify the stability of different solid-solid interfaces incorporating the full anisotropy of the elastic tensor of the two materials. Our results show a high degree of variability in the stability parameter depending on the crystallographic orientation of the solidsmore » in contact, and point to opportunities for exploiting this effect in developing Li metal anodes.« less

Combined flame and electrodeposition synthesis of energetic coaxial tungsten-oxide/aluminum nanowire arrays.

PubMed

Dong, Zhizhong; Al-Sharab, Jafar F; Kear, Bernard H; Tse, Stephen D

2013-09-11

A nanostructured thermite composite comprising an array of tungsten-oxide (WO2.9) nanowires (diameters of 20-50 nm and lengths of >10 μm) coated with single-crystal aluminum (thickness of ~16 nm) has been fabricated. The method involves combined flame synthesis of tungsten-oxide nanowires and ionic-liquid electrodeposition of aluminum. The geometry not only presents an avenue to tailor heat-release characteristics due to anisotropic arrangement of fuel and oxidizer but also eliminates or minimizes the presence of an interfacial Al2O3 passivation layer. Upon ignition, the energetic nanocomposite exhibits strong exothermicity, thereby being useful for fundamental study of aluminothermic reactions as well as enhancing combustion characteristics.

The Electrodeposition of Silver from Supercritical Carbon Dioxide/Acetonitrile

PubMed Central

Bartlett, Philip N; Perdjon-Abel, Magdalena; Cook, David; Reid, Gillian; Levason, William; Cheng, Fei; Zhang, Wenjian; George, Michael W; Ke, Jie; Beanland, Richard; Sloan, Jeremy

2014-01-01

Cyclic voltammetry of silver coordination complexes in acetonitrile and in a single-phase supercritical carbon dioxide/acetonitrile (scCO2/CH3CN) system is reported. Five silver precursors are investigated: (1,5-cyclooctadiene)(hexafluoroacetylacetonato) silver(I) [Ag(hfac)(COD)], (hexafluoroacetylacetonato)(triphenylphosphine) silver(I) [Ag(hfac)(PPh3)], (perfluorooctanoato)bis(triphenylphosphine) silver(I) [Ag(CF3(CF2)6CO2)(PPh3)2], tetrakis(triphenylphosphine) silver(I) tetrafluoroborate [Ag(PPh3)4][BF4] and tetrakis(acetonitrile) silver(I) tetrafluoroborate [Ag(CH3CN)4][BF4]. Of these, [Ag(CH3CN)4][BF4] is found to be the most suitable for electrodeposition of silver from scCO2/CH3CN.

Electrodeposited Structurally Stable V2O5 Inverse Opal Networks as High Performance Thin Film Lithium Batteries.

PubMed

Armstrong, Eileen; McNulty, David; Geaney, Hugh; O'Dwyer, Colm

2015-12-09

High performance thin film lithium batteries using structurally stable electrodeposited V2O5 inverse opal (IO) networks as cathodes provide high capacity and outstanding cycling capability and also were demonstrated on transparent conducting oxide current collectors. The superior electrochemical performance of the inverse opal structures was evaluated through galvanostatic and potentiodynamic cycling, and the IO thin film battery offers increased capacity retention compared to micron-scale bulk particles from improved mechanical stability and electrical contact to stainless steel or transparent conducting current collectors from bottom-up electrodeposition growth. Li(+) is inserted into planar and IO structures at different potentials, and correlated to a preferential exposure of insertion sites of the IO network to the electrolyte. Additionally, potentiodynamic testing quantified the portion of the capacity stored as surface bound capacitive charge. Raman scattering and XRD characterization showed how the IO allows swelling into the pore volume rather than away from the current collector. V2O5 IO coin cells offer high initial capacities, but capacity fading can occur with limited electrolyte. Finally, we demonstrate that a V2O5 IO thin film battery prepared on a transparent conducting current collector with excess electrolyte exhibits high capacities (∼200 mAh g(-1)) and outstanding capacity retention and rate capability.

Iridium Oxide pH Sensor Based on Stainless Steel Wire for pH Mapping on Metal Surface

NASA Astrophysics Data System (ADS)

Shahrestani, S.; Ismail, M. C.; Kakooei, S.; Beheshti, M.; Zabihiazadboni, M.; Zavareh, M. A.

2018-03-01

A simple technique to fabricate the iridium oxide pH sensor is useful in several applications such as medical, food processing and engineering material where it is able to detect the changes of pH. Generally, the fabrication technique can be classified into three types: electro-deposition iridium oxide film (EIrOF), activated iridium oxide film (AIROF) and sputtering iridium oxide film (SIROF). This study focuses on fabricating electrode, calibration and test. Electro-deposition iridium oxide film is a simple and effective method of fabricating this kind of sensor via cyclic voltammetry process. The iridium oxide thick film was successfully electrodeposited on the surface of stainless steel wire with 500 cycles of sweep potential. A further analysis under FESEM shows detailed image of iridium oxide film which has cauliflower-liked microstructure. EDX analysis shows the highest element present are iridium and oxygen which concluded that the process is successful. The iridium oxide based pH sensor has shown a good performance in comparison to conventional glass pH sensor when it is being calibrated in buffer solutions with 2, 4, 7 and 9 pH values. The iridium oxide pH sensor is specifically designed to measure the pH on the surface of metal plate.

Electrodeposition of Isolated Platinum Atoms and Clusters on Bismuth-Characterization and Electrocatalysis.

PubMed

Zhou, Min; Dick, Jeffrey E; Bard, Allen J

2017-12-06

We describe a method for the electrodeposition of an isolated single Pt atom or small cluster, up to 9 atoms, on a bismuth ultramicroelectrode (UME). This deposition was immediately followed by electrochemical characterization via the hydrogen evolution reaction (HER) that occurs readily on the electrodeposited Pt but not on Bi. The observed voltammetric current plateau, even for a single atom, which behaves as an electrode, allows the estimation of deposit size. Pt was plated from solutions of femtomolar PtCl 6 2- , which allowed precise control of the arrival of ions and thus the plating rate on the Bi UME, to one ion every few seconds. This allowed the atom-by-atom fabrication of isolated platinum deposits, ranging from single atoms to 9-atom clusters. The limiting currents in voltammetry gave the size and number of atoms of the clusters. Given the stochasticity of the plating process, we show that the number of atoms plated over a given time (10 and 20 s) follows a Poisson distribution. Taking the potential at a certain current density as a measure of the relative rate of the HER, we found that the potential shifted positively as the size increased, with single atoms showing the largest overpotentials compared to bulk Pt.

Experimental and Theoretical Structural Investigation of AuPt Nanoparticles Synthesized using a Direct Electrochemical Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lapp, Aliya S.; Duan, Zhiyao; Marcella, Nicholas

In this report we examine the structure of bimetallic nanomaterials prepared by an electrochemical approach known as hydride-terminated (HT) electrodeposition. It has been shown previously that this method can lead to deposition of a single Pt monolayer on bulk-phase Au surfaces. Specifically, under appropriate electrochemical conditions and using a solution containing PtCl 4 2-, a monolayer of Pt atoms electrodeposits onto bulk-phase Au immediately followed by a monolayer of H atoms. The H-atom capping layer prevents deposition of Pt multilayers. We applied this method to ~1.6 nm Au nanoparticles (AuNPs) immobilized on an inert electrode surface. In contrast to themore » well-defined, segregated Au/Pt structure of the bulk-phase surface, we observe that HT electrodeposition leads to the formation of AuPt quasi-random alloy NPs rather than the core@shell structure anticipated from earlier reports relating to deposition onto bulk phases. The results provide a good example of how the phase behavior of macro materials does not always translate to the nano world. A key component of this study was the structure determination of the AuPt NPs, which required a combination of electrochemical methods, electron microscopy, X-ray absorption spectroscopy, and theory (DFT and MD).« less

Process for the Production of Star Tracklng [Tracking] Reticles

NASA Technical Reports Server (NTRS)

Smith, Wade O. (Inventor); Toft, Albert R. (Inventor)

1972-01-01

A method for the production of reticles, particularly those for use in outer space, wherein the product is a quartz base coated with highly adherent layers of chromium, chromium-silver, and silver vacuum deposited through a mask, and then coated with an electrodeposit of copper from a copper sulfate solution followed by an electrodeposit of black chromium. The masks are produced by coating a beryllium-copper alloy substrate with a positive working photoresist, developing the photoresist according to a pattern to leave a positive mask, plating uncoated areas with gold, removing the photoresist, coating the substrate with a negative working photoresist, developing the negative working photoresist to expose the base metal of the pattern, and chemically etching the unplated side of the pattern to produce the mask. The mask produced is then used in the vacuum deposition of: (1) chromium metal on the surface of a quartz base to obtain a highly adherent quartz-chromium interface; (2) silver on the chromium deposit, during the final stage of chromium deposit, to produce a silver chromium alloy layer; and (3) silver onto the surface of the alloy layer. The coated quartz base is then coated by electroplating utilizing an acid copper deposit followed by a black chromium electrodeposit to produce the product of the present invention.

Preparation of thin hexagonal highly-ordered anodic aluminum oxide (AAO) template onto silicon substrate and growth ZnO nanorod arrays by electrodeposition

NASA Astrophysics Data System (ADS)

Chahrour, Khaled M.; Ahmed, Naser M.; Hashim, M. R.; Elfadill, Nezar G.; Qaeed, M. A.; Bououdina, M.

2014-12-01

In this study, anodic aluminum oxide (AAO) templates of Aluminum thin films onto Ti-coated silicon substrates were prepared for growth of nanostructure materials. Hexagonally highly ordered thin AAO templates were fabricated under controllable conditions by using a two-step anodization. The obtained thin AAO templates were approximately 70 nm in pore diameter and 250 nm in length with 110 nm interpore distances within an area of 3 cm2. The difference between first and second anodization was investigated in details by in situ monitoring of current-time curve. A bottom barrier layer of the AAO templates was removed during dropping the voltage in the last period of the anodization process followed by a wet etching using phosphoric acid (5 wt%) for several minutes at ambient temperature. As an application, Zn nanorod arrays embedded in anodic alumina (AAO) template were fabricated by electrodeposition. Oxygen was used to oxidize the electrodeposited Zn nanorods in the AAO template at 700 °C. The morphology, structure and photoluminescence properties of ZnO/AAO assembly were analyzed using Field-emission scanning electron microscope (FESEM), Energy dispersive X-ray spectroscopy (EDX), Atomic force microscope (AFM), X-ray diffraction (XRD) and photoluminescence (PL).

Two-step electrodeposition construction of flower-on-sheet hierarchical cobalt hydroxide nano-forest for high-capacitance supercapacitors.

PubMed

Yang, Wanlu; Gao, Zan; Ma, Jing; Wang, Jun; Zhang, Xingming; Liu, Lianhe

2013-11-28

A novel flower-on-sheet hierarchical morphology of α-Co(OH)2 nanostructures was achieved via an easy two-step synthesis strategy. The method is based on first a galvanostatic electrodeposition (GE) of vertically aligned interconnected Co(OH)2 nanosheets to form a branch layer and second a potentiostatic electrodeposition (PE) of Co(OH)2 microflowers on the obtained branch layer from the secondary growth of their sheet-like precursors. The formation mechanism of this special PE time-dependent nanostructure was proposed and their morphology-dependent supercapacitor properties were also investigated. For a given areas mass loading, high specific capacitances of 1822 F g(-1) have been achieved for the electrode obtained after 200 s GE followed by a 300 s PE in a three-electrode configuration, and it maintained 91% of its initial capacity after 1000 constant-current charge/discharge cycles. Even when the discharge current density was increased from 1 to 50 mA cm(-2), the capacitance was still as high as 1499 F g(-1), indicating an excellent rate performance of the fabricated electrodes. The high performances of the electrodes are attributed to the special porous structure, 3D hierarchical morphology, vertical aligned orientation, and low contact resistance between active material and charge collector.

Mace-like gold hollow hierarchical micro/nanostructures fabricated by co-effect of catalytic etching and electrodeposition and their SERS performance

NASA Astrophysics Data System (ADS)

Zhang, Haibao; Wang, Jingjing; Wang, Hua; Tian, Xingyou

2017-09-01

In this paper, we presented the fabrication of mace-like gold hollow hierarchical micro/nanostructures (HMNs) grafted on ZnO nanorods array by using an electrochemical deposition in chloroauric acid solution on gold layer pre-coated ZnO nanorods array. Different from general electrochemical deposition process, the catalytic etching to ZnO and electrodeposition of gold are co-existed in our case, which lead to an inner hollow structure and an outer gold shell. Due to the appropriate electrodeposition conditions, the outer gold shell was built of many wimble-like nanoparticles, and the hierarchical micro/nanostructures were thus formed. In addition, because of the deposition rate is decreased gradually away from the top of ZnO nanorods, the final structures show mace-like appearance. The surface-enhanced Raman scattering (SERS) effect of the as-prepared gold hollow HMNs was further studied by using rhodamine 6G as probe molecule. It is demonstrated that these structures show ultrahigh SERS activity, and the detecting low limit of R6G solution can be to 10-10 M on single mace-like gold HMNs, which is quite important for their potential application in SERS-based surface analysis and sensors.

Pulsed electrodeposition for the synthesis of strontium-substituted calcium phosphate coatings with improved dissolution properties.

PubMed

Drevet, Richard; Benhayoune, Hicham

2013-10-01

Strontium-substituted calcium phosphate coatings are synthesized by pulsed electrodeposition on titanium alloy (Ti6Al4V) substrates. Experimental conditions of the process are optimized in order to obtain a coating with a 5% atomic substitution of calcium by strontium which corresponds to the best observations on the osteoblast cells activity and on the osteoclast cells proliferation. The physical and chemical characterizations of the obtained coating are carried out by scanning electron microscopy associated to energy dispersive X-ray spectroscopy (EDXS) for X-ray microanalysis and the structural characterization of the coating is carried out by X-ray diffraction. The in vitro dissolution/precipitation properties of the coated substrates are investigated by immersion into Dulbecco's Modified Eagle Medium (DMEM) from 1h to 14 days. The calcium, phosphorus and strontium concentrations variations in the biological liquid are assessed by Induced Coupled Plasma - Atomic Emission Spectroscopy for each immersion time. The results show that under specific experimental conditions, the electrodeposition process is suitable to synthesize strontium-substituted calcium phosphate coatings. Moreover, the addition of hydrogen peroxide (H2O2) into the electrolytic solution used in the process allows us to observe a control of the strontium release during the immersion of the prosthetic materials into DMEM. © 2013.

Conformal bi-layered perovskite/spinel coating on a metallic wire network for solid oxide fuel cells via an electrodeposition-based route

NASA Astrophysics Data System (ADS)

Park, Beom-Kyeong; Song, Rak-Hyun; Lee, Seung-Bok; Lim, Tak-Hyoung; Park, Seok-Joo; Jung, WooChul; Lee, Jong-Won

2017-04-01

Solid oxide fuel cells (SOFCs) require low-cost metallic components for current collection from electrodes as well as electrical connection between unit cells; however, the degradation of their electrical properties and surface stability associated with high-temperature oxidation is of great concern. It is thus important to develop protective conducting oxide coatings capable of mitigating the degradation of metallic components under SOFC operating conditions. Here, we report a conformal bi-layered coating composed of perovskite and spinel oxides on a metallic wire network fabricated by a facile electrodeposition-based route. A highly dense, crack-free, and adhesive bi-layered LaMnO3/Co3O4 coating of ∼1.2 μm thickness is conformally formed on the surfaces of wires with ∼100 μm diameter. We demonstrate that the bi-layered LaMnO3/Co3O4 coating plays a key role in improving the power density and durability of a tubular SOFC by stabilizing the surface of the metallic wire network used as a cathode current collector. The electrodeposition-based technique presented in this study offers a low-cost and scalable process to fabricate conformal multi-layered coatings on various metallic structures.

Hollow Microneedles for Intradermal Injection Fabricated by Sacrificial Micromolding and Selective Electrodeposition

PubMed Central

Norman, James J.; Choi, Seong-O; Tong, Nhien T.; Aiyar, Avishek R.; Patel, Samirkumar R.; Prausnitz, Mark R.; Allen, Mark G.

2012-01-01

Limitations with standard intradermal injections have created a clinical need for an alternative, low-cost injection device. In this study, we designed a hollow metal microneedle for reliable intradermal injection and developed a high-throughput micromolding process to produce metal microneedles with complex geometries. To fabricate the microneedles, we laser-ablated a 70 μm × 70 μm square cavity near the tip of poly(lactic acid-co-glyoclic acid) (PLGA) microneedles. The master structure was a template for multiple micromolded PLGA replicas. Each replica was sputtered with a gold seed layer with minimal gold deposited in the cavity due to masking effects. In this way, nickel was electrodeposited selectively outside of the cavity, after which the polymer replica was dissolved to produce a hollow metal microneedle. Force-displacement tests showed the microneedles, with 12 μm thick electrodeposition, could penetrate skin with an insertion force 9 times less than their axial failure force. We injected fluid with the microneedles into pig skin in vitro and hairless guinea pig skin in vivo. The injections targeted 90% of the material within the skin with minimal leakage onto the skin surface. We conclude that hollow microneedles made by this simple microfabrication method can achieve targeted intradermal injection. PMID:23053452

Elimination of a pollution associated with chromic acid during the electro-deposition of Cr(III) using appropriate anodic and membrane materials in a double film bath.

PubMed

Jiang, Xiaojun; Chen, Wenchao; Xu, Hongbo

2009-01-01

A method using trivalent chromium has been used to replace hexavalent chromium for the electro-deposition of chromium. Using a tri-chamber bath system various anodic materials and membranes were evaluated to minimize the production of environmentally and health damaging chromic acid. By measuring the absorbance of Cr(VI) at 640 nm, the results indicate that the use of a titanium plated ruthenium (Ti-Ru) anode produces the least amount of chromic acid byproduct compared to lead-gold alloy and graphite anodes. The concentration of Cr(VI) in the immediate vicinity of the Ti-Ru anode decreased from 0.389 mg/L to 0 during a 40-min deposition period. The use of a Nafion(TM) quaternary cation exchange membrane portioning the buffer and anode selectively prevented Cr(III) from entering the anode compartment whilst allowing the migration of H(+) to maintain overall voltaic continuity. It has been demonstrated that the use of a Ti-Ru anode with a Nafion(TM) membrane can eliminate the production of chromic acid associated with the electro-deposition of chromium plate thereby preventing its health damaging exposure to plant operators and preventing discharge of Cr(VI) into the environment. Addition of a surfactant improved current efficiency by 34.7%.

Experimental and Theoretical Structural Investigation of AuPt Nanoparticles Synthesized using a Direct Electrochemical Method

DOE PAGES

Lapp, Aliya S.; Duan, Zhiyao; Marcella, Nicholas; ...

2018-06-01

In this report we examine the structure of bimetallic nanomaterials prepared by an electrochemical approach known as hydride-terminated (HT) electrodeposition. It has been shown previously that this method can lead to deposition of a single Pt monolayer on bulk-phase Au surfaces. Specifically, under appropriate electrochemical conditions and using a solution containing PtCl 4 2-, a monolayer of Pt atoms electrodeposits onto bulk-phase Au immediately followed by a monolayer of H atoms. The H-atom capping layer prevents deposition of Pt multilayers. We applied this method to ~1.6 nm Au nanoparticles (AuNPs) immobilized on an inert electrode surface. In contrast to themore » well-defined, segregated Au/Pt structure of the bulk-phase surface, we observe that HT electrodeposition leads to the formation of AuPt quasi-random alloy NPs rather than the core@shell structure anticipated from earlier reports relating to deposition onto bulk phases. The results provide a good example of how the phase behavior of macro materials does not always translate to the nano world. A key component of this study was the structure determination of the AuPt NPs, which required a combination of electrochemical methods, electron microscopy, X-ray absorption spectroscopy, and theory (DFT and MD).« less

Performance enhancement of iron-chromium redox flow batteries by employing interdigitated flow fields

NASA Astrophysics Data System (ADS)

Zeng, Y. K.; Zhou, X. L.; Zeng, L.; Yan, X. H.; Zhao, T. S.

2016-09-01

The catalyst for the negative electrode of iron-chromium redox flow batteries (ICRFBs) is commonly prepared by adding a small amount of Bi3+ ions in the electrolyte and synchronously electrodepositing metallic particles onto the electrode surface at the beginning of charge process. Achieving a uniform catalyst distribution in the porous electrode, which is closely related to the flow field design, is critically important to improve the ICRFB performance. In this work, the effects of flow field designs on catalyst electrodeposition and battery performance are investigated. It is found that compared to the serpentine flow field (SFF) design, the interdigitated flow field (IFF) forces the electrolyte through the porous electrode between the neighboring channels and enhances species transport during the processes of both the catalyst electrodeposition and iron/chromium redox reactions, thus enabling a more uniform catalyst distribution and higher mass transport limitation. It is further demonstrated that the energy efficiency of the ICRFB with the IFF reaches 80.7% at a high current density (320 mA cm-2), which is 8.2% higher than that of the ICRFB with the SFF. With such a high performance and intrinsically low-cost active materials, the ICRFB with the IFF offers a great promise for large-scale energy storage.

Emerging materials for solar cell applications: electrodeposited CdTe. Second quarter report, May 16-August 15, 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basol, B.; Stafsudd, O.

1980-09-10

Work was centered about improving electroplating processes and cell fabrication techniques, with emphasis being given to three differing n-CdTe/Au Schottky configurations. The highest values of efficiency-related parmeters achieved with a simulated solar irradiation of 100 mW/cm/sup 2/ were 0.57V for open circuit voltage, 0.6 for fill factor, and 6 mA/cm/sup 2/ for short circuit current. Four important parameters are known to control the quality of the Monosolar electrodeposition process and resultant solar cells. They are electrolyte temperature, Te concentration in the solution at a specific pH, deposition or quasi-rest potential, and flow pattern of the electrolyte (stirring). The first threemore » considerations are believed to be fully understood and optimized. Work is underway to further understand the effects of stirring on the diffusion of ionic components and the effects on CdTe film performance. Work was accelerated during the quarter to increase the short circuit current. Parallel programs using laser irradiation of finished CdTe films, heat treatment, and changes in the electrodeposition process itself to recrystallize films were started. The surface etching technique has been highly refined, while the entire cell manufacturing process is now reproducible when defect-free substrates are used.« less

Experimental and Theoretical Structural Investigation of AuPt Nanoparticles Synthesized Using a Direct Electrochemical Method.

PubMed

Lapp, Aliya S; Duan, Zhiyao; Marcella, Nicholas; Luo, Long; Genc, Arda; Ringnalda, Jan; Frenkel, Anatoly I; Henkelman, Graeme; Crooks, Richard M

2018-05-11

In this report, we examine the structure of bimetallic nanomaterials prepared by an electrochemical approach known as hydride-terminated (HT) electrodeposition. It has been shown previously that this method can lead to deposition of a single Pt monolayer on bulk-phase Au surfaces. Specifically, under appropriate electrochemical conditions and using a solution containing PtCl 4 2- , a monolayer of Pt atoms electrodeposits onto bulk-phase Au immediately followed by a monolayer of H atoms. The H atom capping layer prevents deposition of Pt multilayers. We applied this method to ∼1.6 nm Au nanoparticles (AuNPs) immobilized on an inert electrode surface. In contrast to the well-defined, segregated Au/Pt structure of the bulk-phase surface, we observe that HT electrodeposition leads to the formation of AuPt quasi-random alloy NPs rather than the core@shell structure anticipated from earlier reports relating to deposition onto bulk phases. The results provide a good example of how the phase behavior of macro materials does not always translate to the nano world. A key component of this study was the structure determination of the AuPt NPs, which required a combination of electrochemical methods, electron microscopy, X-ray absorption spectroscopy, and theory (DFT and MD).

Electrodeposition of germanium from supercritical fluids.

PubMed

Ke, Jie; Bartlett, Philip N; Cook, David; Easun, Timothy L; George, Michael W; Levason, William; Reid, Gillian; Smith, David; Su, Wenta; Zhang, Wenjian

2012-01-28

Several Ge(II) and Ge(IV) compounds were investigated as possible reagents for the electrodeposition of Ge from liquid CH(3)CN and CH(2)F(2) and supercritical CO(2) containing as a co-solvent CH(3)CN (scCO(2)) and supercritical CH(2)F(2) (scCH(2)F(2)). For Ge(II) reagents the most promising results were obtained using [NBu(n)(4)][GeCl(3)]. However the reproducibility was poor and the reduction currents were significantly less than the estimated mass transport limited values. Deposition of Ge containing films was possible at high cathodic potential from [NBu(n)(4)][GeCl(3)] in liquid CH(3)CN and supercritical CO(2) containing CH(3)CN but in all cases they were heavily contaminated by C, O, F and Cl. Much more promising results were obtained using GeCl(4) in liquid CH(2)F(2) and supercritical CH(2)F(2). In this case the reduction currents were consistent with mass transport limited reduction and bulk electrodeposition produced amorphous films of Ge. Characterisation by XPS showed the presence of low levels of O, F and C, XPS confirmed the presence of Ge together with germanium oxides, and Raman spectroscopy showed that the as deposited amorphous Ge could be crystallised by the laser used in obtaining the Raman measurements.

Cathodic electrodeposition of mixed molybdenum tungsten oxides from peroxo-polymolybdotungstate solutions.

PubMed

Kondrachova, Lilia; Hahn, Benjamin P; Vijayaraghavan, Ganesh; Williams, Ryan D; Stevenson, Keith J

2006-12-05

Mixed molybdenum tungsten trioxide films of varying stoichiometry (MoxW1 - xO3, 0 < x < 1) were prepared by cathodic electrodeposition on indium tin oxide (ITO)-coated glass substrates from aqueous peroxo-polymolybdotungstate solutions. Electrochemical quartz crystal microbalance (EQCM), cyclic voltammetry, and chronocoulometry were used to gain insight into the electrodeposition mechanism. The compositional and structural properties were characterized for MoxW1 - xO3 films deposited at intermediate potentials (-0.35 V vs Ag/AgCl) and sintered at 250 degrees C using energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. These studies reveal that films consist of homogeneously mixed MoxW1 - xO3, with an enriched Mo content ranging in composition from 0.4 < x < 0.7 depending upon the mol % Mo present in the deposition solution. Chronoamperometry and spectroelectrochemical measurements were conducted to estimate lithium ion diffusion coefficients and coloration efficiencies for the mixed metal oxide films in 1 M LiClO4/propylene carbonate. The subtle interplay between structural and compositional properties due to the uniform mixing of Mo and W oxide components shows that electrochromic and lithium ion transport properties are moderately enhanced relative to those of single-component WO3 and MoO3 and demonstrate improved structural stability over pure MoO3 polymorphs during electrochemical cycling.

Intrinsically water-repellent copper oxide surfaces; An electro-crystallization approach

NASA Astrophysics Data System (ADS)

Akbari, Raziyeh; Ramos Chagas, Gabriela; Godeau, Guilhem; Mohammadizadeh, Mohammadreza; Guittard, Frédéric; Darmanin, Thierry

2018-06-01

Use of metal oxide thin layers is increased due to their good durability under environmental conditions. In this work, the repeatable nanostructured crystalite Cu2O thin films, developed by electrodeposition method without any physical and chemical modifications, demonstrate good hydrophobicity. Copper (I) oxide (Cu2O) layers were fabricated on gold/Si(1 0 0) substrates by different electrodeposition methods i.e. galvanostatic deposition, cyclic voltammetry, and pulse potentiostatic deposition and using copper sulfate (in various concentrations) as a precursor. The greatest crystalline face on prepared Cu2O samples is (1 1 1) which is the most hydrophobic facet of Cu2O cubic structure. Indeed, different crystallite structures such as nanotriangles and truncated octahedrons were formed on the surface for various electrodeposition methods. The increase of the contact angle (θw) measured by the rest time, reaching to about 135°, was seen at different rates and electrodeposition methods. In addition, two-step deposition surfaces were also prepared by applying two of the mentioned methods, alternatively. In general, the morphology of the two-step deposition surfaces showed some changes compared to that of one-step samples, allowing the formation of different crystallite shapes. Moreover, the wettability behavior showd the larger θw of the two-step deposition layers compared to the related one-step deposition layers. Therefore, the highest observed θw was related to the one of two-step deposition layers due to the creation of small octahedral structures on the surface, having narrow and deep valleys. However, there was an exception which was due to the resulted big structures and broad valleys on the surface. So, it is possible to engineer different crystallites shapes using the proposed two-step deposition method. It is expected that hydrophobic crystallite thin films can be used in environmental and electronic applications to save energy and materials properties.

Nucleation, aggregative growth and detachment of metal nanoparticles during electrodeposition at electrode surfaces† †Electronic supplementary information (ESI) available: S1 Scharifker–Hills model, S2 tapping mode-atomic force microscopy (TM-AFM) image of AM grade HOPG, after exposure to a droplet of 50 mM KNO3, S3 distribution of induction times, S4 results of the modified Cottrell fits at different potentials, S5 FE-SEM images of HOPG after control tip breaking, S6 extended current–time trace. See DOI: 10.1039/c4sc02792b Click here for additional data file.

PubMed Central

Lazenby, Robert A.; Kirkman, Paul M.

2015-01-01

The nucleation and growth of metal nanoparticles (NPs) on surfaces is of considerable interest with regard to creating functional interfaces with myriad applications. Yet, key features of these processes remain elusive and are undergoing revision. Here, the mechanism of the electrodeposition of silver on basal plane highly oriented pyrolytic graphite (HOPG) is investigated as a model system at a wide range of length scales, spanning electrochemical measurements from the macroscale to the nanoscale using scanning electrochemical cell microscopy (SECCM), a pipette-based approach. The macroscale measurements show that the nucleation process cannot be modelled as either truly instantaneous or progressive, and that step edge sites of HOPG do not play a dominant role in nucleation events compared to the HOPG basal plane, as has been widely proposed. Moreover, nucleation numbers extracted from electrochemical analysis do not match those determined by atomic force microscopy (AFM). The high time and spatial resolution of the nanoscale pipette set-up reveals individual nucleation and growth events at the graphite basal surface that are resolved and analysed in detail. Based on these results, corroborated with complementary microscopy measurements, we propose that a nucleation-aggregative growth-detachment mechanism is an important feature of the electrodeposition of silver NPs on HOPG. These findings have major implications for NP electrodeposition and for understanding electrochemical processes at graphitic materials generally. PMID:29560200

Electrodeposited binder-free NiCo2O4@carbon nanofiber as a high performance anode for lithium ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Jie; Chu, Ruixia; Chen, Yanli; Jiang, Heng; Zhang, Ying; Huang, Nay Ming; Guo, Hang

2018-03-01

Binder-free nickel cobaltite on a carbon nanofiber (NiCo2O4@CNF) anode for lithium ion batteries was prepared via a two-step procedure of electrospinning and electrodeposition. The CNF was obtained by annealing electrospun poly-acrylonitrile (PAN) in nitrogen (N2). The NiCo2O4 nanostructures were then grown on the CNF by electrodeposition, followed by annealing in air. Experimental results showed that vertically aligned NiCo2O4 nanosheets had uniformly grown on the surface of the CNF, forming an interconnected network. The NiCo2O4@CNF possessed considerable lithium storage capacity and cycling stability. It exhibited a high reversible capacity of 778 mAhg-1 after 300 cycles at a current density of 0.25 C (1 C = 890 mAg-1) with an average capacity loss rate of 0.05% per cycle. The NiCo2O4@CNF had considerable rate capacities, delivering a capacity of 350 mAhg-1 at a current density of 2.0 C. The outstanding electrochemical performance can be mainly attributed to the following: (1) The nanoscale structure of NiCo2O4 could not only shorten the diffusion path of lithium ions and electrons but also increase the specific surface area, providing more active sites for electrochemical reactions. (2) The CNF with considerable mechanical strength and electrical conductivity could function as an anchor for the NiCo2O4 nanostructure and ensure an efficient electron transfer. (3) The porous structure resulted in a high specific surface area and an effective buffer for the volume changes during the repeated charge-discharge processes. Compared with a conventional hydrothermal method, electrodeposition could significantly simplify the preparation of NiCo2O4, with a shorter preparation period and lower energy consumption. This work provides an alternative strategy to obtain a high performance anode for lithium ion batteries.

Electrochemical preparation of vertically aligned, hollow CdSe nanotubes and their p-n junction hybrids with electrodeposited Cu2O

NASA Astrophysics Data System (ADS)

Debgupta, Joyashish; Devarapalli, Ramireddy; Rahman, Shakeelur; Shelke, Manjusha V.; Pillai, Vijayamohanan K.

2014-07-01

Vertically aligned, hollow nanotubes of CdSe are grown on fluorine doped tin oxide (FTO) coated glass substrates by ZnO nanowire template-assisted electrodeposition technique, followed by selective removal of the ZnO core using NH4OH. A detailed mechanism of nucleation and anisotropic growth kinetics of nanotubes have been studied by a combination of characterization tools such as chronoamperometry, SEM and TEM. Interestingly, ``as grown'' CdSe nanotubes (CdSe NTs) on FTO coated glass plates behave as n-type semiconductors exhibiting an excellent photo-response (with a generated photocurrent density value of ~470 μA cm-2) while in contact with p-type Cu2O (p-type semiconductor, grown separately on FTO plates) because of the formation of a n-p heterojunction (type II). The observed photoresponse is 3 times higher than that of a similar device prepared with electrodeposited CdSe films (not nanotubes) and Cu2O on FTO. This has been attributed to the hollow 1-D nature of CdSe NTs, which provides enhanced inner and outer surface areas for better absorption of light and also assists faster transport of photogenerated charge carriers.Vertically aligned, hollow nanotubes of CdSe are grown on fluorine doped tin oxide (FTO) coated glass substrates by ZnO nanowire template-assisted electrodeposition technique, followed by selective removal of the ZnO core using NH4OH. A detailed mechanism of nucleation and anisotropic growth kinetics of nanotubes have been studied by a combination of characterization tools such as chronoamperometry, SEM and TEM. Interestingly, ``as grown'' CdSe nanotubes (CdSe NTs) on FTO coated glass plates behave as n-type semiconductors exhibiting an excellent photo-response (with a generated photocurrent density value of ~470 μA cm-2) while in contact with p-type Cu2O (p-type semiconductor, grown separately on FTO plates) because of the formation of a n-p heterojunction (type II). The observed photoresponse is 3 times higher than that of a similar device prepared with electrodeposited CdSe films (not nanotubes) and Cu2O on FTO. This has been attributed to the hollow 1-D nature of CdSe NTs, which provides enhanced inner and outer surface areas for better absorption of light and also assists faster transport of photogenerated charge carriers. Electronic supplementary information (ESI) available: See DOI: 10.1039/c3nr06917f

A statistical approach for optimizing parameters for electrodeposition of indium (III) sulfide (In2S3) films, potential low-hazard buffer layers for photovoltaic applications

NASA Astrophysics Data System (ADS)

Mughal, Maqsood Ali

Clean and environmentally friendly technologies are centralizing industry focus towards obtaining long term solutions to many large-scale problems such as energy demand, pollution, and environmental safety. Thin film solar cell (TFSC) technology has emerged as an impressive photovoltaic (PV) technology to create clean energy from fast production lines with capabilities to reduce material usage and energy required to manufacture large area panels, hence, lowering the costs. Today, cost ($/kWh) and toxicity are the primary challenges for all PV technologies. In that respect, electrodeposited indium sulfide (In2S3) films are proposed as an alternate to hazardous cadmium sulfide (CdS) films, commonly used as buffer layers in solar cells. This dissertation focuses upon the optimization of electrodeposition parameters to synthesize In2S3 films of PV quality. The work describe herein has the potential to reduce the hazardous impact of cadmium (Cd) upon the environment, while reducing the manufacturing cost of TFSCs through efficient utilization of materials. Optimization was performed through use of a statistical approach to study the effect of varying electrodeposition parameters upon the properties of the films. A robust design method referred-to as the "Taguchi Method" helped in engineering the properties of the films, and improved the PV characteristics including optical bandgap, absorption coefficient, stoichiometry, morphology, crystalline structure, thickness, etc. Current density (also a function of deposition voltage) had the most significant impact upon the stoichiometry and morphology of In2S3 films, whereas, deposition temperature and composition of the solution had the least significant impact. The dissertation discusses the film growth mechanism and provides understanding of the regions of low quality (for example, cracks) in films. In2S3 films were systematically and quantitatively investigated by varying electrodeposition parameters including bath composition, current density, deposition time and temperature, stir rate, and electrode potential. These parameters individually and collectively exhibited significant correlation with the properties of the films. Digital imaging analysis (using fracture and buckling analysis software) of scanning electron microscope (SEM) images helped to quantify the cracks and study the defects in films. In addition, the effects of different annealing treatments (200 oC, 300 oC, and 400 oC in air) and coated-glass substrates (Mo, ITO, FTO) upon the properties of the In2S3 films were analyzed.

Ultrasonic-electrodeposition of PtPd alloy nanoparticles on ionic liquid-functionalized graphene paper: towards a flexible and versatile nanohybrid electrode

NASA Astrophysics Data System (ADS)

Sun, Yimin; Zheng, Huaming; Wang, Chenxu; Yang, Mengmeng; Zhou, Aijun; Duan, Hongwei

2016-01-01

Here we fabricate a new type of flexible and versatile nanohybrid paper electrode by ultrasonic-electrodeposition of PtPd alloy nanoparticles on freestanding ionic liquid (IL)-functionalized graphene paper, and explore its multifunctional applications in electrochemical catalysis and sensing systems. The graphene-based paper materials demonstrate intrinsic flexibility, exceptional mechanical strength and high electrical conductivity, and therefore can serve as an ideal freestanding flexible electrode for electrochemical devices. Furthermore, the functionalization of graphene with IL (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate) not only increases the electroactive surface area of a graphene-based nanohybrid paper electrode, but also improves the adhesion and dispersion of metal nanoparticles on the paper surface. These unique attributes, combined with the merits of an ultrasonic-electrodeposition method, lead to the formation of PtPd alloy nanoparticles on IL-graphene paper with high loading, uniform distribution, controlled morphology and favourable size. Consequently, the resultant nanohybrid paper electrode exhibits remarkable catalytic activity as well as excellent cycle stability and improved anti-poisoning ability towards electrooxidation of fuel molecules such as methanol and ethanol. Furthermore, for nonenzymatic electrochemical sensing of some specific biomarkers such as glucose and reactive oxygen species, the nanohybrid paper electrode shows high selectivity, sensitivity and biocompatibility in these bio-catalytic processes, and can be used for real-time tracking hydrogen peroxide secretion by living human cells. All these features demonstrate its promising application as a versatile nanohybrid electrode material in flexible and lightweight electrochemical energy conversion and biosensing systems such as bendable on-chip power sources, wearable/implantable detectors and in vivo micro-biosensors.Here we fabricate a new type of flexible and versatile nanohybrid paper electrode by ultrasonic-electrodeposition of PtPd alloy nanoparticles on freestanding ionic liquid (IL)-functionalized graphene paper, and explore its multifunctional applications in electrochemical catalysis and sensing systems. The graphene-based paper materials demonstrate intrinsic flexibility, exceptional mechanical strength and high electrical conductivity, and therefore can serve as an ideal freestanding flexible electrode for electrochemical devices. Furthermore, the functionalization of graphene with IL (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate) not only increases the electroactive surface area of a graphene-based nanohybrid paper electrode, but also improves the adhesion and dispersion of metal nanoparticles on the paper surface. These unique attributes, combined with the merits of an ultrasonic-electrodeposition method, lead to the formation of PtPd alloy nanoparticles on IL-graphene paper with high loading, uniform distribution, controlled morphology and favourable size. Consequently, the resultant nanohybrid paper electrode exhibits remarkable catalytic activity as well as excellent cycle stability and improved anti-poisoning ability towards electrooxidation of fuel molecules such as methanol and ethanol. Furthermore, for nonenzymatic electrochemical sensing of some specific biomarkers such as glucose and reactive oxygen species, the nanohybrid paper electrode shows high selectivity, sensitivity and biocompatibility in these bio-catalytic processes, and can be used for real-time tracking hydrogen peroxide secretion by living human cells. All these features demonstrate its promising application as a versatile nanohybrid electrode material in flexible and lightweight electrochemical energy conversion and biosensing systems such as bendable on-chip power sources, wearable/implantable detectors and in vivo micro-biosensors. Electronic supplementary information (ESI) available: The stress-strain curve of the IL-rGOP, EDX spectrum of PtPd/IL-rGOP, the particle size and size distribution of Pt, PtPd and Pd nanoparticles electrodeposited on IL-rGOP derived from SEM, and the structural parameters of Pt, PtPd and Pd nanoparticles electrodeposited on IL-rGOP derived from XRD, influence of the potential interfering species towards glucose detection. See DOI: 10.1039/c5nr06912b

Electroplating on titanium alloy

NASA Technical Reports Server (NTRS)

Lowery, J. R.

1971-01-01

Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process.

Suppression of dendritic lithium growth in lithium metal-based batteries.

PubMed

Li, Linlin; Li, Siyuan; Lu, Yingying

2018-06-19

Lithium metal-based batteries offer promising prospects as alternatives to today's lithium-ion batteries, due to their ultra-high energy density. Unfortunately, the application of lithium metal is full of challenges and has puzzled researchers for more than 40 years. In this feature article, we describe the history of the development of lithium metal batteries and their existing key challenges, which include non-uniform electrodeposition, volume expansion, high reactivity of the lithium metal/unstable solid electrolyte interphase (SEI), and the shuttling of active cathode materials. Then, we focus on the growth mechanisms of uneven lithium electrodeposition and extend the discussion to the approaches to inhibit lithium dendrites. Finally, we discuss future directions that are expected to drive progress in the development of lithium metal batteries.

Investigation of electroforming techniques, literature analysis report

NASA Technical Reports Server (NTRS)

Malone, G. A.

1975-01-01

A literature analysis is presented of reports, specifications, and documented experiences with the use of electroforming to produce copper and nickel structures for aerospace and other engineering applications. The literature period covered is from 1948 to 1974. Specific effort was made to correlate mechanical property data for the electrodeposited material with known electroforming solution compositions and operating conditions. From this survey, electrolytes are suggested for selection to electroform copper and nickel outer shells on regeneratively cooled thrust chamber liners, and other devices subject to thermal and pressure exposure, based on mechanical properties obtainable, performance under various thermal environments, and ease of process control for product reproducibility. Processes of potential value in obtaining sound bonds between electrodeposited copper and nickel and copper alloy substrates are also discussed.

Electrodeposition of Polymer Nanostructures using Three Diffuse Double Layers: Polymerization beyond the Liquid/Liquid Interfaces

NASA Astrophysics Data System (ADS)

Divya, Velpula; Sangaranarayanan, M. V.

2018-04-01

Nanostructured conducting polymers have received immense attention during the past few decades on account of their phenomenal usefulness in diverse contexts, while the interface between two immiscible liquids is of great interest in chemical and biological applications. Here we propose a novel Electrode(solid)/Electrolyte(aqueous)/Electrolyte(organic) Interfacial assembly for the synthesis of polymeric nanostructures using a novel concept of three diffuse double layers. There exist remarkable differences between the morphologies of the polymers synthesized using the conventional electrode/electrolyte method and that of the new approach. In contrast to the commonly employed electrodeposition at liquid/liquid interfaces, these polymer modified electrodes can be directly employed in diverse applications such as sensors, supercapacitors etc.

Influence of deposition time on the surface morphology and photoelectrochemical properties of copper doped titania nanotubes prepared by electrodeposition

NASA Astrophysics Data System (ADS)

Mahmud, M. A.; Chin, L. Y.; Khusaimi, Z.; Zainal, Z.

2018-05-01

A great attention has focused on Cu doped titania nanotubes (Cu/TiNT) as a versatile advance material since it can be employed in various promising technological applications. The current study reported on the influence of various deposition times on the surface morphology and photoelectrochemical properties of Cu/TiNT via electrodeposition technique. Cu loaded on the TiNT surface was detected with prolonged deposition time. For photoelectrochemical (PEC) measurement, the highest responsive photocurrent density was obtained at 20 minutes with 54.3 µA/cm2. Too long duration (40 mins) resulted in poor performance of Cu/TiNT as only 22.6 µA/cm2 of photocurrent being generated.

Electrodeposition at room temperature of amorphous silicon and germanium nanowires in ionic liquid

NASA Astrophysics Data System (ADS)

Martineau, F.; Namur, K.; Mallet, J.; Delavoie, F.; Endres, F.; Troyon, M.; Molinari, M.

2009-11-01

The electrodeposition at room temperature of silicon and germanium nanowires from the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P1,4) containing SiCl4 as Si source or GeCl4 as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germanium nanowires of different diameters. The nanowires are composed of pure amorphous silicon or germanium. The nanowires have homogeneous cylindrical shape with a roughness of a few nanometres on the wire surfaces. The nanowires' diameters and lengths well match with the initial membrane characteristics. Preliminary photoluminescence experiments exhibit strong emission in the near infrared for the amorphous silicon nanowires.

Magneto-impedance in Multilayered [Ni80Fe20/Cu]4 with modification of the line-length pattern on Cu printed circuit board

NASA Astrophysics Data System (ADS)

Eko Prastyo, Wahyu; Maulana, F.; Nuryani, N.; Purnama, B.

2017-11-01

Magneto-impedance of multilayer [Ni80Fe20/Cu]4 on Cu PCB substrate has successfully studied. To enhance the magneto-impedance we modify the geometry the Cu PCB substrate. The multilayer is made by electro-deposition with Pt (Platinum) as elctrodes. Electro-deposition is made at room temperature. Magneto-impedance total is evaluated under the external magnetic field. The results shows that magneto-impedance curve is symmetry. The difference of line-length result in the difference of the magneto-impedance. The samples is with the longest line-length has the largest magneto-impedance ratio. The homogeneity of the samples is on account estimated the increase magneto-impedance ratio.

Mechanical properties of nanocrystalline cobalt

NASA Astrophysics Data System (ADS)

Karimpoor, Amir A.; Erb, Uwe

2006-05-01

Due to their excellent wear and corrosion properties, nanocrystalline cobalt and several cobalt alloys made by electrodeposition are currently being developed as environmentally benign replacement coatings for hard chromium electrodeposits. The focus of this study is on the mechanical properties of nanocrystalline cobalt, which are currently not well understood. A comparison is presented for hardness, tensile properties, Charpy impact properties and fracture surface analysis of both nanocrystalline (grain size: 12 nm) and conventional polycrystalline (grain size: 4.8 m) cobalt. It is shown that the hardness and tensile strength of nanocrystalline cobalt is 2-3 times higher than for polycrystalline cobalt. However, in contrast to other nanocrystalline materials tested previously, nanocrystalline cobalt retains considerable ductility with elongation to fracture values up to 7%.

Nickel as a catalyst for the electro-oxidation of methanol in alkaline medium

NASA Astrophysics Data System (ADS)

Abdel Rahim, M. A.; Abdel Hameed, R. M.; Khalil, M. W.

The use of Ni as a catalyst for the electro-oxidation of methanol in alkaline medium was studied by cyclic voltammetry. It was found that only Ni dispersed on graphite shows a catalytic activity towards methanol oxidation but massive Ni does not. Ni was dispersed on graphite by the electro-deposition from acidic NiSO 4 solution using potentiostatic and galvanostatic techniques. The catalytic activity of the C/Ni electrodes towards methanol oxidation was found to vary with the amount of electro-deposited Ni. The dependence of the oxidation current on methanol concentration and scan rate was discussed. It was concluded from the electro-chemical measurements and SEM analysis that methanol oxidation starts as Ni-oxide is formed on the electrode surface.

Star tracking reticles

NASA Technical Reports Server (NTRS)

Smith, W. O.; Toft, A. R. (Inventor)

1973-01-01

A method for the production of reticles, particularly those for use in outer space, where the product is a quartz base coated with highly adherent layers of chromium, chromium-silver, and silver vacuum deposited through a mask, and then coated with an electrodeposit of copper from a copper sulfate solution followed by an electrodeposit of black chromium is described. The masks are produced by coating a beryllium-copper alloy substrate with a positive working photoresist, developing the photoresist, according to a pattern to leave a positive mask, plating uncoated areas with gold, removing the photoresist, coating the substrate with a negative working photoresist, developing the negative working photoresist to expose the base metal of the pattern, and chemically etching the unplated side of the pattern to produce the mask.

Enhancement of solar hydrogen evolution from water by surface modification with CdS and TiO2 on porous CuInS2 photocathodes prepared by an electrodeposition-sulfurization method.

PubMed

Zhao, Jiao; Minegishi, Tsutomu; Zhang, Li; Zhong, Miao; Gunawan; Nakabayashi, Mamiko; Ma, Guijun; Hisatomi, Takashi; Katayama, Masao; Ikeda, Shigeru; Shibata, Naoya; Yamada, Taro; Domen, Kazunari

2014-10-27

Porous films of p-type CuInS2, prepared by sulfurization of electrodeposited metals, are surface-modified with thin layers of CdS and TiO2. This specific porous electrode evolved H2 from photoelectrochemical water reduction under simulated sunlight. Modification with thin n-type CdS and TiO2 layers significantly increased the cathodic photocurrent and onset potential through the formation of a p-n junction on the surface. The modified photocathodes showed a relatively high efficiency and stable H2 production under the present reaction conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Contact Ageing Effect on Fretting Damage of an Electro-Deposited Coating against an AISI52100 Steel Ball

PubMed Central

Kim, Kyungmok; Ko, Joon Soo

2016-01-01

This article investigates the effect of contact ageing on fretting damage of an epoxy-based cathodic electro-deposited coating for use on automotive seat slide tracks (made of cold-rolled high strength steel). Static normal load was induced at the contact between the coating and an AISI52100 ball for a certain duration. It was identified that plastically deformed contact area increased logarithmically as a function of time when the contact was under static normal load. Fretting tests after various durations of static contact were conducted using a ball-on-flat plate apparatus. All fretting tests were halted when the friction coefficient reached a critical value of 0.5, indicating complete coating failure. The total number of fretting cycles to the critical friction coefficient was found to vary with the duration of static contact before fretting. It was identified that the number of cycles to the critical friction coefficient decreased with the increased duration of static contact. Meanwhile, the friction coefficient at steady-state sliding was not greatly affected by the duration of static contact before fretting. Finally, the relation between coating thickness after indentation creep and the number of cycles to the critical friction coefficient was found to be linear. Obtained results show that the duration of static contact before fretting has an influence on the fretting lifetime of an electro-deposited coating. PMID:28773873

Design and testing of RFID sensor tag fabricated using inkjet-printing and electrodeposition

NASA Astrophysics Data System (ADS)

Chien Dang, Mau; Son Nguyen, Dat; Dung Dang, Thi My; Tedjini, Smail; Fribourg-Blanc, Eric

2014-06-01

The passive RFID tag with an added sensing function is of interest to many applications. In particular, applications where RFID tagging is already considered to be the next step, such as food items, are a specific target. This paper demonstrates a flexible RFID tag sensor fabricated using a low cost technique with an added zero-cost sensing function. It is more specifically applied to the sensing of degradable food, in particular beef meat in our demonstrated example. To reach this, the antenna is designed in such a way to be sensitive to the variation of the dielectric permittivity of the meat over time. The design of the sensing tag as well as its fabrication process are described. The fabrication involves inkjet printing of a silver nanoparticle based ink on a commercial low cost PET film to create a seed layer. It is followed by a copper electrodeposition step on top of the silver pattern to complete the tag to obtain the desired thickness and conductivity of the tag antenna. The results of the electrical tests showed that with the inkjet printing-electrodeposition combination it is possible to produce flexible electrically conductive patterns for practical RFID applications. The tag was then tested in close-to-real-world conditions and it is demonstrated that it can provide a sensing function to detect the consumption limit of the packaged beef.

Morphology-controlled electrodeposition of Cu{sub 2}O microcrystalline particle films for application in photocatalysis under sunlight

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Guodong; Zhai, Wei; Sun, Fengqiang, E-mail: fqsun@scnu.edu.cn

2012-12-15

Graphical abstract: Display Omitted Highlights: ► PEG was used to electro-deposit Cu{sub 2}O microcrystalline particle films. ► Morphologies of Cu{sub 2}O microcrystals could be controlled by the amount of PEG. ► The films showed regularly varied photocatalytic activities under sunlight. ► The films could be recycled and showed stable activities. -- Abstract: Morphology-controlled Cu{sub 2}O microcrystalline particle films had been successfully electrodeposited on tin-doped indium oxide glass substrates in CuSO{sub 4} solutions containing different amounts of polyethylene glycol (PEG) additives. With an increase of PEG, microcrystals gradually changed from irregular shapes to cubes, octahedrons, and spherical shapes. Sizes increasingly becamemore » smaller with an increase of PEG under the same deposition time. These films had been first used as recyclable photocatalysts and showed excellent and photocatalytic activities in photodegradation of methylene blue (MB) under sunlight. Activities were regularly varied relative to the morphologies of films controlled by the amount of PEG and could be further enhanced by adding a little amount of hydrogen peroxide in the MB solution. The method for controllable preparation of Cu{sub 2}O microcrystals with photocatalytic activities was simple and inexpensive. The as-prepared particle films could also be used in photodegradation of many other pollutants under sunlight.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Tingting; Northeast Petroleum University at Qinhuangdao, Qinhuangdao 066004; Shao, Guangjie, E-mail: shaoguangjie@ysu.edu.cn

A method of pulse electrodeposition under supergravity field was proposed to synthesize MnO{sub 2}-graphene composites. Supergravity is very efficient for promoting mass transfer and decreasing concentration polarization during the electrodeposition process. The synthesis was conducted on our homemade supergravity equipment. The strength of supergravity field depended on the rotating speed of the ring electrode. 3D flower like MnO{sub 2} spheres composed of nanoflakes were acquired when the rotating speed was 3000 rpm. Graphene nanosheets play as a role of conductive substrates for MnO{sub 2} growing. The composites are evaluated as electrode materials for supercapacitors. Electrochemical results show that the maximummore » specific capacitance of the MnO{sub 2}-graphene composite is 595.7 F g{sup −1} at a current density of 0.5 A g{sup −1}. In addition, the composite exhibits excellent cycle stability with no capacitance attenuation after 1000 cycles. The approach provides new ideas for developing supercapacitor electrode materials with high performance. - Graphical abstract: 3D flower like MnO{sub 2} spheres composed of nanoflakes were acquired at 3000 rpm. - Highlights: • MnO{sub 2}-graphene composites were prepared by pulse electrodeposition under supergravity. • 3D flower like MnO{sub 2} spheres are anchored on the graphene nanosheets. • The MnO{sub 2}-graphene electrode exhibits a specific capacitance of 595.7 F g{sup −1}.« less

Testing the role of metal hydrolysis in the anomalous electrodeposition of Ni-Fe alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, T.M.; St. Clair, J.

1996-12-01

With the objective of testing several models of the anomalous codeposition (ACD) encountered in the electrodeposition of nickel-iron alloys, the effects of bath pH and complexing agents on the composition of deposits were examined. When the pH of the base line bath was increased from 3.0 to 5.0, the Ni/Fe mass ratio of the deposit increased (i.e., the deposition became less anomalous). The presence of tartrate ion in the bath produced a slight decrease in the Ni/Fe of the deposit. This complexing agent complexes ferric ion and thus prevents its precipitation but has little interaction with ferrous ion or nickelmore » ion under the electrodeposition conditions examined. The addition of ethylenediamine to the bath produced a significant increase in the Ni/Fe mass ratio. This complexing agent does not interact significantly with ferric ion or ferrous ion under the test conditions. None of these observations are consistent with the Dahms and Croll model of ACD. The effects of pH and tartaric acid on the deposit composition are consistent with the predictions of the Grande and Talbot model and the Matlosz model. The effect of ethylenediamine is not consistent with the Grande and Talbot model, but may be interpreted within the framework of the Matlosz model and the Hessami and Tobias model.« less

The Au(111)/IL interfacial nanostructure in the presence of precursors and its influence on the electrodeposition process.

PubMed

Borisenko, Natalia; Lahiri, Abhishek; Pulletikurthi, Giridhar; Cui, Tong; Carstens, Timo; Zahlbach, Janine; Atkin, Rob; Endres, Frank

2018-01-01

Ionic liquids have attracted significant interest as electrolytes for the electrodeposition of metals and semiconductors, but the details of the deposition processes are not yet well understood. In this paper, we give an overview of how the addition of various precursors (TaF 5 , SiCl 4 , and GaCl 3 ) affects the solid/IL interfacial structure. In situ Atomic Force Microscopy (AFM) and vibrational spectroscopy have been employed to study the changes of the Au(111)/IL interface and in the electrolytes, respectively. Ionic liquids with the 1-butyl-1-methylpyrrolidinium ([Py 1,4 ] + ) cation and bis(trifluoromethylsulfonyl)amide ([TFSA] - ), trifluoromethylsulfonate ([TfO] - ) and tris(pentafluoroethyl)trifluorophosphate ([FAP] - ) as anions were chosen for this purpose. In situ AFM force-distance measurements reveal that both the anion of the IL and the solutes (TaF 5 or GaCl 3 ) influence the Electrical Double Layer (EDL) structure of the Au(111)/IL interface, which can affect the deposition process of Ta and the morphology of the Ga electrodeposits, respectively. Furthermore, the concentration of the precursor can significantly alter the Au(111)/[Py 1,4 ][FAP]-SiCl 4 interfacial structure wherein the presence of 0.25 M SiCl 4 a double layer structure forms that facilitates Si deposition. This study may provide some critical insights into the structure of the electrode/IL interface for specific applications.

Ionomer-Liquid Electrolyte Hybrid Ionic Conductor for High Cycling Stability of Lithium Metal Electrodes

PubMed Central

Song, Jongchan; Lee, Hongkyung; Choo, Min-Ju; Park, Jung-Ki; Kim, Hee-Tak

2015-01-01

The inhomogeneous Li electrodeposition of lithium metal electrode has been a major impediment to the realization of rechargeable lithium metal batteries. Although single ion conducting ionomers can induce more homogeneous Li electrodeposition by preventing Li+ depletion at Li surface, currently available materials do not allow room-temperature operation due to their low room temperature conductivities. In the paper, we report that a highly conductive ionomer/liquid electrolyte hybrid layer tightly laminated on Li metal electrode can realize stable Li electrodeposition at high current densities up to 10 mA cm−2 and permit room-temperature operation of corresponding Li metal batteries with low polarizations. The hybrid layer is fabricated by laminating few micron-thick Nafion layer on Li metal electrode followed by soaking 1 M LiPF6 EC/DEC (1/1) electrolyte. The Li/Li symmetric cell with the hybrid layer stably operates at a high current density of 10 mA cm−2 for more than 2000 h, which corresponds to more than five-fold enhancement compared with bare Li metal electrode. Also, the prototype Li/LiCoO2 battery with the hybrid layer offers cycling stability more than 350 cycles. These results demonstrate that the hybrid strategy successfully combines the advantages of bi-ionic liquid electrolyte (fast Li+ transport) and single ionic ionomer (prevention of Li+ depletion). PMID:26411701

Evaluation of a measurement system for Uranium electrodeposition control to radiopharmaceuticals production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tufic Madi Filho; Adonis Marcelo Saliba Silva; Jose Patricio Nahuel Cardenas

2015-07-01

For 2016, studies by international bodies forecast a crisis in the supply of Molybdenum ({sup 99}Mo), which is the generator of {sup 99m}Tc, widely used for medical diagnoses and treatments. As a result, many countries are making efforts to prevent this crisis. Brazil is developing the Brazilian Multipurpose Reactor (RMB) project, under the responsibility of the National Nuclear Energy Commission (CNEN). The RMB is a nuclear reactor for research and production of radioisotopes used in the production of radiopharmaceuticals and radioactive sources, broadly used in industrial and research areas in Brazil. Electrodeposition of uranium is a common practice to createmore » samples for alpha spectrometry and this methodology may be an alternative way to produce targets of low enriched uranium (LEU) to fabricate radiopharmaceuticals, as {sup 99}Mo, used for cancer diagnosis. To study the electrodeposition, a solution of 10 mM uranyl nitrate, in 2-propanol, containing uranium enriched to 2.4% in {sup 235}U, with pH = 1, was prepared and measurements with an alpha spectrometer were performed. These studies are justified by the need to produce {sup 99}Mo since, despite using molybdenum in bulk, Brazil is totally dependent on its import. In this project, we intend to obtain a process that may be technologically feasible to control the radiation targets for {sup 99}Mo production. (authors)« less

The Contact Ageing Effect on Fretting Damage of an Electro-Deposited Coating against an AISI52100 Steel Ball.

PubMed

Kim, Kyungmok; Ko, Joon Soo

2016-09-03

This article investigates the effect of contact ageing on fretting damage of an epoxy-based cathodic electro-deposited coating for use on automotive seat slide tracks (made of cold-rolled high strength steel). Static normal load was induced at the contact between the coating and an AISI52100 ball for a certain duration. It was identified that plastically deformed contact area increased logarithmically as a function of time when the contact was under static normal load. Fretting tests after various durations of static contact were conducted using a ball-on-flat plate apparatus. All fretting tests were halted when the friction coefficient reached a critical value of 0.5, indicating complete coating failure. The total number of fretting cycles to the critical friction coefficient was found to vary with the duration of static contact before fretting. It was identified that the number of cycles to the critical friction coefficient decreased with the increased duration of static contact. Meanwhile, the friction coefficient at steady-state sliding was not greatly affected by the duration of static contact before fretting. Finally, the relation between coating thickness after indentation creep and the number of cycles to the critical friction coefficient was found to be linear. Obtained results show that the duration of static contact before fretting has an influence on the fretting lifetime of an electro-deposited coating.

Assisted deposition of nano-hydroxyapatite onto exfoliated carbon nanotube oxide scaffolds.

PubMed

Zanin, H; Rosa, C M R; Eliaz, N; May, P W; Marciano, F R; Lobo, A O

2015-06-14

Electrodeposited nano-hydroxyapatite (nHAp) is more similar to biological apatite in terms of microstructure and dimension than apatites prepared by other processes. Reinforcement with carbon nanotubes (CNTs) enhances its mechanical properties and increases adhesion of osteoblasts. Here, we carefully studied nHAp deposited onto vertically aligned multi-walled CNT (VAMWCNT) scaffolds by electrodeposition and soaking in a simulated body fluid (SBF). VAMWCNTs are porous biocompatible scaffolds with nanometric porosity and exceptional mechanical and chemical properties. The VAMWCNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method, and then oxidized and exfoliated by oxygen plasma etching (OPE) to produce graphene oxide (GO) at the VAMWCNT tips. The attachment of oxygen functional groups was found to be crucial for nHAp nucleation during electrodeposition. A thin layer of plate-like and needle-like nHAp with high crystallinity was formed without any need for thermal treatment. This composite (henceforth referred to as nHAp-VAMWCNT-GO) served as the scaffold for in vitro biomineralization when soaked in the SBF, resulting in the formation of both carbonate-rich and carbonate-poor globular-like nHAp. Different steps in the deposition of biological apatite onto VAMWCNT-GO and during the short-term biomineralization process were analysed. Due to their unique structure and properties, such nano-bio-composites may become useful in accelerating in vivo bone regeneration processes.

Assisted deposition of nano-hydroxyapatite onto exfoliated carbon nanotube oxide scaffolds

NASA Astrophysics Data System (ADS)

Zanin, H.; Rosa, C. M. R.; Eliaz, N.; May, P. W.; Marciano, F. R.; Lobo, A. O.

2015-05-01

Electrodeposited nano-hydroxyapatite (nHAp) is more similar to biological apatite in terms of microstructure and dimension than apatites prepared by other processes. Reinforcement with carbon nanotubes (CNTs) enhances its mechanical properties and increases adhesion of osteoblasts. Here, we carefully studied nHAp deposited onto vertically aligned multi-walled CNT (VAMWCNT) scaffolds by electrodeposition and soaking in a simulated body fluid (SBF). VAMWCNTs are porous biocompatible scaffolds with nanometric porosity and exceptional mechanical and chemical properties. The VAMWCNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method, and then oxidized and exfoliated by oxygen plasma etching (OPE) to produce graphene oxide (GO) at the VAMWCNT tips. The attachment of oxygen functional groups was found to be crucial for nHAp nucleation during electrodeposition. A thin layer of plate-like and needle-like nHAp with high crystallinity was formed without any need for thermal treatment. This composite (henceforth referred to as nHAp-VAMWCNT-GO) served as the scaffold for in vitro biomineralization when soaked in the SBF, resulting in the formation of both carbonate-rich and carbonate-poor globular-like nHAp. Different steps in the deposition of biological apatite onto VAMWCNT-GO and during the short-term biomineralization process were analysed. Due to their unique structure and properties, such nano-bio-composites may become useful in accelerating in vivo bone regeneration processes.

Bright metal coatings from sustainable electrolytes: the effect of molecular additives on electrodeposition of nickel from a deep eutectic solvent.

PubMed

Abbott, Andrew P; Ballantyne, Andrew; Harris, Robert C; Juma, Jamil A; Ryder, Karl S

2017-01-25

Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the [111] orientation whereas DMH and BA direct crystal growth to the [220] orientation.

Poly(vinyl Alcohol) Borate Gel Polymer Electrolytes Prepared by Electrodeposition and Their Application in Electrochemical Supercapacitors.

PubMed

Jiang, Mengjin; Zhu, Jiadeng; Chen, Chen; Lu, Yao; Ge, Yeqian; Zhang, Xiangwu

2016-02-10

Gel polymer electrolytes (GPEs) have been studied for preparing flexible and compact electrochemical energy storage devices. However, the preparation and use of GPEs are complex, and most GPEs prepared through traditional methods do not have good wettability with the electrodes, which retard them from achieving their performance potential. In this study, these problems are addressed by conceiving and implementing a simple, but effective, method of electrodepositing poly(vinyl alcohol) potassium borate (PVAPB) GPEs directly onto the surfaces of active carbon electrodes for electrochemical supercapacitors. PVAPB GPEs serve as both the electrolyte and the separator in the assembled supercapacitors, and their scale and shape are determined solely by the geometry of the electrodes. PVAPB GPEs have good bonding to the active electrode materials, leading to excellent and stable electrochemical performance of the supercapacitors. The electrochemical performance of PVAPB GPEs and supercapacitors can be manipulated simply by adjusting the concentration of KCl salt used during the electrodeposition process. With a 0.9 M KCl concentration, the as-prepared supercapacitors deliver a specific capacitance of 65.9 F g(-1) at a current density of 0.1 A g(-1) and retain more than 95% capacitance after 2000 charge/discharge cycles at a current density of 1 A g(-1). These supercapacitors also exhibit intelligent high voltage self-protection function due to the electrolysis-induced cross-linking effect of PVAPB GPEs.

Ionomer-Liquid Electrolyte Hybrid Ionic Conductor for High Cycling Stability of Lithium Metal Electrodes

NASA Astrophysics Data System (ADS)

Song, Jongchan; Lee, Hongkyung; Choo, Min-Ju; Park, Jung-Ki; Kim, Hee-Tak

2015-09-01

The inhomogeneous Li electrodeposition of lithium metal electrode has been a major impediment to the realization of rechargeable lithium metal batteries. Although single ion conducting ionomers can induce more homogeneous Li electrodeposition by preventing Li+ depletion at Li surface, currently available materials do not allow room-temperature operation due to their low room temperature conductivities. In the paper, we report that a highly conductive ionomer/liquid electrolyte hybrid layer tightly laminated on Li metal electrode can realize stable Li electrodeposition at high current densities up to 10 mA cm-2 and permit room-temperature operation of corresponding Li metal batteries with low polarizations. The hybrid layer is fabricated by laminating few micron-thick Nafion layer on Li metal electrode followed by soaking 1 M LiPF6 EC/DEC (1/1) electrolyte. The Li/Li symmetric cell with the hybrid layer stably operates at a high current density of 10 mA cm-2 for more than 2000 h, which corresponds to more than five-fold enhancement compared with bare Li metal electrode. Also, the prototype Li/LiCoO2 battery with the hybrid layer offers cycling stability more than 350 cycles. These results demonstrate that the hybrid strategy successfully combines the advantages of bi-ionic liquid electrolyte (fast Li+ transport) and single ionic ionomer (prevention of Li+ depletion).

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100).

PubMed

Abidin, Mastura Shafinaz Zainal; Matsumura, Ryo; Anisuzzaman, Mohammad; Park, Jong-Hyeok; Muta, Shunpei; Mahmood, Mohamad Rusop; Sadoh, Taizoh; Hashim, Abdul Manaf

2013-11-06

We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm -1 corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm -1 corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.

Tailoring magnetic properties in arrays of pulse-electrodeposited Co nanowires: The role of Cu additive

NASA Astrophysics Data System (ADS)

Esmaeili, A.; Almasi Kashi, M.; Ramazani, A.; Montazer, A. H.

2016-01-01

In this study, we aim to report the role of Cu additive in arrays of pulse-electrodeposited Co nanowires (NWs) with diameters from 30 to 75 nm, embedded in porous aluminum oxide templates. This features the role of Cu additive in composition and crystalline characteristics as well as in the magnetic properties of Co NWs. Increasing the duration of off-time between pulses during the electrodeposition of Co NWs made it possible to increase the amount of Cu content, so that Co-rich CoCu NWs were obtained. The parallel coercivity and squareness values increased up to 1500 Oe and 0.8 for 30 nm diameter Co94Cu6 NWs, starting from 500 Oe and 0.3 for pure Co NWs. On the other hand, although there was a substantial difference between the crystalline characteristics of 75 nm diameter pure Co and CoCu NWs, no considerable change in their magnetic properties was observed using hysteresis loop measurements. In this respect, the first-order reversal curve (FORC) analysis revealed strong inter-wire magnetostatic interactions for the CoCu NWs. Moreover, we studied the effect of thermal annealing, which resulted in an increase in the coercivity of CoCu NWs with different diameters up to 15%. As a result, the addition of small amount of Cu provides an alternative approach to tailoring the magnetic properties of Co NWs.

Study on influence of Surface roughness of Ni-Al2O3 nano composite coating and evaluation of wear characteristics

NASA Astrophysics Data System (ADS)

Raghavendra, C. R.; Basavarajappa, S.; Sogalad, Irappa

2018-02-01

Electrodeposition is one of the most technologically feasible and economically superior techniques for producing metallic coating. The advancement in the application of nano particles has grabbed the attention in all fields of engineering. In this present study an attempt has been made on the Ni-Al2O3nano particle composite coating on aluminium substrate by electrodeposition process. The aluminium surface requires a specific pre-treatment for better adherence of coating. In light of this a thin zinc layer is coated on the aluminium substrate by electroless process. In addition to this surface roughness is an important parameter for any coating method and material. In this work Ni-Al2O3 composite coating were successfully coated by varying the process parameters such as bath temperature, current density and particle loading. The experimentation was performed using central composite design based 20 trials of experiments. The effect of process parameters and surface roughness before and after coating is analyzed on wear rate and coating thickness. The results shown a better wear resistance of Ni-Al2O3 composite electrodeposited coating compared to Ni coating. The particle loading and interaction effect of current density with temperature has greater significant effect on wear rate. The surface roughness is significantly affected the wear behaviour and thickness of coating.

Electrochemical synthesis and characterization of zinc oxalate nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com; Roushani, Mahmoud; Department of Chemistry, Ilam University, Ilam

2013-03-15

Highlights: ► Synthesis of zinc oxalate nanoparticles via electrolysis of a zinc plate anode in sodium oxalate solutions. ► Design of a Taguchi orthogonal array to identify the optimal experimental conditions. ► Controlling the size and shape of particles via applied voltage and oxalate concentration. ► Characterization of zinc oxalate nanoparticles by SEM, UV–vis, FT-IR and TG–DTA. - Abstract: A rapid, clean and simple electrodeposition method was designed for the synthesis of zinc oxalate nanoparticles. Zinc oxalate nanoparticles in different size and shapes were electrodeposited by electrolysis of a zinc plate anode in sodium oxalate aqueous solutions. It was foundmore » that the size and shape of the product could be tuned by electrolysis voltage, oxalate ion concentration, and stirring rate of electrolyte solution. A Taguchi orthogonal array design was designed to identify the optimal experimental conditions. The morphological characterization of the product was carried out by scanning electron microscopy. UV–vis and FT-IR spectroscopies were also used to characterize the electrodeposited nanoparticles. The TG–DTA studies of the nanoparticles indicated that the main thermal degradation occurs in two steps over a temperature range of 350–430 °C. In contrast to the existing methods, the present study describes a process which can be easily scaled up for the production of nano-sized zinc oxalate powder.« less

Disulphide linkage: To get cleaved or not? Bulk and nano copper based SERS of cystine

NASA Astrophysics Data System (ADS)

P. J., Arathi; Seemesh, Bhaskar; Rajendra Kumar Reddy, G.; Suresh Kumar, P.; Ramanathan, V.

2018-05-01

Different nano-structures of noble metals have been the conventional substrates for carrying out Surface Enhanced Raman Spectroscopy (SERS). In this paper we examine electrodeposited copper (Cu) nano-structures on pencil graphite as novel substrate to carry out SERS measurements by considering L-cystine (Cys-Cys) (dimer of the amino acid cysteine) as the probe. The formation of monolayer of the probe molecule on the substrates was confirmed using cyclic voltammetric measurements. Mode of adsorption of Cys-Cys was observed to be different on bulk Cu (taken in the wire form) and nano-structured Cu on pencil graphite. Whereas in the former the disulphide bond of Cys-Cys remained intact, it got cleaved when Cys-Cys was adsorbed on electrodeposited copper indicating the activated nature of the nano-structure compared to bulk copper. Csbnd S stretching mode of vibration underwent blue shift in Cys-Cys adsorbed on Cu on pencil graphite vis-à-vis Cys-Cys adsorbed on Cu wire. Further evidence on the cleavage of the Csbnd S bond on an activated substrate was obtained by considering a bimetallic substrate comprising of silver on copper which was electrodeposited on pencil graphite. Our studies have demonstrated that nano-copper surface is an excellent substrate for SERS giving 200 μM as lower detection limit for Cys-Cys.

The effects of anode material type on the optoelectronic properties of electroplated CdTe thin films and the implications for photovoltaic application

NASA Astrophysics Data System (ADS)

Echendu, O. K.; Dejene, B. F.; Dharmadasa, I. M.

2018-03-01

The effects of the type of anode material on the properties of electrodeposited CdTe thin films for photovoltaic application have been studied. Cathodic electrodeposition of two sets of CdTe thin films on glass/fluorine-doped tin oxide (FTO) was carried out in two-electrode configuration using graphite and platinum anodes. Optical absorption spectra of films grown with graphite anode displayed significant spread across the deposition potentials compared to those grown with platinum anode. Photoelectrochemical cell result shows that the CdTe grown with graphite anode became p-type after post-deposition annealing with prior CdCl2 treatment, as a result of carbon incorporation into the films, while those grown with platinum anode remained n-type after annealing. A review of recent photoluminescence characterization of some of these CdTe films reveals the persistence of a defect level at (0.97-0.99) eV below the conduction band in the bandgap of CdTe grown with graphite anode after annealing while films grown with platinum anode showed the absence of this defect level. This confirms the impact of carbon incorporation into CdTe. Solar cell made with CdTe grown with platinum anode produced better conversion efficiency compared to that made with CdTe grown using graphite anode, underlining the impact of anode type in electrodeposition.

Parameters controlling microstructures and resistance switching of electrodeposited cuprous oxide thin films

NASA Astrophysics Data System (ADS)

Yazdanparast, Sanaz

2016-12-01

Cuprous oxide (Cu2O) thin films were electrodeposited cathodically from a highly alkaline bath using tartrate as complexing agent. Different microstructures for Cu2O thin films were achieved by varying the applied potential from -0.285 to -0.395 V versus a reference electrode of Ag/AgCl at 50 °C in potentiostatic mode, and separately by changing the bath temperature from 25 to 50 °C in galvanostatic mode. Characterization experiments showed that both grain size and orientation of Cu2O can be controlled by changing the applied potential. Applying a high negative potential of -0.395 V resulted in smaller grain size of Cu2O thin films with a preferred orientation in [111] direction. An increase in the bath temperature in galvanostatic electrodeposition increased the grain size of Cu2O thin films. All the films in Au/Cu2O/Au-Pd cell showed unipolar resistance switching behavior after an initial FORMING process. Increasing the grain size of Cu2O thin films and decreasing the top electrode area increased the FORMING voltage and decreased the current level of high resistance state (HRS). The current in low resistance state (LRS) was independent of the top electrode area and the grain size of deposited films, suggesting a filamentary conduction mechanism in unipolar resistance switching of Cu2O.

Phase partitioning, crystal growth, electrodeposition and cosmic ray experiments in microgravity

NASA Technical Reports Server (NTRS)

Wessling, Francis C.

1987-01-01

Five experiments are contained in one Get Away Special Canister (5 cu ft). The first utilizes microgravity to separate biological cells and to study the mechanism of phase partitioning in 12 separate cuvettes. Two experiments are designed to grow organic crystals by physical vapor transport. One experiment consists of eight electroplating cells with various chemicals to produce surfaces electroplated in microgravity. Some of the surfaces have micron sized particles of hard materials co-deposited during electrodeposition. The fifth experiment intercepts cosmic ray particles and records their paths on photographic emulsions. The first four experiments are controlled by an on-board C-MOS controller. The fifth experiment is totally passive. These are the first in Space. Their purpose is to create new commercial products with microgravity processing.

Alkaline Ammonia Electrolysis on Electrodeposited Platinum for Controllable Hydrogen Production.

PubMed

Gwak, Jieun; Choun, Myounghoon; Lee, Jaeyoung

2016-02-19

Ammonia is beginning to attract a great deal of attention as an alternative energy source carrier, because clean hydrogen can be produced through electrolytic processes without the emission of COx . In this study, we deposited various shapes of Pt catalysts under potentiostatic mode; the electrocatalytic oxidation behavior of ammonia using these catalysts was studied in alkaline media. The electrodeposited Pt was characterized by both qualitative and quantitative analysis. To discover the optimal structure and the effect of ammonia concentration, the bulk pH value, reaction temperature, and applied current of ammonia oxidation were investigated using potential sweep and galvanostatic methods. Finally, ammonia electrolysis was conducted using a zero-gap cell, producing highly pure hydrogen with an energy efficiency over 80 %. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Forming a structure of the CoNiFe alloys by X-ray irradiation

NASA Astrophysics Data System (ADS)

Valko, Natalia; Kasperovich, Andrey; Koltunowicz, Tomasz N.

The experimental data of electrodeposition kinetics researches and structure formation of ternary CoNiFe alloys deposited onto low-carbon steel 08kp in the presence of X-rays are presented. Relations of deposit rate, current efficiencies, element and phase compositions of CoNiFe coatings formed from sulfate baths with respect to cathode current densities (0.5-3A/dm2), electrolyte composition and irradiation were obtained. It is shown that, the CoNiFe coatings deposited by the electrochemical method involving exposure of the X-rays are characterized by more perfect morphology surfaces with less developed surface geometry than reference coatings. The effect of the X-ray irradiation on the electrodeposition of CoNiFe coatings promotes formatting of alloys with increased electropositive component and modified phase composition.

Pulse Current Electrodeposition and Anticorrosion Performance of Ni-W-Mica Composite Coatings

NASA Astrophysics Data System (ADS)

Yang, Qiangbin; He, Yi; Fan, Yi; Li, Han; Xu, Wei; Zhan, Yingqing

2017-03-01

Ni-W-mica composite coatings were prepared on C45 steel via pulse electrodeposition from a Watts bath containing mica. The mica particles were co-deposited into the Ni-W coating matrix, and the structures, morphologies and mechanical performances of the coatings were investigated. Scanning electron microscopy and energy dispersive x-ray spectroscopy revealed that a small amount of mica caused the Ni-W-mica coating to form of a compact and uniform surface structure. The electrochemical behaviors of the coatings were evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy in 3.5 wt.% NaCl solutions at pH 7 and under typical engineering application environments. The results revealed that the addition of mica to the Ni-W coating could improve the corrosion resistance of the coating.

Computer-Assisted Optimization of Electrodeposited Hydroxyapatite Coating Parameters on Medical Alloys

NASA Astrophysics Data System (ADS)

Coşkun, M. İbrahim; Karahan, İsmail H.; Yücel, Yasin; Golden, Teresa D.

2016-04-01

CoCrMo bio-metallic alloys were coated with a hydroxyapatite (HA) film by electrodeposition using various electrochemical parameters. Response surface methodology and central composite design were used to optimize deposition parameters such as electrolyte pH, deposition potential, and deposition time. The effects of the coating parameters were evaluated within the limits of solution pH (3.66 to 5.34), deposition potential (-1.13 to -1.97 V), and deposition time (6.36 to 73.64 minutes). A 5-level-3-factor experimental plan was used to determine ideal deposition parameters. Optimum conditions for the deposition parameters of the HA coating with high in vitro corrosion performance were determined as electrolyte pH of 5.00, deposition potential of -1.8 V, and deposition time of 20 minutes.

Reproducible and recyclable SERS substrates: Flower-like Ag structures with concave surfaces formed by electrodeposition

NASA Astrophysics Data System (ADS)

Bian, Juncao; Shu, Shiwei; Li, Jianfu; Huang, Chao; Li, Yang Yang; Zhang, Rui-Qin

2015-04-01

Direct synthesis of three-dimensional Ag structures on solid substrates for the purposes of producing reproducible and recyclable surface-enhanced Raman scattering (SERS) applications remains challenging. In this work, flower-like Ag structures with concave surfaces (FACS) were successfully electrodeposited onto ITO glass using the double-potentiostatic method. The FACS, with an enhancement factor of the order of 108, exhibited a SERS signal intensity 3.3 times stronger than that measured from Ag nanostructures without concave surfaces. A cleaning procedure involving lengthy immersion of the sample in ethanol and KNO3 was proposed to recycle the substrate and confirmed by using rhodamine 6G, adenine, and 4-aminothiophenol as target molecules. The findings can help to advance the practical applications of Ag nanostructure-based SERS substrates.

Preparation of transparent conductors ferroelectric memory materials and ferrites

DOEpatents

Bhattacharya, Raghu Nath; Ginley, David S.

1998-01-01

A process for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

Dendritic Ag-Fe nanocrystalline alloy synthesized by pulsed electrodeposition and its characterization

NASA Astrophysics Data System (ADS)

Santhi, Kalavathy; Revathy, T. A.; Narayanan, V.; Stephen, A.

2014-10-01

Synthesis of dendrite shaped Ag-Fe alloy nanomaterial by pulsed electrodeposition route was investigated. The alloy samples were deposited at different current densities from electrolytes of different compositions to study the influence of current density and bath composition on metal contents in the alloy, which was determined by ICP-OES analysis. The XRD studies were carried out to determine the structure of these samples. Magnetic characterization at room temperature and during heating was carried out to understand their magnetic behaviour and to confirm the inferences drawn from the XRD results. The XPS spectra proved the presence of Fe and Ag in the metallic form in the alloy samples. The FESEM and TEM micrographs were taken to view the surface morphology of the nanosized particles.

Electro-deposition painting process improvement of cab truck by Six Sigma concept

NASA Astrophysics Data System (ADS)

Kawitu, Kitiya; Chutima, Parames

2017-06-01

The case study company is a manufacturer of trucks and currently facing a high rework cost due to the thickness of the electro-deposited paint (EDP) of the truck cab is lower than standard. In addition, the process capability is very low. The Six Sigma concept consisting of 5 phases (DMAIC) is applied to determine new parameter settings for each significant controllable factor. After the improvement, EDP thickness of the truck cab increases from 17.88μ to 20μ (i.e. standard = 20 ± 3μ). Moreover, the process capability indexes (Cp and Cpk) are increased from 0.9 to 1.43, and from 0.27 to 1.43, respectively. This improvement could save the rework cost about 1.6M THB per year.

Superhydrophobic surfaces by electrochemical processes.

PubMed

Darmanin, Thierry; Taffin de Givenchy, Elisabeth; Amigoni, Sonia; Guittard, Frederic

2013-03-13

This review is an exhaustive representation of the electrochemical processes reported in the literature to produce superhydrophobic surfaces. Due to the intensive demand in the elaboration of superhydrophobic materials using low-cost, reproducible and fast methods, the use of strategies based on electrochemical processes have exponentially grown these last five years. These strategies are separated in two parts: the oxidation processes, such as oxidation of metals in solution, the anodization of metals or the electrodeposition of conducting polymers, and the reduction processed such as the electrodeposition of metals or the galvanic deposition. One of the main advantages of the electrochemical processes is the relative easiness to produce various surface morphologies and a precise control of the structures at a micro- or a nanoscale. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposited Fe-Co films prepared from a citric-acid-based plating bath

NASA Astrophysics Data System (ADS)

Yanai, T.; Uto, H.; Shimokawa, T.; Nakano, M.; Fukunaga, H.; Suzuki, K.

2013-06-01

Electrodeposited Fe-Co films are commonly prepared in a boric-acid-based bath. In this research, we applied citric acid instead of boric acid for the plating of Fe-Co films because boron in the waste bath is restricted by environmental-protection regulations in Japan. We evaluated the effect of citric acid on the magnetic and structural properties of the films. The saturation magnetization of the Fe-Co films slightly increased while the Fe content in the Fe-Co films decreased with increasing citric acid concentration. The lowest coercivity value of 240 A/m was obtained at a citric acid concentration of 100 g/L. The plating bath with this citric acid concentration enabled us to obtain Fe-Co films with high saturation magnetizations and smooth surface morphologies.

Fractal growth of platinum electrodeposits revealed by in situ electron microscopy.

PubMed

Wang, Lifen; Wen, Jianguo; Sheng, Huaping; Miller, Dean J

2016-10-06

Fractals are commonly observed in nature and elucidating the mechanisms of fractal-related growth is a compelling issue for both fundamental science and technology. Here we report an in situ electron microscopy study of dynamic fractal growth of platinum during electrodeposition in a miniaturized electrochemical cell at varying growth conditions. Highly dendritic growth - either dense branching or ramified islands - are formed at the solid-electrolyte interface. We show how the diffusion length of ions in the electrolyte influences morphology selection and how instability induced by initial surface roughness, combined with local enhancement of electric field, gives rise to non-uniform branched deposition as a result of nucleation/growth at preferred locations. Comparing the growth behavior under these different conditions provides new insight into the fundamental mechanisms of platinum nucleation.

Effect of Mg2+ on acidic calcium phosphate phases grown by electrodeposition

NASA Astrophysics Data System (ADS)

Correia, Matheus Bento; Júnior, José Pedro Gualberto; Macedo, Michelle Cardinale S. S.; Resende, Cristiane Xavier; dos Santos, Euler Araujo

2017-10-01

In this work, the effect of Mg2+ ions on the electrodeposition of dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP) and calcium-deficient hydroxyapatite (CDHA) crystals on a commercially pure titanium (cp-Ti) substrate was evaluated. We demonstrated that Mg2+ ions could change the morphology of the coatings by inhibiting the growth rate of the OCP and CDHA crystals and diminishing the crystallite size of DCPD. The inhibition effect on OCP and CDHA was most likely due to a surface adsorption mechanism since no evidence of a doping process was observed using Rietveld refinement and electron diffraction analyses. Conversely, the presence of Mg2+ ions generated a favorable condition for the nucleation of a new Mg2+-rich DCPD crystal population, presenting smaller crystallite sizes.

Nano-Nucleation Characteristic of Cu-Ag Alloy Directly Electrodeposited on W Diffusion Barrier for Microelectronic Device Interconnect.

PubMed

Kim, Kang O; Kim, Sunjung

2016-05-01

Cu-Ag alloy interconnect is promising for ultra-large-scale integration (ULSI) microelectronic system of which device dimension keeps shrinking. In this study, seedless electrodeposition of Cu-Ag alloy directly on W diffusion barrier as interconnect technology is presented in respect of nano-nucleation control. Chemical equilibrium state of electrolyte was fundamentally investigated according to the pH of electrolyte because direct nano-nucleation of Cu-Ag alloy on W surface is challenging. Chelation behavior of Cu2+ and Ag+ ions with citrate (Cit) and ammonia ligands was dependent on the pH of electrolyte. The amount and kind of Cu- and Ag-based complexes determine the deposition rate, size, elemental composition, and surface morphology of Cu-Ag alloy nano-nuclei formed on W surface.

Method for providing uranium with a protective copper coating

DOEpatents

Waldrop, Forrest B.; Jones, Edward

1981-01-01

The present invention is directed to a method for providing uranium metal with a protective coating of copper. Uranium metal is subjected to a conventional cleaning operation wherein oxides and other surface contaminants are removed, followed by etching and pickling operations. The copper coating is provided by first electrodepositing a thin and relatively porous flash layer of copper on the uranium in a copper cyanide bath. The resulting copper-layered article is then heated in an air or inert atmosphere to volatilize and drive off the volatile material underlying the copper flash layer. After the heating step an adherent and essentially non-porous layer of copper is electro-deposited on the flash layer of copper to provide an adherent, multi-layer copper coating which is essentially impervious to corrosion by most gases.

Flower-like Rh/Cu superhydrophobic coating via electrodeposition and its self-cleaning property

NASA Astrophysics Data System (ADS)

Zhao, N.; Lu, S. X.; Xu, W. G.; Cheng, X. L.

2017-01-01

Rh/Cu superhydrophobic coatings with textured flower-like dual micro-nano structures were fabricated on copper substrates via electrodesposition of Rh followed by annealing treatment. The scanning electron microscopy and X-ray diffraction pattern were conducted to analyse the morphology and chemical composition of the coating surfaces, respectively. The water drops exhibited a water contact angle of 168±1° and a sliding angle of 0±1° on the coating surfaces which were obtained by etching in concentrated hydrochloric acid and nitric acid, electrodeposited at -1.0 V for 30 min and annealing in an oven at 180°C for 60 min. The prepared superhydrophobic coatings showed excellent water repellence and self-cleaning property due to its extremely high water contact angle.

Electrodeposited three-dimensional Ni-Si nanocable arrays as high performance anodes for lithium ion batteries.

PubMed

Liu, Hao; Hu, Liangbin; Meng, Ying Shirley; Li, Quan

2013-11-07

A configuration of three-dimensional Ni-Si nanocable array anodes is proposed to overcome the severe volume change problem of Si during the charging-discharging process. In the fabrication process, a simple and low cost electrodeposition is employed to deposit Si instead of the common expansive vapor phase deposition methods. The optimum composite nanocable array electrode achieves a high specific capacity ~1900 mA h g(-1) at 0.05 C. After 100 cycles at 0.5 C, 88% of the initial capacity (~1300 mA h g(-1)) remains, suggesting its good capacity retention ability. The high performance of the composite nanocable electrode is attributed to its excellent adhesion of the active material on the three-dimensional current collector and short ionic/electronic transport pathways during cycling.

Synthesis of ceria based superhydrophobic coating on Ni20Cr substrate via cathodic electrodeposition.

PubMed

Pedraza, F; Mahadik, S A; Bouchaud, B

2015-12-21

In this work, superhydrophobic cerium oxide coating surface (111) with dual scale texture on Ni20Cr substrate is obtained by combination of electropolishing the substrate and subsequent cathodic electrodeposition and long-term UVH surface relaxation. To form hierarchical structures of CeO2 is controllable by varying the substrate roughness, and electropolishing period. The results indicated that at the optimal condition, the surface of the cerium oxide coating showed a superhydrophobicity with a great water contact angle (151.0 ± 1.4°) with Gecko state. An interface model for electropolishing of substrate surface in cerium nitrate medium is proposed. We expect that this facile process can be readily and widely adopted for the design of superhydrophobic coating on engineering materials.

40 CFR 413.11 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS ELECTROPLATING POINT SOURCE CATEGORY Electroplating of Common Metals Subcategory § 413.11... electroplating process in which a metal is electrodeposited on a basis material and which is followed by a rinse...

40 CFR 413.21 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS ELECTROPLATING POINT SOURCE CATEGORY Electroplating of Precious Metals Subcategory § 413.21... electroplating process in which a metal is electrodeposited on a basis material and which is followed by a rinse...

In Situ Electrochemical Deposition of Microscopic Wires

NASA Technical Reports Server (NTRS)

Yun, Minhee; Myung, Nosang; Vasquez, Richard

2005-01-01

A method of fabrication of wires having micron and submicron dimensions is built around electrochemical deposition of the wires in their final positions between electrodes in integrated circuits or other devices in which the wires are to be used. Heretofore, nanowires have been fabricated by a variety of techniques characterized by low degrees of controllability and low throughput rates, and it has been necessary to align and electrically connect the wires in their final positions by use of sophisticated equipment in expensive and tedious post-growth assembly processes. The present method is more economical, offers higher yields, enables control of wire widths, and eliminates the need for post-growth assembly. The wires fabricated by this method could be used as simple electrical conductors or as transducers in sensors. Depending upon electrodeposition conditions and the compositions of the electroplating solutions in specific applications, the wires could be made of metals, alloys, metal oxides, semiconductors, or electrically conductive polymers. In this method, one uses fabrication processes that are standard in the semiconductor industry. These include cleaning, dry etching, low-pressure chemical vapor deposition, lithography, dielectric deposition, electron-beam lithography, and metallization processes as well as the electrochemical deposition process used to form the wires. In a typical case of fabrication of a circuit that includes electrodes between which microscopic wires are to be formed on a silicon substrate, the fabrication processes follow a standard sequence until just before the fabrication of the microscopic wires. Then, by use of a thermal SiO-deposition technique, the electrodes and the substrate surface areas in the gaps between them are covered with SiO. Next, the SiO is electron-beam patterned, then reactive-ion etched to form channels having specified widths (typically about 1 m or less) that define the widths of the wires to be formed. Drops of an electroplating solution are placed on the substrate in the regions containing the channels thus formed, then the wires are electrodeposited from the solution onto the exposed portions of the electrodes and into the channels. The electrodeposition is a room-temperature, atmospheric-pressure process. The figure shows an example of palladium wires that were electrodeposited into 1-mm-wide channels between gold electrodes.

Electrodeposited reduced graphene oxide incorporating polymerization of l-lysine on electrode surface and its application in simultaneous electrochemical determination of ascorbic acid, dopamine and uric acid.

PubMed

Zhang, Dongdong; Li, Lingzhi; Ma, Weina; Chen, Xia; Zhang, Yanmin

2017-01-01

This paper demonstrates a novel strategy for the construction of a graphene hybrid composites film, which was fabricated by electrodeposited reduced graphene oxide (ERGO) incorporating polymerization of l-lysine (PLL) onto glassy carbon electrode (GCE). Here we show that graphene films can be prepared on electrodes directly from GO dispersions by one-step electrodeposition technique based on electropolymerized PLL as a positively charged polymer interface to adsorb negatively charged GO nanosheets through electrostatic attraction. The thickness of graphene film can be easily controlled by using the electrodeposition technique, a distinct advantage over previously developed methods. The electrochemically reduced process of GO and electropolymerization of l-lysine were investigated by cyclic voltammetry with a wide potential range. The surface morphology of the modified electrode was characterized by scanning electron microscopy. The ERGO/PLL/GCE shows conducive to electron transfer kinetics for Fe(CN) 6 3- /Fe(CN) 6 4- redox probes, compared with bare GCE, PLL/GCE and ERGO/GCE. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA) and uric acid (UA) at ERGO/PLL/GCE were investigated by cyclic voltammetry, and the results suggest that the modified electrode exhibits enhanced electrocatalytic activity toward these important molecules. Under physiological condition and in the co-existence system of AA, DA and UA, the ERGO/PLL/GCE showed linear voltammetric responses in the concentration of 100μM-1200μM for AA, 2.0μM-60μM for DA and 20μM-200μM for UA, and with the detection limits (S/N=3) of 2.0μM, 0.10μM and 0.15μM for AA, DA and UA, respectively. The developed method has been applied to simultaneous determination of AA, DA and UA in human urine with satisfactory recoveries of 104.2%, 95.4% and 99.9%, respectively. This work demonstrates that the attractive features of ERGO/PLL provide promising applications in simultaneous determination of AA, DA and UA in physiological and pathological studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrodeposition of bismuth:tellurium nanowire arrays into porous alumina templates for thermoelectric applications

NASA Astrophysics Data System (ADS)

Trahey, Lynn

Bismuth telluride is a well-known thermoelectric material for refrigeration applications. Thermoelectrics possess several advantages over conventional refrigeration and power generation devices, yet are not widely-used due to low efficiencies. It has been predicted and shown experimentally that the efficiency of thermoelectric devices increases when the semiconducting materials have reduced dimensions. Therefore, the aim of this research was to show enhanced thermoelectric efficiency in one-dimensional nanowires. The nanowires were synthesized via electrochemical deposition into porous alumina templates. Electrodeposition is a versatile technique that ensures electrical continuity in the deposited material. The nanowire templates, porous alumina, were made by the double anodization of high-purity aluminum foil in oxalic acid solutions. This technique produces parallel, hexagonally packed, and nanometer-range diameter pores that can reach high aspect ratios (greater than 2000:1). The main anodization variables (electrolyte concentration, applied potential, 2nd anodization time, and temperature) were studied systematically in order to deconvolute their effects on the resulting pores and to obtain high aspect ratio pores. The porous alumina is of great importance because the pore dimensions determine the dimensions of the electrodeposited nanowires, which influence the thermoelectric performance of the nanowire arrays. Nanowire arrays were characterized in several ways. Powder X-ray diffraction was used to assess crystallinity and preferred orientation of the nanowires, revealing that the nanowires are highly crystalline and grow with strong preferred orientation such that the material is suited for optimal thermoelectric performance. Scanning electron microscopy was used to evaluate the nanowire nucleation percentage and growth-front uniformity, both of which were enhanced by pulsed-potential electrodeposition. Compositional analysis via electron microprobe indicates that the as-grown nanowires are Te-rich or Bi-deficient, which agrees with Seebeck coefficient data showing the arrays are n-type semiconductors. In collaboration with Marlow Industries, the thermoelectric performance of the arrays was gauged. The nanowire arrays were successfully contacted with robust nickel layers as revealed by the low AC resistances of the arrays. One array was incorporated into a hybrid thermoelectric device and a DeltaT of 14.8°C was measured, indicating that the measurement and electrical contact approaches were successful despite further optimization being needed.

Advanced Electrochemistry of Individual Metal Clusters Electrodeposited Atom by Atom to Nanometer by Nanometer.

PubMed

Kim, Jiyeon; Dick, Jeffrey E; Bard, Allen J

2016-11-15

Metal clusters are very important as building blocks for nanoparticles (NPs) for electrocatalysis and electroanalysis in both fundamental and applied electrochemistry. Attention has been given to understanding of traditional nucleation and growth of metal clusters and to their catalytic activities for various electrochemical applications in energy harvesting as well as analytical sensing. Importantly, understanding the properties of these clusters, primarily the relationship between catalysis and morphology, is required to optimize catalytic function. This has been difficult due to the heterogeneities in the size, shape, and surface properties. Thus, methods that address these issues are necessary to begin understanding the reactivity of individual catalytic centers as opposed to ensemble measurements, where the effect of size and morphology on the catalysis is averaged out in the measurement. This Account introduces our advanced electrochemical approaches to focus on each isolated metal cluster, where we electrochemically fabricated clusters or NPs atom by atom to nanometer by nanometer and explored their electrochemistry for their kinetic and catalytic behavior. Such approaches expand the dimensions of analysis, to include the electrochemistry of (1) a discrete atomic cluster, (2) solely a single NP, or (3) individual NPs in the ensemble sample. Specifically, we studied the electrocatalysis of atomic metal clusters as a nascent electrocatalyst via direct electrodeposition on carbon ultramicroelectrode (C UME) in a femtomolar metal ion precursor. In addition, we developed tunneling ultramicroelectrodes (TUMEs) to study electron transfer (ET) kinetics of a redox probe at a single metal NP electrodeposited on this TUME. Owing to the small dimension of a NP as an active area of a TUME, extremely high mass transfer conditions yielded a remarkably high standard ET rate constant, k 0 , of 36 cm/s for outer-sphere ET reaction. Most recently, we advanced nanoscale scanning electrochemical microscopy (SECM) imaging to resolve the electrocatalytic activity of individual electrodeposited NPs within an ensemble sample yielding consistent high k 0 values of ≥2 cm/s for the hydrogen oxidation reaction (HOR) at different NPs. We envision that our advanced electrochemical approaches will enable us to systematically address structure effects on the catalytic activity, thus providing a quantitative guideline for electrocatalysts in energy-related applications.

Variably porous structures

DOEpatents

Braun, Paul V [Savoy, IL; Yu, Xindi [Urbana, IL

2011-01-18

A method of making a monolithic porous structure, comprises electrodepositing a material on a template; removing the template from the material to form a monolithic porous structure comprising the material; and electropolishing the monolithic porous structure.

Presidential Green Chemistry Challenge: 2001 Designing Greener Chemicals Award

EPA Pesticide Factsheets

Presidential Green Chemistry Challenge 2001 award winner, PPG Industries, developed cationic electrodeposition coatings with yttrium that resist corrosion in automobiles. Yttrium is a safe replacement for lead in this use.

46 CFR 161.006-1 - Applicable specifications.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., and strip. (3) Standards of ASTM: ASTM B 117-97, Standard Practice for Operating Salt Spray (Fog) Apparatus—161.006-5 ASTM B 456-95, Standard Specification for Electrodeposited Coatings of Copper Plus...

Reciprocal Sliding Friction Model for an Electro-Deposited Coating and Its Parameter Estimation Using Markov Chain Monte Carlo Method

PubMed Central

Kim, Kyungmok; Lee, Jaewook

2016-01-01

This paper describes a sliding friction model for an electro-deposited coating. Reciprocating sliding tests using ball-on-flat plate test apparatus are performed to determine an evolution of the kinetic friction coefficient. The evolution of the friction coefficient is classified into the initial running-in period, steady-state sliding, and transition to higher friction. The friction coefficient during the initial running-in period and steady-state sliding is expressed as a simple linear function. The friction coefficient in the transition to higher friction is described with a mathematical model derived from Kachanov-type damage law. The model parameters are then estimated using the Markov Chain Monte Carlo (MCMC) approach. It is identified that estimated friction coefficients obtained by MCMC approach are in good agreement with measured ones. PMID:28773359

Single Ferromagnetic Nanocontact Based Devices as Magnetic Field Sensors

DTIC Science & Technology

2008-03-01

the defined  nanohole  dimensions of  the mask for etching of the  nanoholes  and for electrodeposition of ferromagnetic  nanocontacts. The initial trials... nanoholes  produced  in 100 nm PMMA resist using does of 70, 140 and 250 μC. (D) Array of ~40 nm diameter Ni  nanodots electrodeposited into a  nanohole ...success  of  the  of  the  process  and  cleanness of  the  nanoholes   after  developer  is  applied  to  remove  the  exposed  resist. The  typical

The electrode/ionic liquid interface: electric double layer and metal electrodeposition.

PubMed

Su, Yu-Zhuan; Fu, Yong-Chun; Wei, Yi-Min; Yan, Jia-Wei; Mao, Bing-Wei

2010-09-10

The last decade has witnessed remarkable advances in interfacial electrochemistry in room-temperature ionic liquids. Although the wide electrochemical window of ionic liquids is of primary concern in this new type of solvent for electrochemistry, the unusual bulk and interfacial properties brought about by the intrinsic strong interactions in the ionic liquid system also substantially influence the structure and processes at electrode/ionic liquid interfaces. Theoretical modeling and experimental characterizations have been indispensable in reaching a microscopic understanding of electrode/ionic liquid interfaces and in elucidating the physics behind new phenomena in ionic liquids. This Minireview describes the status of some aspects of interfacial electrochemistry in ionic liquids. Emphasis is placed on high-resolution and molecular-level characterization by scanning tunneling microscopy and vibrational spectroscopies of interfacial structures, and the initial stage of metal electrodeposition with application in surface nanostructuring.

Preparation of transparent conductors ferroelectric memory materials and ferrites

DOEpatents

Bhattacharya, R.N.; Ginley, D.S.

1998-07-28

A process is described for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

Plasticity of Micrometer-Scale Single-Crystals in Compression: A Critical Review (PREPRINT)

DTIC Science & Technology

2008-10-01

annealing, FIB milling followed by low‐energy Ar+ milling,  and samples that were grown via  electrodeposition  followed by annealing (which  produced...the three different FIB‐based  processing routes had similar values, while the  electrodeposited  microsamples were  stronger on average but showed...with grain‐size strengthening (n = 0.5) or surface‐controlled  nucleation  (n = 1), for example.  Note that the value of n in Eq. 1 is dependent on the

Electrochemically mediated electrodeposition/electropolymerization to yield a glucose microbiosensor with improved characteristics.

PubMed

Chen, Xiaohong; Matsumoto, Norio; Hu, Yibai; Wilson, George S

2002-01-15

A procedure is described that provides for electrochemically mediated deposition of enzyme and a polymer layer permselective for endogenous electroactive species. Electrodeposition was first employed for the direct immobilization of glucose oxidase to produce a uniform, thin, and compact film on a Pt electrode. Electropolymerization of phenol was then employed to form an anti-interference and protective polyphenol film within the enzyme layer. In addition, a stability-reinforcing membrane derived from (3-aminopropyl)trimethoxysilane was constructed by electrochemically assisted cross-linking. This hybrid film outside the enzyme layer contributed to the improved stability and permselectivity. The resulting glucose sensor was characterized by a short response time (<4 s), high sensitivity (1200 nA/mM x cm2), low interference from endogenous electroactive species, and working lifetime of more than 50 days.

Studies on the electrodeposition of tin from acidic chloride-gluconate solutions

NASA Astrophysics Data System (ADS)

Rudnik, Ewa; Włoch, Grzegorz

2013-01-01

Electrodeposition of tin from acidic chloride-gluconate baths was investigated. Equilibrium distribution of tin(II) species showed domination of Sn(II)-gluconate complexes, but for Sn2+ concentrations 50 mM or higher increased percentage of Sn(II)-chloride complexes was found. Cyclic voltammetry, anodic stripping analysis and potentiostatic measurements indicated that rate of the cathodic process is determined by the release of metal cations from gluconate complexes in diluted bath (5 mM), but for more concentrated solutions reduction of Sn(II) ions run under diffusion control. Studies of anodic response showed that it depends on the Sn(II)/Glu ratio in the bath and deposition potential due to development of different planes of metal crystal. Average effective diffusion coefficients of metal species were determined. Morphology and structure tin deposits were also presented.

Influence of Substrate, Additives, and Pulse Parameters on Electrodeposition of Gold Nanoparticles from Potassium Dicyanoaurate

NASA Astrophysics Data System (ADS)

Vahdatkhah, Parisa; Sadrnezhaad, Sayed Khatiboleslam

2015-12-01

Gold nanoparticles (AuNPs) of less than 50 nm diameter were electrodeposited from cyanide solution by pulsating electric current on modified copper and indium tin oxide (ITO) films coated on glass. Morphology, size, and composition of the deposited AuNPs were studied by X-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscopy. Effects of peak current density, pulse frequency, potassium iodide and cysteine on grain size, and morphology of the AuNPs were determined. Experiments showed that cathode current efficiency increases with the pulse frequency and the iodide ion. Size of the AuNPs increased with the current density. The number of nucleation sites was larger on ITO than on Cu layer; while the average diameter of the crystallites on ITO was smaller than on Cu layer.

Electrodeposition and characterisation of Al-W alloy films from ionic liquid

NASA Astrophysics Data System (ADS)

Höhlich, D.; Wachner, D.; Müller, M.; Scharf, I.; Lampke, T.

2018-06-01

Al–W alloy films were prepared by electrodeposition using anhydrous 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic-liquid solution with aluminium chloride in a ratio of 1:1.5. As a commercially available tungsten precursor, tungsten hexachloride was used. The metal is dissolved in the ionic liquid at concentrations up to 0.06 mol/l. The deposition took place outside the glove box with a continuous argon stream over the electrolyte at a temperature of 60 °C with a current density of 1 A/m2. Resulting alloys show a tungsten content higher than 20 wt% (3.5 at%). The phase composition of Al-W alloys was observed by X-ray diffraction (XRD), and the chemical composition was characterised by scanning electron microscopy (SEM) and inductively-coupled plasma optical emission spectroscopy (ICP-OES).

Carbon Coated α-Fe2O3 Photoanode Synthesized by a Facile Anodic Electrodeposition for Highly Efficient Water Oxidation

NASA Astrophysics Data System (ADS)

Zhang, Honglei; Li, Longzhu; Liu, Changhai; Wang, Wenchang; Liang, Penghua; Mitsuzak, Naotoshi; Chen, Zhidong

2018-05-01

This work provides a facile anodic electrodeposition method for synthesizing carbon coated α-Fe2O3 photoanode followed by annealing treatment with argon atmosphere. Compared with bare hematite photoanode, the carbon coated α-Fe2O3 photoanodes annealed at lower temperature (Fe2O3/C-L) and higher temperature (Fe2O3/C-H) have higher photocurrent density as 0.3 and 0.5 mA cm-2 (at 1.23 V vs. RHE), respectively. The excellent PEC performance is attributed to the synergistic reaction of carbon and vacancy oxygen. The morphology and properties of the sample were characterized with scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, UV-Vis spectra, X-ray diffractometry, X-ray photoelectron spectra, and photoelectrical measurements.

Electrodeposition of nanostructured Sn-Zn coatings

NASA Astrophysics Data System (ADS)

Salhi, Y.; Cherrouf, S.; Cherkaoui, M.; Abdelouahdi, K.

2016-03-01

The electrodeposition of Sn-Zn coating at ambient temperature was investigated. The bath consists of metal salts SnCl2·2H2O and ZnSO4·7H2O and sodium citrate (NaC6H5Na3O7·2H2O) as complexing agent. To prevent precipitation, the pH is fixed at 5. Reducing tin and zinc through Sncit2- and ZnHcit- complex respectively is confirmed by the presence of two cathodic peaks on the voltammogram. The kinetic of tin (II) reduction process is limited by the SnCit2- dissociation. The SEM and TEM observations have showed that the coating consists of a uniform Sn-Zn layer composed of fine grains on which tin aggregates grow up. XRD revealed peaks corresponding to the hexagonal Zn phase and the tetragonal β-Sn phase.

Potentiostatic current and galvanostatic potential oscillations during electrodeposition of cadmium.

PubMed

López-Sauri, D A; Veleva, L; Pérez-Ángel, G

2015-09-14

Cathodic current and potential oscillations were observed during electrodeposition of cadmium from a cyanide electrolyte on a vertical platinum electrode, in potentiostatic and galvanostatic experiments. Electrochemical impedance spectroscopy experiments revealed a region of negative real impedance in a range of non-zero frequencies, in the second descending branch with a positive slope of the N-shape current-potential curve. This kind of dynamical behaviour is characteristic of the HN-NDR oscillators (oscillators with the N-Shape current-potential curve and hidden negative differential resistance). The oscillations could be mainly attributed to the changes in the real active cathodic area, due to the adsorption of hydrogen molecules and their detachment from the surface. The instabilities of the electrochemical processes were characterized by time series, Fast Fourier Transforms and 2-D phase portraits showing quasi-periodic oscillations.

Efficient production of ultrapure manganese oxides via electrodeposition.

PubMed

Cheney, Marcos A; Joo, Sang Woo; Banerjee, Arghya; Min, Bong-Ki

2012-08-01

A new process for the production of electrolytic amorphous nanomanganese oxides (EAMD) with uniform size and morphology is described. EAMD are produced for the first time by cathodic deposition from a basic aqueous solution of potassium permanganate at a constant temperature of 16°C. The synthesized materials are characterized by XRD, SEM, TEM, and HRTEM. The materials produced at 5.0 V at constant temperature are amorphous with homogeneous size and morphology with an average particle size around 20 nm, which appears to be much lesser than the previously reported anodic EAMD. A potentiostatic electrodeposition with much lesser deposition rate (with respect to previously reported anodic depositions) is considered to be the reason behind the very low and homogenous particle size distribution due to the lesser agglomeration of our as-synthesized nanoparticles. Copyright © 2012 Elsevier Inc. All rights reserved.

Direct Observation of Conducting Filaments in Tungsten Oxide Based Transparent Resistive Switching Memory.

PubMed

Qian, Kai; Cai, Guofa; Nguyen, Viet Cuong; Chen, Tupei; Lee, Pooi See

2016-10-05

Transparent nonvolatile memory has great potential in integrated transparent electronics. Here, we present highly transparent resistive switching memory using stoichiometric WO 3 film produced by cathodic electrodeposition with indium tin oxide electrodes. The memory device demonstrates good optical transmittance, excellent operative uniformity, low operating voltages (+0.25 V/-0.42 V), and long retention time (>10 4 s). Conductive atomic force microscopy, ex situ transmission electron microscopy, and X-ray photoelectron spectroscopy experiments directly confirm that the resistive switching effects occur due to the electric field-induced formation and annihilation of the tungsten-rich conductive channel between two electrodes. Information on the physical and chemical nature of conductive filaments offers insightful design strategies for resistive switching memories with excellent performances. Moreover, we demonstrate the promising applicability of the cathodic electrodeposition method for future resistive memory devices.

Effects of Co contents on the microstructures and properties of the electrodeposited NiCo–Zr composite coatings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Fei; Jiang, Chuanhai, E-mail: chuanhaijiang1963@163.com; Zhao, Yuantao

2015-05-15

Highlights: • The novel NiCo–Zr coatings were prepared by electro-deposition. • Surface morphology, crystal structure, grain size and microstrain were examined. • Texture, residual stress and corrosion resistance were investigated. • Addition of Co increased the hardness and corrosion resistance of the coatings. - Abstract: In this study, the NiCo–Zr composite coatings were prepared from the electrolytes with different Co{sup 2+} concentrations by electrodeposition method. The effects of Co contents on the crystal structure, surface morphology, grain size, microstrain and residual stress were examined by X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX) andmore » atomic force microscope (AFM). The corrosion resistance of the composite coatings was also examined by the potentiodynamic polarization and electrochemical impedance (EIS) measurements. The results revealed that the crystal structures of the coatings were dependent on the Co contents and addition of Co content of 58 wt% resulted in the formation of hexagonal (hcp) Co. The increasing Co contents in the NiCo–Zr composite coatings resulted in the smoother and more compact surface, decreased the grain size and increased the microstrain. The micro-hardness and residual stress also increased with increasing Co contents. The addition of Co increased the corrosion resistance of the NiCo–Zr composite coatings compared with the Ni–Zr coating while the corrosion resistance of the NiCo–Zr composite coatings decreased as the Co contents increased.« less

Electrocatalytic activity of spots of electrodeposited noble-metal catalysts on carbon nanotubes modified glassy carbon.

PubMed

Chen, Xingxing; Eckhard, Kathrin; Zhou, Min; Bron, Michael; Schuhmann, Wolfgang

2009-09-15

A strategy for the screening of the electrocatalytic activity of electrocatalysts for possible application in fuel cells and other devices is presented. In this approach, metal nanoclusters (Pt, Au, Ru, and Rh and their codeposits) were prepared using a capillary-based droplet-cell by pulsed electrodeposition in a diffusion-restricted viscous solution. A glassy carbon surface was modified with carbon nanotubes (CNTs) by electrophoretic accumulation and was used as substrate for metal nanoparticle deposition. The formed catalyst spots on the CNT-modified glassy carbon surface were investigated toward their catalytic activity for oxygen reduction as a test reaction employing the redox competition mode of scanning electrochemical microscopy (RC-SECM). Qualitative information on the electrocatalytic activity of the catalysts was obtained by varying the potential applied to the substrate; semiquantitative evaluation was based on the determination of the electrochemically deposited catalyst loading by means of the charge transferred during the metal nanoparticle deposition. Qualitatively, Au showed the highest electrocatalytic activity toward the oxygen reduction reaction (ORR) in phosphate buffer among all investigated single metal catalysts which was attributed to the much higher loading of Au achieved during electrodeposition. Coelectrodeposited Au-Pt catalysts showed a more positive onset potential (-150 mV in RC-SECM experiments) of the ORR in phosphate buffer at pH 6.7. After normalizing the SECM image by the charge during the metal nanocluster deposition which represents the mass loading of the catalyst, Ru showed a higher electrocatalytic activity toward the ORR than Au.

Determination of the “NiOOH” charge and discharge mechanisms at ideal activity

DOE PAGES

Merrill, Matthew; Worsley, Marcus; Wittstock, Arne; ...

2014-01-24

Here, optimization of electrodeposition conditions produced Ni(OH) 2 deposits chargeable up to 1.84 ± 0.02 e – per Ni on and the resulting nickel oxide/hydroxide active material could subsequently deliver 1.58 ± 0.02 e – per Ni ion (462 mA h/g) over a potential range <0.2 V. The ability of the “NiOOH” active material to deliver an approximately ideal charge and discharge facilitated a coulometric and thermodynamic analysis through which the charge/discharge mechanisms were determined from known enthalpies of formation. The (dis)charge states were confirmed with in situ Raman spectroscopy. The mechanisms were additionally evaluated with respect to pH andmore » potential dependence, charge quantities, hysteresis, and fluoride ion partial inhibition of the charge mechanism. The results indicate that the “NiOOH” (dis)charges as a solid-state system with mechanisms consistent with known nickel and oxygen redox reactions. A defect chemistry mechanism known for the LiNiO 2 system also occurs for “NiOOH” to cause both high activity and hysteresis. Similar to other cation insertion nickel oxides, the activity of the “NiOOH” mechanism is predominantly due to oxygen redox activity and does not involve the Ni4 + oxidation state. The “NiOOH” was produced from cathodic electrodeposition of Ni(OH) 2 from nickel nitrate solutions onto highly oriented pyrolytic graphite at ideal electrodeposition current efficiencies and the deposition mechanism was also characterized.« less

Preparation of metastable CoFeNi alloys with ultra-high magnetic saturation (Bs = 2.4-2.59 T) by reverse pulse electrodeposition

NASA Astrophysics Data System (ADS)

Tabakovic, Ibro; Venkatasamy, Venkatram

2018-04-01

The results of reverse pulse electrodeposition of CoFeNi films with ultra-high magnetic saturation, i.e. Bs values between 2.4 and 2.59 T, are presented in this work. Based on valence-bond theory (Hund's rule) it was assumed that the electronic configuration of MOH obtained by one electron reduction of electroactive intermediate (MOH+ads + e → MOHads) or oxidation of metal (M - e + HOH → MOH + H+) would result with larger number of spins per atom for each of transition metals in MOH-precipitated in CoFeNi deposit- with one more spin than their respective neutral metal in the order: Fe > Co > Ni. The experimental results showed that the increase of Bs value above Slater-Pauling curve was not observed for CoFe alloys, thus FeOH and CoOH compounds were not present in deposit. However, the increase of the Bs values above the Slater-Pauling curve (Bs = 2.4-2.59 T) was observed, for CoFeNi films obtained by reverse pulse electrodeposition. Therefore, NiOH as a stable compound is probably formed in a one-electron oxidation step during anodic pulse oxidation reaction precipitated presumably at the grain boundaries, giving rise to the ultra-high magnetic saturation of CoFeNi films. The effects of experimental conditions on elemental composition, magnetic properties, crystal structure, and thermal stability of CoFeNi films were studied.

Effect of tungsten (W) on structural and magnetic properties of electroplated NiFe thin films for MEMS applications

NASA Astrophysics Data System (ADS)

Kannan, R.; Devaki, P.; Premkumar, P. S.; Selvambikai, M.

2018-04-01

Electrodeposition of nanocrystalline NiFe and NiFeW thin films were carried out from ammonium citrate bath at a constant current density and controlled pH of 8 by varying the bath temperature from 40 °C to 70 °C. The surface morphology and chemical composition of the electrodeposited NiFe and NiFeW soft magnetic thin films were studied by using SEM and EDAX. The SEM micrographs of the films coated at higher electrodeposited bath temperature have no micro cracks and also the films have more uniform surface morphology. The existence of crystalline nature of the coated films were analysed by XRD. The presence of predominant peaks in x-ray diffraction pattern (compared with JCPDS data) reveal that the average crystalline size was in the order of few tens of nano meters. The magnetic properties such as coercivity, saturation magnetization and magnetic flux density have been calculated from vibrating sample magnetometer analysis. The VSM result shows that the NiFeW thin film synthesised at 70 °C exhibit the lower coercivity with higher saturation magnetization. The hardness and adhesion of the electroplated films have been investigated. Reasons for variation in magnetic properties and structural characteristics are also discussed. The electroplated NiFe and NiFeW thin films can be used for Micro Electro Mechanical System (MEMS) applications due to their excellent soft magnetic behaviour.

Synthesis of Co3O4 nanosheets via electrodeposition followed by ozone treatment and their application to high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Kung, Chung-Wei; Chen, Hsin-Wei; Lin, Chia-Yu; Vittal, R.; Ho, Kuo-Chuan

2012-09-01

A thin film of Co3O4 nanosheets is electrodeposited on a flexible Ti substrate by a one-step potentiostatic method, followed by an UV-ozone treatment for 30 min. The films before and after the UV-ozone treatment are characterized with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The film is composed of Co(OH)2 before UV-ozone treatment, and of Co3O4 after the treatment. The morphologies of both films are examined by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The obtained films are composed of nanosheets, and there is no change in their sheet-like morphology before and after the UV-ozone treatment. When applied for a supercapacitor, the Co3O4 modified Ti electrode (Co3O4/Ti) shows a far higher capacitance than that of the Co(OH)2 modified Ti electrode. The electrodeposition time and NaOH concentration in the electrolyte are optimized. A remarkably high specific capacitance of 1033.3 F g-1 is obtained for the Co3O4 thin film at a charge-discharge current density of 2.5 A g-1. The long-term stability data shows that there is still 77% of specific capacitance remaining after 3000 repeated charge-discharge cycles. The high specific capacitance and long-term stability suggest the potential use of Co3O4/Ti for making a flexible supercapacitor.

Analysis of the electrolyte convection inside the concentration boundary layer during structured electrodeposition of copper in high magnetic gradient fields.

PubMed

König, Jörg; Tschulik, Kristina; Büttner, Lars; Uhlemann, Margitta; Czarske, Jürgen

2013-03-19

To experimentally reveal the correlation between electrodeposited structure and electrolyte convection induced inside the concentration boundary layer, a highly inhomogeneous magnetic field, generated by a magnetized Fe-wire, has been applied to an electrochemical system. The influence of Lorentz and magnetic field gradient force to the local transport phenomena of copper ions has been studied using a novel two-component laser Doppler velocity profile sensor. With this sensor, the electrolyte convection within 500 μm of a horizontally aligned cathode is presented. The electrode-normal two-component velocity profiles below the electrodeposited structure show that electrolyte convection is induced and directed toward the rim of the Fe-wire. The measured deposited structure directly correlates to the observed boundary layer flow. As the local concentration of Cu(2+) ions is enhanced due to the induced convection, maximum deposit thicknesses can be found at the rim of the Fe-wire. Furthermore, a complex boundary layer flow structure was determined, indicating that electrolyte convection of second order is induced. Moreover, the Lorentz force-driven convection rapidly vanishes, while the electrolyte convection induced by the magnetic field gradient force is preserved much longer. The progress for research is the first direct experimental proof of the electrolyte convection inside the concentration boundary layer that correlates to the deposited structure and reveals that the magnetic field gradient force is responsible for the observed structuring effect.

Structural and optical characterization of electrodeposited CdSe in mesoporous anatase TiO2 for regenerative quantum-dot-sensitized solar cells.

PubMed

Sauvage, Frédéric; Davoisne, Carine; Philippe, Laetitia; Elias, Jamil

2012-10-05

We investigated CdSe-sensitized TiO(2) solar cells by means of electrodeposition under galvanostatic control. The electrodeposition of CdSe within the mesoporous film of TiO(2) gives rise to a uniform, thickness controlled, conformal layer of nanostructured CdSe particles intimately wrapping the anatase TiO(2) nanoparticles. This technique has the advantage of providing not only a fast method for sensitization ( < 5 min) but also being easily scalable to the sensitization of large-area panels. XRD together with SAED analysis highlight that the deposit of CdSe is exclusively constituted of the hexagonal polymorph. In addition, hierarchical growth has also been shown, starting from the formation of a TiO(2)-CdSe core-shell structure followed by the growth of an assembly of CdSe nanoparticles resembling cauliflowers. This assembly exhibits at its core a mosaic texture with crystallites of about 3 nm in size, in contrast to a shell composed of well-crystallized single crystals between 5 and 10 nm in size. Preliminary results on the photovoltaic performance of such a nanostructured composite of TiO(2) and CdSe show 0.8% power conversion efficiency under A.M.1.5 G conditions-100 mW cm(-2) in association with a new regenerative redox couple based on cobalt(+III/+II) polypyridil complex (V(oc ) = 485 mV, J(sc ) = 4.26 mA cm (-2), ff=0.37).