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Sample records for copper electrode application

  1. Copper nanoparticle modified carbon electrode for determination of dopamine

    International Nuclear Information System (INIS)

    Oztekin, Yasemin; Tok, Mutahire; Bilici, Esra; Mikoliunaite, Lina; Yazicigil, Zafer; Ramanaviciene, Almira; Ramanavicius, Arunas

    2012-01-01

    This paper reports the synthesis and characterization of copper nanoparticles (CuNPs) and application of copper nanoparticle-modified glassy carbon electrode for the electrochemical determination of dopamine. Electrochemical measurements were performed using differently modified glassy carbon (GC) electrodes. Bare, oxidized before modification and copper nanoparticle-modified glassy carbon electrodes (bare-GC, ox-GC and CuNP/GC electrodes, respectively) were characterized by cyclic voltammetry and electrochemical impedance spectroscopy in the presence of redox probes. Atomic force microscopy was used for the visualization of electrode surfaces. The CuNP/GC electrode was found to be suitable for the selective determination of dopamine even in the presence of ascorbic acid, uric acid, and p-acetamidophenol. The observed linear range of CuNP/GC for dopamine was from 0.1 nM to 1.0 μM while the detection limit was estimated to be 50 pM. It was demonstrated that here reported glassy carbon electrode modified by copper nanoparticles is suitable for the determination of dopamine in real samples such as human blood serum.

  2. Analytical application of solid contact ion-selective electrodes for determination of copper and nitrate in various food products and drinking water.

    Science.gov (United States)

    Wardak, Cecylia; Grabarczyk, Malgorzata

    2016-08-02

    A simple, fast and cheap method for monitoring copper and nitrate in drinking water and food products using newly developed solid contact ion-selective electrodes is proposed. Determination of copper and nitrate was performed by application of multiple standard additions technique. The reliability of the obtained results was assessed by comparing them using the anodic stripping voltammetry or spectrophotometry for the same samples. In each case, satisfactory agreement of the results was obtained, which confirms the analytical usefulness of the constructed electrodes.

  3. A copper ion-selective electrode with high selectivity prepared by sol-gel and coated wire techniques.

    Science.gov (United States)

    Mazloum Ardakani, M; Salavati-Niasari, M; Khayat Kashani, M; Ghoreishi, S M

    2004-03-01

    A sol-gel electrode and a coated wire ion-selective poly(vinyl chloride) membrane, based on thiosemicarbazone as a neutral carrier, were successfully developed for the detection of Cu (II) in aqueous solutions. The sol-gel electrode and coated electrode exhibited linear response with Nernstian slopes of 29.2 and 28.1 mV per decade respectively, within the copper ion concentration ranges 1.0 x 10(-5) - 1.0 x 10(-1) M and 6.0 x 10(-6) - 1.0 x 10(-1) M for coated and sol-gel sensors. The coated and sol-gel electrodes show detection limits of 3.0 x 10(-6) and 6.0 x 10(-6) M respectively. The electrodes exhibited good selectivities for a number of alkali, alkaline earth, transition and heavy metal ions. The proposed electrodes have response times ranging from 10-50 s to achieve a 95% steady potential for Cu2+ concentration. The electrodes are suitable for use in aqueous solutions over a wide pH range (4-7.5). Applications of these electrodes for the determination of copper in real samples, and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA, are reported. The lifetimes of the electrodes were tested over a period of six months to investigate their stability. No significant change in the performance of the sol-gel electrode was observed over this period, but after two months the coated wire copper-selective electrode exhibited a gradual decrease in the slope. The selectivity of the sol-gel electrode was found to be better than that of the coated wire copper-selective electrode. Based on these results, a novel sol-gel copper-selective electrode is proposed for the determination of copper, and applied to real sample assays.

  4. Copper nanoparticle-deposited graphite felt electrodes for all vanadium redox flow batteries

    International Nuclear Information System (INIS)

    Wei, L.; Zhao, T.S.; Zeng, L.; Zhou, X.L.; Zeng, Y.K.

    2016-01-01

    Highlights: • Copper nanoparticle is proposed as electrocatalyst for VRFBs for the first time. • Propose a binder-free copper nanoparticle decorated electrode. • The energy efficiency is up to 80.1% at 300 mA cm"−"2, enhancing more than 17%. • High stability and capacity retention are achieved by battery with copper catalyst. - Abstract: A copper nanoparticle deposited graphite felt electrode for all vanadium redox flow batteries (VRFBs) is developed and tested. It is found that the copper catalyst enables a significant improvement in the electrochemical kinetics of the V"3"+/V"2"+ redox reaction. The battery’s utilization of the electrolyte and energy efficiency are found to be as high as 83.7% and 80.1%, at a current density of 300 mA cm"−"2, which are 53.1% and 17.8% higher than those of the battery without the catalyst. Moreover, the present battery shows a good stability during the cycle test. The results suggest that the inexpensive copper nanoparticle catalyst without tedious preparation process offers a great promise for VRFB application.

  5. Synthesis and characterization of copper-infiltrated carbonized wood monoliths for supercapacitor electrodes

    International Nuclear Information System (INIS)

    Teng, Shiang; Siegel, Gene; Prestgard, Megan C.; Wang, Wei; Tiwari, Ashutosh

    2015-01-01

    Highlights: • Copper nanoparticles were embedded in the highly porous carbonized wood electrodes. • Copper nanoparticle serves as the pseudocapacitive specie to increase the energy density. • The porous copper-wood electrodes exhibit excellent electrochemical performances with high capacitance, excellent rate capability and stability. - Abstract: Copper nanoparticle-loaded carbonized wood electrodes were synthesized and characterized for the use as supercapacitor electrodes. The electrodes were fabricated by soaking beech wood samples in Cu(NO 3 ) 2 solution followed by carbonization at 800 °C under a N 2 atmosphere. The copper nanoparticle content in the electrodes was controlled by varying the concentration of the Cu(NO 3 ) 2 solution from 0.5 to 2 M. Subsequent X-ray diffraction and scanning electron microscopy measurements confirm that cubic copper was formed and the copper nanoparticles were anchored uniformly both on the surface as well as deep within the pores of the wood electrode. Cyclic voltammetry measurements showed that all of the electrodes had a typical pseudo-capacitive behavior, as indicated by the presence of redox reaction peaks. Charge–discharge testing also confirmed the pseudo-capacitive nature of the electrodes. The reversible oxidation of Cu into Cu 2 O and CuO was verified by performing X-ray photoelectron spectroscopy at different stages of the charge–discharge cycle. The Cu-loaded wood electrodes exhibited excellent cyclability and retaining 95% of their specific capacitance even after 2000 cycles. A maximum specific capacitance of 888 F/g was observed while discharging the 7 wt% Cu electrode at 200 mA/g in a 2 M KOH electrolyte solution. These results demonstrated the potential of the copper nanoparticle-loaded wood electrodes as cheap and high performance supercapacitor electrodes

  6. Application of Copper Solid Amalgam Electrode for Determination of Fungicide Tebuconazole

    Czech Academy of Sciences Publication Activity Database

    Nováková, Kateřina; Navrátil, Tomáš; Jaklová Dytrtová, Jana; Chýlková, J.

    2013-01-01

    Roč. 8, č. 1 (2013), s. 1-16 ISSN 1452-3981 R&D Projects: GA ČR GAP206/11/1638; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388955 ; RVO:61388963 Keywords : tebuconazole * fungicide * copper solid amalgam electrode Subject RIV: CG - Electrochemistry Impact factor: 1.956, year: 2013

  7. Cold-electrode voltage fall for impulse arcs in argon between copper electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, O; Cooray, V, E-mail: oscar.diaz@angstrom.uu.se [Lightning Research Group, Division for Electricity, Uppsala University Angstroemlaboratoriet Box 5234, 751 20, Uppsala (Sweden)

    2011-06-23

    The full electric arc discharge in gases for short gaps in homogeneous electric field and pressure{center_dot}distance (pd) below 150 Torr{center_dot}cm, can be described as a transition between different discharge mechanisms such as: Townsend, glow, and arc. Once the arc is achieved the measured voltage drops to some volts and the current density increases several orders of magnitude. Depending upon the type of gas used, the electrode surface characteristics and type of electrical excitation, the cathode and anode voltage fall might change. The present work is directed to study the electrode fall (sum of anode and cathode falls) during a current impulse arc discharge between copper electrodes in ceramic tubes filled with argon between 0.01 and 6.5 Torr{center_dot}cm. The copper electrodes were cleaned, degassed and hydrogen reduced. The arc voltages were measured with fast/slow rise times and short/long duration current impulses produced by a RLC circuit. An increasing variation of the electrode fall was found at the pressure{center_dot}distance range analyzed.

  8. Fabrication of graphene/polydopamine/copper foam composite material and its application as supercapacitor electrode

    Science.gov (United States)

    Zheng, Y.; Lu, S. X.; Xu, W. G.; He, G.; Cheng, Y. Y.; Xiao, F. Y.; Zhang, Y.

    2018-01-01

    In this work, a composite electrode was fabricated by chemical deposition of polydopamine (PDA) and graphene oxide (GO) on the copper foam (CF) surface, followed by annealing treatment. Owing to the cohesive effect of the PDA middle film, GO was coated on CF surface successfully, and then reduced simultaneously while annealing. The resulted rGO/PDA/CF composite electrode was directly used as a supercapacitor electrode and exhibited excellent electrochemical performance, with a high specific capacitance of 1250 F g-1 at 2 A g-1 and favorable cycle stability.

  9. Fabrication and applications of copper sulfide (CuS) nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Shamraiz, Umair, E-mail: umairshamraiz@gmail.com; Hussain, Raja Azadar, E-mail: hussainazadar@gamil.com; Badshah, Amin, E-mail: aminbadshah@yahoo.com

    2016-06-15

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite). - Highlights: • This review article presents the synthesis and applications of copper sulfide. • CuS has been used over the years for different applications in nanoscience. • Different synthetic protocols are followed for their preparation which help in the possible modifications in the morphology of CuS.

  10. Photoelectrochemistry of copper(I) acetylide films electrodeposited onto copper electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Zotti, G.; Cattarin, S.; Mengoli, G.; Fleischmann, M.; Peter, L.M.

    1986-01-01

    Films of copper acetylide (Cu/sub 2/C/sub 2/) were grown electrochemically on copper and characterized by transmittance and reflectance techniques. The photoelectrochemical properties of the filmed electrodes in alkaline solution indicate that Cu/sub 2/C/sub 2/ behaves as a p-type semiconducting material (1.5 eV band gap). The photocurrents depend on film thickness and aging and high resistivity or recombination losses limit the quantum yield to some 4% for thicknesses of practical importance (250 nm).

  11. Nickel–copper hybrid electrodes self-adhered onto a silicon wafer by supersonic cold-spray

    International Nuclear Information System (INIS)

    Lee, Jong-Gun; Kim, Do-Yeon; Kang, Byungjun; Kim, Donghwan; Song, Hee-eun; Kim, Jooyoung; Jung, Woonsuk; Lee, Dukhaeng; Al-Deyab, Salem S.; James, Scott C.; Yoon, Sam S.

    2015-01-01

    High-performance electrodes are fabricated through supersonic spraying of nickel and copper particles. These electrodes yield low specific resistivities, comparable to electrodes produced by screen-printed silver paste and light-induced plating. The appeal of this fabrication method is the low cost of copper and large area scalability of supersonic spray-coating techniques. The copper and nickel electrode was fabricated in the open air without any pre- or post-treatment. The spray-coated copper–nickel electrode was characterized by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, and energy dispersive spectroscopy. Although both SEM and TEM images confirmed voids trapped between flattened particles in the fabricated electrode, this electrode’s resistivity was order 10 −6 Ω cm, which is comparable to the bulk value for pure copper

  12. Visual Observation of Dissolution of Copper Ions from a Copper Electrode

    Science.gov (United States)

    Ikemoto, Isao; Saitou, Kouichi

    2013-01-01

    During electrolysis, to visually observe the conversion of a metal to its cation, either the cation or its complex ion should have a distinct color while the electrolyte solution must be colorless and transparent. A demonstration is described in which copper is used as the electrodes and sodium polyacrylate (a superabsorbent polymer) solution is…

  13. Sheath-flow electrochemical detection of amino acids with a copper wire electrode in capillary electrophoresis.

    Science.gov (United States)

    Inoue, Junji; Kaneta, Takashi; Imasaka, Totaro

    2012-09-01

    Here, we report the detection of native amino acids using a sheath-flow electrochemical detector with a working electrode made of copper wire. A separation capillary that was inserted into a platinum tube in the detector acted as a grounded electrode for electrophoresis and as a flow channel for sheath liquid. Sheath liquid flowed outside the capillary to support the transport of the separated analytes to the working electrode for electrochemical detection. The copper wire electrode was aligned at the outlet of the capillary in a wall-jet configuration. Amino acids injected into the capillary were separated following elution from the end of the capillary and detection by the copper electrode. Three kinds of copper electrodes with different diameters-50, 125, and 300 μm-were examined to investigate the effect of the electrode diameter on sensitivity. The peak widths of the analytes were independent of the diameter of the working electrode, while the 300-μm electrode led to a decrease in the signal-to-noise ratio compared with the 50- and 125-μm electrodes, which showed no significant difference. The flow rate of the sheath liquid was also varied to optimize the detection conditions. The limits of detection for amino acids ranged from 4.4 to 27 μM under optimal conditions. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Simultaneous detection of ascorbic acid, uric acid and homovanillic acid at copper modified electrode

    International Nuclear Information System (INIS)

    Selvaraju, T.; Ramaraj, R.

    2007-01-01

    The copper was deposited on glassy carbon (GC) and indium tin oxide (ITO) electrodes by electrochemical method. The copper structures on electrode were characterized by atomic force microscope, X-ray diffractometeric pattern and differential pulse voltammetric studies. Optimal conditions for uniform growth of copper structures on the electrode were established. Voltammetric sensor was fabricated using the copper deposited GC electrode for the simultaneous detection and determination of uric acid (UA) and homovanillic acid (HVA) in the presence of excess concentrations of ascorbic acid (AA). The voltammetric signals due to AA and UA oxidation were well separated with a potential difference of 400 mV and AA did not interfere with the measurement of UA and HVA at the GC/Cu electrode. Linear calibration curves were obtained in the concentration range 1-40 μM for AA and 20-50 μM for UA at physiological pH and a detection limit of 10 nM of UA in the presence of 10-fold excess concentrations of AA was achieved. The simultaneous detection of submicromolar concentrations of AA, UA and HVA was achieved at the GC/Cu electrode. The practical utility of the present GC/Cu modified electrode was demonstrated by measuring the AA content in Vitamin C tablet, UA content in human urine and blood serum samples with satisfactory results

  15. Achieving copper sulfide leaf like nanostructure electrode for high performance supercapacitor and quantum-dot sensitized solar cells

    Science.gov (United States)

    Durga, Ikkurthi Kanaka; Rao, S. Srinivasa; Reddy, Araveeti Eswar; Gopi, Chandu V. V. M.; Kim, Hee-Je

    2018-03-01

    Copper sulfide is an important multifunctional semiconductor that has attracted considerable attention owing to its outstanding properties and multiple applications, such as energy storage and electrochemical energy conversion. This paper describes a cost-effective and simple low-temperature solution approach to the preparation of copper sulfide for supercapacitors (SCs) and quantum-dot sensitized solar cells (QDSSCs). X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy confirmed that the nickel foam with a coriander leaf like nanostructure had been coated successfully with copper sulfide. As an electrode material for SCs, the CC-3 h showed excellent specific capacitance (5029.28 at 4 A g-1), energy density (169.73 W h kg-1), and superior cycling durability with 107% retention after 2000 cycles. Interestingly, the QDSSCs equipped with CC-2 h and CC-3 h counter electrodes (CEs) exhibited a maximum power conversion efficiency of 2.52% and 3.48%, respectively. The improved performance of the CC-3 h electrode was attributed mainly to the large surface area (which could contribute sufficient electroactive species), good conductivity, and high electrocatalytic activity. Overall, this work delivers novel insights into the use of copper sulfide and offers an important guidelines for the fabrication of next level energy storage and conversion devices.

  16. Enhanced electrochemical oxidation of methanol on copper electrodes modified by electrocorrosion and electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Carugno, Sofía [INQUIMAE – DQIAQF, Facultad de Ciencias, Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires (Argentina); Chassaing, Elisabeth [IRDEP (UMR7174), EDF R and D, 6 Quai Watier, 78401 Chatou (France); Rosso, Michel [LPMC (UMR7643), CNRS, Ecole Polytechnique, F91128 Palaiseau Cedex (France); González, Graciela A., E-mail: graciela@qi.fcen.uba.ar [INQUIMAE – DQIAQF, Facultad de Ciencias, Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires (Argentina)

    2014-02-14

    In this paper, we report a study of electrocatalytic oxidation of methanol on copper electrodes subjected to different surface treatments, either electrocorrosion or electrodeposition in the absence of strong hydrogen co-deposition. The surface morphology of treated electrodes was examined by Field Emission Scanning Electron Microscopy (FE-SEM). The effect of different treatment conditions and the methanol concentration dependence were evaluated by cyclic voltammetric technique. The results indicate that the oxidation of methanol can be enhanced by a suitable micro and nano structure generated by these treatments. This enhanced electrode activity is related to an increase of the effective surface area and/or to an increase of the surface concentration of electroactive molecules or intermediates. - Highlights: • We presented simple treatments to increase the response of copper electrodes. • Copper electrodes were modified by electrocorrosion and electrodeposition. • Scanning Electron Microscopy images reveal the effects of the different treatments. • The response is enhanced by an area increase and/or intermediates concentration. • For each treatment the concentration range of the diffusion control is analyzed.

  17. Low-cost optical fabrication of flexible copper electrode via laser-induced reductive sintering and adhesive transfer

    Science.gov (United States)

    Back, Seunghyun; Kang, Bongchul

    2018-02-01

    Fabricating copper electrodes on heat-sensitive polymer films in air is highly challenging owing to the need of expensive copper nanoparticles, rapid oxidation of precursor during sintering, and limitation of sintering temperature to prevent the thermal damage of the polymer film. A laser-induced hybrid process of reductive sintering and adhesive transfer is demonstrated to cost-effectively fabricate copper electrode on a polyethylene film with a thermal resistance below 100 °C. A laser-induced reductive sintering process directly fabricates a high-conductive copper electrode onto a glass donor from copper oxide nanoparticle solution via photo-thermochemical reduction and agglomeration of copper oxide nanoparticles. The sintered copper patterns were transferred in parallel to a heat-sensitive polyethylene film through self-selective surface adhesion of the film, which was generated by the selective laser absorption of the copper pattern. The method reported here could become one of the most important manufacturing technologies for fabricating low-cost wearable and disposable electronics.

  18. Recorded corrosion rates on copper electrodes in the Prototype Repository at the Aespoe HRL

    Energy Technology Data Exchange (ETDEWEB)

    Rosborg, Bo [Rosborg Consulting, Nykoeping (Sweden)

    2013-04-15

    Real-time corrosion monitoring by means of electrochemical methods has been applied in an effort to measure corrosion rates of pure copper in the Prototype Repository at the Aspo Hard Rock Laboratory. Copper electrodes were installed in bentonite blocks on top of the electrically heated copper canisters in two deposition holes (dh). Three nominally identical cylindrical copper electrodes were installed in dh 1 and another three in dh 5 a few days before the heat was turned on to the canisters in September 2001 and in May 2003 respectively. The temperature of the copper electrodes has been around 30 deg C in dh 1 and somewhat below 35 deg C in dh 5. Real-time corrosion monitoring for both electrode setups was first applied in January 2004, and then periodically in 2005, 2006, 2008, and most recently in the end of 2010 just before work to open the outer section of the Prototype Repository was started. The recorded corrosion rates fall below 1.3 {mu}m/year (using a default value of n=2 in the software to convert the corrosion current density to a penetration rate by means of Faraday's law, and with no correction applied for the used measuring frequency of 0.01 Hz; also disregarding highly scattered data obtained for the copper electrodes in dh 1 during 2010). While the recorded rates on the electrodes in dh 5 first increased from about 0.2 {mu}m/year in 2004 up to a maximum of 1.3 {mu}m/year a year later (the drainage of the inner and outer sections was temporary closed in the end of 2004), and then gradually decreased to 0.7 {mu}m/year in the end of 2010, the recorded rates on the electrodes in dh 1 show a quite different picture. The recorded rates fall in the range 0.4-0.7 {mu}m/year and do not reflect any obvious decrease. However, it is anticipated that a similar time dependence as observed for the electrodes in dh 5 could have been present early on in the exposure; the electrodes were installed in 2001 but the first measurements were performed in 2004. Also

  19. Recorded corrosion rates on copper electrodes in the Prototype Repository at the Aespoe HRL

    International Nuclear Information System (INIS)

    Rosborg, Bo

    2013-04-01

    Real-time corrosion monitoring by means of electrochemical methods has been applied in an effort to measure corrosion rates of pure copper in the Prototype Repository at the Aspo Hard Rock Laboratory. Copper electrodes were installed in bentonite blocks on top of the electrically heated copper canisters in two deposition holes (dh). Three nominally identical cylindrical copper electrodes were installed in dh 1 and another three in dh 5 a few days before the heat was turned on to the canisters in September 2001 and in May 2003 respectively. The temperature of the copper electrodes has been around 30 deg C in dh 1 and somewhat below 35 deg C in dh 5. Real-time corrosion monitoring for both electrode setups was first applied in January 2004, and then periodically in 2005, 2006, 2008, and most recently in the end of 2010 just before work to open the outer section of the Prototype Repository was started. The recorded corrosion rates fall below 1.3 μm/year (using a default value of n=2 in the software to convert the corrosion current density to a penetration rate by means of Faraday's law, and with no correction applied for the used measuring frequency of 0.01 Hz; also disregarding highly scattered data obtained for the copper electrodes in dh 1 during 2010). While the recorded rates on the electrodes in dh 5 first increased from about 0.2 μm/year in 2004 up to a maximum of 1.3 μm/year a year later (the drainage of the inner and outer sections was temporary closed in the end of 2004), and then gradually decreased to 0.7 μm/year in the end of 2010, the recorded rates on the electrodes in dh 1 show a quite different picture. The recorded rates fall in the range 0.4-0.7 μm/year and do not reflect any obvious decrease. However, it is anticipated that a similar time dependence as observed for the electrodes in dh 5 could have been present early on in the exposure; the electrodes were installed in 2001 but the first measurements were performed in 2004. Also, saturation of

  20. Post-test examination of a copper electrode from deposition hole 5 in the Prototype Repository

    International Nuclear Information System (INIS)

    Rosborg, Bo

    2013-04-01

    Three copper electrodes have been exposed for eight years in the outer section of the Prototype Repository at Aespoe. The electrodes were installed in the upper bentonite block of deposition hole 5 in May 2003. Most of the time the temperature of the electrodes has been somewhat below 35 deg C. The electrodes were retrieved for post-test examination in September 2011. This report presents results from electrochemical measurements and the post-test examination of one of the electrodes. The corrosion potential of the examined copper electrode was -40 mV SHE (2011-02-04) when part of the concrete plug to the outer section of the repository had been removed and made measurements possible. When the back-fill in the deposition tunnel had been removed it was 25 mV SHE (2011-09-12). Finally, before letting loose the copper electrode from the retrieved bentonite block, the corrosion potential was found to be 165 mV SHE (2011-11-15) being a sign of air ingress to the electrode/ bentonite interface. It was immediately obvious from the appearance of the copper electrode, when part of the surrounding bentonite had been removed, that both Cu(I) and Cu(II) corrosion products existed on the electrode surface. X-ray diffraction measurements also verified the presence of cuprite, Cu 2 O, and malachite, Cu 2 (OH) 2 CO 3 , on the electrode; however, paratacamite, Cu 2 (OH) 3 Cl, was not found. The performed Fourier transform infrared and Raman spectroscopy confirmed these observations. The corrosion product film, of which cuprite is the main part, was quite uneven and porous. No unmistakable signs of pitting have been found. The appearance of the copper electrode reminded of the coupons from the retrieved LOT test parcels, but was different from the appearance of the surface on the full-size canisters. For the latter blue-green Cu(II) corrosion products have not or only rarely been observed from visual examination immediately after removing the surrounding bentonite. Differences that

  1. Post-test examination of a copper electrode from deposition hole 5 in the Prototype Repository

    Energy Technology Data Exchange (ETDEWEB)

    Rosborg, Bo [Rosborg Consulting, Nykoeping (Sweden)

    2013-04-15

    Three copper electrodes have been exposed for eight years in the outer section of the Prototype Repository at Aespoe. The electrodes were installed in the upper bentonite block of deposition hole 5 in May 2003. Most of the time the temperature of the electrodes has been somewhat below 35 deg C. The electrodes were retrieved for post-test examination in September 2011. This report presents results from electrochemical measurements and the post-test examination of one of the electrodes. The corrosion potential of the examined copper electrode was -40 mV SHE (2011-02-04) when part of the concrete plug to the outer section of the repository had been removed and made measurements possible. When the back-fill in the deposition tunnel had been removed it was 25 mV SHE (2011-09-12). Finally, before letting loose the copper electrode from the retrieved bentonite block, the corrosion potential was found to be 165 mV SHE (2011-11-15) being a sign of air ingress to the electrode/ bentonite interface. It was immediately obvious from the appearance of the copper electrode, when part of the surrounding bentonite had been removed, that both Cu(I) and Cu(II) corrosion products existed on the electrode surface. X-ray diffraction measurements also verified the presence of cuprite, Cu{sub 2}O, and malachite, Cu{sub 2}(OH){sub 2}CO{sub 3}, on the electrode; however, paratacamite, Cu{sub 2}(OH){sub 3}Cl, was not found. The performed Fourier transform infrared and Raman spectroscopy confirmed these observations. The corrosion product film, of which cuprite is the main part, was quite uneven and porous. No unmistakable signs of pitting have been found. The appearance of the copper electrode reminded of the coupons from the retrieved LOT test parcels, but was different from the appearance of the surface on the full-size canisters. For the latter blue-green Cu(II) corrosion products have not or only rarely been observed from visual examination immediately after removing the surrounding

  2. Study of copper and purine-copper complexes on modified carbon electrodes by cyclic and elimination voltammetry

    Czech Academy of Sciences Publication Activity Database

    Trnková, L.; Zerzánková, L.; Dyčka, F.; Mikelová, R.; Jelen, František

    2008-01-01

    Roč. 8, č. 1 (2008), s. 429-444 ISSN 1424-8220 R&D Projects: GA AV ČR(CZ) IAA100040602; GA AV ČR(CZ) IAA400040804 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : copper-purine complexes * paraffin-impregnated graphite electrode * mercury-film electrode Subject RIV: BO - Biophysics Impact factor: 1.870, year: 2008

  3. Determination of Zinc, Cadmium, Lead, Copper and Silver Using a Carbon Paste Electrode and a Screen Printed Electrode Modified with Chromium(III Oxide

    Directory of Open Access Journals (Sweden)

    Zuzana Koudelkova

    2017-08-01

    Full Text Available In this study, the preparation and electrochemical application of a chromium(III oxide modified carbon paste electrode (Cr-CPE and a screen printed electrode (SPE, made from the same material and optimized for the simple, cheap and sensitive simultaneous determination of zinc, cadmium, lead, copper and the detection of silver ions, is described. The limits of detection and quantification were 25 and 80 µg·L−1 for Zn(II, 3 and 10 µg·L−1 for Cd(II, 3 and 10 µg·L−1 for Pb(II, 3 and 10 µg·L−1 for Cu(II, and 3 and 10 µg·L−1 for Ag(I, respectively. Furthermore, this promising modification was transferred to the screen-printed electrode. The limits of detection for the simultaneous determination of zinc, cadmium, copper and lead on the screen printed electrodes were found to be 350 µg·L−1 for Zn(II, 25 µg·L−1 for Cd(II, 3 µg·L−1 for Pb(II and 3 µg·L−1 for Cu(II. Practical usability for the simultaneous detection of these heavy metal ions by the Cr-CPE was also demonstrated in the analyses of wastewaters.

  4. Determination of Zinc, Cadmium, Lead, Copper and Silver Using a Carbon Paste Electrode and a Screen Printed Electrode Modified with Chromium(III) Oxide.

    Science.gov (United States)

    Koudelkova, Zuzana; Syrovy, Tomas; Ambrozova, Pavlina; Moravec, Zdenek; Kubac, Lubomir; Hynek, David; Richtera, Lukas; Adam, Vojtech

    2017-08-09

    In this study, the preparation and electrochemical application of a chromium(III) oxide modified carbon paste electrode (Cr-CPE) and a screen printed electrode (SPE), made from the same material and optimized for the simple, cheap and sensitive simultaneous determination of zinc, cadmium, lead, copper and the detection of silver ions, is described. The limits of detection and quantification were 25 and 80 µg·L -1 for Zn(II), 3 and 10 µg·L -1 for Cd(II), 3 and 10 µg·L -1 for Pb(II), 3 and 10 µg·L -1 for Cu(II), and 3 and 10 µg·L -1 for Ag(I), respectively. Furthermore, this promising modification was transferred to the screen-printed electrode. The limits of detection for the simultaneous determination of zinc, cadmium, copper and lead on the screen printed electrodes were found to be 350 µg·L -1 for Zn(II), 25 µg·L -1 for Cd(II), 3 µg·L -1 for Pb(II) and 3 µg·L -1 for Cu(II). Practical usability for the simultaneous detection of these heavy metal ions by the Cr-CPE was also demonstrated in the analyses of wastewaters.

  5. Copper-decorated carbon nanotubes-based composite electrodes for nonenzymatic detection of glucose

    NARCIS (Netherlands)

    Pop, A.; Manea, F.; Orha, C.; Motoc, S.; Llinoiu, E.; Vaszilcsin, N.; Schoonman, J.

    2012-01-01

    The aim of this study was to prepare three types of multiwall carbon nanotubes (CNT)-based composite electrodes and to modify their surface by copper electrodeposition for nonenzymatic oxidation and determination of glucose from aqueous solution. Copper-decorated multiwall carbon nanotubes composite

  6. Electrochemical sensing of hydroxylamine using a wax impregnated graphite electrode modified with a nanocomposite consisting of ferric oxide and copper hexacyanoferrate

    International Nuclear Information System (INIS)

    Allibai Mohanan, Vinu Mohan; Kacheri Kunnummal, Aswini; Biju, Valsala Madhavan Nair

    2016-01-01

    The authors describe a wax-impregnated graphite electrode modified with ferric oxide (Fe_2O_3) and copper hexacyanoferrate(II), and its application as an electrochemical sensor for hydroxylamine. The presence of Fe_2O_3 nanoparticles enhance the electron transfer kinetics and electrocatalytic activities, and also enlarge the surface area of the modified electrode. As compared to the unmodified electrode, 16.9 and 30.1 fold enhancements in amperometric response was observed for copper hexacyanoferrate(II) and the nanocomposite modified electrodes, respectively. Also, the presence of Fe_2O_3 in the nanocomposite enhances the anodic current response by 1.78 fold when compared to copper hexacyanoferrate(II) alone modified electrode. The electron transfer coefficient, electron transfer rate constant, diffusion coefficient and catalytic rate constant for the electro-oxidation of hydroxylamine were determined. Amperometry performed at a working voltage of 750 mV (vs. Ag/AgCl) revealed a detection range that extends from 0.8 μM to 100 μM, a detection limit of 0.5 μM (at an S/N ratio of 3) and a sensitivity of 0.0924 mA⋅mM"−"1. The modified electrode is remarkably stable and was successfully applied to the determination of hydroxylamine in spiked water samples. (author)

  7. Reaction and nucleation mechanisms of copper electrodeposition on disposable pencil graphite electrode

    Energy Technology Data Exchange (ETDEWEB)

    Majidi, M.R. [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, 29th Bahman Bolvard, Tabriz 51664 (Iran, Islamic Republic of)], E-mail: sr.majidi@gmail.com; Asadpour-Zeynali, K.; Hafezi, B. [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, 29th Bahman Bolvard, Tabriz 51664 (Iran, Islamic Republic of)

    2009-01-01

    The reaction and nucleation mechanism of copper electrodeposition on disposable pencil graphite electrode (PGE) in acidic sulphate solution were investigated using cyclic voltammetry (CV) and chronoamperometry (CA) techniques, respectively. Electrochemical experiments were followed by morphological studies with scanning electron microscopy (SEM). The effect of some experimental parameters, namely copper concentration, pH, scan rate, background electrolyte, deposition potential, and conditioning surface of the electrode were described. At the surface of PGE, Cu{sup 2+} ions were reduced at -250 mV vs. SCE. It was found that electrodeposition of copper is affected by rough surface of PGE. The nucleation mechanisms were examined by fitting the experimental CA data into Scharifker-Hills nucleation models. The nuclei population densities were also determined by means of two common fitting models developed for three-dimensional nucleation and growth (Scharifker-Mostany and Mirkin-Nilov-Herrman-Tarallo). It was found that deposition potential and background electrolyte affect the distribution of the deposited copper. The morphology of the deposited copper is affected by background electrolyte.

  8. Cost-effective disposable thiourea film modified copper electrode for capacitive immunosensor

    International Nuclear Information System (INIS)

    Limbut, Warakorn; Thavarungkul, Panote; Kanatharana, Proespichaya; Wongkittisuksa, Booncharoen; Asawatreratanakul, Punnee; Limsakul, Chusak

    2010-01-01

    Cost-effective disposable electrodes were fabricated from copper clad laminate, usually used for printed circuit board (PCB) in electronic industries, by using dry film photoresist. Electro-oxidation (anodisation) was employed to obtain a good formation of thiourea film on the electrode surface. The affinity binding pair of carcinoembryonic antigen (CEA) and anti-carcinoembryonic antigen (anti-CEA) was used as a model system. Anti-CEA was immobilized on thiourea film via covalent coupling. This modified electrode was incorporated with a capacitive system for CEA analysis. This capacitive immunosensor provided a linear range between 0.01 and 10 ng ml -1 with a detection limit of 10 pg ml -1 . When applied to analyze CEA in serum samples, the results agreed well with the enzyme linked fluorescent assay (ELFA) technique (P > 0.05). The proposed strategy for the preparation of disposable modified copper electrode is very cost effective and simple. Moreover, it provides good reproducibility. This technique can easily be applied to immobilize other biological sensing elements for biosensors development.

  9. Copper hexacyanoferrate battery electrodes with long cycle life and high power

    KAUST Repository

    Wessells, Colin D.; Huggins, Robert A.; Cui, Yi

    2011-01-01

    Short-term transients, including those related to wind and solar sources, present challenges to the electrical grid. Stationary energy storage systems that can operate for many cycles, at high power, with high round-trip energy efficiency, and at low cost are required. Existing energy storage technologies cannot satisfy these requirements. Here we show that crystalline nanoparticles of copper hexacyanoferrate, which has an ultra-low strain open framework structure, can be operated as a battery electrode in inexpensive aqueous electrolytes. After 40,000 deep discharge cycles at a 17g-C rate, 83% of the original capacity of copper hexacyanoferrate is retained. Even at a very high cycling rate of 83g-C, two thirds of its maximum discharge capacity is observed. At modest current densities, round-trip energy efficiencies of 99% can be achieved. The low-cost, scalable, room-temperature co-precipitation synthesis and excellent electrode performance of copper hexacyanoferrate make it attractive for large-scale energy storage systems. © 2011 Macmillan Publishers Limited. All rights reserved.

  10. Copper hexacyanoferrate battery electrodes with long cycle life and high power

    KAUST Repository

    Wessells, Colin D.

    2011-11-22

    Short-term transients, including those related to wind and solar sources, present challenges to the electrical grid. Stationary energy storage systems that can operate for many cycles, at high power, with high round-trip energy efficiency, and at low cost are required. Existing energy storage technologies cannot satisfy these requirements. Here we show that crystalline nanoparticles of copper hexacyanoferrate, which has an ultra-low strain open framework structure, can be operated as a battery electrode in inexpensive aqueous electrolytes. After 40,000 deep discharge cycles at a 17g-C rate, 83% of the original capacity of copper hexacyanoferrate is retained. Even at a very high cycling rate of 83g-C, two thirds of its maximum discharge capacity is observed. At modest current densities, round-trip energy efficiencies of 99% can be achieved. The low-cost, scalable, room-temperature co-precipitation synthesis and excellent electrode performance of copper hexacyanoferrate make it attractive for large-scale energy storage systems. © 2011 Macmillan Publishers Limited. All rights reserved.

  11. Indirect potentiometric titration of ascorbic acid in pharmaceutical preparations using copper based mercury film electrode.

    Science.gov (United States)

    Abdul Kamal Nazer, Meeran Mohideen; Hameed, Abdul Rahman Shahul; Riyazuddin, Patel

    2004-01-01

    A simple and rapid potentiometric method for the estimation of ascorbic acid in pharmaceutical dosage forms has been developed. The method is based on treating ascorbic acid with iodine and titration of the iodide produced equivalent to ascorbic acid with silver nitrate using Copper Based Mercury Film Electrode (CBMFE) as an indicator electrode. Interference study was carried to check possible interference of usual excipients and other vitamins. The precision and accuracy of the method was assessed by the application of lack-of-fit test and other statistical methods. The results of the proposed method and British Pharmacopoeia method were compared using F and t-statistical tests of significance.

  12. Fabrication of Chitosan-complexed Electrode and Evaluation of Its Efficiency in Removal of Copper Ion from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Yoon Young-Chan

    2016-01-01

    Full Text Available In this study, we fabricated chitosan/PVA/activated carbon complexed electrode to remove copper ion from aqueous solution. The prepared composite electrode was analyzed by BET and SEM to investigate its physicochemical properties. Electrochemical properties of prepared composite electrodes were analyzed via cyclic voltammetry. Adsorption performance of copper ion on chitosan composite complexed electrodes was evaluated. Almost similar pore size distribution results were observed in the series of ACP not included electrodes while observed differences in pore size distribution for the ACP included one. Cyclic voltammetry results exhibited that oxidation-reduction reaction does not occur in a potential range of -1.0 ~ 1.0 V. The amount of copper ion during adsroption reaction is increase according to increase of adsorption potential to 1.0 V.

  13. Spray-Deposited Large-Area Copper Nanowire Transparent Conductive Electrodes and Their Uses for Touch Screen Applications.

    Science.gov (United States)

    Chu, Hsun-Chen; Chang, Yen-Chen; Lin, Yow; Chang, Shu-Hao; Chang, Wei-Chung; Li, Guo-An; Tuan, Hsing-Yu

    2016-05-25

    Large-area conducting transparent conducting electrodes (TCEs) were prepared by a fast, scalable, and low-cost spray deposition of copper nanowire (CuNW) dispersions. Thin, long, and pure copper nanowires were obtained via the seed-mediated growth in an organic solvent-based synthesis. The mean length and diameter of nanowires are, respectively, 37.7 μm and 46 nm, corresponding to a high-mean-aspect ratio of 790. These wires were spray-deposited onto a glass substrate to form a nanowire conducting network which function as a TCE. CuNW TCEs exhibit high-transparency and high-conductivity since their relatively long lengths are advantageous in lowering in the sheet resistance. For example, a 2 × 2 cm(2) transparent nanowire electrode exhibits transmittance of T = 90% with a sheet resistance as low as 52.7 Ω sq(-1). Large-area sizes (>50 cm(2)) of CuNW TCEs were also prepared by the spray coating method and assembled as resistive touch screens that can be integrated with a variety of devices, including LED lighting array, a computer, electric motors, and audio electronic devices, showing the capability to make diverse sizes and functionalities of CuNW TCEs by the reported method.

  14. Electrodeposited porous and amorphous copper oxide film for application in supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Patake, V.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, (M.S.) (India); Joshi, S.S. [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of); Lokhande, C.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, (M.S.) (India); Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: l_chandrakant@yahoo.com; Joo, Oh-Shim [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: joocat@kist.rre.kr

    2009-03-15

    In present study, the porous amorphous copper oxide thin films have been deposited from alkaline sulphate bath. The cathodic electrodeposition method was employed to deposit copper oxide film at room temperature on stainless steel substrate. Their structural and surface morphological properties were investigated by means of X-ray diffraction (XRD) and scanning electron micrograph (SEM), respectively. To propose this as a new material for possible application in the supercapacitor, its electrochemical properties have been studied in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte using cyclic voltammetry. The structural analysis from XRD pattern showed the formation of amorphous copper oxide film on the substrate. The surface morphological studies from scanning electron micrographs revealed the formation of porous cauliflower-like copper oxide film. The cyclic voltammetric curves showed symmetric nature and increase in capacitance with increase in film thickness. The maximum specific capacitance of 36 F g{sup -1} was exhibited for the 0.6959 mg cm{sup -2} film thickness. This shows that low-cost copper oxide electrode will be a potential application in supercapacitor.

  15. Fabrication of copper-selective PVC membrane electrode based on newly synthesized copper complex of Schiff base as carrier

    Directory of Open Access Journals (Sweden)

    Sulekh Chandra

    2016-09-01

    Full Text Available The newly synthesized copper(II complex of Schiff base p-hydroxyacetophenone semicarbazone was explored as neutral ionophore for the fabrication of poly(vinylchloride (PVC based membrane electrode selective to Cu(II ions. The electrode shows a Nernstian slope of 29.8 ± 0.3 mV/decade with improved linear range of 1.8 × 10−7 to 1.0 × 10−1 M, comparatively lower detection limit 5.7 × 10−8 M between pH range of 2.0–8.0, giving a relatively fast response within 5s and can be used for at least 16 weeks without any divergence in potential. The selectivity coefficient was calculated using the fixed interference method (FIM. The electrode can also be used in partially non-aqueous media having up to 25% (v/v methanol, ethanol or acetone content with no significant change in the value of slope or working concentration range. It was successfully applied for the direct determination of copper content in water and tea samples with satisfactory results. The electrode has been used in the potentiometric titration of Cu2+ with EDTA.

  16. Electro-oxidation nitrite based on copper calcined layered double hydroxide and gold nanoparticles modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cui Lin; Meng Xiaomeng; Xu Minrong; Shang Kun [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Ai Shiyun, E-mail: ashy@sdau.edu.cn [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Liu Yinping [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China)

    2011-11-30

    Highlights: > A nitrite sensor fabricated based on copper calcined layered double hydroxides and gold nanoparticles modified electrode. > This sensor exhibited excellent electrocatalytic oxidation to nitrite. > This nitrite sensor exhibited very good analytical performance with low cost, convenient preparation and rapid detection. - Abstract: In this paper, a novel nitrite sensor was constructed based on electrodeposition of gold nanoparticles (AuNPs) on a copper calcined layered double hydroxide (Cu-CLDH) modified glassy carbon electrode. Electrochemical experiments showed that AuNPs/CLDH composite film exhibited excellent electrocatalytic oxidation activity with nitrite due to the synergistic effect of the Cu-CLDH with AuNPs. The fabricated sensor exhibited excellent performance for nitrite detection within a wide concentration interval of 1-191 {mu}M and with a detection limit of 0.5 {mu}M. The superior electrocatalytic response to nitrite was mainly attributed to the large surface area, minimized diffusion resistance, and enhanced electron transfer of the Cu-CLDH and AuNPs composition film. This platform offers a novel route for nitrite sensing with wide analytical applications and will supply the practical applications for a variety of simple, robust, and easy-to-manufacture analytical approaches in the future.

  17. Electro-oxidation nitrite based on copper calcined layered double hydroxide and gold nanoparticles modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Cui Lin; Meng Xiaomeng; Xu Minrong; Shang Kun; Ai Shiyun; Liu Yinping

    2011-01-01

    Highlights: → A nitrite sensor fabricated based on copper calcined layered double hydroxides and gold nanoparticles modified electrode. → This sensor exhibited excellent electrocatalytic oxidation to nitrite. → This nitrite sensor exhibited very good analytical performance with low cost, convenient preparation and rapid detection. - Abstract: In this paper, a novel nitrite sensor was constructed based on electrodeposition of gold nanoparticles (AuNPs) on a copper calcined layered double hydroxide (Cu-CLDH) modified glassy carbon electrode. Electrochemical experiments showed that AuNPs/CLDH composite film exhibited excellent electrocatalytic oxidation activity with nitrite due to the synergistic effect of the Cu-CLDH with AuNPs. The fabricated sensor exhibited excellent performance for nitrite detection within a wide concentration interval of 1-191 μM and with a detection limit of 0.5 μM. The superior electrocatalytic response to nitrite was mainly attributed to the large surface area, minimized diffusion resistance, and enhanced electron transfer of the Cu-CLDH and AuNPs composition film. This platform offers a novel route for nitrite sensing with wide analytical applications and will supply the practical applications for a variety of simple, robust, and easy-to-manufacture analytical approaches in the future.

  18. Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO2 Reduction

    DEFF Research Database (Denmark)

    Cavalca, Filippo Carlo; Ferragut, Rafael; Aghion, Stefano

    2017-01-01

    Oxide-derived copper (OD-Cu) electrodes exhibit higher activity than pristine copper during the carbon dioxide reduction reaction (CO2RR) and higher selectivity towards ethylene. The presence of residual subsurface oxygen in OD-Cu has been proposed to be responsible for such improvements, although...

  19. Electrochemical determination of copper ions in spirit drinks using carbon paste electrode modified with biochar.

    Science.gov (United States)

    Oliveira, Paulo Roberto; Lamy-Mendes, Alyne C; Rezende, Edivaltrys Inayve Pissinati; Mangrich, Antonio Sálvio; Marcolino, Luiz Humberto; Bergamini, Márcio F

    2015-03-15

    This work describes for first time the use of biochar as electrode modifier in combination with differential pulse adsorptive stripping voltammetric (DPAdSV) techniques for preconcentration and determination of copper (II) ions in spirit drinks samples (Cachaça, Vodka, Gin and Tequila). Using the best set of the experimental conditions a linear response for copper ions in the concentration range of 1.5 × 10(-6) to 3.1 × 10(-5) mol L(-1) with a Limit of Detection (LOD) of 4.0 × 10(-7) mol L(-1). The repeatability of the proposed sensor using the same electrode surface was measured as 3.6% and 6.6% using different electrodes. The effect of foreign species on the voltammetric response was also evaluated. Determination of copper ions content in different samples of spirit drinks samples was also realized adopting inductively coupled plasma optical emission spectroscopy (ICP-OES) and the results achieved are in agreement at a 95% of confidence level. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Copper-based electrochemical sensor with palladium electrode for cathodic stripping voltammetry of manganese.

    Science.gov (United States)

    Kang, Wenjing; Pei, Xing; Bange, Adam; Haynes, Erin N; Heineman, William R; Papautsky, Ian

    2014-12-16

    In this work, we report on the development of a palladium-based, microfabricated point-of-care electrochemical sensor for the determination of manganese using square wave cathodic stripping voltammetry. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Voltammetry offers an attractive approach to metal detection on the microscale, but traditional carbon, gold, or platinum electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor uses palladium working and auxiliary electrodes and integrates them with a copper-based reference electrode for simple fabrication and compatibility with microfabrication and printed circuit board processing, while maintaining competitive performance in electrochemical detection. Copper electrodes were prepared on glass substrate using a combination of microfabrication procedures followed by electrodeposition of palladium. The disposable sensor system was formed by bonding a poly(dimethylsiloxane) (PDMS) well to the glass substrate. Cathodic stripping voltammetry of manganese using our new disposable palladium-based sensors exhibited 334 nM (18.3 ppb) limit of detection in borate buffer. The sensor was used to demonstrate manganese determination in natural water samples from a pond in Burnet Woods, located in Cincinnati, OH, and the Ohio River.

  1. Determination of trace arsenic on hanging copper amalgam drop electrode.

    Science.gov (United States)

    Piech, Robert; Baś, Bogusław; Niewiara, Ewa; Kubiak, Władysław W

    2007-04-30

    Hanging copper amalgam drop electrode has been applied for trace determination of arsenic by cathodic stripping analysis. Detection limit for As(III) as low as 0.33nM (0.02mug/L) at deposition time (240s) could be obtained. For seven successive determinations of As(III) at concentration of 5nM relative standard deviation was 2.5% (n=7). Interferences from selected metals and surfactant substances were examined. Absence of copper ions in sample solution causes easier optimization and makes method less vulnerable on contamination. The developed method was validated by analysis of certified reference materials (CRMs) and applied to arsenic determinations in natural water samples.

  2. Formation of ultralong copper nanowires by hydrothermal growth for transparent conducting applications

    Science.gov (United States)

    Balela, Mary Donnabelle L.; Tan, Michael

    2017-07-01

    Transparent conducting electrodes are key components of optoelectronic devices, such as touch screens, organic light emitting diodes (OLEDs) and solar cells. Recent market surveys have shown that the demands for these devices are rapidly growing at a tremendous rate. Semiconducting oxides, in particular indium tin oxide (ITO) are the material of choice for transparent conducting electrodes. However, these conventional oxides are typically brittle, which limits their applicability in flexible electronics. Metal nanowires, e.g. copper (Cu) nanowires, are considered as the best candidate as substitute for ITO due to their excellent mechanical and electrical properties. In this paper, ultralong copper (Cu) nanowires with were successfully prepared by hydrothermal growth at 50-80°C for 1 h. Ethylenediamine was employed as the structure-directing agents, while hydrazine was used as the reductant. In situ mixed potential measurement was also carried out to monitor Cu deposition. Higher temperature shifted the mixed potential negatively, leading to thicker Cu nanowires. Transparent conducting electrode, with a sheet resistance of 197 Ω sq-1 at an optical transmittance of around 61 %, was fabricated with the Cu nanowire ink.

  3. Effect of acrylonitrile on the electrode processes ivolving copper cations

    Directory of Open Access Journals (Sweden)

    Viktor F. Vargalyuk

    2016-03-01

    Full Text Available Based on the results of cyclic voltammetry and study of deposits morphology, it has been shown that acrylonitrile does not have significant effect on the mechanism of Cu2+ + 2ē → Cu0 reaction. This distinguishes acrylonitrile from the unsaturated polyfunctional organic substances (acrylic acid, acrylamide which forms stable complexes with Cu2+ ions. Acrylonitrile just inhibits cathodic process by adsorbing on the surface of electrode thus blocking its active sites. But the presence of acrylonitrile significantly changes the mechanism of the anodic process. It has been found that acrylonitrile interacts with surface copper atoms thus forming thermodynamically stable [Cu π-AN]0 π‑complexes. Ionization potential of these π‑complexes is more negative if compare to copper atoms. As the result acceleration of anodic process takes place in the low polarization area. However, since the chemisorption is a slow process the presence of acrylonitrile mainly affects dissolution of the first surface layers of copper atoms. Further ionization of copper atoms runs out directly and requires higher polarization.

  4. Fabrication of Stretchable Copper Coated Carbon Nanotube Conductor for Non-Enzymatic Glucose Detection Electrode with Low Detection Limit and Selectivity

    Directory of Open Access Journals (Sweden)

    Dawei Jiang

    2018-03-01

    Full Text Available The increasing demand for wearable glucose sensing has stimulated growing interest in stretchable electrodes. The development of the electrode materials having large stretchability, low detection limit, and good selectivity is the key component for constructing high performance wearable glucose sensors. In this work, we presented fabrication of stretchable conductor based on the copper coated carbon nanotube sheath-core fiber, and its application as non-enzymatic electrode for glucose detection with high stretchability, low detection limit, and selectivity. The sheath-core fiber was fabricated by coating copper coated carbon nanotube on a pre-stretched rubber fiber core followed by release of pre-stretch, which had a hierarchically buckled structure. It showed a small resistance change as low as 27% as strain increasing from 0% to 500% strain, and a low resistance of 0.4 Ω·cm−1 at strain of 500%. This electrode showed linear glucose concentration detection in the range between 0.05 mM and 5 mM and good selectivity against sucrose, lactic acid, uric acid, acrylic acid in phosphate buffer saline solution, and showed stable signal in high salt concentration. The limit of detection (LOD was 0.05 mM, for the range of 0.05–5 mM, the sensitivity is 46 mA·M−1. This electrode can withstand large strain of up to 60% with negligible influence on its performance.

  5. Improving the Response of Copper(II) Selective PVC Membrane Electrode by Modification of N2S2 Donor Ligand.

    Science.gov (United States)

    Brinić, Slobodan; Buzuk, Marijo; Generalić, Eni; Bralić, Marija

    2010-06-01

    S,S'-bis(2-aminophenyl)ethanebis(thioate), (APhET), is reported as N2S2 ligand which form chelate with copper of high stability as compared to the other metals. Two modification of APhET, simpler 1,2-di-(o-aminophenylthio)ethane (DAPhTE), and the complex one 1,2-di-(o-salicylaldiminophenylthio)ethane (SAPhTE), were examined as the active material for copper(II) ion selective PVC membrane electrodes, and observed results are correlated. The obtained results with DAPhTE based electrodes show that only coordination abilities of ligand are insufficient for preparing the efficient membrane material. On the other hand, the results that are achieved with electrodes based on SAPhTE actuate interaction of ligand with polymer membrane matrix and necessity of ionophore immobilization in membrane. Optimized SAPhTE based membrane electrode has a linear range down to 10-6 mol L-1, with slope of 27.0 mV per decade, very rapid response time (under 5 seconds) and detection limit of 5.1 × 10-7 mol L-1. Such electrode is suitable for determination of copper(II) in analytical measurements by direct potentiometry and in potentiometric titrations, within pH between 2 and 7. The electrode is selective for copper(II) ions over a large number of metal ions, with the exception on Hg2+ ion when is present in concentrations above 2 × 10-5 mol L-1.

  6. Cathodic Stripping Voltammetry of Cysteine Using Silver and Copper Solid Amalgam Electrodes

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Novotný, Ladislav

    2002-01-01

    Roč. 56, č. 5 (2002), s. 971-976 ISSN 0039-9140 R&D Projects: GA ČR GV204/97/K084 Institutional research plan: CEZ:AV0Z4040901 Keywords : silver or copper solid amalgam electrode * cysteine * voltammetry Subject RIV: CG - Electrochemistry Impact factor: 2.054, year: 2002

  7. AGNES at vibrated gold microwire electrode for the direct quantification of free copper concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Domingos, Rute F., E-mail: rdomingos@ipgp.fr [Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Torre Sul Lab 11-6.3, Av. Rovisco Pais #1, 1049-001 Lisbon (Portugal); Carreira, Sara [Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Torre Sul Lab 11-6.3, Av. Rovisco Pais #1, 1049-001 Lisbon (Portugal); Galceran, Josep [Department of Chemistry, University of Lleida and Agrotecnio, Rovira Roure 191, 25198 Lleida (Spain); Salaün, Pascal [School of Environmental Sciences, University of Liverpool, 4 Brownlow Street, Liverpool L693 GP (United Kingdom); Pinheiro, José P. [LIEC/ENSG, UMR 7360 CNRS – Université de Lorraine, 15 Avenue du Charmois, 54500 Vandoeuvre-les-Nancy (France)

    2016-05-12

    The free metal ion concentration and the dynamic features of the metal species are recognized as key to predict metal bioavailability and toxicity to aquatic organisms. Quantification of the former is, however, still challenging. In this paper, it is shown for the first time that the concentration of free copper (Cu{sup 2+}) can be quantified by applying AGNES (Absence of Gradients and Nernstian equilibrium stripping) at a solid gold electrode. It was found that: i) the amount of deposited Cu follows a Nernstian relationship with the applied deposition potential, and ii) the stripping signal is linearly related with the free metal ion concentration. The performance of AGNES at the vibrating gold microwire electrode (VGME) was assessed for two labile systems: Cu-malonic acid and Cu-iminodiacetic acid at ionic strength 0.01 M and a range of pH values from 4.0 to 6.0. The free Cu concentrations and conditional stability constants obtained by AGNES were in good agreement with stripping scanned voltammetry and thermodynamic theoretical predictions obtained by Visual MinteQ. This work highlights the suitability of gold electrodes for the quantification of free metal ion concentrations by AGNES. It also strongly suggests that other solid electrodes may be well appropriate for such task. This new application of AGNES is a first step towards a range of applications for a number of metals in speciation, toxicological and environmental studies for the direct determination of the key parameter that is the free metal ion concentration. - Highlights: • AGNES principles are valid at the vibrating gold microwire electrode (VGME). • VGME was successfully employed to quantify free Cu concentrations by using AGNES. • Stability constants of labile systems were in good agreement with predictions.

  8. Dielectric material in lead-based perovskite and fabrication process for multilayer ceramic capacitor with copper internal electrode

    International Nuclear Information System (INIS)

    Kato, J.; Yokotani, Y.; Kagata, H.; Nakatani, S.; Kugimiya, K.

    1990-01-01

    This paper reports on the development of a multilayer ceramic capacitor with copper internal electrodes. Dielectric materials of the capacitor is lead- based perovskite (Pb a Ca b ) (Mg 1/3 Nb 2/3 ) x Ti y (Ni 1/2 W 1/2 ) z O 2 + a + b where a + b gt 1 and x + y + z = 1. The materials can be fired below 1000 degrees C and have high resistivity even when fired in the atmosphere below the equilibrium oxygen partial pressure of copper and CuO. The fabrication process of the capacitor has following features. The electrode paste is composed of copper oxide to prevent breaking of the laminated body in a burn out process. Then the copper oxide is first metalized and fired in a controlled atmosphere. The obtained capacitor of 20 dielectric layers of 17 micron meter meets to Z5U specification and has low loss tangent of 0.6% and stability under d.c. bias voltage and high a.c. field

  9. ELECTRODEPOSITION OF COPPER IONS ON FIXED BED ELECTRODES: KINETIC AND HYDRODYNAMIC STUDY

    Directory of Open Access Journals (Sweden)

    L.A.M. Ruotolo

    2002-03-01

    Full Text Available The kinetic and hydrodynamic behaviour of a fixed-bed electrochemical reactor was studied in terms of current efficiency (CE and energy efficiency (EE. In the kinetic experiments the effects of fixed bed thickness (L, current density (i and initial concentration of copper (C0 were studied. In the hydrodynamic experiments the permeability (k of the electrode and the coefficient for inertial forces (c were also studied as functions of the applied current density. At low current densities and bed thicknesses greater than 1.0 cm, negative CE and EE were observed as a consequence of the dissolution of the porous matrix. At high current densities low CE and EE were observed and a powdery deposit was formed on the surface of the particles. From the results of the kinetic study bed thickness and the range of current densities employed in the hydrodynamic experiments were chosen. In these experiments the electrodeposition process continued until the whole electrode had been clogged and no more electrolyte could pass through it. The relationship between pressure drop and flow rate was well described by the Forchheimer equation. It was observed that the reduction in porosity due to copper electrodeposition causes the flow rate to decrease because of the decrease in electrode permeability, but it had no influence on current efficiency.

  10. Glassy carbon electrode modified with polyanilne/ethylenediamine for detection of copper ions

    Science.gov (United States)

    Patil, Harshada K.; Deshmukh, Megha A.; Bodkhe, Gajanan A.; Shirsat, Mahendra D.

    2018-05-01

    Increasing water pollution is having high concern, since it creates the threats to all leaving organisms of existence. Industrial sewages have not only polluted the main stream lines of water, also the ground level water is having serious contaminations. Heavy metal ions are the pollutants which are not degradable and can be accumulated on living things ultimately the excess accumulation results into the serious concerns. Therefore, it is necessary to develop the sensors which can detect the heavy metal ions up to its maximum contamination limits. Conducting polymers are the materials which possess large application spectra. This investigation reports the electrochemically synthesized polyaniline (PANI) for modification of glassy carbon electrode (GCE). Ethylenediamine (EDA) - chelating ligand used for the modification of polyaniline so as to inculcate the selectivity toward copper ions Cu (II). The electrochemical cyclic voltammetry (CV) was used for the study of redox characteristics of PANI and influence of EDA modification. The result of CV has shown the reduced oxidation and reduction peak currents after modification indicating the domination of EDA. GCE modified with PANI/EDA was then employed for the detection of divalent copper ions and have shown the affinity toward Cu ions. The detection limit achieved was equal to 10mg/lit.

  11. Preparation of Electrospun Polymer Fibers Using a Copper Wire Electrode in a Capillary Tube

    Science.gov (United States)

    Shinbo, Kazunari; Onozuka, Shintaro; Hoshino, Rikiya; Mizuno, Yoshinori; Ohdaira, Yasuo; Baba, Akira; Kato, Keizo; Kaneko, Futao

    2010-04-01

    Polymer fibers were prepared by an electrospinning method utilizing a copper wire electrode in a capillary tube. The morphology of electrospun poly(vinyl alcohol) (PVA) fibers was observed, and was found to be dependent on the wire electrode tip position in the capillary tube, the concentration of the polymer solution, the distance between the electrodes, and the applied voltage. By using the wire electrode, the experimental setup is simple and the distance between the electrodes and the applied voltage can be easily reduced. Furthermore, the preparation of poly(3-hexylthiophene) (P3HT) fibers was carried out. P3HT fibers were successfully prepared by mixing poly(ethylene oxide) (PEO) in P3HT solution. Orientation control was also carried out by depositing the fibers on a rotating collector electrode, and the alignment of the P3HT:PEO fibers was confirmed. Anisotropy of the optical absorption spectra was also observed for the aligned fibers.

  12. Utilization of Copper Alloys for Marine Applications

    Science.gov (United States)

    Drach, Andrew

    Utilization of copper alloy components in systems deployed in marine environment presents potential improvements by reducing maintenance costs, prolonging service life, and increasing reliability. However, integration of these materials faces technological challenges, which are discussed and addressed in this work, including characterization of material performance in seawater environment, hydrodynamics of copper alloy components, and design procedures for systems with copper alloys. To characterize the hydrodynamic behavior of copper alloy nets, mesh geometry of the major types of copper nets currently used in the marine aquaculture are analyzed and formulae for the solidity and strand length are proposed. Experimental studies of drag forces on copper alloy net panels are described. Based on these studies, empirical values for normal drag coefficients are proposed for various types of copper netting. These findings are compared to the previously published data on polymer nets. It is shown that copper nets exhibit significantly lower resistance to normal currents, which corresponds to lower values of normal drag coefficient. The seawater performance (corrosion and biofouling) of copper alloys is studied through the field trials of tensioned and untensioned specimens in a one-year deployment in the North Atlantic Ocean. The corrosion behavior is characterized by weight loss, optical microscopy, and SEM/EDX analyses. The biofouling performance is quantified in terms of the biomass accumulation. To estimate the effects of stray electrical currents on the seawater corrosion measurements, a low cost three-axis stray electric current monitoring device is designed and tested both in the lab and in the 30-day field deployment. The system consists of a remotely operated PC with a set of pseudo-electrodes and a digital compass. The collected data is processed to determine magnitudes of AC and DC components of electric field and dominant AC frequencies. Mechanical behavior of

  13. Experimental Study of Nonequilibrium Electrodeposition of Nanostructures on Copper and Nickel for Photochemical Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Rajesh K. Shanmugam

    2011-01-01

    Full Text Available To increase the performance of photochemical fuel cells, nonequilibrium electrodeposition has been performed on Cu and Ni to make photosensitive anodes. Processing parameters including electrolyte concentration, and electrode potential were studied using cyclic voltammetry. Scanning electron microscopy (SEM and X-ray Spectroscopy (EDS were performed to understand the formation of the nanostructures during the nonequilibrium deposition of copper fractals. An increase in the deposition rate was observed with the increase in electrolyte concentration (from 0.05 M to 1.0 M. Similar trend was found when the cathode potential was decreased from −0.5 V to −4.5 V. The effect of substrate material was also examined. Porous fractal structures on copper were achieved, while the deposited material showed high density of surface cracks on nickel. The fractal structures deposited on copper electrode with the increased surface area were converted into copper oxide by oxidation in air. Such oxide samples were made into anodes for photochemical fuel cell application. We demonstrated that an increase in the magnitude of open circuit output voltage is associated with the increase in the fractal surface area under the ultraviolet irradiation test conditions. However, the electrodeposited fractals on nickel showed very limited increase in the magnitude of open circuit voltage.

  14. Enhanced electrochemical performances with a copper/xylose-based carbon composite electrode

    Science.gov (United States)

    Sirisomboonchai, Suchada; Kongparakul, Suwadee; Nueangnoraj, Khanin; Zhang, Haibo; Wei, Lu; Reubroycharoen, Prasert; Guan, Guoqing; Samart, Chanatip

    2018-04-01

    Copper/carbon (Cu/C) composites were prepared through the simple and environmentally benign hydrothermal carbonization of xylose in the presence of Cu2+ ions. The morphology, specific surface area, phase structure and chemical composition were investigated. Using a three-electrode system in 0.1 M H2SO4 aqueous electrolyte, the Cu/C composite (10 wt% Cu) heat-treated at 600 °C gave the highest specific capacitance (316.2 and 350.1 F g-1 at 0.5 A g-1 and 20 mV s-1, respectively). The addition of Cu was the major factor in improving the electrochemical performance, enhancing the specific capacitance more than 30 times that of the C without Cu. Therefore, the Cu/C composite presented promising results in improving biomass-based C electrodes for supercapacitors.

  15. A novel application of the CuI thin film for preparing thin copper nanowires

    International Nuclear Information System (INIS)

    Shi Shuo; Sun Jialin; Zhang Jianhong; Cao Yang

    2005-01-01

    We present a novel application of the CuI thin film for preparing thin copper nanowires under a direct current electric field (DCEF). The CuI thin film was used as a medium for transmitting cuprous ions during the growing process of copper nanowires. As electrodes are the source of cuprous ions, high-purity copper films were deposited on both ends of the CuI thin film. At 353 K, under whole solid condition, without any templates, and having applied a DCEF of 1.5x10 4 V/m, cuprous ions were generated at the anode and migrated towards the cathode through the CuI film. At the edge of the cathode, cuprous ions obtained electrons and congregated to form a disordered thin copper nanowires bundle. The SEM images showed that these copper nanowires were from 10 to 20 nm in diameter and several hundred nanometers in length. The effect of the electric field intensity and the growth temperature on the diameter of the nanowires was also studied

  16. Determination of total and electrolabile copper in agricultural soil by using disposable modified-carbon screen-printed electrodes.

    Science.gov (United States)

    Faucher, Stéphane; Cugnet, Cyril; Authier, Laurent; Lespes, Gaëtane

    2014-02-01

    The objective of the study is to evaluate modified-carbon screen-printed working electrodes (SPE) combined with square wave anodic stripping voltammetry (SWASV) to determine electrolabile and total copper in soils with the perspective to assess the environmental hazard resulting from copper anthropogenic contamination. The voltammetric method was investigated using a mineralized certified reference soil such that it can be assumed that the copper was totally under electrolabile form in the solution of mineralized soil. In optimal conditions, a copper recovery of 97% and a relative standard deviation (RSD) of 9% were found. The limits of detection and quantification for copper were 0.4 and 1.3 μg L(-1), respectively. Finally, the method was applied on soil leachates, which allowed evaluating the cupric transfer from the soil to the leachates and quantifying the electrolabile copper part in leachates.

  17. Copper-substituted perovskite compositions for solid oxide fuel cell cathodes and oxygen reduction electrodes in other electrochemical devices

    Science.gov (United States)

    Rieke, Peter C [Pasco, WA; Coffey, Gregory W [Richland, WA; Pederson, Larry R [Kennewick, WA; Marina, Olga A [Richland, WA; Hardy, John S [Richland, WA; Singh, Prabhaker [Richland, WA; Thomsen, Edwin C [Richland, WA

    2010-07-20

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells. Also provided are electrochemical devices that include active oxygen reduction electrodes, such as solid oxide fuel cells, sensors, pumps and the like. The compositions comprises a copper-substituted ferrite perovskite material. The invention also provides novel methods for making and using the electrode compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having cathodes comprising the compositions.

  18. A bioinspired copper 2,2-bipyridyl complex immobilized MWCNT modified electrode prepared by a new strategy for elegant electrocatalytic reduction and sensing of hydrogen peroxide

    International Nuclear Information System (INIS)

    Mayuri, Pinapeddavari; Saravanan, Natarajan; Senthil Kumar, Annamalai

    2017-01-01

    Owing to facile electron-transfer reaction, metal complex based molecular architecture has attracted much interest in electrochemistry, especially for bioinspired electrocatalytic and electrochemical sensor applications. Indeed, preparation of stable surface-confined molecular system is a challenging task. In general, derivatization methodology, in which, a specific functional groups such as thiol, carboxylic acid, pyrene and amino bearing inorganic complexes synthesized discreetly by chemical approach have been attached suitably on electrode surface via any one of the following techniques; self-assembly, covalent immobilization, electrostatic interaction, ionic exchange and encapsulation. Herein, we report a copper-bipyridyl complex immobilized multiwalled carbon nanotube (MWCNT)-Nafion (Nf) modified glassy carbon electrode (GCE/Nf-MWCNT@bpy-Cu"2"+) prepared by a new strategy in which sequential modification of bipyridyl (bpy) ligand on MWCNT via π-π interaction followed by in-situ complexation with copper ion for efficient electrochemical reduction of H_2O_2. The copper species chemically modified electrode showed highly stable and well-defined surface-confined Cu"2"+"/"1"+ redox peak response, without any Cu"1"+"/"0 redox transition, at an equilibrium potential, E_1_/_2 = −135 mV vs Ag/AgCl in a pH 7 phosphate buffer solution. Detailed physico-chemical characterization by SEM, FT-IR, Raman and ESI-MS and electrochemical characterization reveals that [Cu(bpy)_2(H_2O)_2]"+ (molecular weight 413.4) like species was immobilized as a major species on the modified electrode. A bioinspired electro-catalytic reduction of H_2O_2 was studied using cyclic voltammetric and rotating disc electrode techniques. In further, electrochemical sensing of H_2O_2 by amperometric i-t and flow injection analysis methods with a detection limit values 4.5 and 0.49 μM respectively were demonstrated.

  19. The direct determination, by differential pulse anodic-stripping voltammetry at the thin mercury-film electrode, of cadmium, lead and copper

    International Nuclear Information System (INIS)

    Lee, A.F.

    1981-01-01

    This report describes the development and application of a voltammetric procedure for the direct, simultaneous determination of cadmium, lead, and copper in three SAROC reference materials (carbonatite, magnesite, and quartz). The electrolyte was a mixture of 1 M ammonium chloride, 0,1 M citric acid, and 0,025 M ascorbic acid. No interferences were encountered from Fe(III), As(III), Sb(V), Tl(I), or In(III) at the concentrations present in the samples. Intermetallic interferences were eliminated by the use of thin mercury-film electrodes not less than 80nm thick. Limits of detection were determined by the degree to which the supporting electrolyte could be purified, and were estimated to be 10ng/g, 250ng/g, and 150ng/g for cadmium, lead, and copper respectively

  20. Effect of humic acid on the underpotential deposition-stripping voltammetry of copper in acetic acid soil extract solutions at mercaptoacetic acid-modified gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, Gregoire; Beni, Valerio; Dillon, Patrick H.; Barry, Thomas; Arrigan, Damien W.M

    2004-05-24

    Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bare and modified gold electrodes in 0.11 M acetic acid, the first fraction of the European Union's Bureau Communautaire de References (BCR) sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showed higher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acid solutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l{sup -1} of humic acid, the mercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayer formed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of the humic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modified electrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic results yielded the straight-line equation y ({mu}g l{sup -1}) = 1.10x - 44 (ppb) (R=0.992, n=6), indicating good agreement between the two methods.

  1. Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode

    KAUST Repository

    Wu, Hui

    2010-10-13

    Transparent electrodes, indespensible in displays and solar cells, are currently dominated by indium tin oxide (ITO) films although the high price of indium, brittleness of films, and high vacuum deposition are limiting their applications. Recently, solution-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted great attention as replacements. A low junction resistance between nanostructures is important for decreasing the sheet resistance. However, the junction resistances between CNTs and boundry resistances between graphene nanostructures are too high. The aspect ratios of silver nanowires are limited to ∼100, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh aspect ratios of up to 100000 and fused crossing points with ultralow junction resistances, which result in high transmitance at low sheet resistance, e.g., 90% at 50 Ω/sq. The copper nanofiber networks also show great flexibility and stretchabilty. Organic solar cells using copper nanowire networks as transparent electrodes have a power efficiency of 3.0%, comparable to devices made with ITO electrodes. © 2010 American Chemical Society.

  2. Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode

    KAUST Repository

    Wu, Hui; Hu, Liangbing; Rowell, Michael W.; Kong, Desheng; Cha, Judy J.; McDonough, James R.; Zhu, Jia; Yang, Yuan; McGehee, Michael D.; Cui, Yi

    2010-01-01

    Transparent electrodes, indespensible in displays and solar cells, are currently dominated by indium tin oxide (ITO) films although the high price of indium, brittleness of films, and high vacuum deposition are limiting their applications. Recently, solution-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted great attention as replacements. A low junction resistance between nanostructures is important for decreasing the sheet resistance. However, the junction resistances between CNTs and boundry resistances between graphene nanostructures are too high. The aspect ratios of silver nanowires are limited to ∼100, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh aspect ratios of up to 100000 and fused crossing points with ultralow junction resistances, which result in high transmitance at low sheet resistance, e.g., 90% at 50 Ω/sq. The copper nanofiber networks also show great flexibility and stretchabilty. Organic solar cells using copper nanowire networks as transparent electrodes have a power efficiency of 3.0%, comparable to devices made with ITO electrodes. © 2010 American Chemical Society.

  3. Measurement of labile copper in wine by medium exchange stripping potentiometry utilising screen printed carbon electrodes.

    Science.gov (United States)

    Clark, Andrew C; Kontoudakis, Nikolaos; Barril, Celia; Schmidtke, Leigh M; Scollary, Geoffrey R

    2016-07-01

    The presence of copper in wine is known to impact the reductive, oxidative and colloidal stability of wine, and techniques enabling measurement of different forms of copper in wine are of particular interest in understanding these spoilage processes. Electrochemical stripping techniques developed to date require significant pretreatment of wine, potentially disturbing the copper binding equilibria. A thin mercury film on a screen printed carbon electrode was utilised in a flow system for the direct analysis of labile copper in red and white wine by constant current stripping potentiometry with medium exchange. Under the optimised conditions, including an enrichment time of 500s and constant current of 1.0μA, the response range was linear from 0.015 to 0.200mg/L. The analysis of 52 red and white wines showed that this technique generally provided lower labile copper concentrations than reported for batch measurement by related techniques. Studies in a model system and in finished wines showed that the copper sulfide was not measured as labile copper, and that loss of hydrogen sulfide via volatilisation induced an increase in labile copper within the model wine system. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Electrochemical removal of copper ions from dilute solutions using packed bed electrode. Part І

    Directory of Open Access Journals (Sweden)

    I.A. Khattab

    2013-06-01

    Full Text Available Removal of some hazardous waste like copper from effluent streams has an industrial importance. In this field, this paper is directed towards electrochemical removal of copper ions from sulfate solution using packed bed electrode. The cathode packing is in static mode, consisted of graphite particles, with mean particle size equal to 0.125 cm. The high surface area of this cell is expected to give high current efficiency and removal percent. The effect of current density and liquid flow rate were tested. Experimental results obtained indicate that the efficiencies are in direct proportional with current density while inversely proportional with liquid flow rate. It was observed that, using this cell was effective in reducing copper concentration to less than 4 mg/l with R.E of 96.2% during 30 min electrolysis time.

  5. Three-dimensional porous hollow fibre copper electrodes for efficient and high-rate electrochemical carbon dioxide reduction

    NARCIS (Netherlands)

    Kas, Recep; Hummadi, Khalid Khazzal; Kortlever, Ruud; de Wit, Patrick; Milbrat, Alexander; Luiten-Olieman, Maria W.J.; Benes, Nieck Edwin; Koper, Marc T.M.; Mul, Guido

    2016-01-01

    Aqueous-phase electrochemical reduction of carbon dioxide requires an active, earth-abundant electrocatalyst, as well as highly efficient mass transport. Here we report the design of a porous hollow fibre copper electrode with a compact three-dimensional geometry, which provides a large area,

  6. Applications of porous electrodes to metal-ion removal and the design of battery systems

    International Nuclear Information System (INIS)

    Trost, G.G.

    1983-09-01

    This dissertation treats the use of porous electrodes as electrochemical reactors for the removal of dilute metal ions. A methodology for the scale-up of porous electrodes used in battery applications is given. Removal of 4 μg Pb/cc in 1 M sulfuric acid was investigated in atmospheric and high-pressure, flow-through porous reactors. The atmospheric reactor used a reticulated vitreous carbon porous bed coated in situ with a mercury film. Best results show 98% removal of lead from the feed stream. Results are summarized in a dimensionless plot of Sherwood number vs Peclet number. High-pressure, porous-electrode experiments were performed to investigate the effect of pressure on the current efficiency. Pressures were varied up to 120 bar on electrode beds of copper or lead-coated spheres. The copper spheres showed high hydrogen evolution rates which inhibited lead deposition, even at high cathodic overpotentials. Use of lead spheres inhibited hydrogen evolution but often resulted in the formation of lead sulfate layers; these layers were difficult to reduce back to lead. Experimental data of one-dimensional porous battery electrodes are combined with a model for the current collector and cell connectors to predict ultimate specific energy and maximum specific power for complete battery systems. Discharge behavior of the plate as a whole is first presented as a function of depth of discharge. These results are combined with the voltage and weight penalties of the interconnecting bus and post, positive and negative active material, cell container, etc. to give specific results for the lithium-aluminum/iron sulfide high-temperature battery. Subject to variation is the number of positive electrodes, grid conductivity, minimum current-collector weight, and total delivered capacity. The battery can be optimized for maximum energy or power, or a compromise design may be selected

  7. Applications of porous electrodes to metal-ion removal and the design of battery systems

    Energy Technology Data Exchange (ETDEWEB)

    Trost, G.G.

    1983-09-01

    This dissertation treats the use of porous electrodes as electrochemical reactors for the removal of dilute metal ions. A methodology for the scale-up of porous electrodes used in battery applications is given. Removal of 4 ..mu..g Pb/cc in 1 M sulfuric acid was investigated in atmospheric and high-pressure, flow-through porous reactors. The atmospheric reactor used a reticulated vitreous carbon porous bed coated in situ with a mercury film. Best results show 98% removal of lead from the feed stream. Results are summarized in a dimensionless plot of Sherwood number vs Peclet number. High-pressure, porous-electrode experiments were performed to investigate the effect of pressure on the current efficiency. Pressures were varied up to 120 bar on electrode beds of copper or lead-coated spheres. The copper spheres showed high hydrogen evolution rates which inhibited lead deposition, even at high cathodic overpotentials. Use of lead spheres inhibited hydrogen evolution but often resulted in the formation of lead sulfate layers; these layers were difficult to reduce back to lead. Experimental data of one-dimensional porous battery electrodes are combined with a model for the current collector and cell connectors to predict ultimate specific energy and maximum specific power for complete battery systems. Discharge behavior of the plate as a whole is first presented as a function of depth of discharge. These results are combined with the voltage and weight penalties of the interconnecting bus and post, positive and negative active material, cell container, etc. to give specific results for the lithium-aluminum/iron sulfide high-temperature battery. Subject to variation is the number of positive electrodes, grid conductivity, minimum current-collector weight, and total delivered capacity. The battery can be optimized for maximum energy or power, or a compromise design may be selected.

  8. Nanoscale Copper and Copper Compounds for Advanced Device Applications

    Science.gov (United States)

    Chen, Lih-Juann

    2016-12-01

    Copper has been in use for at least 10,000 years. Copper alloys, such as bronze and brass, have played important roles in advancing civilization in human history. Bronze artifacts date at least 6500 years. On the other hand, discovery of intriguing properties and new applications in contemporary technology for copper and its compounds, particularly on nanoscale, have continued. In this paper, examples for the applications of Cu and Cu alloys for advanced device applications will be given on Cu metallization in microelectronics devices, Cu nanobats as field emitters, Cu2S nanowire array as high-rate capability and high-capacity cathodes for lithium-ion batteries, Cu-Te nanostructures for field-effect transistor, Cu3Si nanowires as high-performance field emitters and efficient anti-reflective layers, single-crystal Cu(In,Ga)Se2 nanotip arrays for high-efficiency solar cell, multilevel Cu2S resistive memory, superlattice Cu2S-Ag2S heterojunction diodes, and facet-dependent Cu2O diode.

  9. Rapid determination of trace level copper in tea infusion samples by solid contact ion selective electrode

    Directory of Open Access Journals (Sweden)

    Aysenur Birinci

    2016-07-01

    Full Text Available A new solid contact copper selective electrode with a poly (vinyl chloride (PVC membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds and near-Nernstian response to Cu2+ activity from 10−1 to 10−6 mol/L at the pH range of 4.0–6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS.

  10. Facile Synthesis of Ultralong and Thin Copper Nanowires and Its Application to High-Performance Flexible Transparent Conductive Electrodes

    Science.gov (United States)

    Wang, Yaxiong; Liu, Ping; Zeng, Baoqing; Liu, Liming; Yang, Jianjun

    2018-03-01

    A hydrothermal method for synthesizing ultralong and thin copper nanowires (CuNWs) with average diameter of 35 nm and average length of 100 μm is demonstrated in this paper. The concerning raw materials include copric (II) chloride dihydrate (CuCl2·2H2O), octadecylamine (ODA), and ascorbic acid, which are all very cheap and nontoxic. The effect of different reaction time and different molar ratios to the reaction products were researched. The CuNWs prepared by the hydrothermal method were applied to fabricate CuNW transparent conductive electrode (TCE), which exhibited excellent conductivity-transmittance performance with low sheet resistance of 26.23 Ω /\\square and high transparency at 550 nm of 89.06% (excluding Polyethylene terephthalate (PET) substrate). The electrode fabrication process was carried out at room temperature, and there was no need for post-treatment. In order to decrease roughness and protect CuNW TCEs against being oxidized, we fabricated CuNW/poly(methyl methacrylate) (PMMA) hybrid TCEs (HTCEs) using PMMA solution. The CuNW/PMMA HTCEs exhibited low surface roughness and chemical stability as compared with CuNW TCEs.

  11. [Applications of atomic emission spectrum from liquid electrode discharge to metal ion detection].

    Science.gov (United States)

    Mao, Xiu-Ling; Wu, Jian; Ying, Yi-Bin

    2010-02-01

    The fast and precise detection of metal ion is an important research project concerning studies in diverse academic fields and different kinds of detecting technologies. In the present paper, the authors review the research on atomic emission spectrum based on liquid electrode discharge and its applications in the detection of metal ion. In the first part of this paper the principles and characteristics of the methods based on electrochemistry and spectroscopy were introduced. The methods of ion-selective electrode (ISE), anodic stripping voltammetry, atomic emission spectrum and atomic absorption spectrum were included in this part and discussed comparatively. Then the principles and characteristics of liquid electrode spectra for metal ion detection were introduced. The mechanism of the plasma production and the characteristics of the plasma spectrum as well as its advantages compared with other methods were discussed. Secondly, the authors divided the discharge system into two types and named them single liquid-electrode discharge and double-liquid electrode respectively, according to the number of the liquid electrode and the configuration of the discharge system, and the development as well as the present research status of each type was illustrated. Then the characteristics and configurations of the discharge systems including ECGD, SCGD, LS-APGD and capillary discharge were discussed in detail as examples of the two types. By taking advantage of the technology of atomic emission spectrum based on liquid electrode discharge, the detecting limit of heavy metals such as copper, mercury and argent as well as active metal ions including sodium, potass and magnesium can achieve microg x L(-1). Finally, the advantages and problems of the liquid-electrode discharge applied in detection of metal ion were discussed. And the applications of the atomic emission spectrum based on liquid electrode discharge were prospected.

  12. Voltammetry and Electrocatalysis of Achrornobacter Xylosoxidans Copper Nitrite Reductase on Functionalized Au(111)-Electrode Surfaces

    DEFF Research Database (Denmark)

    Welinder, Anna C.; Zhang, Jingdong; Hansen, Allan G.

    2007-01-01

    A long-standing issue in protein film voltammetry (PFV), particularly electrocatalytic voltammetry of redox enzyme monolayers, is the variability of protein adsorption modes, reflected in distributions of catalytic activity of the adsorbed protein/enzyme molecules. Use of well-defined, atomically...... planar electrode surfaces is a step towards the resolution of this central issue. We report here the voltammetry of copper nitrite reductase (CNiR, Achromobacter xylosoxidons) on Au(111)-electrode surfaces modified by monolayers of a broad variety of thiol-based linker molecules. These represent......NiR thus shows highly efficient, close to ideal reversible electrocatalytic voltammetry on cysteamine-covered Au(111)-electrode surfaces, most likely due to two cysteamine orientations previously disclosed by in situ scanning tunnelling microscopy. Such a dual orientation exposes both a hydrophobic...

  13. The reversal constituent structure of photo-electrode in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Ting, Chen-Ching; Chao, Wei-Shi

    2011-01-01

    Highlights: → The new structure of photo-electrode in DSSC increases absorption of incident photons. → The substrate of copper mesh as photo-electrode reduces electric resistance. → Application of the copper mesh as substrate reduces the fabricating cost. → There are ca. 3 times increment of photoelectric conversion efficiency. → Application of the copper mesh as substrate can achieve the flexible DSSCs. - Abstract: This article presents significant experimental data about the dye-sensitized nano solar cells (DSSCs) using the new developed photo-electrode with reversal constituent structure in our CCT laboratory. The conventional constituent structure of a photo-electrode arranged in sequence from the incident light is the transparent conductive glass, the nano TiO 2 semi-conductive porous film, and the dye. In process, the photons energy of the incident light is mainly absorbed by the dye for DSSCs. This causes excited electrons in the dye to jump into conductive band of the TiO 2 and further to transfer into the outer circuit through the conductive glass. That is, a correct constituent structure of the photo-electrode arranged in sequence from the incident light in terms of the working principle should be the dye, the nano TiO 2 film, and the conductive substrate. The conventional constituent structure of the photo-electrode causes the incident light to be hindered by the TiO 2 layer. To reduce the light hindrance for the dye, this work used copper mesh as the conductive substrate and the nano TiO 2 was coated on it. In this way, the copper mesh connects the nano TiO 2 layer with the outer circuit and the holes of the copper mesh also allow the dye to contact with the electrolyte. The new developed constituent structure of the photo-electrode arranged in sequence from the incident light is the dye, the nano TiO 2 film, and the copper mesh. This new constituent structure, which increases amounts of the absorption light in the dye and further improved the

  14. Fabrication of new carbon paste electrodes based on gold nano-particles self-assembled to mercapto compounds as suitable ionophores for potentiometric determination of copper ions

    Directory of Open Access Journals (Sweden)

    Rasoul Pourtaghavi Talemi

    2013-12-01

    Full Text Available In the present study, we investigate the potentiometric behavior of Cu2+ carbon paste electrodes based on two mercapto compounds 2-ethylmino-5-mercapto-1,3,4-thiadiazole (EAMT and 2-acetylamino-5-mercapto-1,3,4-thiadiazole (AAMT self-assembled on gold nano-paricle (GNP as ionophore. Then, the obtained results from the modified electrodes are compared. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu2+, in which the sulfur and nitrogen atoms in their structure play a significant role as the effective coordination donor site for the copper ion. Among these electrodes, the best performance was obtained with the sensor with a EAMT/graphite powder/paraffin oil weight ratio of 4.0/68/28 with 200 µL of GNP which exhibits the working concentration range of 1.6×10−9 to 6.3×10−2 M and a nernstian slope of 28.9±0.4 mVdecade−1 of copper(II activity. The detection limit of electrode was 2.9(±0.2×10−10M and potential response was pH ; in other words, it was independent across the range of 2.8–6.3. The proposed electrode presented very good selectivity and sensitivity towards the Cu2+ ions over a wide variety of cations including alkali, alkaline earth, transition and heavy metal ions. Moreover, the proposed electrode was successfully applied as an indicator electrode in the potentiometric titration of Cu(II ions with EDTA and also the potentiometric determination of copper ions in spiked water samples.

  15. Direct electrochemistry of blue copper proteins at boron-doped diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    McEvoy, James P. [Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA (United Kingdom); Foord, John S. [Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA (United Kingdom)]. E-mail: john.foord@chem.ox.ac.uk

    2005-05-05

    Boron-doped diamond (BDD) is a promising electrode material for use in the spectro-electrochemical study of redox proteins and, in this investigation, cyclic voltammetry was used to obtain quasi-reversible electrochemical responses from two blue copper proteins, parsley plastocyanin and azurin from Pseudomonas aeruginosa. No voltammetry was observed at the virgin electrodes, but signals were observed if the electrodes were anodised, or abraded with alumina, prior to use. Plastocyanin, which has a considerable overall negative charge and a surface acidic patch which is important in forming a productive electron transfer complex with its redox partners, gave a faradaic signal at pre-treated BDD only in the presence of neomycin, a positively charged polyamine. The voltammetry of azurin, which has a small overall charge and no surface acidic patch, was obtained identically in the presence and absence of neomycin. Investigations were also carried out into the voltammetry of two site-directed mutants of azurin, M64E azurin and M44K azurin, each of which introduce a charge into the protein's surface hydrophobic patch. The oxidizing and cleaning effects of the BDD electrode pre-treatments were studied electrochemically using two inorganic probe ions, Fe(China){sub 6} {sup 3-} and Ru(NH{sub 3}){sub 6} {sup 3+}, and by X-ray photoelectron spectroscopy (XPS). All of the electrochemical results are discussed in relation to the electrostatic and hydrophobic contributions to the protein/diamond electrochemical interaction.

  16. Direct electrochemistry of blue copper proteins at boron-doped diamond electrodes

    International Nuclear Information System (INIS)

    McEvoy, James P.; Foord, John S.

    2005-01-01

    Boron-doped diamond (BDD) is a promising electrode material for use in the spectro-electrochemical study of redox proteins and, in this investigation, cyclic voltammetry was used to obtain quasi-reversible electrochemical responses from two blue copper proteins, parsley plastocyanin and azurin from Pseudomonas aeruginosa. No voltammetry was observed at the virgin electrodes, but signals were observed if the electrodes were anodised, or abraded with alumina, prior to use. Plastocyanin, which has a considerable overall negative charge and a surface acidic patch which is important in forming a productive electron transfer complex with its redox partners, gave a faradaic signal at pre-treated BDD only in the presence of neomycin, a positively charged polyamine. The voltammetry of azurin, which has a small overall charge and no surface acidic patch, was obtained identically in the presence and absence of neomycin. Investigations were also carried out into the voltammetry of two site-directed mutants of azurin, M64E azurin and M44K azurin, each of which introduce a charge into the protein's surface hydrophobic patch. The oxidizing and cleaning effects of the BDD electrode pre-treatments were studied electrochemically using two inorganic probe ions, Fe(China) 6 3- and Ru(NH 3 ) 6 3+ , and by X-ray photoelectron spectroscopy (XPS). All of the electrochemical results are discussed in relation to the electrostatic and hydrophobic contributions to the protein/diamond electrochemical interaction

  17. Performance capabilities of EDM of high carbon high chromium steel with copper and brass electrodes

    Science.gov (United States)

    Surekha, B.; Swain, Sudiptha; Suleman, Abu Jafar; Choudhury, Suvan Dev

    2017-07-01

    The paper address the statistical modeling of input-output relationships of electric discharge machining. In the present work, peak current (I) pulse on time (T) and gap voltage of electric discharge machining (EDM) process are chosen as control parameters to analyze the performance of the process. The output characteristics, namely radial overcut, electrode wear rate (EWR) and metal removal rate (MRR) are treated as the responses. A full factorial design (FFD) of experiments has been used to conduct the experiments and linear regression models are developed for different process characteristics. While conducting the experiments, high carbon and high chromium steel is considered as work piece material and brass and copper are used as electrode material. It is important to note that the experimental conditions are kept similar while machining with the help of different electrode materials. The data obtained from the experiments has been used to develop the regression models for three process parameters for two electrode materials.

  18. In situ spectroscopic monitoring of CO2 reduction at copper oxide electrode.

    Science.gov (United States)

    Wang, Liying; Gupta, Kalyani; Goodall, Josephine B M; Darr, Jawwad A; Holt, Katherine B

    2017-04-28

    Copper oxide modified electrodes were investigated as a function of applied electrode potential using in situ infrared spectroscopy and ex situ Raman and X-ray photoelectron spectroscopy. In deoxygenated KHCO 3 electrolyte bicarbonate and carbonate species were found to adsorb to the electrode during reduction and the CuO was reduced to Cu(i) or Cu(0) species. Carbonate was incorporated into the structure and the CuO starting material was not regenerated on cycling to positive potentials. In contrast, in CO 2 saturated KHCO 3 solution, surface adsorption of bicarbonate and carbonate was not observed and adsorption of a carbonato-species was observed with in situ infrared spectroscopy. This species is believed to be activated, bent CO 2 . On cycling to negative potentials, larger reduction currents were observed in the presence of CO 2 ; however, less of the charge could be attributed to the reduction of CuO. In the presence of CO 2 CuO underwent reduction to Cu 2 O and potentially Cu, with no incorporation of carbonate. Under these conditions the CuO starting material could be regenerated by cycling to positive potentials.

  19. Voltammetric behaviour at gold electrodes immersed in the BCR sequential extraction scheme media Application of underpotential deposition-stripping voltammetry to determination of copper in soil extracts

    Energy Technology Data Exchange (ETDEWEB)

    Beni, Valerio; Newton, Hazel V.; Arrigan, Damien W.M.; Hill, Martin; Lane, William A.; Mathewson, Alan

    2004-01-30

    The development of mercury-free electroanalytical systems for in-field analysis of pollutants requires a foundation on the electrochemical behaviour of the chosen electrode material in the target sample matrices. In this work, the behaviour of gold working electrodes in the media employed in the BCR sequential extraction protocol, for the fractionation of metals in solid environmental matrices, is reported. All three of the BCR sequential extraction media are redox active, on the basis of acidity and oxygen content as well as the inherent reducing or oxidising nature of some of the reagents employed: 0.11 M acetic acid, 0.1 M hydroxylammonium chloride (adjusted to pH 2) and 1 M ammonium acetate (adjusted to pH 2) with added trace hydrogen peroxide. The available potential ranges together with the demonstrated detection of target metals in these media are presented. Stripping voltammetry of copper or lead in the BCR extract media solutions reveal a multi-peak behaviour due to the stripping of both bulk metal and underpotential metal deposits. A procedure based on underpotential deposition-stripping voltammetry (UPD-SV) was evaluated for application to determination of copper in 0.11 M acetic acid soil extracts. A preliminary screening step in which different deposition times are applied to the sample enables a deposition time commensurate with UPD-SV to be selected so that no bulk deposition or stripping occurs thus simplifying the shape and features of the resulting voltammograms. Choice of the suitable deposition time is then followed by standards addition calibration. The method was validated by the analysis of a number of BCR 0.11 M acetic acid soil extracts. Good agreement was obtained been the UPD-SV method and atomic spectroscopic results.

  20. Voltammetric behaviour at gold electrodes immersed in the BCR sequential extraction scheme media Application of underpotential deposition-stripping voltammetry to determination of copper in soil extracts

    International Nuclear Information System (INIS)

    Beni, Valerio; Newton, Hazel V.; Arrigan, Damien W.M.; Hill, Martin; Lane, William A.; Mathewson, Alan

    2004-01-01

    The development of mercury-free electroanalytical systems for in-field analysis of pollutants requires a foundation on the electrochemical behaviour of the chosen electrode material in the target sample matrices. In this work, the behaviour of gold working electrodes in the media employed in the BCR sequential extraction protocol, for the fractionation of metals in solid environmental matrices, is reported. All three of the BCR sequential extraction media are redox active, on the basis of acidity and oxygen content as well as the inherent reducing or oxidising nature of some of the reagents employed: 0.11 M acetic acid, 0.1 M hydroxylammonium chloride (adjusted to pH 2) and 1 M ammonium acetate (adjusted to pH 2) with added trace hydrogen peroxide. The available potential ranges together with the demonstrated detection of target metals in these media are presented. Stripping voltammetry of copper or lead in the BCR extract media solutions reveal a multi-peak behaviour due to the stripping of both bulk metal and underpotential metal deposits. A procedure based on underpotential deposition-stripping voltammetry (UPD-SV) was evaluated for application to determination of copper in 0.11 M acetic acid soil extracts. A preliminary screening step in which different deposition times are applied to the sample enables a deposition time commensurate with UPD-SV to be selected so that no bulk deposition or stripping occurs thus simplifying the shape and features of the resulting voltammograms. Choice of the suitable deposition time is then followed by standards addition calibration. The method was validated by the analysis of a number of BCR 0.11 M acetic acid soil extracts. Good agreement was obtained been the UPD-SV method and atomic spectroscopic results

  1. Graphite electrodes modified by 8-hydroxyquinolines and its application for the determination of copper in trace levels

    Directory of Open Access Journals (Sweden)

    Sousa Eliane R. de

    2006-01-01

    Full Text Available Surface modification by 8-hydroxyquinoline-5-sulfonic acid (8-HQS or 8-hydroxyquinoline (8-HQ on a graphite electrode through irreversible adsorption is reported in this paper. Cyclic voltammetry was used to characterize the surface behavior. The modified surface exhibited an affinity to chelating Cu(II in the solution, forming a Cu(II complex, which was employed for Cu(II trace analysis. Of the metals Zn, Ni, Pb, Co, and Cd, none presented interference until excess concentration of 10 times. Significant interference could be observed from Co(II, Cd(II and Fe(II for an excess concentration of 100 times on the analyte. A differential pulse voltammetry, combined with a preconcentrating-stripping process and a standard addition method was used for the analysis. A detection limit for trace copper determination in water, such as 5.110-9 mol L-1, was obtained.

  2. Diffusion-controlled oxygen reduction on multi-copper oxidase-adsorbed carbon aerogel electrodes without mediator

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, S.; Kamitaka, Y.; Kano, K. [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto (Japan)

    2007-12-15

    Bioelectrocatalytic reduction of O{sub 2} into water was archived at diffusion-controlled rate by using enzymes (laccase from Trametes sp. and bilirubin oxidase from Myrothecium verrucaria, which belong to the family of multi-copper oxidase) adsorbed on mesoporous carbon aerogel particle without a mediator. The current density was predominantly controlled by the diffusion of dissolved O{sub 2} in rotating-disk electrode experiments, and reached a value as large as 10 mA cm{sup -2} at 1 atm O{sub 2}, 25 C, and 8,000 rpm on the laccase-adsorbed electrode. The overpotential of the bioelectrocatalytic reduction of O{sub 2} was 0.4-0.55 V smaller than that observed on a Pt disk electrode. Without any optimization, the laccase-adsorbed biocathode showed stable current intensity of the O{sub 2} reduction in an air-saturated buffer at least for 10 days under continuous flow system. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  3. Copper oxide assisted cysteine hierarchical structures for immunosensor application

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Chandra Mouli [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India); Sumana, Gajjala, E-mail: sumanagajjala@gmail.com [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Tiwari, Ida [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India)

    2014-09-08

    The present work describes the promising electrochemical immunosensing strategy based on copper (II) assisted hierarchical cysteine structures (CuCys) varying from star to flower like morphology. The CuCys having average size of 10 μm have been synthesised using L-Cysteine as initial precursor in presence of copper oxide under environmentally friendly conditions in aqueous medium. To delineate the synthesis mechanism, detailed structural investigations have been carried out using characterization techniques such as X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The electrochemical behaviour of self-assembled CuCys on gold electrode shows surface controlled electrode reaction with an apparent electron transfer rate constant of 3.38 × 10{sup −4 }cm s{sup −1}. This innovative platform has been utilized to fabricate an immunosensor by covalently immobilizing monoclonal antibodies specific for Escherichia coli O157:H7 (E. coli). Under the optimal conditions, the fabricated immunosensor is found to be sensitive and specific for the detection of E. coli with a detection limit of 10 cfu/ml.

  4. Feasibility of Parylene Coating for Planar Electroporation Copper Electrodes

    Directory of Open Access Journals (Sweden)

    Vitalij NOVICKIJ

    2017-08-01

    Full Text Available This paper is focused on the feasibility study of parylene as a biocompatible coating for planar electroporation microelectrodes. The planar parallel and the circular interdigitated electrodes are applied in the analysis. The electrodes feature 100 μm width with a 300 μm gap between anode and cathode. The parylene coating thickness was varied in the 250 nm – 2 μm range. The resultant electric field distribution evaluation has been performed using the finite element method. The electrodes have been applied in electroporation experiments with Saprolegnia parasitica. For reference the additional experiments using conventional electroporation cuvette (1 mm gap have been performed. It has been determined that the parylene coating with hydrophobic properties has limited applicability for the passivation of the planar electroporation electrodes.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.14953

  5. Electrochemical study of the interaction between dsDNA and copper(I) using carbon paste and hanging mercury drop electrode.

    Science.gov (United States)

    Stanić, Z; Girousi, S

    2008-06-30

    The interaction of copper(I) with double-stranded (ds) calf thymus DNA was studied in solution and at the electrode surface by means of transfer voltammetry using a carbon paste electrode (CPE) as working electrode in 0.2 M acetate buffer solution (pH 5.0). As a result of the interaction of Cu(I) between the base pairs of the dsDNA, the characteristic peaks of dsDNA, due to the oxidation of guanine and adenine, increased and after a certain concentration of Cu(I) a new peak at +1.37 V appeared, probably due to the formation of a purine-Cu(I) complex (dsDNA-Cu(I) complex). Accordingly, the interaction of copper(I) with calf thymus dsDNA was studied in solution as well as at the electrode surface using hanging mercury drop electrode (HMDE) by means of alternating current voltammetry (AC voltammetry) in 0.3 M NaCl and 50 mM sodium phosphate buffer (pH 8.5) as supporting electrolyte. Its interaction with DNA is shown to be time dependent. Significant changes in the characteristic peaks of dsDNA were observed after addition of higher concentration of Cu(I) to a solution containing dsDNA, as a result of the interaction between Cu(I) and dsDNA. All the experimental results indicate that Cu(I) can bind to DNA by electrostatic binding and form an association complex.

  6. SPOT WELDING COPPER–1%Cr ELECTRODE TIPS PRODUCED VIA EQUAL CHANNEL ANGULAR PRESSING

    Directory of Open Access Journals (Sweden)

    Luay Bakir Hussain

    2010-09-01

    Full Text Available A sharp 120o Equal channel angular pressing (ECAP following rout Bc was applied at room temperature to refine the grains sizes of pure copper and copper-1%Chromium alloy for spot welding electrode tips application. Initially deformation behavior was investigated with the position using colorful plasticine as work piece followed by copper alloy. It was found the deformation at the central part of the work piece is heavily sheared than the outer part. Optical and Scanning electron microscopy were used to study the progress of grain refining under the influence of rotation and number of passes during pressing. The influnece of elongated fibrous nano graines on electrical conductivity and hardness were discussed. Shear test of spot welded 303 stainless steel indicated that nano structural Cu-1%Cr electrode tips used showed a superior results compared to commercial electrodes

  7. Facile synthesis of flower like copper oxide and their application to hydrogen peroxide and nitrite sensing

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2011-12-01

    Full Text Available Abstract Background The detection of hydrogen peroxide (H2O2 and nitrite ion (NO2- is of great important in various fields including clinic, food, pharmaceutical and environmental analyses. Compared with many methods that have been developed for the determination of them, the electrochemical detection method has attracted much attention. In recent years, with the development of nanotechnology, many kinds of micro/nano-scale materials have been used in the construction of electrochemical biosensors because of their unique and particular properties. Among these catalysts, copper oxide (CuO, as a well known p-type semiconductor, has gained increasing attention not only for its unique properties but also for its applications in many fields such as gas sensors, photocatalyst and electrochemistry sensors. Continuing our previous investigations on transition-metal oxide including cuprous oxide and α-Fe2O3 modified electrode, in the present paper we examine the electrochemical and electrocatalytical behavior of flower like copper oxide modified glass carbon electrodes (CuO/GCE. Results Flower like copper oxide (CuO composed of many nanoflake was synthesized by a simple hydrothermal reaction and characterized using field-emission scanning electron microscopy (FE-SEM and X-ray diffraction (XRD. CuO modified glass carbon electrode (CuO/GCE was fabricated and characterized electrochemically. A highly sensitive method for the rapid amperometric detection of hydrogen peroxide (H2O2 and nitrite (NO2- was reported. Conclusions Due to the large specific surface area and inner characteristic of the flower like CuO, the resulting electrode show excellent electrocatalytic reduction for H2O2 and oxidation of NO2-. Its sensitivity, low detection limit, fast response time and simplicity are satisfactory. Furthermore, this synthetic approach can also be applied for the synthesis of other inorganic oxides with improved performances and they can also be extended to

  8. Polypyrrole Coated Cellulosic Substrate Modified by Copper Oxide as Electrode for Nitrate Electroreduction

    Science.gov (United States)

    Hamam, A.; Oukil, D.; Dib, A.; Hammache, H.; Makhloufi, L.; Saidani, B.

    2015-08-01

    The aim of this work is to synthesize polypyrrole (PPy) films on nonconducting cellulosic substrate and modified by copper oxide particles for use in the nitrate electroreduction process. Firstly, the chemical polymerization of polypyrrole onto cellulosic substrate is conducted by using FeCl3 as an oxidant and pyrrole as monomer. The thickness and topography of the different PPy films obtained were estimated using a profilometer apparatus. The electrochemical reactivity of the obtained electrodes was tested by voltamperometry technique and electrochemical impedance spectroscopy. Secondly, the modification of the PPy film surface by incorporation of copper oxide particles is conducted by applying a galvanostatic procedure from a CuCl2 solution. The SEM, EDX and XRD analysis showed the presence of CuO particles in the polymer films with dimensions less than 50 nm. From cyclic voltamperometry experiments, the composite activity for the nitrate electroreduction reaction was evaluated and the peak of nitrate reduction is found to vary linearly with initial nitrate concentration.

  9. Possibilities of radioisotopic fluorescence analysis application in copper industry

    International Nuclear Information System (INIS)

    Parus, J.; Kierzek, J.

    1983-01-01

    The main applications of X-ray fluorescence analysis in copper industry such as: copper ores and other materials from flotation analysis, lead and silver determination in blister copper, analysis of metallurgic dusts and copper base alloys analysis are presented. (A.S.)

  10. Application of vertical micro-disk MHD electrode to the analysis of heterogeneous magneto-convection

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, A. [Saitama Industrial Technology Center, Japan Society for the Promotion of Science, Kawaguchi (Japan). Domestic Research Fellowship; Hashiride, M.; Morimoto, R.; Nagai, Y. [Saitama Industrial Technology Center, Kawaguchi (Japan). Materials Engineering Division; Aogaki, R. [Polytechnic University, Sagamihara (Japan). Department of Product Design

    2004-11-01

    With a micro-disk electrode in vertical magnetic fields, heterogeneous magneto-convection in vertical magnetic fields was quantitatively examined for the redox reaction of ferrocyanide-ferricyanide ions. It was concluded that the current density controlled by the magneto-convection is in proportion to the 1/3rd power of the product of the magnetic flux density and its gradient. Then, by using the same electrode system, the diffusion current induced by the vertical MHD (magnetohydrodynamic) flow was measured for the reduction of cuprous ions to copper atoms. The current density in this case was, as theoretically predicted, a function of the 1st power of the magnetic flux density. Finally, to visualize this characteristic flow pattern of the vertical MHD flow, copper electrodeposition onto the micro-disk electrode in a vertical magnetic field was performed; a typical morphological pattern of the deposit (single micro-mystery circle) was observed, as expected. (author)

  11. Application of vertical micro-disk MHD electrode to the analysis of heterogeneous magneto-convection

    International Nuclear Information System (INIS)

    Sugiyama, Atsushi; Hashiride, Makoto; Morimoto, Ryoichi; Nagai, Yutaka; Aogaki, Ryoichi

    2004-01-01

    With a micro-disk electrode in vertical magnetic fields, heterogeneous magneto-convection in vertical magnetic fields was quantitatively examined for the redox reaction of ferrocyanide-ferricyanide ions. It was concluded that the current density controlled by the magneto-convection is in proportion to the 1/3rd power of the product of the magnetic flux density and its gradient. Then, by using the same electrode system, the diffusion current induced by the vertical MHD (magnetohydrodynamic) flow was measured for the reduction of cuprous ions to copper atoms. The current density in this case was, as theoretically predicted, a function of the 1st power of the magnetic flux density. Finally, to visualize this characteristic flow pattern of the vertical MHD flow, copper electrodeposition onto the micro-disk electrode in a vertical magnetic field was performed; a typical morphological pattern of the deposit (single micro-mystery circle) was observed, as expected

  12. Glucose sensing on graphite screen-printed electrode modified by sparking of copper nickel alloys.

    Science.gov (United States)

    Riman, Daniel; Spyrou, Konstantinos; Karantzalis, Alexandros E; Hrbac, Jan; Prodromidis, Mamas I

    2017-04-01

    Electric spark discharge was employed as a green, fast and extremely facile method to modify disposable graphite screen-printed electrodes (SPEs) with copper, nickel and mixed copper/nickel nanoparticles (NPs) in order to be used as nonenzymatic glucose sensors. Direct SPEs-to-metal (copper, nickel or copper/nickel alloys with 25/75, 50/50 and 75/25wt% compositions) sparking at 1.2kV was conducted in the absence of any solutions under ambient conditions. Morphological characterization of the sparked surfaces was performed by scanning electron microscopy, while the chemical composition of the sparked NPs was evaluated with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The performance of the various sparked SPEs towards the electro oxidation of glucose in alkaline media and the critical role of hydroxyl ions were evaluated with cyclic voltammetry and kinetic studies. Results indicated a mixed charge transfer- and hyroxyl ion transport-limited process. Best performing sensors fabricated by Cu/Ni 50/50wt% alloy showed linear response over the concentration range 2-400μM glucose and they were successfully applied to the amperometric determination of glucose in blood. The detection limit (S/N 3) and the relative standard deviation of the method were 0.6µM and green methods in sensor's development. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Electrochemical behavior of copper metal core/oxide shell ultra-fine particles on mercury electrodes in aqueous dispersions

    Czech Academy of Sciences Publication Activity Database

    Korshunov, A.; Heyrovský, Michael

    2009-01-01

    Roč. 629, 1-2 (2009), s. 23-29 ISSN 0022-0728 R&D Projects: GA ČR GA203/07/1195; GA AV ČR IAA400400806 Institutional research plan: CEZ:AV0Z40400503 Keywords : ultrafine copper powders * surface oxide layers * aqueous dispersions * voltammetry * Hg electrodes Subject RIV: CG - Electrochemistry Impact factor: 2.580, year: 2007

  14. 76 FR 78628 - Copper Valley Electric Association, Inc.; Notice of Application and Applicant-Prepared EA...

    Science.gov (United States)

    2011-12-19

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-003] Copper Valley... Application: Major License. b. Project No.: P-13124-003. c. Date filed: August 30, 2011. d. Applicant: Copper.... 791 (a)-825(r). h. Applicant Contact: Robert A. Wilkinson, CEO, Copper Valley Electric Association...

  15. Dielectric elastomers with novel highly-conducting electrodes

    Science.gov (United States)

    Böse, Holger; Uhl, Detlev

    2013-04-01

    Beside the characteristics of the elastomer material itself, the performance of dielectric elastomers in actuator, sensor as well as generator applications depends also on the properties of the electrode material. Various electrode materials based on metallic particles dispersed in a silicone matrix were manufactured and investigated. Anisotropic particles such as silver-coated copper flakes and silver-coated glass flakes were used for the preparation of the electrodes. The concentration of the metallic particles and the thickness of the electrode layers were varied. Specific conductivities derived from resistance measurements reached about 100 S/cm and surmount those of the reference materials based on graphite and carbon black by up to three orders of magnitude. The high conductivities of the new electrode materials can be maintained even at very large stretch deformations up to 200 %.

  16. Analysis of the Surface of Deposited Copper After Electroerosion Treatment

    Science.gov (United States)

    Ablyaz, T. R.; Simonov, M. Yu.; Shlykov, E. S.

    2018-03-01

    An electron microscope analysis of the surface of deposited copper is performed after a profiling-piercing electroerosion treatment. The deposited copper is treated with steel, duralumin, and copper electrode tools at different pulse energies. The treatment with the duralumin electrode produces on the treated surface a web-like structure and cubic-morphology polyhedral dimples about 10 μm in size. The main components of the surface treated with the steel electrode are developed polyhedral dimples with a size of 10 - 50 μm. After the treatment with the copper electrode the main components of the treated surface are large polyhedral dimples about 30 - 80 μm in size.

  17. Patterned electrochemical deposition of copper using an electron beam

    Directory of Open Access Journals (Sweden)

    Mark den Heijer

    2014-02-01

    Full Text Available We describe a technique for patterning clusters of metal using electrochemical deposition. By operating an electrochemical cell in the transmission electron microscope, we deposit Cu on Au under potentiostatic conditions. For acidified copper sulphate electrolytes, nucleation occurs uniformly over the electrode. However, when chloride ions are added there is a range of applied potentials over which nucleation occurs only in areas irradiated by the electron beam. By scanning the beam we control nucleation to form patterns of deposited copper. We discuss the mechanism for this effect in terms of electron beam-induced reactions with copper chloride, and consider possible applications.

  18. Infrared spectroscopic and voltammetric study of adsorbed CO on stepped surfaces of copper monocrystalline electrodes

    International Nuclear Information System (INIS)

    Koga, O.; Teruya, S.; Matsuda, K.; Minami, M.; Hoshi, N.; Hori, Y.

    2005-01-01

    Voltammetric and infrared (IR) spectroscopic measurements were carried out to study adsorbed CO on two series of copper single crystal electrodes n(111)-(111) and n(111)-(100) in 0.1M KH 2 PO 4 +0.1M K 2 HPO 4 at 0 o C. Reversible voltammetric waves were observed below -0.55V versus SHE for adsorption of CO which displaces preadsorbed phosphate anions. The electric charge of the redox waves is proportional to the step atom density for both single crystal series. This fact indicates that phosphate anions are specifically adsorbed on the step sites below -0.55V versus SHE. Voltammetric measurements indicated that (111) terrace of Cu is covered with adsorbed CO below -0.5V versus SHE. Nevertheless, no IR absorption band of adsorbed CO is detected from (111) terrace. Presence of adsorbed CO on (111) terrace is presumed which is not visible by the potential difference spectroscopy used in the present work. IR spectroscopic measurements showed that CO is reversibly adsorbed with an on-top manner on copper single crystal electrodes of n(111)-(111) and n(111)-(100) with approximately same wavenumber of C?O stretching vibration of 2070cm -1 . The IR band intensity is proportional to the step atom density. Thus CO is adsorbed on (111) or (100) steps on the single crystal surfaces. An analysis of the IR band intensity suggested that one CO molecule is adsorbed on every two or more Cu step atom of the monocrystalline surface. The spectroscopic data were compared with those reported for uhv system. The C-O stretching wavenumber of adsorbed CO in the electrode-electrolyte system is 30-40cm -1 lower than those in uhv system

  19. Aptamer-based electrochemical assay of 17β-estradiol using a glassy carbon electrode modified with copper sulfide nanosheets and gold nanoparticles, and applying enzyme-based signal amplification

    International Nuclear Information System (INIS)

    Huang, Ke-Jing; Liu, Yu-Jie; Zhang, Ji-Zong

    2015-01-01

    We have developed an electrochemical method for the determination of 17β-estradiol. A glassy carbon electrode was modified with a composite made from copper sulfide nanosheets, gold nanoparticles, and glucose oxidase. The copper sulfide nanosheet was prepared by a single-step hydrothermal process, and its properties were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Finally, an estradiol-specific aptamer was assembled on the electrode. The copper sulfide nanosheet on the electrode surface acts as a relatively good electrical conductor. Glucose oxidase acts as an indicator, and the dual modification of glucose oxidase and gold nanoparticles for signal amplification. The determination of 17β-estradiol was performed by differential pulse voltammetry of glucose oxidase because the signal measured at typically −0.43 V depends on the concentration of 17β-estradiol because addition of 17β-estradiol at electrode hinders electron transfer. A linear relationship exists between the peak current and the logarithm of concentration of 17β-estradiol in the 0.5 pM to 5 nM range, with a 60 f. detection limit (at 3σ/S). The method displays good selectivity over bisphenol A, 1-aminoanthraquinone and naphthalene even if present in 100-fold concentrations. (author)

  20. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S.; Easton, E.B. [Univ. of Ontario Inst. of Technology, Oshawa, ON (Canada). Faculty of Science

    2009-07-01

    A thermochemical cycle is a process by which water is decomposed into hydrogen and oxygen through a series of chemical reactions. The chemicals that are used in these reactions are regenerated and recycled during the process. Sol-gel chemistry is becoming more common for the synthesis of electrode materials. The sol-gel reaction can be conducted in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together through the ceramic binder, which can also promote ion transport. The CCE structure also has a high active surface area and is chemically and thermally robust. This paper presented an investigation of CCE materials prepared using 3-aminopropyl trimethoxysilane. Several electrochemical experiments including cyclic voltammetry and electrochemical impedance spectroscopy were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the copper-chlorine thermochemical cycle. Subsequent experiments included the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements were also presented. Specifically, the paper presented the experiment with particular reference to the CCE preparation; electrochemical experiments; thermal analysis; and scanning electron microscopy. Results were also provided. These included TGA analysis; scanning electron microscopy analysis; electrochemical characterization; and anodic polarization. Characterization of these CCE material demonstrated that they had good thermal stability, could be used at high temperatures, and were therefore, very promising anode materials. 15 refs., 7 figs.

  1. The use of a hierarchically platinum-free electrode composed of tin oxide decorated polypyrrole on nanoporous copper in catalysis of methanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Asghari, Elnaz, E-mail: elnazasghari@yahoo.com; Ashassi-Sorkhabi, Habib; Vahed, Akram; Rezaei-Moghadam, Babak; Charmi, Gholam Reza

    2016-01-01

    Tin oxide nanoparticles were synthesized through a galvanostatic pathway on polypyrrole, PPy, coated nanoporous copper. The morphology and surface analysis of the assemblies were evaluated by field emission scanning electron microscopy, FESEM, and energy dispersive X-ray, EDX, analysis, respectively. The electrocatalytic behavior of electrodes was studied by cyclic voltammetry and chronoamperometry tests in methanol solution. FESEM results showed that uniformly distributed nanoparticles with diameters of about 20–30 nm have been dispersed on PPy matrix. Cyclic voltammetry and chronoamperometry tests in methanol solution showed a significant enhancement in the catalytic action of PPy after decoration of tin oxide nanoparticles. Porous Cu/PPy/SnO{sub x} electrodes showed enhanced anodic peak current density for methanol oxidation compared to smooth Cu/PPy/SnO{sub x} and porous Cu/PPy. The effects of synthesis current density and time on the electrocatalytic behavior of the electrodes were evaluated. The significant enhancement of electrocatalytic behavior of the Cu/PPy electrode after decoration of SnO{sub x} overlayer was attributed to the effect of tin oxide on the adsorption of intermediates of methanol oxidation as well as oxidation of bi-products such as CO; huge tendency of tin oxides for dehydrogenation of the alcohols and the increase in microscopic surface area of the electrodes were introduced as other affecting factors. - Highlights: • Nanoporous copper–zinc substrates were formed by chemical leaching of zinc. • Polypyrrole thin film was electrodeposited on nanoporous copper. • Thin oxide nanoparticles were synthesized electrochemically on polypyrrole layer. • The catalytic performance of the electrodes was evaluated for methanol oxidation.

  2. Copper alloys for high heat flux structure applications

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Fabritsiev, S.A.

    1994-01-01

    The mechanical and physical properties of copper alloys are reviewed and compared with the requirements for high heat flux structural applications in fusion reactors. High heat flux structural materials must possess a combination of high thermal conductivity and high mechanical strength. The three most promising copper alloys at the present time are oxide dispersion-strengthened copper (Cu-Al 2 O 3 ) and two precipitation-hardened copper alloys (Cu-Cr-Zr and Cu-Ni-Be). These three alloys are capable of room temperature yield strengths >400 MPa and thermal conductivities up to 350 W/m-K. All of these alloys require extensive cold working to achieve their optimum strength. Precipitation-hardened copper alloys such Cu-Cr-Zr are susceptible to softening due to precipitate overaging and recrystallization during brazing, whereas the dislocation structure in Cu-Al 2 O 3 remains stabilized during typical high temperature brazing cycles. All three alloys exhibit good resistance to irradiation-induced softening and void swelling at temperatures below 300 degrees C. The precipitation-strengthened allows typically soften during neutron irradiation at temperatures above about 300 degrees C and therefore should only be considered for applications operating at temperatures 2 O 3 ) is considered to be the best candidate for high heat flux structural applications

  3. Copper hexacyanoferrate formation on the modified silica surface with DAB-Am-16 dendrimer

    International Nuclear Information System (INIS)

    Carmo, Devaney R. do; Gabriel Junior, Suelino; Bicalho, Urquisa O.; Paim, Leonardo L.

    2009-01-01

    The dendrimer hexadecamine poly(propylene)imine (DAB-Am-16) of third generation (G-3) was anchored on the silica gel surface. The modified silica interact easily with Cu 2+ and then with hexacyanoferrate to form copper hexacyanoferrate. The modified silica was characterized by following techniques: nuclear magnetic resonance (NMR), infrared (FTIR), energy dispersive X-ray (EDX) and cyclic voltammetry. As application of the composite obtained, the modified silica containing copper hexacyanoferrate (CuHCFSD) was tested for a voltammetric determination of nitrite using a graphite paste modified electrode. The modified graphite paste electrode can be applied also to the determination of others biological substances with success. (author)

  4. Indicator electrodes from d-elements for application in different types of potentiometric analytical methods

    Directory of Open Access Journals (Sweden)

    Z. Kunasheva

    2012-05-01

    Full Text Available The article covers the use of metal electrodes from titanium, tungsten, molybdenum as indicator electrodes at potentiometric method of analysis. The condition of measuring operation in dependence on pH, ionic strength of solutions is described in the article. Electrode potential of testing electrodes are measured in the interval of concentration of salts from 0,1∙10-1 mole/l till 0,1∙10-6 mole/l. The results of testing of electrical-analytical description of metal electrodes made of d-elements, in particular, titanium, tungsten, molybdenum in solutions of cations of some metals and anions were mentioned. As ions of metal cations Cu2+, Cd2+, Zn2+, Pb2+ and anions Cl-, I-, F- were chosen.It is identified that titanic electrode has different response to ions of copper (II, zinc and cadmium. However, dependence of electrode potential on concentration of ions of metal is rectilinear, that is vequired of indicator electrodes in the direct potential metrics.  

  5. Preparation and characterization of Ti/SnO2-Sb electrode with copper nanorods for AR 73 removal

    International Nuclear Information System (INIS)

    Xu, Li; Li, Ming; Xu, Wei

    2015-01-01

    Novel Ti/Cu-NRs/SnO 2 -Sb electrode modified by copper (Cu) nanorods was fabricated through anodic aluminum oxide (AAO) template assisted electrochemical deposition (ECD) for wastewater treatment. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and electrochemical methods such as linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface morphology, crystal structure and electrochemical performance of the electrodes. Acid dye AR 73 was selected as target pollutants to investigate the electro-catalyst behavior, and UV/vis spectroscopy was used to monitor the concentration changes with time. The results indicated that the presence of Cu nanorods on the Ti substrate promoted the electrodes' property obviously. Ti/Cu-NRs/SnO 2 -Sb anode possessed smaller charge transfer resistance and longer service life than Ti/SnO 2 -Sb anode. The oxygen evolution potential (OEP) of Ti/Cu-NRs/SnO 2 -Sb electrodes reach 2.17 V (vs. Ag/AgCl). Removal of pollutants and reaction rate were all promoted due to the introduction of Cu nanorods in the process of AR 73 decomposing with Ti/Cu-NRs/SnO 2 -Sb electrodes. And specific energy consumption also reduced remarkably. Our study has shown that the fabricated Ti/Cu-NRs/SnO 2 -Sb electrodes are very promising for the electrochemical treatment of wastewater

  6. Nanocarbon-copper thin film as transparent electrode

    International Nuclear Information System (INIS)

    Isaacs, R. A.; Zhu, H.; Preston, Colin; LeMieux, M.; Jaim, H. M. Iftekhar; Hu, L.; Salamanca-Riba, L. G.; Mansour, A.; Zavalij, P. Y.; Rabin, O.

    2015-01-01

    Researchers seeking to enhance the properties of metals have long pursued incorporating carbon in the metallic host lattice in order to combine the strongly bonded electrons in the metal lattice that yield high ampacity and the free electrons available in carbon nanostructures that give rise to high conductivity. The incorporation of carbon nanostructures into the copper lattice has the potential to improve the current density of copper to meet the ever-increasing demands of nanoelectronic devices. We report on the structure and properties of carbon incorporated in concentrations up to 5 wt. % (∼22 at. %) into the crystal structure of copper. Carbon nanoparticles of 5 nm–200 nm in diameter in an interconnecting carbon matrix are formed within the bulk Cu samples. The carbon does not phase separate after subsequent melting and re-solidification despite the absence of a predicted solid solution at such concentrations in the C-Cu binary phase diagram. This material, so-called, Cu covetic, makes deposition of Cu films containing carbon with similar microstructure to the metal possible. Copper covetic films exhibit greater transparency, higher conductivity, and resistance to oxidation than pure copper films of the same thickness, making them a suitable choice for transparent conductors

  7. Nanocarbon-copper thin film as transparent electrode

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, R. A.; Zhu, H.; Preston, Colin; LeMieux, M.; Jaim, H. M. Iftekhar; Hu, L., E-mail: binghu@umd.edu; Salamanca-Riba, L. G., E-mail: riba@umd.edu [Materials Science and Engineering Department, University of Maryland, College Park, Maryland 20742 (United States); Mansour, A. [Carderock Division, Naval Surface Warfare Center, West Bethesda, Maryland 20817 (United States); Zavalij, P. Y. [Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 (United States); Rabin, O. [Materials Science and Engineering Department, University of Maryland, College Park, Maryland 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2015-05-11

    Researchers seeking to enhance the properties of metals have long pursued incorporating carbon in the metallic host lattice in order to combine the strongly bonded electrons in the metal lattice that yield high ampacity and the free electrons available in carbon nanostructures that give rise to high conductivity. The incorporation of carbon nanostructures into the copper lattice has the potential to improve the current density of copper to meet the ever-increasing demands of nanoelectronic devices. We report on the structure and properties of carbon incorporated in concentrations up to 5 wt. % (∼22 at. %) into the crystal structure of copper. Carbon nanoparticles of 5 nm–200 nm in diameter in an interconnecting carbon matrix are formed within the bulk Cu samples. The carbon does not phase separate after subsequent melting and re-solidification despite the absence of a predicted solid solution at such concentrations in the C-Cu binary phase diagram. This material, so-called, Cu covetic, makes deposition of Cu films containing carbon with similar microstructure to the metal possible. Copper covetic films exhibit greater transparency, higher conductivity, and resistance to oxidation than pure copper films of the same thickness, making them a suitable choice for transparent conductors.

  8. Chemical sensors in natural water: peculiarities of behaviour of chalcogenide glass electrodes for determination of copper, lead and cadmium ions

    International Nuclear Information System (INIS)

    Seleznev, B.L.; Legin, A.V.; Vlasov, Yu.G.

    1996-01-01

    Specific features of chemical sensors (chalcogenide glass and crystal ion-selective electrodes) behaviour have been studied to determine copper (2), lead, cadmium and fluorine in the course of in situ measurements, including long-term uninterrupted testing, for solving the problem of inspection over natural water contamination. 16 refs., 3 figs., 2 tabs

  9. Hardness and wear analysis of Cu/Al2O3 composite for application in EDM electrode

    Science.gov (United States)

    Hussain, M. Z.; Khan, U.; Jangid, R.; Khan, S.

    2018-02-01

    Ceramic materials, like Aluminium Oxide (Al2O3), have high mechanical strength, high wear resistance, high temperature resistance and good chemical durability. Powder metallurgy processing is an adaptable method commonly used to fabricate composites because it is a simple method of composite preparation and has high efficiency in dispersing fine ceramic particles. In this research copper and novel material aluminium oxide/copper (Al2O3/Cu) composite has been fabricated for the application of electrode in Electro-Discharge Machine (EDM) using powder metallurgy technique. Al2O3 particles with different weight percentages (0, 1%, 3% and 5%) were reinforced into copper matrix using powder metallurgy technique. The powders were blended and compacted at a load of 100MPa to produce green compacts and sintered at a temperature of 574 °C. The effect of aluminium oxide content on mass density, Rockwell hardness and wear behaviour were investigated. Wear behaviour of the composites was investigated on Die-Sink EDM (Electro-Discharge Machine). It was found that wear rate is highly depending on hardness, mass density and green protective carbonate layer formation at the surface of the composite.

  10. APPLICATIONS OF A SINGLE CARBON ELECTRODE

    African Journals Online (AJOL)

    Preferred Customer

    Page 1 ... ABSTRACT: A single carbon electrode used with a common arc welder has been successfully used on steel to weld, to surface harden, to spot weld sheet, to pierce holes and to do simple brazing. ... applications: welding, spot welding, hole piercing, etc. The metal tube holding the carbon electrodes is banded with ...

  11. Layer-by-layer self-assembling copper tetrasulfonated phthalocyanine on carbon nanotube modified glassy carbon electrode for electro-oxidation of 2-mercaptoethanol

    International Nuclear Information System (INIS)

    Shaik, Mahabul; Rao, V.K.; Gupta, Manish; Pandey, P.

    2012-01-01

    This paper describes the electrocatalytic activity of layer-by-layer self-assembled copper tetrasulfonated phthalocyanine (CuPcTS) on carbon nanotube (CNT)-modified glassy carbon (GC) electrode. CuPcTS is immobilized on the negatively charged CNT surface by alternatively assembling a cationic poly(diallyldimethylammonium chloride) (PDDA) layer and a CuPcTS layer. UV–vis absorption spectra and electrochemical measurements suggested the successive linear depositions of the bilayers of CuPcTs and PDDA on CNT. The surface morphology was observed using scanning electron microscopy. The viability of this CuPcTS/PDDA/CNT modified GC electrode as a redox mediator for the anodic oxidation and sensitive amperometric determination of 2-mercaptoethanol (2-ME) in alkaline conditions is described. The effect of number of bilayers of CuPcTS/PDDA and pH on electrochemical oxidation of 2-ME was studied. The proposed electrochemical sensor displayed excellent characteristics towards the determination of 2-ME in 0.1 M NaOH; such as low overpotentials (− 0.15 V vs Ag/AgCl), linear concentration range of 3 × 10 −5 M to 6 × 10 −3 M, and with a detection limit of 2.5 × 10 −5 M using simple amperometry. - Highlights: ► Carbon nanotubes (CNT) were drop-dried on glassy carbon electrode (GCE). ► Copper tetrasulfonated phthalocyanine (CuPcTS) was deposited on CNT/GCE. ► Layer-by-layer self-assembling method is used for depositing CuPcTS. ► Electrocatalytic oxidation of 2-mercaptoethanol (ME) was studied at this electrode ► The detection limit of ME at modified electrode was 25 μM by amperometry.

  12. Electrochemical in-situ impregnation of wood using a copper nail as source for copper

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Block, Thomas; Nymark, Morten

    2011-01-01

    A new method for copper impregnation of wood in structures was suggested and tested in laboratory scale with specimen of new pine sapwood. A copper nail and a steel screw were placed in the wood, and an electric direct current field was applied, so the copper nail was anode and the screw...... was cathode. At the anode, copper ions were generated. The copper ions were transported into the wood by electromigration (movement of ions in an applied electric field) towards the cathode, and a volume between the two electrodes was thereby impregnated. Copper also moved to a lesser degree in the opposite...

  13. Non-noble metal graphene oxide-copper (II) ions hybrid electrodes for electrocatalytic hydrogen evolution reaction

    KAUST Repository

    Muralikrishna, S.

    2015-08-25

    Non-noble metal and inexpensive graphene oxide-copper (II) ions (GO-Cu2+) hybrid catalysts have been explored for the hydrogen evolution reaction (HER). We were able to tune the binding abilities of GO toward the Cu2+ ions and hence their catalytic properties by altering the pH. We have utilized the oxygen functional moieties such as carboxylate, epoxide, and hydroxyl groups on the edge and basal planes of the GO for binding the Cu2+ ions through dative bonds. The GO-Cu2+ hybrid materials were characterized by cyclic voltammetry in sodium acetate buffer solution. The morphology of the hybrid GO-Cu2+ was characterized by atomic force microscopy. The GO-Cu2+ hybrid electrodes show good electrocatalytic activity for HER with low overpotential in acidic solution. The Tafel slope for the GO-Cu2+ hybrid electrode implies that the primary discharge step is the rate determining step and HER proceed with Volmer step. © 2015 American Institute of Chemical Engineers Environ Prog.

  14. Metal nanogrids, nanowires, and nanofibers for transparent electrodes

    KAUST Repository

    Hu, Liangbing; Wu, Hui; Cui, Yi

    2011-01-01

    Metals possess the highest conductivity among all room-temperature materials; however, ultrathin metal films demonstrate decent optical transparency but poor sheet conductance due to electron scattering from the surface and grain boundaries. This article discusses engineered metal nanostructures in the form of nanogrids, nanowires, or continuous nanofibers as efficient transparent and conductive electrodes. Metal nanogrids are discussed, as they represent an excellent platform for understanding the fundamental science. Progress toward low-cost, nano-ink-based printed silver nanowire electrodes, including silver nanowire synthesis, film fabrication, wire-wire junction resistance, optoelectronic properties, and stability, are also discussed. Another important factor for low-cost application is to use earth-abundant materials. Copper-based nanowires and nanofibers are discussed in this context. Examples of device integrations of these materials are also given. Such metal nanostructure-based transparent electrodes are particularly attractive for solar cell applications. © 2011 Materials Research Society.

  15. Metal nanogrids, nanowires, and nanofibers for transparent electrodes

    KAUST Repository

    Hu, Liangbing

    2011-10-01

    Metals possess the highest conductivity among all room-temperature materials; however, ultrathin metal films demonstrate decent optical transparency but poor sheet conductance due to electron scattering from the surface and grain boundaries. This article discusses engineered metal nanostructures in the form of nanogrids, nanowires, or continuous nanofibers as efficient transparent and conductive electrodes. Metal nanogrids are discussed, as they represent an excellent platform for understanding the fundamental science. Progress toward low-cost, nano-ink-based printed silver nanowire electrodes, including silver nanowire synthesis, film fabrication, wire-wire junction resistance, optoelectronic properties, and stability, are also discussed. Another important factor for low-cost application is to use earth-abundant materials. Copper-based nanowires and nanofibers are discussed in this context. Examples of device integrations of these materials are also given. Such metal nanostructure-based transparent electrodes are particularly attractive for solar cell applications. © 2011 Materials Research Society.

  16. The effect of antimony presence in anodic copper on kinetics and mechanism of anodic dissolution and cathodic deposition of copper

    Directory of Open Access Journals (Sweden)

    Stanković Z.D.

    2008-01-01

    Full Text Available The influence of the presence of Sb atoms, as foreign metal atoms in anode copper, on kinetics, and, on the mechanism of anodic dissolution and cathodic deposition of copper in acidic sulfate solution has been investigated. The galvanostatic single-pulse method has been used. Results indicate that presence of Sb atoms in anode copper increase the exchange current density as determined from the Tafel analysis of the electrode reaction. It is attributed to the increase of the crystal lattice parameter determined from XRD analysis of the electrode material.

  17. Visibility and oxidation stability of hybrid-type copper mesh electrodes with combined nickel-carbon nanotube coating

    Science.gov (United States)

    Kim, Bu-Jong; Hwang, Young-Jin; Park, Jin-Seok

    2017-04-01

    Hybrid-type transparent conductive electrodes (TCEs) were fabricated by coating copper (Cu) meshes with carbon nanotube (CNT) via electrophoretic deposition, and with nickel (Ni) via electroplating. For the fabricated electrodes, the effects of the coating with CNT and Ni on their transmittance and reflectance in the visible-light range, electrical sheet resistance, and chromatic parameters (e.g., redness and yellowness) were characterized. Also, an oxidation stability test was performed by exposing the electrodes to air for 20 d at 85 °C and 85% temperature and humidity conditions, respectively. It was discovered that the CNT coating considerably reduced the reflectance of the Cu meshes, and that the Ni coating effectively protected the Cu meshes against oxidation. Furthermore, after the coating with CNT, both the redness and yellowness of the Cu mesh regardless of the Ni coating approached almost zero, indicating a natural color. The experiment results confirmed that the hybrid-type Cu meshes with combined Ni-CNT coating improved characteristics in terms of reflectance, sheet resistance, oxidation stability, and color, superior to those of the primitive Cu mesh, and also simultaneously satisfied most of the requirements for TCEs.

  18. Modified electrode voltammetric sensors for trace metals in environmental samples

    Directory of Open Access Journals (Sweden)

    Brett Christopher M.A.

    2000-01-01

    Full Text Available Nafion-modified mercury thin film electrodes have been investigated for the analysis of trace metals in environmental samples of waters and effluent by batch injection analysis with square wave anodic stripping voltammetry. The method, involving injection over the detector electrode of untreated samples of volume of the order of 50 microlitres has fast response, blocking and fouling of the electrode is minimum as shown by studies with surface-active components. Comparison is made between glassy carbon substrate electrodes and carbon fibre microelectrode array substrates, the latter leading to a small sensitivity enhancement. Application to analysis of river water and industrial effluent for labile zinc, cadmium, lead and copper ions is demonstrated in collected samples and after acid digestion.

  19. Quantitative Determination of NTA and Other Chelating Agents in Detergents by Potentiometric Titration with Copper Ion Selective Electrode.

    Science.gov (United States)

    Ito, Sana; Morita, Masaki

    2016-01-01

    Quantitative analysis of nitrilotriacetate (NTA) in detergents by titration with Cu 2+ solution using a copper ion selective electrode was achieved. This method tolerates a wide range of pH and ingredients in detergents. In addition to NTA, other chelating agents, having relatively lower stability constants toward Cu 2+ , were also qualified with sufficient accuracy by this analytical method for model detergent formulations. The titration process was automated by automatic titrating systems available commercially.

  20. 40 CFR 464.20 - Applicability; description of the copper casting subcategory.

    Science.gov (United States)

    2010-07-01

    ... copper casting subcategory. 464.20 Section 464.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

  1. Phosphomolybdic acid functionalized graphene loading copper nanoparticles modified electrodes for non-enzymatic electrochemical sensing of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jiaoyan; Cao, Xiyue [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Xia, Jianfei, E-mail: xiajianfei@126.com [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Gong, Shida [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Wang, Zonghua, E-mail: wangzonghua@qdu.edu.cn [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Lu, Lin [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Zibo Normal College, Zibo, Shandong 255100 (China)

    2016-08-31

    A sensitive non-enzymatic glucose electrochemical biosensor (Cu/PMo{sub 12}-GR/GCE) was developed based on the combination of copper nanoparticles (CuNPs) and phosphomolybdic acid functionalized graphene (PMo{sub 12}-GR). PMo{sub 12}-GR films were modified on the surface of glassy carbon electrode (GCE) through electrostatic self-assembly with the aid of poly diallyl dimethyl ammonium chloride (PDDA). Then CuNPs were successfully decorated onto the PMo{sub 12}-GR modified GCE through electrodeposition. The morphology of Cu/PMo{sub 12}-GR/GCE was characterized by scanning electron microscope (SEM). Cyclic voltammetry (CV) and chronoamperometry were used to investigate the electrochemical performances of the biosensor. The results indicated that the modified electrode displayed a synergistic effect of PMo{sub 12}-GR sheets and CuNPs towards the electro-oxidation of glucose in the alkaline solution. At the optimal detection potential of 0.50 V, the response towards glucose presented a linear response ranging from 0.10 μM to 1.0 mM with a detection limit of 3.0 × 10{sup −2} μM (S/N = 3). In addition, Cu/PMo{sub 12}-GR/GCE possessed a high selectivity, good reproducibility, excellent stability and acceptable recovery, which indicating the potential application in clinical field. - Highlights: • Cu/PMo{sub 12}-GR/GCE as a non-enzymatic glucose electrochemical sensor. • PMo{sub 12} is efficient for the uniform growth of Cu-NPs and electron transport. • The sensor exhibits good sensitivity and specificity towards glucose.

  2. Copper atomic-scale transistors.

    Science.gov (United States)

    Xie, Fangqing; Kavalenka, Maryna N; Röger, Moritz; Albrecht, Daniel; Hölscher, Hendrik; Leuthold, Jürgen; Schimmel, Thomas

    2017-01-01

    We investigated copper as a working material for metallic atomic-scale transistors and confirmed that copper atomic-scale transistors can be fabricated and operated electrochemically in a copper electrolyte (CuSO 4 + H 2 SO 4 ) in bi-distilled water under ambient conditions with three microelectrodes (source, drain and gate). The electrochemical switching-on potential of the atomic-scale transistor is below 350 mV, and the switching-off potential is between 0 and -170 mV. The switching-on current is above 1 μA, which is compatible with semiconductor transistor devices. Both sign and amplitude of the voltage applied across the source and drain electrodes ( U bias ) influence the switching rate of the transistor and the copper deposition on the electrodes, and correspondingly shift the electrochemical operation potential. The copper atomic-scale transistors can be switched using a function generator without a computer-controlled feedback switching mechanism. The copper atomic-scale transistors, with only one or two atoms at the narrowest constriction, were realized to switch between 0 and 1 G 0 ( G 0 = 2e 2 /h; with e being the electron charge, and h being Planck's constant) or 2 G 0 by the function generator. The switching rate can reach up to 10 Hz. The copper atomic-scale transistor demonstrates volatile/non-volatile dual functionalities. Such an optimal merging of the logic with memory may open a perspective for processor-in-memory and logic-in-memory architectures, using copper as an alternative working material besides silver for fully metallic atomic-scale transistors.

  3. Electrodeposited nanostructured raspberry-like gold-modified electrodes for electrocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Manivannan, Shanmugam; Ramaraj, Ramasamy, E-mail: ramarajr@yahoo.com [Madurai Kamaraj University, Centre for Photoelectrochemistry, School of Chemistry (India)

    2013-10-15

    A facile method for fabrication of raspberry-like Au nanostructures (Au NRBs)-modified electrode by electrodeposition and its applications toward the electrocatalytic oxidation of methanol (MOR) in alkaline medium and oxygen reduction reaction (ORR) in both alkaline and acidic media are demonstrated. The Au NRBs are characterized by UV-Vis absorption spectra, SEM, X-ray diffraction, and electrochemical measurements. The growth of Au NRBs was monitored by recording the in-situ absorption spectral changes during electrodeposition using spectroelectrochemical technique. Here we systematically studied the MOR by varying several reaction parameters such as potential scan rate and methanol concentration. The electrocatalytic poisoning effect due to the MOR products are not observed at the Au NRBs-modified electrode. At the alkaline medium the Au NRBs-modified electrode shows the better catalytic activities toward the MOR and ORR when compared to the poly crystalline gold and bare glassy carbon electrodes. The Au NRBs-modified electrode is a promising and inexpensive electrode material for other electrocatalytic applications.Graphical AbstractRaspberry-like Au nanostructures modified electrode is prepared and used for electrocatalytic applications.

  4. Copper-beryllium alloys for technical applications

    International Nuclear Information System (INIS)

    Heller, W.

    1976-01-01

    Data of physical properties are compiled for the most commonly used copper-beryllium alloys (CuBe 2, CuBe 1.7, CuCoBe, and CuCoAgBe), with emphasis on their temperature dependence and their variation with particular annealing and hardening treatments. The purpose is to provide a reference source and to indicate the versatility of these materials with respect to other copper alloys and to pure copper. The special features of CuBe alloys include high mechanical strength with reasonably high electrical conductivity, as well as good wear and corrosion resistance. For example, CuBe 2 has a yield strength of up to 1200 N/mm 2 , about three times that of pure copper, whilst the electrical conductivity of CuCoBe can be as high as 28 MS/m, nearly half that of pure copper. Typical applications are springs and electrical contacts. The importance of a proper heat treatment is discussed in some detail, notably the metallurgy and effects of low-temperature annealing (precipitation-hardening). A chapter on manufacturing processes covers machining, brazing, welding, and cleaning. This is followed by some remarks on safety precautions against beryllium poisoning. CuBe alloys are commercially available in the form of wires, strips, rods, and bars. Typical dimensions, specifications, a brief cost estimate, and addresses of suppliers are listed. (Author)

  5. Polypyrrole electrodeposited on copper from an aqueous phosphate solution: Corrosion protection properties

    OpenAIRE

    Redondo, Clara; Breslin, Carmel B.

    2007-01-01

    Highly adherent and homogenous polypyrrole films were electrodeposited at copper from a dihydrogen phosphate solution. The polypyrrole films were electrosynthesized in the overoxidized state by cycling the copper electrode from –0.4 to 1.8 V (SCE) in a pyrrole-containing phosphate solution. The growth of the polypyrrole films was facilitated by the initial oxidation of the copper electrode in the phosphate solution to generate a mixed copper–phosphate, copper oxide or hydroxide layer. This la...

  6. Preparation, characterization and simulation studies of carbon nanotube electrodes for electrochemical energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Frank; Endler, Ingolf [Fraunhofer-Institut fuer Keramische Technologien und Systeme (IKTS), Dresden (Germany); Lorrmann, Henning [Fraunhofer-Institut fuer Silicatforschung (ISC), Wuerzburg (Germany); Pastewka, Lars [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    2010-07-01

    Chemical Vapor Deposition (CVD) was employed to synthesize multiwalled carbon nanotubes (MWCNT) on different carrier materials for electrode applications. In the field of electrochemical energy storage it is essential to grow MWCNT on conducting substrates. For this reason titanium nitride (TiN) layers as well as a copper foil were used as substrates. The MWCNT grown on TiN layers show diameters of about 20 nm and lengths up to 13 {mu}m. In the case of copper foil substrates a remarkably higher nanotube diameter of several tens of nanometers was found. First electrochemical characterization via cyclic voltammetry shows the potential of MWCNT as electrodes for energy storage applications. The CNT were measured in an organic carbonate electrolyte vs. a lithium counter electrode with various scan rates. Until now the preliminary investigations by cyclic voltammetry for electrodes consisting of aligned MWCNT on TiN showed a capacity of around 130 F g{sup -1} in the range of 1 - 3 V vs. Li/Li{sup +}. In support of the experiments we construct a one dimensional Poisson-Nernst-Planck (PNP) continuum model that has been shown to yield agreement with corresponding molecular dynamics simulations to model ion transport into these types of electrodes. Our simulations show that first the ions accumulate at the tips of the tubes because the inner volume of the electrodes is initially field-free. A homogeneous charge distribution is then established through diffusion. The PNP model is used to compute cyclic voltammograms which show qualitative agreement with the experiments. (orig.)

  7. Adsorption on smooth electrodes: A radiotracer study

    International Nuclear Information System (INIS)

    Rice-Jackson, L.M.

    1990-01-01

    Adsorption on solids is a complicated process and in most cases, occurs as the early stage of other more complicated processes, i.e. chemical reactions, electrooxidation, electroreduction. The research reported here combines the electroanalytical method, cyclic voltammetry, and the use of radio-labeled isotopes, soft beta emitters, to study adsorption processes at smooth electrodes. The in-situ radiotracer method is highly anion (molecule) specific and provides information on the structure and composition of the electric double layer. The emphasis of this research was on studying adsorption processes at smooth electrodes of copper, gold, and platinum. The application of the radiotracer method to these smooth surfaces have led to direct in-situ measurements from which surface coverage was determined; anions and molecules were identified; and weak interactions of adsorbates with the surface of the electrodes were readily monitored. 179 refs

  8. Multilayer core-shell structured composite paper electrode consisting of copper, cuprous oxide and graphite assembled on cellulose fibers for asymmetric supercapacitors

    Science.gov (United States)

    Wan, Caichao; Jiao, Yue; Li, Jian

    2017-09-01

    An easily-operated and inexpensive strategy (pencil-drawing-electrodeposition-electro-oxidation) is proposed to synthesize a novel class of multilayer core-shell structured composite paper electrode, which consists of copper, cuprous oxide and graphite assembled on cellulose fibers. This interesting electrode structure plays a pivotal role in providing more active sites for electrochemical reactions, facilitating ion and electron transport and shorting their diffusion pathways. This electrode demonstrates excellent electrochemical properties with a high specific capacitance of 601 F g-1 at 2 A g-1 and retains 83% of this capacitance when operated at an ultrahigh current density of 100 A g-1. In addition, a high energy density of 13.4 W h kg-1 at the power density of 0.40 kW kg-1 and a favorable cycling stability (95.3%, 8000 cycles) were achieved for this electrode. When this electrode was assembled into an asymmetric supercapacitor with carbon paper as negative electrode, the device displays remarkable electrochemical performances with a large areal capacitances (122 mF cm-2 at 1 mA cm-2), high areal energy density (10.8 μW h cm-2 at 402.5 μW cm-2) and outstanding cycling stability (91.5%, 5000 cycles). These results unveil the potential of this composite electrode as a high-performance electrode material for supercapacitors.

  9. ESD coating of copper with TiC and TiB2 based ceramic matrix composites

    Science.gov (United States)

    Talas, S.; Mertgenç, E.; Gökçe, B.

    2016-08-01

    In automotive industry, the spot welding is a general practice to join smaller sections of a car. This welding is specifically carried out in short time and in an elevated number with certain pressure applied on copper electrodes. In addition, copper electrodes are expected to endure against cyclic mechanical pressure and temperature that is released during the passage of the current. The deformation and oxidation behaviour of copper electrodes during service appear with increasing temperature of medium and they also need to be cleaned and cooled or replaced for the continuation of joining process. The coating of copper electrodes with ceramic matrix composites can provide alternative excellent high temperature strength and ensures both economic and efficient use of resources. This study shows that the ESD coating of copper electrodes with a continuous film of ceramic phase ensures an improved resistance to thermal effects during the service and the change in content of film may be critical for cyclic alloying.

  10. Applications and Preparation Methods of Copper Chromite Catalysts: A Review

    Directory of Open Access Journals (Sweden)

    Ram Prasad

    2011-11-01

    Full Text Available In this review article various applications and preparation methods of copper chromite catalysts have been discussed. While discussing it is concluded that copper chromite is a versatile catalyst which not only catalyses numerous processes of commercial importance and national program related to defence and space research but also finds applications in the most concerned problem worldwide i.e. environmental pollution control. Several other very useful applications of copper chromite catalysts are in production of clean energy, drugs and agro chemicals, etc. Various preparation methods about 15 have been discussed which depicts clear idea about the dependence of catalytic activity and selectivity on way of preparation of catalyst. In view of the globally increasing interest towards copper chromite catalysis, reexamination on the important applications of such catalysts and their useful preparation methods is thus the need of the time. This review paper encloses 369 references including a well-conceivable tabulation of the newer state of the art. Copyright © 2011 by BCREC UNDIP. All rights reserved.(Received: 19th March 2011, Revised: 03rd May 2011, Accepted: 23rd May 2011[How to Cite: R. Prasad, and P. Singh. (2011. Applications and Preparation Methods of Copper Chromite Catalysts: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 63-113. doi:10.9767/bcrec.6.2.829.63-113][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.2.829.63-113 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/829 ] | View in 

  11. Adsorption of 2-mercaptobenzothiazole on copper surface from phosphate solutions

    International Nuclear Information System (INIS)

    Kazansky, L.P.; Selyaninov, I.A.; Kuznetsov, Yu.I.

    2012-01-01

    Analysis of the electrochemical and XPS results has shown that adsorption of 2-mercaptobenzothiazole (MBT) on copper electrodes in neutral phosphate solutions proceeds through the formation of the chemical bonds by copper (I) cations with exo-sulfur and nitrogen atoms. A protection layer formed of Cu(I)MBT complex prevents precipitation of copper (II) phosphate on a copper surface. The thickness of the surface film consisting of a complex [Cu(I)MBT] n (having probably polymeric nature), where MBT acts as at least three-dentate ligand, increases depending on the exposure time, reaching 8-9 nm after immersing for 12 h in test solution. Even in a case of the preliminary formation of copper (II) phosphate on the copper electrode at the anodic potential addition of small amounts of MBT results in complete removal of copper (II) phosphate from the surface.

  12. Determination of sub-parts per billion levels of copper in complex matrices by adsorptive string voltammetry on a mercury electrode

    International Nuclear Information System (INIS)

    Shahbaazi, H.R.; Shahbaazi, H.R.; Safavi, A.; Maleki, N.

    2008-01-01

    The voltammetric characteristics of Cu(II)-SSA complex at the mercury electrode were investigated. An analytical method that based on the adsorptive accumulation of Cu(II)-SSA complex followed by the reduction of the complexed copper was developed for the copper determination in complex matrices in presence of the large amount of foreign ions. Adsorptive voltammetry determination showed that the Cu(II)-SSA complex behaves irreversibly exchanging two electrons on the hanging mercury drop electrode (HMDE). Factor affecting on the complextion, accumulation and stripping steps were studied and a procedure was developed. The instrumental parameters in the measurement step were also tested. The optimum conditions of pH, SSA concentration, accumulation potential and accumulation time were studied. Under optimal conditions (pH=12.9 glycin Buffer, 7 x 10 - '3 M SSA and accumulation potential -100 mV vs. Ag/ AgCl), a linear calibration graph in the range 1.25 μg L -1 to 42.5 μg L'- 1 and a detection limit of 0.8 μ L -1 were obtained. The average relative standard deviation (RSD) for seven determinations was calculated as 7 %, 5.5 % and 3 % for the concentrations between 3, 15 and 23 μg L'- 1 . The effect of foreign ions and surfactants on the peak height of Cu(II)-SSA complex was evaluated. The method was applied for the determination of the copper in different real samples such as crude oil, crude oil tank button sludge, waste water and tap water samples. The accuracy of the results was checked by ICP. (author)

  13. Effects of specific adsorption of copper (II) ion on charge transfer reaction at the thin film LiMn2O4 electrode/aqueous electrolyte interface

    International Nuclear Information System (INIS)

    Nakayama, N.; Yamada, I.; Huang, Y.; Nozawa, T.; Iriyama, Y.; Abe, T.; Ogumi, Z.

    2009-01-01

    This study investigated the effect of a specific adsorption ion, copper (II) ion, on the kinetics of the charge transfer reaction at a LiMn 2 O 4 thin film electrode/aqueous solution (1 mol dm -3 LiNO 3 ) interface. The zeta potential of LiMn 2 O 4 particles showed a negative value in 1 x 10 -2 mol dm -3 LiNO 3 aqueous solution, while it was measured as positive in the presence of 1 x 10 -2 mol dm -3 Cu(NO 3 ) 2 in the solution. The presence of copper (II) ions in the solution increased the charge transfer resistance, and CV measurement revealed that the lithium insertion/extraction reaction was retarded by the presence of small amount of copper (II) ions. The activation energy for the charge transfer reaction in the solution with Cu(NO 3 ) 2 was estimated to be 35 kJ mol -1 , which was ca. 10 kJ mol -1 larger than that observed in the solution without Cu(NO 3 ) 2 . These results suggest that the interaction between the lithium ion and electrode surface is a factor in the kinetics of charge transfer reaction

  14. Cu mesh for flexible transparent conductive electrodes.

    Science.gov (United States)

    Kim, Won-Kyung; Lee, Seunghun; Hee Lee, Duck; Hee Park, In; Seong Bae, Jong; Woo Lee, Tae; Kim, Ji-Young; Hun Park, Ji; Chan Cho, Yong; Ryong Cho, Chae; Jeong, Se-Young

    2015-06-03

    Copper electrodes with a micromesh/nanomesh structure were fabricated on a polyimide substrate using UV lithography and wet etching to produce flexible transparent conducting electrodes (TCEs). Well-defined mesh electrodes were realized through the use of high-quality Cu thin films. The films were fabricated using radio-frequency (RF) sputtering with a single-crystal Cu target--a simple but innovative approach that overcame the low oxidation resistance of ordinary Cu. Hybrid Cu mesh electrodes were fabricated by adding a capping layer of either ZnO or Al-doped ZnO. The sheet resistance and the transmittance of the electrode with an Al-doped ZnO capping layer were 6.197 ohm/sq and 90.657%, respectively, and the figure of merit was 60.502 × 10(-3)/ohm, which remained relatively unchanged after thermal annealing at 200 °C and 1,000 cycles of bending. This fabrication technique enables the mass production of large-area flexible TCEs, and the stability and high performance of Cu mesh hybrid electrodes in harsh environments suggests they have strong potential for application in smart displays and solar cells.

  15. High-power copper vapour lasers and applications

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.J.; Warner, B.E.; Boley, C.D.; Dragon, E.P.

    1995-08-01

    Expanded applications of copper vapor lasers has prompted increased demand for higher power and better beam quality. This paper reports recent progress in laser power scaling, MOPA operation, beam quality improvement, and applications in precision laser machining. Issues such as gas heating, radial delay, discharge instability, and window heating will also be discussed.

  16. Glucose Oxidation on Gold-modified Copper Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jieun; Pyo, Sung Gyu; Son, Hyungbin; Kim, Sookil [Chung-Ang Univ., Seoul (Korea, Republic of); Ahn, Sang Hyun; Son, Hyungbin [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2013-09-15

    The activities of Au-modified Cu electrodes toward glucose oxidation are evaluated according to their fabrication conditions and physico-chemical properties. The Au-modified Cu electrodes are fabricated by the galvanic displacement of Au on a Cu substrate and the characteristics of the Au particles are controlled by adjusting the displacement time. From the glucose oxidation tests, it is found that the Au modified Cu has superior activity to the pure Au or Cu film, which is evidenced by the negative shift in the oxidation potential and enhanced current density during the electrochemical oxidation. Though the activity of the Au nanoparticles is a contributing factor, the enhanced activity of the Au-modified Cu electrode is due to the increased oxidation number of Cu through the electron transfer from Cu to more electronegative Au. The depletion of electron in Cu facilitates the oxidation of glucose. The stability of the Au-modified Cu electrode was also studied by chronoamperometry.

  17. Polycrystalline boron-doped diamond electrodes for electrocatalytic and electrosynthetic applications.

    Science.gov (United States)

    Ivandini, Tribidasari A; Einaga, Yasuaki

    2017-01-24

    Boron-doped diamond (BDD) electrodes are recognized as being superior to other electrode materials due to their outstanding chemical and dimensional stability, their exceptionally low background current, the extremely wide potential window for water electrolysis that they have, and their excellent biocompatibility. However, whereas these properties have been utilized in the rapid development of electroanalytical applications, very few studies have been done in relation to their applications in electrocatalysis or electrosynthesis. In this report, following on from reports of the electrosynthesis of various products through anodic and cathodic reactions using BDD electrodes, the potential use of these electrodes in electrosynthesis is discussed.

  18. Modified diamond electrodes for electrolysis and electroanalysis applications

    International Nuclear Information System (INIS)

    Einaga, Yasuaki; Sato, Rika; Olivia, Herlambang; Shin, Dongchan; Ivandini, T.A.; Fujishima, Akira

    2004-01-01

    The outstanding properties of diamond make it a very attractive material for use in many potential applications. In particular, the superior electrochemical properties of highly boron-doped conductive diamond films, prepared by the chemical vapor deposition (CVD) process, have received attention from electrochemists. This paper reports several diversified applications of boron-doped diamond electrodes; highly sensitive and interference-free microfiber electrodes with over-oxidized polypyrrole modification, integrated electrochemical detector for microchip capillary electrophoresis (CE), and smoothing treatments of micro-polycrystalline surface. Studies have been made of the electrochemical properties of each system and their application in electroanalysis is discussed

  19. Deep Ultraviolet Copper(I) Thiocyanate (CuSCN) Photodetectors Based on Coplanar Nanogap Electrodes Fabricated via Adhesion Lithography

    KAUST Repository

    Wyatt-Moon, Gwenhivir

    2017-11-28

    Adhesion lithography (a-Lith) is a versatile fabrication technique used to produce asymmetric coplanar electrodes separated by a <15 nm nanogap. Here, we use a-Lith to fabricate deep ultraviolet (DUV) photodetectors by combining coplanar asymmetric nanogap electrode architectures (Au/Al) with solution-processable wide-band-gap (3.5–3.9 eV) p-type semiconductor copper(I) thiocyanate (CuSCN). Because of the device’s unique architecture, the detectors exhibit high responsivity (≈79 A W–1) and photosensitivity (≈720) when illuminated with a DUV-range (λpeak = 280 nm) light-emitting diode at 220 μW cm–2. Interestingly, the photosensitivity of the photodetectors remains fairly high (≈7) even at illuminating intensities down to 0.2 μW cm–2. The scalability of the a-Lith process combined with the unique properties of CuSCN paves the way to new forms of inexpensive, yet high-performance, photodetectors that can be manufactured on arbitrary substrate materials including plastic.

  20. Deep Ultraviolet Copper(I) Thiocyanate (CuSCN) Photodetectors Based on Coplanar Nanogap Electrodes Fabricated via Adhesion Lithography

    KAUST Repository

    Wyatt-Moon, Gwenhivir; Georgiadou, Dimitra G; Semple, James; Anthopoulos, Thomas D.

    2017-01-01

    Adhesion lithography (a-Lith) is a versatile fabrication technique used to produce asymmetric coplanar electrodes separated by a <15 nm nanogap. Here, we use a-Lith to fabricate deep ultraviolet (DUV) photodetectors by combining coplanar asymmetric nanogap electrode architectures (Au/Al) with solution-processable wide-band-gap (3.5–3.9 eV) p-type semiconductor copper(I) thiocyanate (CuSCN). Because of the device’s unique architecture, the detectors exhibit high responsivity (≈79 A W–1) and photosensitivity (≈720) when illuminated with a DUV-range (λpeak = 280 nm) light-emitting diode at 220 μW cm–2. Interestingly, the photosensitivity of the photodetectors remains fairly high (≈7) even at illuminating intensities down to 0.2 μW cm–2. The scalability of the a-Lith process combined with the unique properties of CuSCN paves the way to new forms of inexpensive, yet high-performance, photodetectors that can be manufactured on arbitrary substrate materials including plastic.

  1. Electrokinetic remediation of copper mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrián; Ottosen, Lisbeth M.

    2007-01-01

    Important process parameters to optimize in electrokinetic soil remediation are those influencing remediation time and power consumption since these directly affect the cost of a remediation action. This work shows how the electrokinetic remediation (EKR) process could be improved by implementing...... bipolar electrodes in the porous material. The bipolar electrodes in EKR meant two improvements: (1) a shorter migration pathway for the contaminant, and (2) an increased electrical conductivity in the remediation system. All together the remediation proceeded faster with lower electrical resistance than...... in similar experiments but without the bipolar electrodes. The new electrokinetic remediation design was tested on copper mine tailings with different applied electric fields, remediation times and pre-treatment. The results showed that the copper removal was increased from 8% (applying 20V for 8 days...

  2. Inkjet printed electronics using copper nanoparticle ink

    OpenAIRE

    Kang, Jin Sung; Kim, Hak Sung; Ryu, Jongeun; Thomas Hahn, H.; Jang, Seonhee; Joung, Jae Woo

    2010-01-01

    Inkjet printing of electrode using copper nanoparticle ink is presented. Electrode was printed on a flexible glass epoxy composite substrate using drop on demand piezoelectric dispenser and was sintered at 200 °C of low temperature in N2 gas condition. The printed electrodes were made with various widths and thickness. In order to control the thickness of the printed electrode, number of printing was varied. Resistivity of printed electrode was calculated from the cross-sectional area measure...

  3. Preparation and Evaluation of Acetabularia-Modified Carbon Paste Electrode in Anodic Stripping Voltammetry of Copper and Lead Ions

    Directory of Open Access Journals (Sweden)

    Muhammad Raziq Rahimi Kooh

    2013-01-01

    Full Text Available Seaweed is well known about for potential in chelating heavy metals. In this study, carbon paste electrodes were fabricated with siphonous seaweed Acetabularia acetabulum as the modifiers to sense lead (II and copper (II by square-wave anodic stripping voltammetry. Various scan rates and deposition potentials were measured to obtain the optimal peak current for Pb(II and Cu(II. Optimum conditions of Acetabularia-CPE for sensing Pb(II were at the scan rate of 75 mV/s and deposition potential of −800 mV, while for Cu(II sensing were at 100 mV/s and −300 mV, respectively. The electrodes were characterized by the duration of accumulation time, preconcentration over a range of standards, supporting electrolyte, and standard solutions of various pH values. Interference studies were carried out. Both Zn(II and Cu(II were found to interfere with Pb(II sensing, whereas only Zn(II causes interference with Cu(II sensing. The electrode was found to have good regeneration ability via electrochemical cleaning. Preliminary testing of complex samples such as NPK fertilisers, black soil, and sea salt samples was included.

  4. Copper-gold nanoparticles: Fabrication, characteristic and application as drug carriers

    Energy Technology Data Exchange (ETDEWEB)

    Woźniak-Budych, Marta J., E-mail: marta.budych@amu.edu.pl; Langer, Krzysztof; Peplińska, Barbara; Przysiecka, Łucja; Jarek, Marcin; Jarzębski, Maciej; Jurga, Stefan

    2016-08-15

    In this investigation, the fabrication of porous core/shell nanostructures consisting of copper (core) and copper-gold nanoalloy (shell) for medical applications is presented. As a core triangular-shaped copper nanoparticles were used. The porous bimetallic nanoshell was prepared via galvanic reaction in the presence of oil-in water emulsion. It was proved that porous nanoalloy layer can be prepared at pH 7 and in the presence 0.1% and 0.5% oil-in water emulsion. The porous structure fabrication was mainly determined by volume fraction of hexadecane to acetone in the oil-in water emulsion and Zeta-potential of emulsion droplets (pH of emulsion). The influence of emulsion droplets size before galvanic reaction on porous structure preparation was negligible. It was found that doxorubicin could be easily introduced and released from porous core/shell nanostructures, due to spontaneous adsorption on the copper-gold nanoporous surface. The in vitro test showed that cytotoxic effect was more prominent once the doxorubicin was adsorbed on the porous copper-gold nanocarriers. It was demonstrated, that doxorubicin-loaded copper-gold nanostructures caused inhibition cell proliferation and viability of cancer cells, in a concentration-dependent manner. The results indicates that presented coper-gold nanocarrier have potential to be used in targeted cancer therapy, due to its porous structure and cytotoxic effect in cancer cells. - Highlights: • Porous copper-gold nanostructure as a cytostatic drug carrier was prepared. • Kinetics and thermodynamics of drug adsorption were studied. • DOX-loaded copper-gold nanoparticles showed a pH-controlled release rate. • DOX-loaded copper-gold NPs caused inhibition cell proliferation of cancer cells. • The Cu-Au NPs could serve as a theranostic platform for biomedical applications.

  5. Cu2Sb thin film electrodes prepared by pulsed laser deposition f or lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Song, Seung-Wan; Reade, Ronald P.; Cairns, Elton J.; Vaughey, Jack T.; Thackeray, Michael M.; Striebel, Kathryn A.

    2003-08-01

    Thin films of Cu2Sb, prepared on stainless steel and copper substrates with a pulsed laser deposition technique at room temperature, have been evaluated as electrodes in lithium cells. The electrodes operate by a lithium insertion/copper extrusion reaction mechanism, the reversibility of which is superior when copper substrates are used, particularly when electrochemical cycling is restricted to the voltage range 0.65-1.4 V vs. Li/Li+. The superior performance of Cu2Sb films on copper is attributed to the more active participation of the extruded copper in the functioning of the electrode. The continual and extensive extrusion of copper on cycling the cells leads to the isolation of Li3Sb particles and a consequent formation of Sb. Improved cycling stability of both types of electrodes was obtained when cells were cycled between 0.65 and 1.4 V. A low-capacity lithium-ion cell with Cu2Sb and LiNi0.8Co0.15Al0.05O2 electrodes, laminated from powders, shows excellent cycling stability over the voltage range 3.15 - 2.2 V, the potential difference corresponding to approximately 0.65-1.4 V for the Cu2Sb electrode vs. Li/Li+. Chemical self-discharge of lithiated Cu2Sb electrodes by reaction with the electrolyte was severe when cells were allowed to relax on open circuit after reaching a lower voltage limit of 0.1 V. The solid electrolyte interphase (SEI) layer formed on Cu2Sb electrodes after cells had been cycled between 1.4 and 0.65 V vs. Li/Li+ was characterized by Fourier-transform infrared spectroscopy; the SEI layer contributes to the large irreversible capacity loss on the initial cycle of these cells. The data contribute to a better understanding of the electrochemical behavior of intermetallic electrodes in rechargeable lithium batteries.

  6. Properties of thermal air plasma with admixing of copper and carbon

    International Nuclear Information System (INIS)

    Fesenko, S; Veklich, A; Boretskij, V; Cressault, Y; Gleizes, A; Teulet, Ph

    2014-01-01

    This paper deals with investigations of air plasma with admixing of copper and carbon. Model plasma source unit with real breaking arc was used for the simulation of real discharges, which can be occurred during sliding of Cu-C composite electrodes on copper wire at electromotive vehicles. The complex technique of plasma property studies is developed. From one hand, the radial profiles of temperature and electron density in plasma of electric arc discharge in air between Cu-C composite and copper electrodes in air flow were measured by optical spectroscopy techniques. From another hand, the radial profiles of electric conductivity of plasma mixture were calculated by solution of energy balance equation. It was assumed that the thermal conductivity of air plasma is not depending on copper or carbon vapor admixtures. The electron density is obtained from electric conductivity profiles by calculation in assumption of local thermodynamic equilibrium in plasma. Computed in such way radial profiles of electron density in plasma of electric arc discharge in air between copper electrodes were compared with experimentally measured profiles. It is concluded that developed techniques of plasma diagnostics can be reasonably used in investigations of thermal plasma with copper and carbon vapors

  7. Enabling electrocatalytic Fischer-Tropsch synthesis from carbon dioxide over copper-based electrodes

    NARCIS (Netherlands)

    Shibata, H.; Moulijn, J.A.; Mul, Guido

    2008-01-01

    We report on the discovery that paraffins and olefins up to C6 hydrocarbons can be obtained in CO2 electroreduction at room temperature and atmospheric pressure by application of a commercially available Cu-electrode (Eurofysica), provided pretreatment by electropolishing is avoided. The product

  8. Enabling Electrocatalytic Fischer–Tropsch Synthesis from Carbon Dioxide Over Copper-based Electrodes

    NARCIS (Netherlands)

    Shibata, H.; Moulijn, J.A.; Mul, G.

    2008-01-01

    We report on the discovery that paraffins and olefins up to C6 hydrocarbons can be obtained in CO2 electroreduction at room temperature and atmospheric pressure by application of a commercially available Cu-electrode (Eurofysica), provided pretreatment by electropolishing is avoided. The product

  9. Electrochemical sensor for nitrite using a glassy carbon electrode modified with gold-copper nanochain networks

    International Nuclear Information System (INIS)

    Huang, Su-Su; Mei, Li-Ping; Zhou, Jia-Ying; Guo, Fei-Ying; Wang, Ai-Jun; Feng, Jiu-Ju; Liu, Li

    2016-01-01

    Bimetallic gold-copper nanochain networks (AuCu NCNs) were prepared by a single-step wet-chemical approach using metformin as a growth-directing agent. The formation mechanism was investigated in detail, and the AuCu NCNs were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The nanocrystals were deposited on glassy carbon electrode and this resulted in a highly sensitive sensor for nitrite. Features include a low working potential (best at 0.684 V vs. SCE), fair sensitivity (17.55 μA mM −1 ), a wide linear range (0.01 to 4.0 mM), a low detection limit (0.2 μM, S/N = 3), and superior selectivity as compared to other sensors. (author)

  10. A thermally regenerative ammonia battery with carbon-silver electrodes for converting low-grade waste heat to electricity

    Science.gov (United States)

    Rahimi, Mohammad; Kim, Taeyoung; Gorski, Christopher A.; Logan, Bruce E.

    2018-01-01

    Thermally regenerative ammonia batteries (TRABs) have shown great promise as a method to convert low-grade waste heat into electrical power, with power densities an order of magnitude higher than other approaches. However, previous TRABs based on copper electrodes suffered from unbalanced anode dissolution and cathode deposition rates during discharging cycles, limiting practical applications. To produce a TRAB with stable and reversible electrode reactions over many cycles, inert carbon electrodes were used with silver salts. In continuous flow tests, power production was stable over 100 discharging cycles, demonstrating excellent reversibility. Power densities were 23 W m-2-electrode area in batch tests, which was 64% higher than that produced in parallel tests using copper electrodes, and 30 W m-2 (net energy density of 490 Wh m-3-anolyte) in continuous flow tests. While this battery requires the use a precious metal, an initial economic analysis of the system showed that the cost of the materials relative to energy production was 220 per MWh, which is competitive with energy production from other non-fossil fuel sources. A substantial reduction in costs could be obtained by developing less expensive anion exchange membranes.

  11. Microstructure of the regions on a plane copper electrode surface affected by a spark discharge in air in the point-plane gap

    Science.gov (United States)

    Tren'kin, A. A.; Karelin, V. I.; Shibitov, Yu. M.; Blinova, O. M.; Yasnikov, I. S.

    2017-09-01

    The microstructure of the regions affected by spark discharge on the surface of a plane copper electrode in atmospheric air in the point-plane gap has been studied using a scanning electron microscope for both the positive and negative polarity of the point electrode. It has been found that the affected regions have the shape of round spots or groups of spots with diameters of individual spots varying in the range of 20-200 μm. It has been revealed that the spots have an internal spatial structure in the form of an aggregate of concentric rings. These rings are aggregates of a large number of microscopic craters with diameters of 0.1-1.0 μm.

  12. Recycling and refining of copper for electrical application

    Directory of Open Access Journals (Sweden)

    Dablement Sébastien

    2013-11-01

    Full Text Available Copper is, after silver, the best electrical conductor. All residual impurities inside the matrix have high consequences on these properties. Thus, the Nexans factory in Lens “purifies” the copper scraps by a fire refining in order to remove all the internal pollutant. This process, unique in France, is complementary to a traditional process using an electrolytic cathode. It allows, first, to diversify the raw material and, second, to increase the ecological balance compare to the traditional way of scrap treatment for electrical application.

  13. Copper and copper-nickel-alloys - An overview

    Energy Technology Data Exchange (ETDEWEB)

    Klassert, Anton; Tikana, Ladji [Deutsches Kupferinstitut e.V. Am Bonneshof 5, 40474 Duesseldorf (Germany)

    2004-07-01

    With the increasing level of industrialization the demand for and the number of copper alloys rose in an uninterrupted way. Today, the copper alloys take an important position amongst metallic materials due to the large variety of their technological properties and applications. Nowadays there exist over 3.000 standardized alloys. Copper takes the third place of all metals with a worldwide consumption of over 15 millions tons per year, following only to steel and aluminum. In a modern industrial society we meet copper in all ranges of the life (electro-technology, building and construction industry, mechanical engineering, automotive, chemistry, offshore, marine engineering, medical applications and others.). Copper is the first metal customized by humanity. Its name is attributed to the island Cyprus, which supplied in the antiquity copper to Greece, Rome and the other Mediterranean countries. The Romans called it 'ore from Cyprus' (aes cyprium), later cuprum. Copper deposited occasionally also dapper and could be processed in the recent stone age simply by hammering. Already in early historical time copper alloys with 20 to 50 percent tin was used for the production of mirrors because of their high reflecting power. Although the elementary nickel is an element discovered only recently from a historical perspective, its application in alloys - without any knowledge of the alloy composition - occurred at least throughout the last 2.000 years. The oldest copper-nickel coin originates from the time around 235 B.C.. Only around 1800 AD nickel was isolated as a metallic element. In particular in the sea and offshore technology copper nickel alloys found a broad field of applications in piping systems and for valves and armatures. The excellent combination of characteristics like corrosion resistance, erosion stability and bio-fouling resistance with excellent mechanical strength are at the basis of this success. An experience of many decades supports the use

  14. Decolorization Treatment of Copper Phthalocyanine Textile Dye Wastewater by Electrochemical Methods

    Directory of Open Access Journals (Sweden)

    K. Dermentzis

    2013-01-01

    Full Text Available Electrochemical decolorization and degradation treatment of aqueous copper phthalocyanine reactive dye solutions was comparatively studied by electrocoagulation, electrooxidation and electro-Fenton processes. In the electrocoagulation process with aluminum electrodes the colored aqueous solutions of initial pH 6.4 containing 50 mg L-1 copper phthalocyanine and 6 g L-1 NaCl were treated at applied current densities of 2.5 and 5 mA cm-2. Fast and 100% decolorization was achieved in 4 and 2 minutes of electroprocessing respectively. The indirect electrooxidation process was conducted in acidic electrolyte solutions containing 50 mg L-1 copper phthalocyanine and 6 g L-1 NaCl with Ti/Pt and graphite plate electrodes at the applied current density of 10 mA cm-2. Even after 90 minutes of electrolysis time the dye remained by 23 and 18.8 % respectively undegradable. By the direct and indirect electrooxidation with the same amount of Na2SO4 electrolyte and added H2O2 respectively and using the same electrodes, the copper phthalocyanine dye was not or was only barely degraded respectively. In the electro-Fenton process with Fe electrodes and added amounts of H2O2 at pH 3 and an applied current density of 5 mA/cm2 complete degradation of copper phthalocyanine occurred in 15 minutes.

  15. Integrating Copper Nanowire Electrodes for Low Temperature Perovskite Photovoltaic Cells

    Science.gov (United States)

    Mankowski, Trent

    Recent advances in third generation photovoltaics, particularly the rapid increase in perovskite power conversion efficiencies, may provide a cheap alternative to silicon solar cells in the near future. A key component to these devices is the transparent front electrode, and in the case of Dye Sensitized Solar Cells, it is the most expensive part. A lightweight, cost-effective, robust, and easy-to-fabricate new generation TCE is required to enable competition with silicon. Indium Tin Oxide, commonly used in touchscreen devices, Organic Light Emitting Diodes (OLEDs), and thin film photovoltaics, is widely used and commonly referred to as the industry standard. As the global supply of indium decreases and the demand for this TCE increases, a similar alternative TCE is required to accompany the next generation solar cells that promise energy with lighter and significantly cheaper modules. This alternative TCE needs to provide similar sheet resistance and optical transmittance to ITO, while also being mechanically and chemically robust. The work in this thesis begins with an exploration of several synthesized ITO replacement materials, such as copper nanowires, conductive polymer PEDOT:PSS, zinc oxide thin films, reduced graphene oxide and combinations of the above. A guiding philosophy to this work was prioritizing cheap, easy deposition methods and overall scalability. Shortcomings of these TCEs were investigated and different materials were hybridized to take advantage of each layers strengths for development of an ideal ITO replacement. For CuNW-based composite electrodes, 85% optical transmittance and 25 O/sq were observed and characterized to understand the underlying mechanisms for optimization. The second half of this work is an examination of many different perovskite synthesis methods first to achieve highest performance, and then to integrate compatible methods with our CuNW TCEs. Several literature methods investigated were irreproducible, and those that

  16. Nonenzymatic glucose sensor based on disposable pencil graphite electrode modified by copper nanoparticles

    Directory of Open Access Journals (Sweden)

    Sima Pourbeyram

    2016-10-01

    Full Text Available A nonenzymatic glucose sensor based on a disposable pencil graphite electrode (PGE modified by copper nanoparticles [Cu(NP] was prepared for the first time. The prepared Cu(NP exhibited an absorption peak centered at ∼562 nm using UV-visible spectrophotometry and an almost homogenous spherical shape by scanning electron microscopy. Cyclic voltammetry of Cu(NP-PGE showed an adsorption controlled charge transfer process up to 90.0 mVs−1. The sensor was applied for the determination of glucose using an amperometry technique with a detection limit of [0.44 (±0.01 μM] and concentration sensitivity of [1467.5 (±1.3 μA/mMcm−2]. The preparation of the Cu(NP-PGE sensor was reproducible (relative standard deviation = 2.10%, n = 10, very simple, fast, and inexpensive, and the Cu(NP-PGE is suitable to be used as a disposable glucose sensor.

  17. Ferrocene-functionalized graphene electrode for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Rabti, Amal [Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Spain); Université de Tunis El–Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie (LR99ES15), Campus universitaire de Tunis El–Manar, 2092, Tunis (Tunisia); Mayorga-Martinez, Carmen C.; Baptista-Pires, Luis [Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Spain); Raouafi, Noureddine, E-mail: n.raouafi@fst.rnu.tn [Université de Tunis El–Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie (LR99ES15), Campus universitaire de Tunis El–Manar, 2092, Tunis (Tunisia); Merkoçi, Arben, E-mail: arben.merkoci@icn2.cat [Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Spain); ICREA, Barcelona, Catalonia (Spain)

    2016-07-05

    A novel ferrocene-functionalized reduced graphene oxide (rGO)-based electrode is proposed. It was fabricated by the drop casting of ferrocene-functionalized graphene onto polyester substrate as the working electrode integrated within screen-printed reference and counter electrodes. The ferrocene-functionalized rGO has been fully characterized using FTIR, XPS, contact angle measurements, SEM and TEM microscopy, and cyclic voltammetry. The XPS and EDX analysis showed the presence of Fe element related to the introduced ferrocene groups, which is confirmed by a clear CV signal at ca. 0.25 V vs. Ag/AgCl (0.1 KCl). Mediated redox catalysis of H{sub 2}O{sub 2} and bio-functionalization with glucose oxidase for glucose detection were achieved by the bioelectrode providing a proof for potential biosensing applications. - Graphical abstract: An easy-to-prepare standalone graphene electrode was obtained by the drop-casting ferrocene-functionalized rGO on PET polymer. This electrode can be used as an enzymeless electrochemical sensor for the detection of hydrogen peroxide or as an amperometric enzyme-based biosensor for sensitive glucose detection. - Highlights: • A novel ferrocene-functionalized reduced graphene oxide based electrode. • Ease of preparation by drop-casting of Fc-modified graphene and chitosan mixture. • Well-defined and exploitable ferrocene CV signal for sensing purposes. • Sensitive enzymeless detection of hydrogen peroxide at low potentials. • Enzymatic Sensitive detection of glucose on GOx-modified graphene electrode.

  18. Ferrocene-functionalized graphene electrode for biosensing applications

    International Nuclear Information System (INIS)

    Rabti, Amal; Mayorga-Martinez, Carmen C.; Baptista-Pires, Luis; Raouafi, Noureddine; Merkoçi, Arben

    2016-01-01

    A novel ferrocene-functionalized reduced graphene oxide (rGO)-based electrode is proposed. It was fabricated by the drop casting of ferrocene-functionalized graphene onto polyester substrate as the working electrode integrated within screen-printed reference and counter electrodes. The ferrocene-functionalized rGO has been fully characterized using FTIR, XPS, contact angle measurements, SEM and TEM microscopy, and cyclic voltammetry. The XPS and EDX analysis showed the presence of Fe element related to the introduced ferrocene groups, which is confirmed by a clear CV signal at ca. 0.25 V vs. Ag/AgCl (0.1 KCl). Mediated redox catalysis of H_2O_2 and bio-functionalization with glucose oxidase for glucose detection were achieved by the bioelectrode providing a proof for potential biosensing applications. - Graphical abstract: An easy-to-prepare standalone graphene electrode was obtained by the drop-casting ferrocene-functionalized rGO on PET polymer. This electrode can be used as an enzymeless electrochemical sensor for the detection of hydrogen peroxide or as an amperometric enzyme-based biosensor for sensitive glucose detection. - Highlights: • A novel ferrocene-functionalized reduced graphene oxide based electrode. • Ease of preparation by drop-casting of Fc-modified graphene and chitosan mixture. • Well-defined and exploitable ferrocene CV signal for sensing purposes. • Sensitive enzymeless detection of hydrogen peroxide at low potentials. • Enzymatic Sensitive detection of glucose on GOx-modified graphene electrode.

  19. Modeling of Changing Electrode Profiles

    Energy Technology Data Exchange (ETDEWEB)

    Prentice, Geoffrey Allen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

    1980-12-01

    A model for simulating the transient behavior of solid electrodes undergoing deposition or dissolution has been developed. The model accounts for ohmic drop, charge transfer overpotential, and mass transport limitations. The finite difference method, coupled with successive overrelaxation, was used as the basis of the solution technique. An algorithm was devised to overcome the computational instabilities associated with the calculations of the secondary and tertiary current distributions. Simulations were performed on several model electrode profiles: the sinusoid, the rounded corner, and the notch. Quantitative copper deposition data were obtained in a contoured rotating cylinder system, Sinusoidal cross-sections, machined on stainless steel cylinders, were used as model geometries, Kinetic parameters for use in the simulation were determined from polarization curves obtained on copper rotating cylinders, These parameters, along with other physical property and geometric data, were incorporated in simulations of growing sinusoidal profiles. The copper distributions on the sinusoidal cross-sections were measured and found to compare favorably with the simulated results. At low Wagner numbers the formation of a slight depression at the profile peak was predicted by the simulation and observed on the profile. At higher Wagner numbers, the simulated and experimental results showed that the formation of a depression was suppressed. This phenomenon was shown to result from the competition between ohmic drop and electrode curvature.

  20. Development of new metal matrix composite electrodes for electrical discharge machining through powder metallurgy process

    Directory of Open Access Journals (Sweden)

    C. Mathalai Sundaram

    2014-12-01

    Full Text Available Electrical discharge machining (EDM is one of the widely used nontraditional machining methods to produce die cavities by the erosive effect of electrical discharges. This method is popular due to the fact that a relatively soft electrically conductive tool electrode can machine hard work piece. Copper electrode is normally used for machining process. Electrode wear rate is the major drawback for EDM researchers. This research focus on fabrication of metal matrix composite (MMC electrode by mixing copper powder with titanium carbide (TiC and Tungsten carbide (WC powder through powder metallurgy process, Copper powder is the major amount of mixing proportion with TiC and WC. However, this paper focus on the early stage of the project where powder metallurgy route was used to determine suitable mixing time, compaction pressure and sintering and compacting process in producing EDM electrode. The newly prepared composite electrodes in different composition are tested in EDM for OHNS steel.

  1. High efficiency graphene coated copper based thermocells connected in series

    Science.gov (United States)

    Sindhuja, Mani; Indubala, Emayavaramban; Sudha, Venkatachalam; Harinipriya, Seshadri

    2018-04-01

    Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2W/m2 for normalized cross sectional electrode area is obtained at 60ºC of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

  2. Direct patterning of highly-conductive graphene@copper composites using copper naphthenate as a resist for graphene device applications.

    Science.gov (United States)

    Bi, Kaixi; Xiang, Quan; Chen, Yiqin; Shi, Huimin; Li, Zhiqin; Lin, Jun; Zhang, Yongzhe; Wan, Qiang; Zhang, Guanhua; Qin, Shiqiao; Zhang, Xueao; Duan, Huigao

    2017-11-09

    We report an electron-beam lithography process to directly fabricate graphene@copper composite patterns without involving metal deposition, lift-off and etching processes using copper naphthenate as a high-resolution negative-tone resist. As a commonly used industrial painting product, copper naphthenate is extremely cheap with a long shelf time but demonstrates an unexpected patterning resolution better than 10 nm. With appropriate annealing under a hydrogen atmosphere, the produced graphene@copper composite patterns show high conductivity of ∼400 S cm -1 . X-ray diffraction, conformal Raman spectroscopy and X-ray photoelectron spectroscopy were used to analyze the chemical composition of the final patterns. With the properties of high resolution and high conductivity, the patterned graphene@copper composites could be used as conductive pads and interconnects for graphene electronic devices with ohmic contacts. Compared to common fabrication processes involving metal evaporation and lift-off steps, this pattern-transfer-free fabrication process using copper naphthenate resist is direct and simple but allows comparable device performance in practical device applications.

  3. The effect of gamma radiation on the stability of miniature reference electrodes

    International Nuclear Information System (INIS)

    Galuszka-Muga, B.; Muga, M.L.; Hanrahan, R.J.

    2006-01-01

    The design and fabrication of four types of miniature reference electrodes and their long term stability in a radiation field are described. Miniature versions of a saturated calomel electrode (MSCE), a silver/silver chloride electrode (MAG), a tungsten/tungsten oxide (MWO) and a copper/copper ion (MCU) electrode were tested in a 10 kGy/h (1 Mrad/h) radiation field for up to 30 days total at 25 and 40 o C. The latter two (MWO and MCU) varied appreciably over time periods of several hours whereas the former two (MSCE and MAG) varied less than 1 mV over periods of 6-8 h and are deemed suitable as reference electrodes for corrosion studies of systems immersed in a radiation field at elevated temperature

  4. ELECTROCHEMICAL BEHAVIOR OF POLYCRYSTALLINE COPPER DURING THE ADSORPTION OF CO ABSTRACT

    Directory of Open Access Journals (Sweden)

    J. Salimon

    2017-12-01

    Full Text Available The electrochemical properties of electrode copper in carbon monoxide-saturated phosphate buffered solution were investigated. The electrochemistry of copper surface was sufficiently changed after the supporting electrolyte solution was saturated with CO. The hydrogen evolution region was depressed and shifted cathodically due to the adsorption process of CO on the copper surface in a linear or terminally bonded manner, Cu-CO . The oxidation and the reduction peaks of copper were significantly changed with two couple of redox peaks. This is due to the subsequent formation and the corresponding reduction of copper(I and the copper carbon monoxides species. Further changed in electrochemical properties occurred when the electrode surface was polarized at high cathodic potential (-1.4 V for a period of time (15 min. The hydrogen evolution region was further depressed due to the adsorption of CO process in multiple bonding sites as adsorbed bridge bonded CO, Cu-CO B L that occurred predominantly.

  5. Applications of Graphene-Modified Electrodes in Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Fei Yu

    2016-09-01

    Full Text Available Graphene-modified materials have captured increasing attention for energy applications due to their superior physical and chemical properties, which can significantly enhance the electricity generation performance of microbial fuel cells (MFC. In this review, several typical synthesis methods of graphene-modified electrodes, such as graphite oxide reduction methods, self-assembly methods, and chemical vapor deposition, are summarized. According to the different functions of the graphene-modified materials in the MFC anode and cathode chambers, a series of design concepts for MFC electrodes are assembled, e.g., enhancing the biocompatibility and improving the extracellular electron transfer efficiency for anode electrodes and increasing the active sites and strengthening the reduction pathway for cathode electrodes. In spite of the challenges of MFC electrodes, graphene-modified electrodes are promising for MFC development to address the reduction in efficiency brought about by organic waste by converting it into electrical energy.

  6. Cyclic voltammetry deposition of copper nanostructure on MWCNTs modified pencil graphite electrode: An ultra-sensitive hydrazine sensor

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, Hamid [Faculty of Sciences, Razi University, Kermanshah (Iran, Islamic Republic of); Gholivand, Mohammad B., E-mail: mbgholivand@razi.ac.ir [Faculty of Sciences, Razi University, Kermanshah (Iran, Islamic Republic of); Abdolmaleki, Abbas [Department of Chemistry, Malek Ashtar University of Technology, Tehran (Iran, Islamic Republic of)

    2016-09-01

    In this study, Copper (Cu) nanostructures (CuNS) were electrochemically deposited on a film of multiwall carbon nanotubes (MWCNTs) modified pencil graphite electrode (MWCNTs/PGE) by cyclic voltammetry method to fabricate a CuNS–MWCNTs composite sensor (CuNS–MWCNT/PGE) for hydrazine detection. Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) were used for the characterization of CuNS on the MWCNTs matrix. The composite of CuNS-MWCNTs was characterized with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The preliminary studies showed that the proposed sensor have a synergistic electrocatalytic activity for the oxidation of hydrazine in phosphate buffer. The catalytic currents of square wave voltammetry had a linear correlation with the hydrazine concentration in the range of 0.1 to 800 μM with a low detection limit of 70 nM. Moreover, the amperometric oxidation current exhibited a linear correlation with hydrazine concentration in the concentration range of 50–800 μM with the detection limit of 4.3 μM. The proposed electrode was used for the determination of hydrazine in real samples and the results were promising. Empirical results also indicated that the sensor had good reproducibility, long-term stability, and the response of the sensor to hydrazine was free from interferences. Moreover, the proposed sensor benefits from simple preparation, low cost, outstanding sensitivity, selectivity, and reproducibility for hydrazine determination. - Highlights: • The Copper nanostructures (CuNS) were prepared by cyclic voltammetry deposition. • The CuNS-MWCNT/PGE sensor shows high activity toward hydrazine (N{sub 2}H{sub 4}). • The proposed sensor exhibits a wide linear range (0.1 to 800 μM), low detection limit (70 nM), high sensitivity and stability for hydrazine.

  7. Visualization and mechanisms of splashing erosion of electrodes in a DC air arc

    International Nuclear Information System (INIS)

    Wu, Yi; Cui, Yufei; Rong, Mingzhe; Yang, Fei; Sun, Hao; Niu, Chunping; Fan, Shaodi; Murphy, Anthony B

    2017-01-01

    The splashing erosion of electrodes in a DC atmospheric-pressure air arc has been investigated by visualization of the electrode surface and the sputtered droplets, and tracking of the droplet trajectories, using image processing techniques. A particle tracking velocimetry algorithm has been introduced to measure the sputtering velocity distribution. Erosion of both tungsten–copper and tungsten–ceria electrodes is studied; in both cases electrode erosion is found to be dominated by droplet splashing rather than metal evaporation. Erosion is directly influenced by both melting and the formation of plasma jets, and can be reduced by the tuning of the plasma jet and electrode material. The results provide an understanding of the mechanisms that lead to the long lifetime of tungsten–copper electrodes, and may provide a path for the design of the electrode system subjected to electric arc to minimize erosion. (letter)

  8. Visualization and mechanisms of splashing erosion of electrodes in a DC air arc

    Science.gov (United States)

    Wu, Yi; Cui, Yufei; Rong, Mingzhe; Murphy, Anthony B.; Yang, Fei; Sun, Hao; Niu, Chunping; Fan, Shaodi

    2017-11-01

    The splashing erosion of electrodes in a DC atmospheric-pressure air arc has been investigated by visualization of the electrode surface and the sputtered droplets, and tracking of the droplet trajectories, using image processing techniques. A particle tracking velocimetry algorithm has been introduced to measure the sputtering velocity distribution. Erosion of both tungsten-copper and tungsten-ceria electrodes is studied; in both cases electrode erosion is found to be dominated by droplet splashing rather than metal evaporation. Erosion is directly influenced by both melting and the formation of plasma jets, and can be reduced by the tuning of the plasma jet and electrode material. The results provide an understanding of the mechanisms that lead to the long lifetime of tungsten-copper electrodes, and may provide a path for the design of the electrode system subjected to electric arc to minimize erosion.

  9. Construction of Hierarchical CuO/Cu₂O@NiCo₂S₄ Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes.

    Science.gov (United States)

    Zhou, Luoxiao; He, Ying; Jia, Congpu; Pavlinek, Vladimir; Saha, Petr; Cheng, Qilin

    2017-09-15

    Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu₂O@NiCo₂S₄) core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu₂O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo₂S₄ nanosheets on the surface of CuO/Cu₂O nanowires to form the CuO/Cu₂O@NiCo₂S₄ core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo₂S₄ nanosheets is ~20 nm and the diameter of CuO/Cu₂O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm -2 at 10 mA cm -2 , good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm -2 ) and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm -2 . These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer.

  10. High Efficiency Graphene Coated Copper Based Thermocells Connected in Series

    Directory of Open Access Journals (Sweden)

    Mani Sindhuja

    2018-04-01

    Full Text Available Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2 W/m2 for normalized cross sectional electrode area is obtained at 60°C of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

  11. Direct reform of graphite oxide electrodes by using ambient plasma for supercapacitor applications

    Science.gov (United States)

    Kim, Ho Jun; Jeong, Hae Kyung

    2017-10-01

    Ambient plasma is applied to graphite oxide electrodes directly to improve electrochemical properties for supercapacitor applications. Surface morphology of the electrodes after the plasma treatment changes dramatically and amount of oxygen reduced significantly, demonstrating a reduction effect on the graphite oxide electrode by the ambient plasma. Equivalent series resistance of the electrode also reduced from 108 Ω to 84 Ω after the plasma treatment. Corresponding specific capacitance, therefore, increases from 0.45 F cm-2 to 0.85 F cm-2, proving that the ambient plasma treatment is very efficient, clean, economic, and environment-friendly method to reform the graphite oxide electrodes directly for the supercapacitor applications.

  12. Material for electrodes of low temperature plasma generators

    Science.gov (United States)

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

    2008-12-09

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  13. Chemical Modification of Boron-Doped Diamond Electrodes for Applications to Biosensors and Biosensing.

    Science.gov (United States)

    Svítková, Jana; Ignat, Teodora; Švorc, Ľubomír; Labuda, Ján; Barek, Jiří

    2016-05-03

    Boron-doped diamond (BDD) is a prospective electrode material that possesses many exceptional properties including wide potential window, low noise, low and stable background current, chemical and mechanical stability, good biocompatibility, and last but not least exceptional resistance to passivation. These characteristics extend its usability in various areas of electrochemistry as evidenced by increasing number of published articles over the past two decades. The idea of chemically modifying BDD electrodes with molecular species attached to the surface for the purpose of creating a rational design has found promising applications in the past few years. BDD electrodes have appeared to be excellent substrate materials for various chemical modifications and subsequent application to biosensors and biosensing. Hence, this article presents modification strategies that have extended applications of BDD electrodes in electroanalytical chemistry. Different methods and steps of surface modification of this electrode material for biosensing and construction of biosensors are discussed.

  14. Synthesis of carbon nanotubes bridging metal electrodes

    International Nuclear Information System (INIS)

    Kotlar, M.; Vojs, M.; Marton, M.; Vesel, M.; Redhammer, R.

    2012-01-01

    In our work we demonstrate growth of carbon nanotubes that can conductively bridge the metal electrodes. The role of different catalysts was examined. Interdigitated metal electrodes are made from copper and we are using bimetal Al/Ni as catalyst for growth of carbon nanotubes. We are using this catalyst composition for growth of the single-walled carbon nanotube network. (authors)

  15. Corrosion and passivation of copper in artificial sea water

    International Nuclear Information System (INIS)

    Chon, Jung Kyoon; Kim, Youn Kyoo

    2007-01-01

    Based on the cyclic voltammograms, potentiodynamic polarizations, transient and steady state Tafel plots and electrochemical impedance spectroscopy, we proposed the copper redox mechanism of the corrosion and passivation in artificial sea water. The copper redox mechanism showed the dependence of the concentration of oxygen in artificial sea water and electrode potentials

  16. Estudo voltamétrico do complexo de cobre(II com o ligante vermelho de alizarina S, adsorvido na superfície do eletrodo de grafite pirolítico Voltammetric study of complex of copper (II with alizarin red S ligand, absorbed on surface of pyrolytic graphite electrode

    Directory of Open Access Journals (Sweden)

    Victor E. Mouchrek Filho

    1999-06-01

    Full Text Available The alizarin red S (ARS has been used as a spectrophotometric reagent of several metals for a long time. Now this alizarin has been used as modifier agent of electrodes, for voltammetric analyses. In this work cyclic voltammetry experiments was accomplished on closed circuit, with the objective of studying the voltammetric behavior of alizarin red S adsorbed and of its copper complex, on the surface of the pyrolytic graphite electrode. These studies showed that ARS strongly adsorbs on the surface of this electrode. This adsorption was used to immobilize ions copper(II from the solution.

  17. Controlled atmosphere for fabrication of cermet electrodes

    Science.gov (United States)

    Ray, Siba P.; Woods, Robert W.

    1998-01-01

    A process for making an inert electrode composite wherein a metal oxide and a metal are reacted in a gaseous atmosphere at an elevated temperature of at least about 750.degree. C. The metal oxide is at least one of the nickel, iron, tin, zinc and zirconium oxides and the metal is copper, silver, a mixture of copper and silver or a copper-silver alloy. The gaseous atmosphere has an oxygen content that is controlled at about 5-3000 ppm in order to obtain a desired composition in the resulting composite.

  18. Design and physical features of inductive coaxial copper vapor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Batenin, V. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Kazaryan, M. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Karpukhin, V. T. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Lyabin, N. A. [Istok Research and Production Corporation (Russian Federation); Malikov, M. M., E-mail: mmalikov@oivtran.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2016-11-15

    A physical model of a copper vapor laser pumped by a pulse-periodic inductive (electrodeless) discharge is considered. The feasibility of efficient laser pumping by an inductive discharge and reaching high output parameters comparable to those of conventional copper vapor lasers pumped by a longitudinal electrode discharge is demonstrated. The design and physical features of an inductive copper vapor laser with an annular working volume are discussed.

  19. Comparative study of atmospheric pressure low and radio frequency microjet plasmas produced in a single electrode configuration

    International Nuclear Information System (INIS)

    Kim, Dan Bee; Rhee, J. K.; Gweon, B.; Moon, S. Y.; Choe, W.

    2007-01-01

    Microsize jet-type plasmas were generated in a single pin electrode structure source for two separate input frequencies of 50 kHz and 13.56 MHz in the ambient air. The copper pin electrode radius was 360 μm, and it was placed in a Pyrex tube with a radius of 3 mm for helium gas supply. Due to the input frequency difference, the generated plasmas showed distinct discharge characteristics for their plasma physical appearances, electrical properties, gas temperatures, and optical properties. Strengths and weaknesses of both plasmas were discussed for further applications

  20. Multi-polar resistance switching and memory effect in copper phthalocyanine junctions

    International Nuclear Information System (INIS)

    Qiao Shi-Zhu; Kang Shi-Shou; Li Qiang; Zhong Hai; Kang Yun; Yu Shu-Yun; Han Guang-Bing; Yan Shi-Shen; Mei Liang-Mo; Qin Yu-Feng

    2014-01-01

    Copper phthalocyanine junctions, fabricated by magnetron sputtering and evaporating methods, show multi-polar (unipolar and bipolar) resistance switching and the memory effect. The multi-polar resistance switching has not been observed simultaneously in one organic material before. With both electrodes being cobalt, the unipolar resistance switching is universal. The high resistance state is switched to the low resistance state when the bias reaches the set voltage. Generally, the set voltage increases with the thickness of copper phthalocyanine and decreases with increasing dwell time of bias. Moreover, the low resistance state could be switched to the high resistance state by absorbing the phonon energy. The stability of the low resistance state could be tuned by different electrodes. In Au/copper phthalocyanine/Co system, the low resistance state is far more stable, and the bipolar resistance switching is found. Temperature dependence of electrical transport measurements demonstrates that there are no obvious differences in the electrical transport mechanism before and after the resistance switching. They fit quite well with Mott variable range hopping theory. The effect of Al 2 O 3 on the resistance switching is excluded by control experiments. The holes trapping and detrapping in copper phthalocyanine layer are responsible for the resistance switching, and the interfacial effect between electrodes and copper phthalocyanine layer affects the memory effect. (interdisciplinary physics and related areas of science and technology)

  1. Microstructure & Other Properties of Pulse-Plated Copper for Electroforming Applications

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Jensen, Jens Dahl; Dam, H.C.

    2002-01-01

    Microstructure, hardness, material distribution and current efficiency were studied for various pulse patterns (both direct current, on/off and pulse reverse plating) and different bath compositions of copper sulfate and sulfuric acid, with additions of chloride. The objective was to develop a re...... a reliable copper electroforming process to provide a fine-grained and hard (above HV 125) deposit with good micro- and macrothrowing power. Potential applications include solar cell panels, tools for micro injection molding and various microelectromechanical systems (MEMS)....

  2. Progress in Effect of Nano-modified Coatings and Welding Process Parameters on Wear of Contact Tube for Non-copper Coated Solid Wires

    Directory of Open Access Journals (Sweden)

    LI Zhuo-xin

    2017-12-01

    Full Text Available Environment-friendly non-copper coated solid wire is the main developing trend for gas shielded solid wires, whereas wear of contact tube limits their wide application. The effect of nano-modified coatings and welding process parameters on wear of contact tube for non-copper coated solid wires was reviewed. It was found that the wear of contact tube can be reduced due to the formation of tribo-films on the rubbing surfaces of welding wires against contact tube; it is feasible to decrease contact tube wear when non-copper coated solid wires are coated with nano-modified lubricants, thereby displaying excellent lubricating and thermal or electrical conduction characteristics. The wear of contact tube increases with the increase of welding current. The wear of contact tube is worse in direct-current electrode positive (DCEP than in direct-current electrode negative (DCEN. Arc ablation and electrical erosion are the dominant wear mechanisms of contact tube.

  3. Copper ion fluxes through the floating water bridge under strong electric potential.

    Science.gov (United States)

    Giuliani, Livio; D'Emilia, Enrico; Lisi, Antonella; Grimaldi, Settimio; Brizhik, Larissa; Del Giudice, Emilio

    2015-01-01

    We have performed a series of experiments applying high voltage between two electrodes, immersed in two beakers containing bidistilled water in a way similar to experiments conducted by Fuchs and collaborators, which showed that a water bridge can be formed between the two containers. We also observed the formation of water bridge. Moreover, choosing different pairs of electrodes depending on the material they are made up of, we observed that copper ions flow can pass along the bridge if the negative electrode is made up of copper. We show that the direction of the flux not only depends on the applied electrostatic field but on the relative electronegativity of the electrodes too. These results open new perspectives in understanding the properties of water. We suggest a possible explanation of the obtained results.

  4. Boron-doped diamond electrode: synthesis, characterization, functionalization and analytical applications.

    Science.gov (United States)

    Luong, John H T; Male, Keith B; Glennon, Jeremy D

    2009-10-01

    In recent years, conductive diamond electrodes for electrochemical applications have been a major focus of research and development. The impetus behind such endeavors could be attributed to their wide potential window, low background current, chemical inertness, and mechanical durability. Several analytes can be oxidized by conducting diamond compared to other carbon-based materials before the breakdown of water in aqueous electrolytes. This is important for detecting and/or identifying species in solution since oxygen and hydrogen evolution do not interfere with the analysis. Thus, conductive diamond electrodes take electrochemical detection into new areas and extend their usefulness to analytes which are not feasible with conventional electrode materials. Different types of diamond electrodes, polycrystalline, microcrystalline, nanocrystalline and ultrananocrystalline, have been synthesized and characterized. Of particular interest is the synthesis of boron-doped diamond (BDD) films by chemical vapor deposition on various substrates. In the tetrahedral diamond lattice, each carbon atom is covalently bonded to its neighbors forming an extremely robust crystalline structure. Some carbon atoms in the lattice are substituted with boron to provide electrical conductivity. Modification strategies of doped diamond electrodes with metallic nanoparticles and/or electropolymerized films are of importance to impart novel characteristics or to improve the performance of diamond electrodes. Biofunctionalization of diamond films is also feasible to foster several useful bioanalytical applications. A plethora of opportunities for nanoscale analytical devices based on conducting diamond is anticipated in the very near future.

  5. Work function measurements of copper nanoparticle intercalated polyaniline nanocomposite thin films

    Science.gov (United States)

    Patil, U. V.; Ramgir, Niranjan S.; Bhogale, A.; Debnath, A. K.; Muthe, K. P.; Gadkari, S. C.; Kothari, D. C.

    2017-05-01

    The nature of contact between the electrode and the sensing material plays a crucial role in governing the sensing mechanism. Thin films of polyaniline (PANI) and copper-polyaniline nanocomposite (NC) have been deposited at room temperatures by in-situ oxidative polymerization of aniline in the presence of Cu nanoparticles. For sensing applications a thin film Au (gold) ˜100 nm is deposited and used as a conducting electrode. To understand the nature of contact (i.e., ohmic or Schottky) the work function of the conducting polyaniline and nanocomposite films were measured using Kelvin Probe method. I-V characteristics of PANI and NC films investigated at room temperatures further corroborates and confirms the formation of Ohmic contact as evident from work function measurements.

  6. Low cost chemical oxygen demand sensor based on electrodeposited nano-copper film

    Directory of Open Access Journals (Sweden)

    Hamdy H. Hassan

    2018-02-01

    Full Text Available A commercially available copper electrical cable and pure Cu disk were used as substrates for the electrodeposition of copper nanoparticles (nano-Cu. The surface morphology of the prepared nano-Cu/Cu electrodes was investigated by scanning electron microscope (SEM and energy dispersive X-ray spectrometer (EDX. The bare copper substrates and the nano-copper modified electrodes were utilized and optimized for electrochemical assay of chemical oxygen demand (COD using glycine as a standard. A comparison was made among the four electrodes (i.e., bare and nano-Cu coated copper cable and pure copper disk as potential COD sensors. The oxidation behavior of glycine was investigated on the surface of the prepared sensors using linear sweep voltammetry (LSV. The results indicate significant enhancement of the electrochemical oxidation of glycine by the deposited nano-Cu. The effects of different deposition parameters, such as Cu2+ concentration, deposition potential, deposition time, pH, and scan rate on the response of the prepared sensors were investigated. Under optimized conditions, the optimal nano-Cu based COD sensor exhibited a linear range of 2–595 mg/L, lower limit of detection (LOD as low as 1.07 mg/L (S/N = 3. The developed method exhibited high tolerance level to Cl− ion where 1.0 M Cl− exhibited minimal influence. The sensor was utilized for the detection of COD in different real water samples. The results obtained were validated using the standard dichromate method.

  7. Evaluation of Synthesizing Al2O3 Nano Particles in Copper Matrix by Mechanical Alloying of Cu-1% Al and Copper Oxide

    Directory of Open Access Journals (Sweden)

    S. Safi

    2017-06-01

    Full Text Available Strengthening of copper matrix by dispersion of metallic oxides particles as an efficient way to increase strength without losing thermal and electrical conductivities has been recognized for many years. Such a composite can withstand high temperatures and keep its properties. Such copper alloys have many applications especially in high temperature including resistance welding electrodes, electrical motors and switches. In the present work, at first, the Cu-1%Al solid solution was prepared by the mechanical alloying process via 48 hours of milling. Subsequently, 0.66 gr of copper oxide was added to Cu-1%Al solid solution and mechanically milled for different milling times of 0,16, 32, 48 hours. The milled powder mixtures were investigated by X-Ray Diffraction and scanning electron microscopy techniques. The lattice parameter of Cu increased at first, but then decreased at longer milling times. The internal strain increased and the average Cu crystal size decreased during milling process.The particle size decreased during the whole process. With increasing annealing temprature from 450°C to 750°C, the microhardness values of samples decreased at the beginning but then increased. From these results, it can be concluded that nanosize aluminaparticles are formed in the copper matrix.

  8. Transparent Electrodes with Nanotubes and Graphene for Printed Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Marcin Słoma

    2014-01-01

    Full Text Available We report here on printed electroluminescent structures containing transparent electrodes made of carbon nanotubes and graphene nanoplatelets. Screen-printing and spray-coating techniques were employed. Electrodes and structures were examined towards optical parameters using spectrophotometer and irradiation meter. Electromechanical properties of transparent electrodes are exterminated with cyclical bending test. Accelerated aging process was conducted according to EN 62137 standard for reliability tests of electronics. We observed significant negative influence of mechanical bending on sheet resistivity of ITO, while resistivity of nanotube and graphene based electrodes remained stable. Aging process has also negative influence on ITO based structures resulting in delamination of printed layers, while those based on carbon nanomaterials remained intact. We observe negligible changes in irradiation for structures with carbon nanotube electrodes after accelerated aging process. Such materials demonstrate a high application potential in general purpose electroluminescent devices.

  9. On the ''memory'' effect and its relation to the mechanism of formation of mercury-graphite electrode in inversion voltammetry

    International Nuclear Information System (INIS)

    Nejman, E.Ya.; Petrova, L.G.; Dolgopolova, G.M.; Ignatov, V.I.

    1977-01-01

    Simultaneous discharge ionization of lead-copper and cadmium-copper systems on the surface of mercury-plated graphite and graphite electrodes has been studied. A model is suggested of the preparation process of a mercury-plated graphite electrode obtained in simultaneous electroposition of mercury and elements determined as microimpurities. Processes, which occur on the electrode during relaxation time between electrolysis beginning and formation of the mercury phase, may be probable reasons for mutual effects of elements of the mercury-plated graphite electrode

  10. Manufacturing of copper-graphite brushes for automobile applications

    International Nuclear Information System (INIS)

    Answar, M.Y.

    2006-01-01

    Copper-graphite brushes are used in high-volume automotive applications, such as ignition switches, window lifts, wiper motors, engine cooling fans, ABS break system and seat actuators etc. The amount of graphite in these brushes may range from 5 -20 wt. %. In this paper, some of the results of a study carried out using locally produced electrolytic copper powder and imported graphite powder are being summarized. The green compacts were produced by compaction at 650 MPa. These compacts were sintered at temperatures between 950 to 1050 degree C for various time intervals. The effects of sintering temperatures and time on the properties are analyzed. The influence of small additions of zinc on hardness of the sintered alloy compacts is also investigated. (author)

  11. Printable inorganic nanomaterials for flexible transparent electrodes: from synthesis to application

    Science.gov (United States)

    Wang, Dingrun; Mei, Yongfeng; Huang, Gaoshan

    2018-01-01

    Printed and flexible electronics are definitely promising cutting-edge electronic technologies of the future. They offer a wide-variety of applications such as flexible circuits, flexible displays, flexible solar cells, skin-like pressure sensors, and radio frequency identification tags in our daily life. As the most-fundamental component of electronics, electrodes are made of conductive materials that play a key role in flexible and printed electronic devices. In this review, various inorganic conductive materials and strategies for obtaining highly conductive and uniform electrodes are demonstrated. Applications of printed electrodes fabricated via these strategies are also described. Nevertheless, there are a number of challenges yet to overcome to optimize the processing and performance of printed electrodes. Project supported by the National Natural Science Foundation of China (Nos. 51475093, U1632115), the Science and Technology Commission of Shanghai Municipality (No. 14JC1400200), the National Key Technologies R&D Program of China (No. 2015ZX02102-003), and the Changjiang Young Scholars Programme of China.

  12. Extension of E7024 Electrode Applications in Shipbuilding

    National Research Council Canada - National Science Library

    1980-01-01

    The primary objective of the project is to determine the extent to which use of AWS type E7O24 electrodes can be broadened in regard to fillet welding applications with particular emphasis on single pass fillet welding...

  13. Copper nanofiber-networked cobalt oxide composites for high performance Li-ion batteries

    Directory of Open Access Journals (Sweden)

    Shim Hee-Sang

    2011-01-01

    Full Text Available Abstract We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoO x . The copper nanofibers (CuNFs were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide. Compared to bare CoO x thin-film (CoO x TF electrodes, the CuNFs@CoO x electrodes exhibited a significant enhancement of rate performance by at least six-fold at an input current density of 3C-rate. Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network. Consequently, the CuNFs@CoO x composite structure demonstrated here can be used as a promising high-performance electrode for Li-ion batteries.

  14. Ultra-nanocrystalline diamond electrodes: optimization towards neural stimulation applications.

    Science.gov (United States)

    Garrett, David J; Ganesan, Kumaravelu; Stacey, Alastair; Fox, Kate; Meffin, Hamish; Prawer, Steven

    2012-02-01

    Diamond is well known to possess many favourable qualities for implantation into living tissue including biocompatibility, biostability, and for some applications hardness. However, conducting diamond has not, to date, been exploited in neural stimulation electrodes due to very low electrochemical double layer capacitance values that have been previously reported. Here we present electrochemical characterization of ultra-nanocrystalline diamond electrodes grown in the presence of nitrogen (N-UNCD) that exhibit charge injection capacity values as high as 163 µC cm(-2) indicating that N-UNCD is a viable material for microelectrode fabrication. Furthermore, we show that the maximum charge injection of N-UNCD can be increased by tailoring growth conditions and by subsequent electrochemical activation. For applications requiring yet higher charge injection, we show that N-UNCD electrodes can be readily metalized with platinum or iridium, further increasing charge injection capacity. Using such materials an implantable neural stimulation device fabricated from a single piece of bio-permanent material becomes feasible. This has significant advantages in terms of the physical stability and hermeticity of a long-term bionic implant.

  15. Carbon Nanotubes Counter Electrode for Dye-Sensitized Solar Cells Application

    Directory of Open Access Journals (Sweden)

    Drygała A.

    2016-06-01

    Full Text Available The influence of the carbon nanotubes counter electrode deposited on the FTO glass substrates on the structure and optoelectrical properties of dye-sensitized solar cells counter electrode (CE was analysed. Carbon materials have been applied in DSSC s in order to produce low-cost solar cells with reasonable efficiency. Platinum is a preferred material for the counter electrode because of its high conductivity and catalytic activity. However, the costs of manufacturing of the platinum counter electrode limit its use to large-scale applications in solar cells. This paper presents the results of examining the structure and properties of the studied layers, defining optical properties of conductive layers and electrical properties of dye-sensitized solar cells manufactured with the use of carbon nanotubes.

  16. Control of Compact-Toroid Characteristics by External Copper Shell

    Science.gov (United States)

    Matsumoto, T.; Sekiguchi, J.; Asai, T.; Gota, H.; Roche, T.; Allfrey, I.; Cordero, M.; Garate, E.; Kinley, J.; Valentine, T.; Waggoner, W.; the TAE Team

    2015-11-01

    A collaborative research project by Tri Alpha Energy and Nihon University has been conducted for several years, which led to the development of a new compact toroid (CT) injector for efficient FRC particle refueling in the C-2U experiment. The CT is formed by a magnetized coaxial plasma gun (MCPG), consisting of coaxial cylindrical electrodes. In CT formation via MCPG, the magnetic helicity content of the generated CT is one of the critical parameters. A bias coil is inserted into the inner electrode to generate a poloidal flux. The resultant bias magnetic field is spread out of MCPG with time due to its low-frequency bias current. To obtain a more effectively distributed bias magnetic field as well as to improve the voltage breakdown between electrodes, the MCPG incorporates a novel ~ 1 mm thick copper shell mounted outside of the outer electrode. This allows for reliable and controlled operation and more robust CT generation. A detailed discussion of the copper shell and experimental test results will be presented.

  17. Copper and nickel alloys and titanium for seawater applications

    International Nuclear Information System (INIS)

    Richter, H.

    1977-01-01

    Copper and nickel alloys and titanium have been successfully used for heat exchangers on ships, in power plants and for chemical apparatus and piping systems because of their resistance against corrosion in sea water. Aluminium brass and copper nickel alloys, the standard materials for condensers and coolers, however, may be attacked, the corrosion depending on water quality, water velocity, and structural conditions. The mechanisms of corrosion are discussed. Under severe conditions the use of titanium may be indicated. The use of nickel base alloys is advantageous at elevated temperatures, e.g. for chemical reactions and for evaporation processes. Examples are given for application and for prevention of corrosion. (orig.) [de

  18. Investigations on the Formation of Copper Polyvanadates as a Function of pH

    Directory of Open Access Journals (Sweden)

    Prasad Shiva

    2002-01-01

    Full Text Available The formation and composition of copper vanadates obtained by the interaction of copper sulfate with different sodium vanadates (ortho, pyro, meta and poly have been studied by means of electrometric techniques involving glass electrode and conductometric titrations between the reactants at several concentrations in aqueous and aqueous-ethanolic media. The well defined inflections and breaks in the titration curves provide cogent evidence for the formation and precipitation of copper ortho-3CuO.V2O5, pyro-2CuO.V2O5 and meta-CuO.V2O5 vanadates in the vicinity of pH 8.1, 7.4 and 6.2, respectively. The studies on formation of copper poly-vanadate failed to give any dependable results. Analytical investigations of the compounds formed confirm the results of the electrometric study. The precipitation of copper ortho-vanadate is almost quantitative and the glass electrode titrations ofers a simple and rapid method for determination of vanadium(V in solutions.

  19. Strategies for "wiring" redox-active proteins to electrodes and applications in biosensors, biofuel cells, and nanotechnology.

    Science.gov (United States)

    Nöll, Tanja; Nöll, Gilbert

    2011-07-01

    In this tutorial review the basic approaches to establish electrochemical communication between redox-active proteins and electrodes are elucidated and examples for applications in electrochemical biosensors, biofuel cells and nanotechnology are presented. The early stage of protein electrochemistry is described giving a short overview over electron transfer (ET) between electrodes and proteins, followed by a brief introduction into experimental procedures for studying proteins at electrodes and possible applications arising thereof. The article starts with discussing the electrochemistry of cytochrome c, the first redox-active protein, for which direct reversible ET was obtained, under diffusion controlled conditions and after adsorption to electrodes. Next, examples for the electrochemical study of redox enzymes adsorbed on electrodes and modes of immobilization are discussed. Shortly the experimental approach for investigating redox-active proteins adsorbed on electrodes is outlined. Possible applications of redox enzymes in electrochemical biosensors and biofuel cells working by direct ET (DET) and mediated ET (MET) are presented. Furthermore, the reconstitution of redox active proteins at electrodes using molecular wire-like units in order to "wire" the proteins to the electrode surface and possible applications in nanotechnology are discussed.

  20. The importance of surface morphology in controlling the selectivity of polycrystalline copper for CO(2) electroreduction

    DEFF Research Database (Denmark)

    Tang, Wei; Peterson, Andrew A; Varela Gasque, Ana Sofia

    2012-01-01

    This communication examines the effect of the surface morphology of polycrystalline copper on electroreduction of CO(2). We find that a copper nanoparticle covered electrode shows better selectivity towards hydrocarbons compared with the two other studied surfaces, an electropolished copper elect...

  1. Low-Temperature Solution Processable Electrodes for Piezoelectric Sensors Applications

    Science.gov (United States)

    Tuukkanen, Sampo; Julin, Tuomas; Rantanen, Ville; Zakrzewski, Mari; Moilanen, Pasi; Lupo, Donald

    2013-05-01

    Piezoelectric thin-film sensors are suitable for a wide range of applications from physiological measurements to industrial monitoring systems. The use of flexible materials in combination with high-throughput printing technologies enables cost-effective manufacturing of custom-designed, highly integratable piezoelectric sensors. This type of sensor can, for instance, improve industrial process control or enable the embedding of ubiquitous sensors in our living environment to improve quality of life. Here, we discuss the benefits, challenges and potential applications of piezoelectric thin-film sensors. The piezoelectric sensor elements are fabricated by printing electrodes on both sides of unmetallized poly(vinylidene fluoride) film. We show that materials which are solution processable in low temperatures, biocompatible and environmental friendly are suitable for use as electrode materials in piezoelectric sensors.

  2. Graphene-based transparent electrodes for hybrid solar cells

    Directory of Open Access Journals (Sweden)

    Pengfei eLi

    2014-11-01

    Full Text Available The graphene-based transparent and conductive films were demonstrated to be cost-effective electrodes working in organic-inorganic hybrid Schottky solar cells. Large area graphene films were produced by chemical vapor deposition (CVD on copper foils and transferred onto glass as transparent electrodes. The hybrid solar cell devices consist of solution processed poly (3, 4-ethlenedioxythiophene: poly (styrenesulfonate (PEDOT: PSS which is sandwiched between silicon wafer and graphene electrode. The solar cells based on graphene electrodes, especially those doped with HNO3, has comparable performance to the reference devices using commercial indium tin oxide (ITO. Our work suggests that graphene-based transparent electrode is a promising candidate to replace ITO.

  3. Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries.

    Science.gov (United States)

    He, Jianjiang; Wang, Ning; Cui, Zili; Du, Huiping; Fu, Lin; Huang, Changshui; Yang, Ze; Shen, Xiangyan; Yi, Yuanping; Tu, Zeyi; Li, Yuliang

    2017-10-27

    Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g -1 for lithium ion batteries and 650 mAh g -1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

  4. Nanomolar Trace Metal Analysis of Copper at Gold Microband Arrays

    Science.gov (United States)

    Wahl, A.; Dawson, K.; Sassiat, N.; Quinn, A. J.; O'Riordan, A.

    2011-08-01

    This paper describes the fabrication and electrochemical characterization of gold microband electrode arrays designated as a highly sensitive sensor for trace metal detection of copper in drinking water samples. Gold microband electrodes have been routinely fabricated by standard photolithographic methods. Electrochemical characterization were conducted in 0.1 M H2SO4 and found to display characteristic gold oxide formation and reduction peaks. The advantages of gold microband electrodes as trace metal sensors over currently used methods have been investigated by employing under potential deposition anodic stripping voltammetry (UPD-ASV) in Cu2+ nanomolar concentrations. Linear correlations were observed for increasing Cu2+ concentrations from which the concentration of an unknown sample of drinking water was estimated. The results obtained for the estimation of the unknown trace copper concentration in drinking was in good agreement with expected values.

  5. Nanomolar Trace Metal Analysis of Copper at Gold Microband Arrays

    International Nuclear Information System (INIS)

    Wahl, A; Dawson, K; Sassiat, N; Quinn, A J; O'Riordan, A

    2011-01-01

    This paper describes the fabrication and electrochemical characterization of gold microband electrode arrays designated as a highly sensitive sensor for trace metal detection of copper in drinking water samples. Gold microband electrodes have been routinely fabricated by standard photolithographic methods. Electrochemical characterization were conducted in 0.1 M H 2 SO 4 and found to display characteristic gold oxide formation and reduction peaks. The advantages of gold microband electrodes as trace metal sensors over currently used methods have been investigated by employing under potential deposition anodic stripping voltammetry (UPD-ASV) in Cu 2+ nanomolar concentrations. Linear correlations were observed for increasing Cu 2+ concentrations from which the concentration of an unknown sample of drinking water was estimated. The results obtained for the estimation of the unknown trace copper concentration in drinking was in good agreement with expected values.

  6. Application of a CCA-treated wood waste decontamination process to other copper-based preservative-treated wood after disposal

    Energy Technology Data Exchange (ETDEWEB)

    Janin, Amelie, E-mail: amelie.janin@ete.inrs.ca [University of Toronto, Faculty of Forestry, 33, Willcocks St., Toronto, ON, M5S 3B3 (Canada); Coudert, Lucie, E-mail: lucie.coudert@ete.inrs.ca [Institut national de la recherche scientifique (Centre Eau, Terre et Environnement), Universite du Quebec, 490 rue de la Couronne, Quebec, QC, G1K 9A9 (Canada); Riche, Pauline, E-mail: pauline.riche@ete.inrs.ca [Institut national de la recherche scientifique (Centre Eau, Terre et Environnement), Universite du Quebec, 490 rue de la Couronne, Quebec, QC, G1K 9A9 (Canada); Mercier, Guy, E-mail: guy_mercier@ete.inrs.ca [Institut national de la recherche scientifique (Centre Eau, Terre et Environnement), Universite du Quebec, 490 rue de la Couronne, Quebec, QC, G1K 9A9 (Canada); Cooper, Paul, E-mail: p.cooper@utoronto.ca [University of Toronto, Faculty of Forestry, 33, Willcocks St., Toronto, ON, M5S 3B3 (Canada); Blais, Jean-Francois, E-mail: blaisjf@ete.inrs.ca [Institut national de la recherche scientifique (Centre Eau, Terre et Environnement), Universite du Quebec, 490 rue de la Couronne, Quebec, QC, G1K 9A9 (Canada)

    2011-02-28

    Research highlights: {yields} This paper describes a process for the metal removal from treated (CA-, ACQ- or MCQ-) wood wastes. {yields} This sulfuric acid leaching process is simple and economic. {yields} The remediated wood could be recycled in the industry. - Abstract: Chromated copper arsenate (CCA)-treated wood was widely used until 2004 for residential and industrial applications. Since 2004, CCA was replaced by alternative copper preservatives such as alkaline copper quaternary (ACQ), copper azole (CA) and micronized copper quaternary (MCQ), for residential applications due to health concerns. Treated wood waste disposal is becoming an issue. Previous studies identified a chemical process for decontaminating CCA-treated wood waste based on sulfuric acid leaching. The potential application of this process to wood treated with the copper-based preservatives (alkaline copper quaternary (ACQ), copper azole (CA) and micronized copper quaternary (MCQ)) is investigated here. Three consecutive leaching steps with 0.1 M sulfuric acid at 75 deg, C for 2 h were successful for all the types of treated wood and achieved more than 98% copper solubilisation. The different acidic leachates produced were successively treated by coagulation using ferric chloride and precipitation (pH = 7) using sodium hydroxide. Between 94 and 99% of copper in leachates could be recovered by electrodeposition after 90 min using 2 A electrical current. Thus, the process previously developed for CCA-treated wood waste decontamination could be efficiently applied for CA-, ACQ- or MCQ-treated wood.

  7. Electrochemical behaviour of copper in N,N-dimethylformamide + 0.5 M potassium perchlorate solution

    Directory of Open Access Journals (Sweden)

    S. MENTUS

    2000-09-01

    Full Text Available The electrochemical deposition and dissolution of copper in 0.0025 M CuSO4 + N,N-dimethylformamide + 0.5 M KClO4 solution was examined by the rotating disc and potentiodynamic methods. Both platinum and copper were used as working electrodes. A wide polarization range –1 to +2 V vs. SCE, and several temperatures between 25 and 55°C were encompased. The Cu/electrolyte interface was found to be permanently out of equilibrium, as a consequence of the development of a passivating layer. In accordance with the classic theory of a copper electrode in acidified aqueous solutions, the cathodic and anodic Tafel lines of metallic copper define a unique value of the exchange current density, however, their slopes do not correspond to the classic theory.

  8. A novel nanostructured composite formed by interaction of copper octa(3-aminopropyl)octasilsesquioxane with azide ligands: Preparation, characterization and a voltammetric application

    International Nuclear Information System (INIS)

    Ribeiro do Carmo, Devaney; Paim, Leonardo Lataro; Metzker, Gustavo; Dias Filho, Newton Luiz; Stradiotto, Nelson Ramos

    2010-01-01

    This study presents the preparation, characterization and application of copper octa(3-aminopropyl)octasilsesquioxane following its subsequent reaction with azide ions (ASCA). The precursor (AC) and the novel compound (ASCA) were characterized by Fourier transform infrared spectra (FTIR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), scanning electronic microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric analyses and voltammetric technique. The cyclic voltammogram of the modified graphite paste electrode with ASCA (GPE-ASCA), showed one redox couple with formal potential (E 1/2 ox ) = 0.30 V and an irreversible process at 1.1 V (vs. Ag/AgCl; NaCl 1.0 M; v=20mVs -1 ). The material is very sensitive to nitrite concentrations. The modified graphite paste electrode (GPE-ASCA) gives a linear range from 1.0 x 10 -4 to 4.0 x 10 -3 mol L -1 for the determination of nitrite, with a detection limit of 2.1 x 10 -4 mol L -1 and the amperometric sensitivity of 8.04 mA/mol L -1 .

  9. Anodic behaviour of iron electrode in complexing media for a application in coulometric analysis

    International Nuclear Information System (INIS)

    Kostromin, A.I.; Makarova, L.L.

    1977-01-01

    Anodic behaviour is studied of the iron electrode in phosphate solutions (pH 4.88-8.40) in the presence of 0.01 M complexone 3 and in the alcaline environment of triethanolamine with the addition of potassium chloride. The product of anodic dissolution will be iron (2). The d.c. electrogenerated iron (2) was used for the coulometric determination of copper (2), silver (1), VO 2+ , UO 2 2+ in artificial solutions, and also for the determination of silver in motion picture and photographic films of various types

  10. A Porphyrin Complex as a Self-Conditioned Electrode Material for High-Performance Energy Storage.

    Science.gov (United States)

    Gao, Ping; Chen, Zhi; Zhao-Karger, Zhirong; Mueller, Jonathan E; Jung, Christoph; Klyatskaya, Svetlana; Diemant, Thomas; Fuhr, Olaf; Jacob, Timo; Behm, R Jürgen; Ruben, Mario; Fichtner, Maximilian

    2017-08-21

    The novel functionalized porphyrin [5,15-bis(ethynyl)-10,20-diphenylporphinato]copper(II) (CuDEPP) was used as electrodes for rechargeable energy-storage systems with an extraordinary combination of storage capacity, rate capability, and cycling stability. The ability of CuDEPP to serve as an electron donor or acceptor supports various energy-storage applications. Combined with a lithium negative electrode, the CuDEPP electrode exhibited a long cycle life of several thousand cycles and fast charge-discharge rates up to 53 C and a specific energy density of 345 Wh kg -1 at a specific power density of 29 kW kg -1 . Coupled with a graphite cathode, the CuDEPP anode delivered a specific power density of 14 kW kg -1 . Whereas the capacity is in the range of that of ordinary lithium-ion batteries, the CuDEPP electrode has a power density in the range of that of supercapacitors, thus opening a pathway toward new organic electrodes with excellent rate capability and cyclic stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Graphene Transparent Conductive Electrodes for Next- Generation Microshutter Arrays

    Science.gov (United States)

    Li, Mary; Sultana, Mahmooda; Hess, Larry

    2012-01-01

    Graphene is a single atomic layer of graphite. It is optically transparent and has high electron mobility, and thus has great potential to make transparent conductive electrodes. This invention contributes towards the development of graphene transparent conductive electrodes for next-generation microshutter arrays. The original design for the electrodes of the next generation of microshutters uses indium-tin-oxide (ITO) as the electrode material. ITO is widely used in NASA flight missions. The optical transparency of ITO is limited, and the material is brittle. Also, ITO has been getting more expensive in recent years. The objective of the invention is to develop a graphene transparent conductive electrode that will replace ITO. An exfoliation procedure was developed to make graphene out of graphite crystals. In addition, large areas of single-layer graphene were produced using low-pressure chemical vapor deposition (LPCVD) with high optical transparency. A special graphene transport procedure was developed for transferring graphene from copper substrates to arbitrary substrates. The concept is to grow large-size graphene sheets using the LPCVD system through chemical reaction, transfer the graphene film to a substrate, dope graphene to reduce the sheet resistance, and pattern the film to the dimension of the electrodes in the microshutter array. Graphene transparent conductive electrodes are expected to have a transparency of 97.7%. This covers the electromagnetic spectrum from UV to IR. In comparison, ITO electrodes currently used in microshutter arrays have 85% transparency in mid-IR, and suffer from dramatic transparency drop at a wavelength of near-IR or shorter. Thus, graphene also has potential application as transparent conductive electrodes for Schottky photodiodes in the UV region.

  12. Immobilization of [Cu(bpy)2]Br2 complex onto a glassy carbon electrode modified with alpha-SiMo12O40(4-) and single walled carbon nanotubes: application to nanomolar detection of hydrogen peroxide and bromate.

    Science.gov (United States)

    Salimi, Abdollah; Korani, Aazam; Hallaj, Rahman; Khoshnavazi, Roshan; Hadadzadeh, Hasan

    2009-03-02

    A simple procedure has been used for preparation of modified glassy carbon electrode with carbon nanotubes and copper complex. Copper complex [Cu(bpy)(2)]Br(2) was immobilized onto glassy carbon (GC) electrode modified with silicomolybdate, alpha-SiMo(12)O(40)(4-) and single walled carbon nanotubes (SWCNTs). Copper complex and silicomolybdate irreversibly and strongly adsorbed onto GC electrode modified with CNTs. Electrostatic interactions between polyoxometalates (POMs) anions and Cu-complex, cations mentioned as an effective method for fabrication of three-dimensional structures. The modified electrode shows three reversible redox couples for polyoxometalate and one redox couple for Cu-complex at wide range of pH values. The electrochemical behavior, stability and electron transfer kinetics of the adsorbed redox couples were investigated using cyclic voltammetry. Due to electrostatic interaction, copper complex immobilized onto GC/CNTs/alpha-SiMo(12)O(40)(4-) electrode shows more stable voltammetric response compared to GC/CNTs/Cu-complex modified electrode. In comparison to GC/CNTs/Cu-complex the GC/CNTs/alpha-SiMo(12)O(40)(4-) modified electrodes shows excellent electrocatalytic activity toward reduction H(2)O(2) and BrO(3)(-) at more reduced overpotential. The catalytic rate constants for catalytic reduction hydrogen peroxide and bromate were 4.5(+/-0.2)x10(3) M(-1) s(-1) and 3.0(+/-0.10)x10(3) M(-1) s(-1), respectively. The hydrodynamic amperommetry technique at 0.08 V was used for detection of nanomolar concentration of hydrogen peroxide and bromate. Detection limit, sensitivity and linear concentration range proposed sensor for bromate and hydrogen peroxide detection were 1.1 nM and 6.7 nA nM(-1), 10 nM-20 microM, 1 nM, 5.5 nA nM(-1) and 10 nM-18 microM, respectively.

  13. Low-Cost Facile Fabrication of Flexible Transparent Copper Electrodes by Nanosecond Laser Ablation

    KAUST Repository

    Paeng, Dongwoo

    2015-03-27

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Low-cost Cu flexible transparent conducting electrodes (FTCEs) are fabricated by facile nanosecond laser ablation. The fabricated Cu FTCEs show excellent opto-electrical properties (transmittance: 83%, sheet resistance: 17.48 Ω sq-1) with outstanding mechanical durability. Successful demonstration of a touch-screen panel confirms the potential applicability of Cu FTCEs to the flexible optoelectronic devices.

  14. Development of reliable lithium microreference electrodes for long-term in situ studies of lithium-based battery systems

    NARCIS (Netherlands)

    Zhou, J.; Notten, P.H.L.

    2004-01-01

    An in situ method to prepare lithium microreference electrodes has been developed. The microreference electrodes are made by electrochemical deposition of metallic lithium from both the positive and negative electrodes onto a copper wire positioned in-between the two Li-based battery electrodes. The

  15. Electrochemical impedance study of copper in phosphate buffered solution

    International Nuclear Information System (INIS)

    Salimon, J.; Mohamad, M.; Yamin, B.M.; Kalaji, M.

    2003-01-01

    The processes occurring on the copper electrode surface in phosphate buffered solution were investigated using the Electrochemical Impedance Spectroscopy. The electrochemical behaviors of copper through their charge transfer resistance and double-layer capacitance at the onset of the hydrogen evolution region and the anodic passivation layer formation and diffusion of copper species at anodic potential regions are discussed. The specific adsorption of anions (hydroxide and/or H/sub 2/PO/sub 4/) occurred at potential less negative than -0.9V. Adsorbed hydrogen appeared at hydrogen evolution region at potential range of -1.5 to -1.0 V. The deposition of insoluble copper species occurred at anodic potential regions. (author)

  16. Development of a Compact Wireless Laplacian Electrode Module for Electromyograms and Its Human Interface Applications

    Directory of Open Access Journals (Sweden)

    Akira Ichikawa

    2013-02-01

    Full Text Available In this study, we developed a compact wireless Laplacian electrode module for electromyograms (EMGs. One of the advantages of the Laplacian electrode configuration is that EMGs obtained with it are expected to be sensitive to the firing of the muscle directly beneath the measurement site. The performance of the developed electrode module was investigated in two human interface applications: character-input interface and detection of finger movement during finger Braille typing. In the former application, the electrode module was combined with an EMG-mouse click converter circuit. In the latter, four electrode modules were used for detection of finger movements during finger Braille typing. Investigation on the character-input interface indicated that characters could be input stably by contraction of (a the masseter, (b trapezius, (c anterior tibialis and (d flexor carpi ulnaris muscles. This wide applicability is desirable when the interface is applied to persons with physical disabilities because the disability differs one to another. The investigation also demonstrated that the electrode module can work properly without any skin preparation. Finger movement detection experiments showed that each finger movement was more clearly detectable when comparing to EMGs recorded with conventional electrodes, suggesting that the Laplacian electrode module is more suitable for detecting the timing of finger movement during typing. This could be because the Laplacian configuration enables us to record EMGs just beneath the electrode. These results demonstrate the advantages of the Laplacian electrode module.

  17. Investigation on power discharge in micro-EDM stainless steel drilling using different electrodes

    Energy Technology Data Exchange (ETDEWEB)

    D' Urso, G.; Maccarini, G.; Quarto, M.; Ravasio, C. [University of Bergamo, Bergamo (Italy)

    2015-10-15

    The present work deals with the execution of through micro-holes on stainless steel plates using a micro-EDM (Electrical discharge machining) machine. The investigation focuses on the influence of different electrodes' materials and power discharge on both the process performance and the dimensional characteristics of the holes. The experimental campaign was carried out by varying peak current and voltage in order to achieve both high and low power discharge conditions. Tubular electrodes made of three different materials (tungsten carbide, brass and copper) were used. The indexes taken into account were Material removal rate (MRR), Tool wear ratio (TWR), Diametral overcut (DOC) and Taper rate (TR). Brass and copper electrodes always resulted to be the best solution in terms of drilling speed even though the wear of these electrode types is remarkable higher than the tungsten one. On the opposite, tungsten carbide electrodes resulted to be the best solution when high dimensional and geometrical precision is required. Concerning the finishing of the hole inner surface, the best results were achieved using tungsten carbide electrode.

  18. Investigation on power discharge in micro-EDM stainless steel drilling using different electrodes

    International Nuclear Information System (INIS)

    D'Urso, G.; Maccarini, G.; Quarto, M.; Ravasio, C.

    2015-01-01

    The present work deals with the execution of through micro-holes on stainless steel plates using a micro-EDM (Electrical discharge machining) machine. The investigation focuses on the influence of different electrodes' materials and power discharge on both the process performance and the dimensional characteristics of the holes. The experimental campaign was carried out by varying peak current and voltage in order to achieve both high and low power discharge conditions. Tubular electrodes made of three different materials (tungsten carbide, brass and copper) were used. The indexes taken into account were Material removal rate (MRR), Tool wear ratio (TWR), Diametral overcut (DOC) and Taper rate (TR). Brass and copper electrodes always resulted to be the best solution in terms of drilling speed even though the wear of these electrode types is remarkable higher than the tungsten one. On the opposite, tungsten carbide electrodes resulted to be the best solution when high dimensional and geometrical precision is required. Concerning the finishing of the hole inner surface, the best results were achieved using tungsten carbide electrode.

  19. Application of electrochemical impedance spectroscopy to monitor seawater fouling on stainless steels and copper alloys

    International Nuclear Information System (INIS)

    Feron, D.

    1991-01-01

    Electrochemical impedance spectroscopy may be applied to detect and to follow seawater fouling. Experiments have been conducted with natural seawater flowing inside tube-electrodes at temperatures between 30 deg C and 85 deg C. With stainless steel tubes, mineral and organic foulings have been followed; a linear relationship between the dry weight of the organic fouling and its electrical resistance, has been observed. On copper alloy tubes, only mineral deposits have occurred and so have been detected by impedance spectroscopy. (Author). 5 refs., 6 figs

  20. Recent Developments of Nanostructured Electrodes for Bioelectrocatalysis of Dioxygen Reduction

    Directory of Open Access Journals (Sweden)

    Marcin Opallo

    2011-01-01

    Full Text Available The recent development of nanostructured electrodes for bioelectrocatalytic dioxygen reduction catalysed by two copper oxidoreductases, laccase and bilirubin oxidase, is reviewed. Carbon-based nanomaterials as carbon nanotubes or carbon nanoparticles are frequently used for electrode modification, whereas there are only few examples of biocathodes modified with metal or metal oxide nanoparticles. These nanomaterials are adsorbed on the electrode surface or embedded in multicomponent film. The nano-objects deposited act as electron shuttles between the enzyme and the electrode substrate providing favourable conditions for mediatorless bioelectrocatalysis.

  1. Role of electrodes in ambient electrolytic decomposition of hydroxylammonium nitrate (HAN solutions

    Directory of Open Access Journals (Sweden)

    Kai Seng Koh

    2013-09-01

    Full Text Available Decomposition of hydroxylammonium nitrate (HAN solution with electrolytic decomposition method has attracted much attention in recent years due to its efficiencies and practicability. However, the phenomenon has not been well-studied till now. By utilizing mathematical model currently available, the effect of water content and power used for decomposition was studied. Experiment data shows that sacrificial material such as copper or aluminum outperforms inert electrodes in the decomposition of HAN solution. In the case of using copper wire to electrolyse HAN solutions, approximately 10 seconds is required to reach 100 °C regardless of concentration of HAN. In term of power consumption, 100 W–300 W was found to be the range in which decomposition could be triggered effectively using copper wire as electrodes.

  2. The electrochemical impedance of metal hydride electrodes

    DEFF Research Database (Denmark)

    Valøen, Lars Ole; Lasia, Andrzej; Jensen, Jens Oluf

    2002-01-01

    The electrochemical impedance responses for different laboratory type metal hydride electrodes were successfully modeled and fitted to experimental data for AB5 type hydrogen storage alloys as well as one MgNi type electrode. The models fitted the experimental data remarkably well. Several AC......, explaining the experimental impedances in a wide frequency range for electrodes of hydride forming materials mixed with copper powder, were obtained. Both charge transfer and spherical diffusion of hydrogen in the particles are important sub processes that govern the total rate of the electrochemical...... hydrogen absorption/desorption reaction. To approximate the experimental data, equations describing the current distribution in porous electrodes were needed. Indications of one or more parallel reduction/oxidation processes competing with the electrochemical hydrogen absorption/desorption reaction were...

  3. Role of the adsorbed oxygen species in the selective electrochemical reduction of CO_2 to alcohols and carbonyls on copper electrodes

    International Nuclear Information System (INIS)

    Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi

    2017-01-01

    The electrochemical reduction of CO_2 into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO_2 to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO_2 on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO_2 reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. 78 FR 61984 - Copper Valley Electric Association, Inc.; Notice of Application To Amend License and Accepted for...

    Science.gov (United States)

    2013-10-09

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-005] Copper Valley...: Amendment to License. b. Project No: 13124-005. c. Date Filed: September 27, 2013. d. Applicant: Copper..., Copper Valley Electric Association, Inc., P.O. Box 45, Mile 187 Glenn Highway, Glennallen, AK 99588, (907...

  5. DNA-modified electrodes fabricated using copper-free click chemistry for enhanced protein detection.

    Science.gov (United States)

    Furst, Ariel L; Hill, Michael G; Barton, Jacqueline K

    2013-12-31

    A method of DNA monolayer formation has been developed using copper-free click chemistry that yields enhanced surface homogeneity and enables variation in the amount of DNA assembled; extremely low-density DNA monolayers, with as little as 5% of the monolayer being DNA, have been formed. These DNA-modified electrodes (DMEs) were characterized visually, with AFM, and electrochemically, and were found to facilitate DNA-mediated reduction of a distally bound redox probe. These low-density monolayers were found to be more homogeneous than traditional thiol-modified DNA monolayers, with greater helix accessibility through an increased surface area-to-volume ratio. Protein binding efficiency of the transcriptional activator TATA-binding protein (TBP) was also investigated on these surfaces and compared to that on DNA monolayers formed with standard thiol-modified DNA. Our low-density monolayers were found to be extremely sensitive to TBP binding, with a signal decrease in excess of 75% for 150 nM protein. This protein was detectable at 4 nM, on the order of its dissociation constant, with our low-density monolayers. The improved DNA helix accessibility and sensitivity of our low-density DNA monolayers to TBP binding reflects the general utility of this method of DNA monolayer formation for DNA-based electrochemical sensor development.

  6. Mixed complex combinations with a new schiff base used as membranes ion-selective for copper and nickel ions, analytical applications)

    International Nuclear Information System (INIS)

    Mitu, L.; Tigae, C.

    2009-01-01

    Four electrodes with liquid membrane, Cu/sup 2+/ -selective and Ni/sup 2+/ -selective, not previously described in the literature, were prepared and characterized. Electrodes 1 and 2 are based on mixed complexes of Cu(II) and Ni(II) with isonicotinoylhydrazone-2-aldehyde pyrrole (INH2AP= HL/sup 1/) as ligand and electrodes 3 and 4 are based on the mixed complexes with isonicotinoyl- hydrazone-2-hydroxy-l-naphthaldehyde (INH2HNA = H/sub 2/L/sup 2/ ) Cu/sup 2+/. selective and Ni/sup 2+/ -selective electrodes have been used to determine the copper and nickel ions in aqueous solutions, by both direct potentiometric and potentiometric titration with EDTA. They have also been used for determining the Cu/sup 2+/ and Ni/sup 2+/ ions in industrial waters by direct potentiometry. The analytical results obtained have been checked by the standard addition method and by comparison with determinations through atomic absorption spectrometry. (author)

  7. High performance fuel electrodes fabricated by electroless plating of copper on BaZr0.8Ce0.1Y0.1O3-δ proton-conducting ceramic

    Science.gov (United States)

    Patki, Neil S.; Way, J. Douglas; Ricote, Sandrine

    2017-10-01

    The stability of copper at high temperatures in reducing and hydrocarbon-containing atmospheres makes it a good candidate for fabricating fuel electrodes on proton-conducting ceramics, such as BaZr0.9-xCexY0.1O3-δ (BZCY). In this work, the electrochemical performance of Cu-based electrodes fabricated by electroless plating (ELP) on BaZr0.8Ce0.1Y0.1O3-δ is studied with impedance spectroscopy. Three activation catalysts (Pd, Ru, and Cu) are investigated and ELP is compared to a commercial Cu paste (ESL 2312-G) for electrode fabrication. The area specific resistances (ASR) for Pd, Ru, and Cu activations at 700 °C in moist 5% H2 in Ar are 2.1, 3.2, and 13.4 Ω cm2, respectively. That is a 1-2 orders of magnitude improvement over the commercial Cu paste (192 Ω cm2). Furthermore, the ASR has contributions from electrode processes and charge transfer at the electrode/electrolyte interface. Additionally, the morphology of the as-fabricated electrode is unaffected by the activation catalyst. However, heat treatment at 750 °C in H2 for 24 h leads to sintering and large reorganization of the electrode fabricated with Cu activation (micron sized pores seen in the tested sample), while Pd and Ru activations are immune to such reorganization. Thus, Pd and Ru are identified as candidates for future work with improvements to charge transfer required for the former, and better electrode processes required for the latter.

  8. Graphite fiber/copper matrix composites for space power heat pipe fin applications

    International Nuclear Information System (INIS)

    Mcdanels, D.L.; Baker, K.W.; Ellis, D.L.

    1991-01-01

    High specific thermal conductivity (thermal conductivity divided by density) is a major design criterion for minimizing system mass for space power systems. For nuclear source power systems, graphite fiber reinforced copper matrix (Gr/Cu) composites offer good potential as a radiator fin material operating at service temperatures above 500 K. Specific thermal conductivity in the longitudinal direction is better than beryllium and almost twice that of copper. The high specific thermal conductivity of Gr/Cu offers the potential of reducing radiator mass by as much as 30 percent. Gr/Cu composites also offer the designer a range of available properties for various missions and applications. The properties of Gr/Cu are highly anisotropic. Longitudinal elastic modulus is comparable to beryllium and about three times that of copper. Thermal expansion in the longitudinal direction is near zero, while it exceeds that of copper in the transverse direction. 5 refs

  9. Fungal laccase: copper induction, semi-purification, immobilization ...

    African Journals Online (AJOL)

    Fungal laccase: copper induction, semi-purification, immobilization, phenolic effluent treatment and electrochemical measurement. ... In order to apply in an effluent treatment, laccase was immobilized on different vitroceramics supports, pyrolytic graphite and also on a carbon fiber electrode as biosensor. The maximum ...

  10. Solid contact potassium selective electrodes for biomedical applications – a review

    NARCIS (Netherlands)

    van de Velde, Lennart; d'Angremont, E.; Olthuis, Wouter

    2016-01-01

    Ion-selective electrodes (ISE) are used in several biomedical applications, including laboratory sensing of potassium concentration in blood and urine samples. For on-site determination of potassium concentration and usage in other applications such as determination of extracellular potassium

  11. A high efficacy antimicrobial acrylate based hydrogels with incorporated copper for wound healing application

    Energy Technology Data Exchange (ETDEWEB)

    Vuković, Jovana S.; Babić, Marija M.; Antić, Katarina M.; Miljković, Miona G.; Perić-Grujić, Aleksandra A.; Filipović, Jovanka M.; Tomić, Simonida Lj., E-mail: simonida@tmf.bg.ac.rs

    2015-08-15

    In this study, three series of hydrogels based on 2-hydroxyethyl acrylate and itaconic acid, unloaded, with incorporated copper(II) ions and reduced copper, were successfully prepared, characterized and evaluated as novel wound healing materials. Fourier transform infrared spectroscopy (FTIR) confirmed the expected structure of obtained hydrogels. Scanning electron microscopy (SEM) revealed porous morphology of unloaded hydrogels, and the morphological modifications in case of loaded hydrogels. Thermal characteristics were examined by differential scanning calorimetry (DSC) and the glass transition temperatures were observed in range of 12–50 °C. Swelling study was conducted in wide range of pHs at 37 °C, confirming pH sensitive behaviour for all three series of hydrogels. The in vitro copper release was investigated and the experimental data were analysed using several models in order to elucidate the transport mechanism. The antimicrobial assay revealed excellent antimicrobial activity, over 99% against Escherichia coli, Staphylococcus aureus and Candida albicans, as well as good correlation with the copper release experiments. In accordance with potential application, water vapour transmission rate, oxygen penetration, dispersion characteristics, fluid retention were observed and the suitability of the hydrogels for wound healing application was discussed. - Graphical abstract: Display Omitted - Highlights: • Design and evaluation of novel pH responsive hydrogel series. • Structural, morphological, thermal characterization and controlled copper release. • Antibacterial activity against Escherichia coli and Staphylococcus aureus over 99%. • Antifungal activity against Candida albicans over 99%. • In vitro evaluation studies revealed great potential for wound healing application.

  12. Highly crumpled solar reduced graphene oxide electrode for supercapacitor application

    Science.gov (United States)

    Mohanapriya, K.; Ahirrao, Dinesh J.; Jha, Neetu

    2018-04-01

    Highly crumpled solar reduced graphene oxide (CSRGO) was synthesized by simple and rapid method through freezing the solar reduced graphene oxide aqueous suspension using liquid nitrogen and used as electrode material for supercapacitor application. This electrode material was characterized by transmission electron microscope (TEM), X-Ray diffractometer (XRD) and Raman Spectroscopy techniques to understand the morphology and structure. The electrochemical performance was studied by cyclic voltammetry (CV), galvanostatic charge/discharge (CD) and electrochemical impedance spectroscopy (EIS) using 6M KOH electrolyte. The CSRGO exhibit high specifc capacitance of 210.1 F g-1 at the current density of 0.5 A g-1 and shows excellent rate capability. These features make the CSRGO material as promising electrode for high-performance supercapacitors.

  13. Construction of Hierarchical CuO/Cu2O@NiCo2S4 Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes

    Science.gov (United States)

    Zhou, Luoxiao; He, Ying; Jia, Congpu; Pavlinek, Vladimir; Saha, Petr; Cheng, Qilin

    2017-01-01

    Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4) core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2) and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer. PMID:28914819

  14. Construction of Hierarchical CuO/Cu2O@NiCo2S4 Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes

    Directory of Open Access Journals (Sweden)

    Luoxiao Zhou

    2017-09-01

    Full Text Available Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4 core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2 and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer.

  15. Uniformly Distributed Graphene Domain Grows on Standing Copper via Low-Pressure Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Shih-Hao Chan

    2013-01-01

    Full Text Available Uniformly distributed graphene domains were synthesized on standing copper foil by a low-pressure chemical vapor deposition system. This method improved the distribution of the graphene domains at different positions on the same piece of copper foil along the forward direction of the gas flow. Scanning electron microscopy (SEM showed the average size of the graphene domains to be about ~20 m. This results show that the sheet resistance of monolayer graphene on a polyethylene terephthalate (PET substrate is about ~359 /□ whereas that of the four-layer graphene films is about ~178 /□, with a transmittance value of 88.86% at the 550 nm wavelength. Furthermore, the sheet resistance can be reduced with the addition of HNO3 resulting in a value of 84 /□. These values meet the absolute standard for touch sensor applications, so we believe that this method can be a candidate for some transparent conductive electrode applications.

  16. Effect of Post Treatment For Cu-Cr Source/Drain Electrodes on a-IGZO TFTs

    OpenAIRE

    Hu, Shiben; Fang, Zhiqiang; Ning, Honglong; Tao, Ruiqiang; Liu, Xianzhe; Zeng, Yong; Yao, Rihui; Huang, Fuxiang; Li, Zhengcao; Xu, Miao; Wang, Lei; Lan, Linfeng; Peng, Junbiao

    2016-01-01

    We report a high-performance amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with new copper-chromium (Cu-Cr) alloy source/drain electrodes. The TFT shows a high mobility of 39.4 cm 2 ?V ? 1 ?s ? 1 a turn-on voltage of ?0.8 V and a low subthreshold swing of 0.47 V/decade. Cu diffusion is suppressed because pre-annealing can protect a-IGZO from damage during the electrode sputtering and reduce the copper diffusion paths by making film denser. Due to the interaction of C...

  17. Electrode systems for in situ vitrification

    Science.gov (United States)

    Buelt, James L.; Carter, John G.; Eschbach, Eugene A.; FitzPatrick, Vincent F.; Koehmstedt, Paul L.; Morgan, William C.; Oma, Kenton H.; Timmerman, Craig L.

    1990-01-01

    An electrode comprising a molybdenum rod is received within a conductive collar formed of graphite. The molybdenum rod and the graphite collar may be physically joined at the bottom. A pair of such electrodes are placed in soil containing buried waste material and an electric current is passed therebetween for vitrifying the soil. The graphite collar enhances the thermal conductivity of the combination, bringing heat to the surface, and preventing formation of a cold cap of material above the ground surface. The annulus between the molybdenum rod electrode and the graphite collar is suitably filled with a conductive ceramic powder that sinters upon the molybdenum rod, protecting the same from oxidation as graphite material is consumed, or a metal powder which liquefies at operating temperatures. The center of the molybdenum rod, used with a collar of separately, can be hollow and filled with a powdered metal, such as copper, which liquefies at operating temperatures. Connection to electrodes can be provided below ground level to avoid open circuit due to electrode deterioration, or sacrificial electrodes may be employed when operation is started. Outboard electrodes cna be utilized to square up a vitrified area.

  18. Fabrication of free-standing copper foils covered with highly-ordered copper nanowire arrays

    Science.gov (United States)

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

    2012-07-01

    The through-hole nanoporous anodic aluminum oxide (AAO) membranes with relatively large surface area (ca. 2 cm2) were employed for fabrication of free-standing and mechanically stable copper foils covered with close-packed and highly-ordered copper nanowire arrays. The home-made AAO membranes with different pore diameters and interpore distances were fabricated via a two-step self-organized anodization of aluminum performed in sulfuric acid, oxalic acid and phosphoric acid followed by the pore opening/widening procedure. The direct current (DC) electrodeposition of copper was performed efficiently on both sides of AAO templates. The bottom side of the AAO templates was not insulated and consequently Cu nanowire arrays on thick Cu layers were obtained. The proposed template-assisted fabrication of free-standing copper nanowire array electrodes is a promising method for synthesis of nanostructured current collectors. The composition of Cu nanowires was confirmed by energy dispersive X-Ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The structural features of nanowires were evaluated from field emission scanning electron microscopy (FE-SEM) images and compared with the characteristic parameters of anodic alumina membranes.

  19. Fabrication of free-standing copper foils covered with highly-ordered copper nanowire arrays

    International Nuclear Information System (INIS)

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

    2012-01-01

    The through-hole nanoporous anodic aluminum oxide (AAO) membranes with relatively large surface area (ca. 2 cm 2 ) were employed for fabrication of free-standing and mechanically stable copper foils covered with close-packed and highly-ordered copper nanowire arrays. The home-made AAO membranes with different pore diameters and interpore distances were fabricated via a two-step self-organized anodization of aluminum performed in sulfuric acid, oxalic acid and phosphoric acid followed by the pore opening/widening procedure. The direct current (DC) electrodeposition of copper was performed efficiently on both sides of AAO templates. The bottom side of the AAO templates was not insulated and consequently Cu nanowire arrays on thick Cu layers were obtained. The proposed template-assisted fabrication of free-standing copper nanowire array electrodes is a promising method for synthesis of nanostructured current collectors. The composition of Cu nanowires was confirmed by energy dispersive X-Ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The structural features of nanowires were evaluated from field emission scanning electron microscopy (FE-SEM) images and compared with the characteristic parameters of anodic alumina membranes.

  20. Printable Electrochemical Biosensors: A Focus on Screen-Printed Electrodes and Their Application

    Directory of Open Access Journals (Sweden)

    Keiichiro Yamanaka

    2016-10-01

    Full Text Available In this review we present electrochemical biosensor developments, focusing on screen-printed electrodes (SPEs and their applications. In particular, we discuss how SPEs enable simple integration, and the portability needed for on-field applications. First, we briefly discuss the general concept of biosensors and quickly move on to electrochemical biosensors. Drawing from research undertaken in this area, we cover the development of electrochemical DNA biosensors in great detail. Through specific examples, we describe the fabrication and surface modification of printed electrodes for sensitive and selective detection of targeted DNA sequences, as well as integration with reverse transcription-polymerase chain reaction (RT-PCR. For a more rounded approach, we also touch on electrochemical immunosensors and enzyme-based biosensors. Last, we present some electrochemical devices specifically developed for use with SPEs, including USB-powered compact mini potentiostat. The coupling demonstrates the practical use of printable electrode technologies for application at point-of-use. Although tremendous advances have indeed been made in this area, a few challenges remain. One of the main challenges is application of these technologies for on-field analysis, which involves complicated sample matrices.

  1. Exploiting Stretchable Metallic Springs as Compliant Electrodes for Cylindrical Dielectric Elastomer Actuators (DEAs

    Directory of Open Access Journals (Sweden)

    Chien-Hao Liu

    2017-11-01

    Full Text Available In recent years, dielectric elastomer actuators (DEAs have been widely used in soft robots and artificial bio-medical applications. Most DEAs are composed of a thin dielectric elastomer layer sandwiched between two compliant electrodes. DEAs vary in their design to provide bending, torsional, and stretch/contraction motions under the application of high external voltages. Most compliant electrodes are made of carbon powders or thin metallic films. In situations involving large deformations or improper fabrication, the electrodes are susceptible to breakage and increased resistivity. The worst cases result in a loss of conductivity and functional failure. In this study, we developed a method by which to exploit stretchable metallic springs as compliant electrodes for cylindrical DEAs. This design was inspired by the extensibility of mechanical springs. The main advantage of this approach is the fact that the metallic spring-like compliant electrodes remain conductive and do not increase the stiffness as the tube-like DEAs elongate in the axial direction. This can be attributed to a reduction in thickness in the radial direction. The proposed cylindrical structure is composed of highly-stretchable VHB 4905 film folded within a hollow tube and then sandwiched between copper springs (inside and outside to allow for stretching and contraction in the axial direction under the application of high DC voltages. We fabricated a prototype and evaluated the mechanical and electromechanical properties of the device experimentally using a high-voltage source of 9.9 kV. This device demonstrated a non-linear increase in axial stretching with an increase in applied voltage, reaching a maximum extension of 0.63 mm (axial strain of 2.35% at applied voltage of 9.9 kV. Further miniaturization and the incorporation of compressive springs are expected to allow the implementation of the proposed method in soft micro-robots and bio-mimetic applications.

  2. Polyethylenedioxythiophene and molybdenum disulfide nanocomposite electrodes for supercapacitor applications

    International Nuclear Information System (INIS)

    Alamro, Turki; Ram, Manoj K.

    2017-01-01

    Highlights: • MoS_2-PEDOT nanocomposite electrode material was synthesized using polyanion ‘PSS’ and surfactant CTAB in an aqueous media. • The supercapacitor based on composite MoS_2-PEDOT electrode revealed higher energy density than graphene composite electrodes. • The specific capacitance of 361 Farad/gram (F/g) was obtained for 1:2 weight ratio of MoS2 to the EDOT monomer in MoS_2-PEDOT nanocomposite based electrodes. - Abstract: An innovative nanocomposite electrode was chemically synthesized using molybdenum disulphide (MoS_2)- polyethylenedioxythiophene (PEDOT) to understand the charge mechanism in a symmetric supercapacitor. The MoS_2-PEDOT nanocomposite was produced at various ratios of MoS_2 to ethylenedioxythiophene (EDOT) in an aqueous medium of polyanions polystyrene sulfonate (PSS) and cetyltrimethylammonium bromide (CTAB) at controlled conditions. The morphology, crystallinity, and optical properties of MoS_2-PEDOT nanocomposite materials were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, particle size analyzer, Raman spectroscopy, X-ray-diffraction, and transmission electron microscopy (TEM) techniques, respectively. The electrochemical properties of the supercapacitor were investigated using cyclic voltammetry, charging–discharging at constant current and electrochemical impedance spectroscopy (EIS) techniques. The specific capacitance, power and energy densities of the supercapacitor were estimated using cyclic voltammetry (CV), charging–discharging, Nyquist and Bode plots. The specific capacitance was estimated to be 361 Farad/gram (F/g) for the 1:2 weight ratio of MoS_2 to the EDOT monomer in the MoS_2-PEDOT nanocomposite based electrodes. Nevertheless, this study provides a fundamental aspect of synthesis of nanocomposite material for optimum attainment supercapacitive properties based on the MoS_2-PEDOT nanocomposite electrode for practical energy storage applications.

  3. Silver-Copper Nanoalloy Catalyst Layer for Bifunctional Air Electrodes in Alkaline Media.

    Science.gov (United States)

    Wu, Xiaoqiang; Chen, Fuyi; Jin, Yachao; Zhang, Nan; Johnston, Roy L

    2015-08-19

    A carbon-free and binder-free catalyst layer composed of a Ag-Cu nanoalloy on Ni foam was used as the air cathode in a zinc-air battery for the first time. The Ag-Cu catalyst was prepared using pulsed laser deposition. The structures of the catalysts were found to consist of crystalline Ag-Cu nanoalloy particles with an average size of 2.58 nm embedded in amorphous Cu films. As observed in the X-ray photoelectron spectra, the Ag 3d core levels shifted to higher binding energies, whereas the Cu 2p core levels shifted to lower binding energies, indicating alloying of the silver and copper. Rotating disk electrode measurements indicated that the oxygen reduction reaction (ORR) proceeded through a four-electron pathway on the Ag50Cu50 and Ag90Cu10 nanoalloy catalysts in alkaline solution. Moreover, the catalytic activity of Ag50Cu50 in the ORR is more efficient than that of Ag90Cu10. By performing charge and discharge cycling measurements, the Ag50Cu50 catalyst layer was confirmed to have a maximum power density of approximately 86.3 mW cm(-2) and an acceptable cell voltage at 0.863 V for current densities up to 100 mA cm(-2) in primary zinc-air batteries. In addition, a round-trip efficiency of approximately 50% at a current density of 20 mA cm(-2) was also obtained in the test.

  4. Role of the adsorbed oxygen species in the selective electrochemical reduction of CO{sub 2} to alcohols and carbonyls on copper electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi [School of Chemistry, University of Birmingham, Edgbaston (United Kingdom)

    2017-10-09

    The electrochemical reduction of CO{sub 2} into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO{sub 2} to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO{sub 2} on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO{sub 2} reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Metallization of cyanide-modified Pt(111) electrodes with copper

    DEFF Research Database (Denmark)

    Escribano, Maria Escudero; Wildi, Christopher; Mwanda, Jonathan A.

    2016-01-01

    -cyanide-copper sandwich configuration. STM also shows that the Cu deposit consists of isolated bidimensional nanoislands, which slowly grow through an Ostwald ripening mechanism if the potential is kept negative of the reduction peak. Metallization is not possible in perchloric acid solutions, which implies...

  6. Application of copper to prevent and control infection. Where are we now?

    LENUS (Irish Health Repository)

    O'Gorman, J

    2012-08-01

    The antimicrobial effect of copper has long been recognized and has a potential application in the healthcare setting as a mechanism to reduce environmental contamination and thus prevent healthcare-associated infection (HCAI).

  7. GEMs with Double Layred Micropattern Electrodes and their Applications

    CERN Document Server

    Di Mauro, A.; Nappi, E.; Oliveira, R.; Peskov, V.; Pietropaolo, F.; Picchi, P.

    We have developed and tested several new designs of GEM detectors with micropattern electrodes manufactured by microelectronic technology. In one design, the inner layer of the detector electrode consists of thin metallic strips and the outer layer is made of a resistive grid manufactured by a screen printing technology. In other designs, the electrodes were made of metallic strips fed by HV via micro-resistors manufactured by a screen printing technology. Due to these features, the new detectors have several important advantages over conventional GEMs or ordinary thick GEMs. For example, the resistive grid (in the first design) and the screen printed resistors (in other designs) limited the current in case of discharges, making these detectors intrinsically spark-protected. We will here describe our tests with the photosensitive versions of these detectors (coated with CsI layers) and the efforts of implementing them in several applications. In particular, we will focus on our activity towards the ALICE RICH...

  8. Application of adsorptive stripping voltammetry to the simultaneous determination of bismuth and copper in the presence of nuclear fast red

    International Nuclear Information System (INIS)

    Gholivand, M.B.; Romiani, A.A.

    2006-01-01

    A sensitive and selective method for the simultaneous determination of copper and bismuth by adsorptive stripping was developed using nuclear fast red (2-anthracenesulfonic acid, 4-amino-9,10-dihydro-1,3-dihydroxy-9,10-dioxo-, monosodium salt) as selective complexing agent onto hanging mercury drop electrode. In a single scan both metals gave peaks that were distinctly separated by 85 mV allowing their determination in the presence of each other. Optimal analytical conditions were found to be: nuclear fast red concentration of 80 μM, pH of 2.8 and adsorptive potential of -300 mV versus Ag/AgCl. With accumulation time of 180 s the peaks currents are proportional to concentration of copper and bismuth over the 1-100 and 5-60 ng mL -1 range with detection limits of 0.2 and 1.2 ng mL -1 , respectively. The procedure was applied to simultaneous determination of copper and bismuth in some real samples

  9. All-Carbon Electrode Consisting of Carbon Nanotubes on Graphite Foil for Flexible Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Je-Hwang Ryu

    2014-03-01

    Full Text Available We demonstrate the fabrication of an all-carbon electrode by plasma-enhanced chemical vapor deposition for use in flexible electrochemical applications. The electrode is composed of vertically aligned carbon nanotubes that are grown directly on a flexible graphite foil. Being all-carbon, the simple fabrication process and the excellent electrochemical characteristics present an approach through which high-performance, highly-stable and cost-effective electrochemical applications can be achieved.

  10. Study of the influence of surface-active substances on the initial stage of copper electrodeposition

    Directory of Open Access Journals (Sweden)

    Amantay Dalbanbay

    2017-12-01

    Full Text Available In this research, the effect of surface-active substances (CMC and DFP on the electrolysis of copper by cyclic voltammetry (CVA and chronoamperometric methods was studied. The working electrode was a glassy carbon electrode. Studies show that in the acid solution of copper sulfate (10-2 M CuSO4 + 0.5 M H2SO4, the three-dimensional electrochemical deposition of copper occurs by the mechanism of instantaneous nucleation. The added surface active substances affect the dischargeionization process, the standard electroreduction potential is shifted to the negative side. The added DFP reduces the cathodic peak current, and the addition of CMC results in its increase. At the deposition potentials corresponding to the regions up to the CVA peak current (here, still, the mixed electrodeposition kinetics, the number of nuclei formed is greater for a pure solution, but at current decay potentials, where the diffusion regime takes place, the nuclei population density (NPD is higher for solutions with surfactants. The most powerful effect here is caused by the addition of DFP. In the case of mixed additives, the NPD values are close to those of the CMC, obviously indicating the preferential adsorption of CMC, whereas the DFP as complexes with copper ions is closer to the near-electrode region.

  11. Galvanic corrosion of copper-cast iron couples

    International Nuclear Information System (INIS)

    Smart, N.R.; Rance, A.P.; Fennell, P.A.H.

    2005-01-01

    To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Cast Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water would enter the annulus between the inner and outer canister and at points of contact between the two metals there would be the possibility of galvanic interactions. Although this subject has been considered previously from both a theoretical standpoint and by experimental investigations there was a need for further experimental studies in support of information provided by SKB to the Swedish regulators (SKI). In the work reported here copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial porewaters at 30 deg C and 50 deg C, under aerated and deaerated conditions. Tests were also carried out in a 30 wt% bentonite slurry made up in artificial groundwater. The potential of the couples and the currents passing between the coupled electrodes were monitored for several months. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was investigated. In addition, some crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg C, galvanic corrosion rates as low as 0.02 μm/year for iron were observed after deaeration, but

  12. Electropolymerization of poly (aniline-co-o-anisidine) on copper and its anticorrosion properties

    International Nuclear Information System (INIS)

    Ozyilmaz, A T

    2008-01-01

    Poly(aniline-co-o-anisidine) of copolymer coatings was synthesized on the copper surface (Cu) with two different amounts of p-toluenesulfonic acid (p-TSA) added to the aqueous sodium oxalate (NaOX) solution. The copper substrates in NaOX solutions containing p-TSA acid had a fairly reliable passive surface mainly due to the formation of copper (II) oxalate layer. The addition of p-TSA acid to the working electrolyte contributed to both the amount of copolymer deposition (growth) and that of copolymer coated per unit time of electropolymerization (growth rate). The growth of copolymer coating on Cu electrode was characterized by scanning electron microscopy. The corrosion performances of copolymer coatings were investigated in 3.5% NaCl solution with anodic polarization curves and electrochemical impedance spectroscopy. The results showed that p-TSA acid led to the diminishing of the permeability of the copolymer films. The copolymer coatings exhibited an effective barrier property on copper electrode and a remarkable anodic protection to substrate for longer exposure time

  13. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    International Nuclear Information System (INIS)

    Ranganathan, S.; Easton, E.B.

    2009-01-01

    Sol-gel chemistry is becoming more popular for the synthesis of electrode materials. For example, the sol-gel reaction can be performed in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together via the ceramic binder, which can also promote ion transport. Furthermore, the CCE structure has a high active surface area and is chemical and thermally robust. We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments (cyclic voltammetry, electrochemical impedance spectroscopy) were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. Our initial results have shown that CCE-based electrodes vastly outperform a bare carbon electrode, and thus are highly promising and cost-effective electrode material. Subsequent experiments involved the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements will be presented. (author)

  14. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S.; Easton, E.B. [Faculty of Science, Univ. of Ontario Inst. of Technology, Oshawa, Ontario (Canada)], E-mail: ranga@uoit.ca, Brad.Easton@uoit.ca

    2009-07-01

    Sol-gel chemistry is becoming more popular for the synthesis of electrode materials. For example, the sol-gel reaction can be performed in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together via the ceramic binder, which can also promote ion transport. Furthermore, the CCE structure has a high active surface area and is chemical and thermally robust. We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments (cyclic voltammetry, electrochemical impedance spectroscopy) were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. Our initial results have shown that CCE-based electrodes vastly outperform a bare carbon electrode, and thus are highly promising and cost-effective electrode material. Subsequent experiments involved the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements will be presented. (author)

  15. Silicon/copper dome-patterned electrodes for high-performance hybrid supercapacitors

    Science.gov (United States)

    Liu, Xuyan; Jung, Hun-Gi; Kim, Sang-Ok; Choi, Ho-Suk; Lee, Sangwha; Moon, Jun Hyuk; Lee, Joong Kee

    2013-12-01

    This study proposes a method for manufacturing high-performance electrode materials in which controlling the shape of the current collector and electrode material for a Li-ion capacitor (LIC). In particular, the proposed LIC manufacturing method maintains the high voltage of a cell by using a microdome-patterned electrode material, allowing for reversible reactions between the Li-ion and the active material for an extended period of time. As a result, the LICs exhibit initial capacities of approximately 42 F g-1, even at 60 A g-1. The LICs also exhibit good cycle performance up to approximately 15,000 cycles. In addition, these advancements allow for a considerably higher energy density than other existing capacitor systems. The energy density of the proposed LICs is approximately nine, two, and 1.5 times higher than those of the electrochemical double layer capacitor (EDLC), AC/LiMn2O4 hybrid capacitor, and intrinsic Si/AC LIC, respectively.

  16. New Three-Dimensional Porous Electrode Concept: Vertically-Aligned Carbon Nanotubes Directly Grown on Embroidered Copper Structures.

    Science.gov (United States)

    Aguiló-Aguayo, Noemí; Amade, Roger; Hussain, Shahzad; Bertran, Enric; Bechtold, Thomas

    2017-12-11

    New three-dimensional (3D) porous electrode concepts are required to overcome limitations in Li-ion batteries in terms of morphology (e.g., shapes, dimensions), mechanical stability (e.g., flexibility, high electroactive mass loadings), and electrochemical performance (e.g., low volumetric energy densities and rate capabilities). Here a new electrode concept is introduced based on the direct growth of vertically-aligned carbon nanotubes (VA-CNTs) on embroidered Cu current collectors. The direct growth of VA-CNTs was achieved by plasma-enhanced chemical vapor deposition (PECVD), and there was no application of any post-treatment or cleaning procedure. The electrochemical behavior of the as-grown VA-CNTs was analyzed by charge/discharge cycles at different specific currents and with electrochemical impedance spectroscopy (EIS) measurements. The results were compared with values found in the literature. The as-grown VA-CNTs exhibit higher specific capacities than graphite and pristine VA-CNTs found in the literature. This together with the possibilities that the Cu embroidered structures offer in terms of specific surface area, total surface area, and designs provide a breakthrough in new 3D electrode concepts.

  17. Approaching the theoretical capacitance of graphene through copper foam integrated three-dimensional graphene networks

    DEFF Research Database (Denmark)

    Dey, Ramendra Sundar; Hjuler, Hans Aage; Chi, Qijin

    2015-01-01

    We report a facile and low-cost approach for the preparation of all-in-one supercapacitor electrodes using copper foam (CuF) integrated three-dimensional (3D) reduced graphene oxide (rGO) networks. The binderfree 3DrGO@CuF electrodes are capable of delivering high specific capacitance approaching...

  18. Ceramic component for M.H.D electrode

    International Nuclear Information System (INIS)

    Marchant, D.D.; Bates, J.L.

    1980-01-01

    A ceramic component which exhibits electrical conductivity down to near room temperatures has the formula: Hfsub(x)Insub(y)Asub(z)O 2 where x = 0.1 to 0.4, y = 0.3 to 0.6, z = 0.1 to 0.4 and A is a rare earth or yttrium. The rare earth may be Yb, Tb, Pr or Ce. The component is suitable for use in the fabrication of MHD electrodes or as the current lead-out portion of a composite electrode with other ceramic components. An MHD electrode comprises a cap of a known ceramic, e.g. stabilised zirconium or hafnium oxide or terbium stabilised hafnium, a current lead-out ceramic according to the invention, and a copper frame. (author)

  19. Electrochemical stripping determination of traces of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide

    International Nuclear Information System (INIS)

    Stulik, K.; Beran, P.; Dolezal, J.; Opekar, F.

    1978-01-01

    Procedures have been developed for the determination of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide, at concentrations of 1ppm or less. Zirconium metal was dissolved in sulphuric acid, and zirconium dioxide decomposed under pressure with hydrofluoric acid. Sample solutions were prepared in dilute sulphuric acid. For the stripping determination, the sample solution was either mixed with a complexing tartrate base electrolyte or the pre-electrolysis was carried out in acid solution, with the acid solution being exchanged for a pure base electrolyte (e.g. an acetate buffer) for the stripping step. The stripping step was monitored by d.c., differential pulse and Kalousek commutator voltammetry and the three methods were compared. A stationary mercury-drop electrode can generally be used for all the methods, whereas a mercury-film electrode is suitable only for the d.c. voltammetric determination of copper, lead and cadmium, as pulse measurements with films are poorly reproducible and the electrodes are easily damaged. The relative standard deviation does not exceed 20%. Some samples contained relatively large amounts of copper, which is best separated by electrodeposition on a platinum electrode. (author)

  20. Improved field emission performance of carbon nanotube by introducing copper metallic particles

    Directory of Open Access Journals (Sweden)

    Chen Yiren

    2011-01-01

    Full Text Available Abstract To improve the field emission performance of carbon nanotubes (CNTs, a simple and low-cost method was adopted in this article. We introduced copper particles for decorating the CNTs so as to form copper particle-CNT composites. The composites were fabricated by electrophoretic deposition technique which produced copper metallic particles localized on the outer wall of CNTs and deposited them onto indium tin oxide (ITO electrode. The results showed that the conductivity increased from 10-5 to 4 × 10-5 S while the turn-on field was reduced from 3.4 to 2.2 V/μm. Moreover, the field emission current tended to be undiminished after continuous emission for 24 h. The reasons were summarized that introducing copper metallic particles to decorate CNTs could increase the surface roughness of the CNTs which was beneficial to field emission, restrain field emission current from saturating when the applied electric field was above the critical field. In addition, it could also improve the electrical contact by increasing the contact area between CNT and ITO electrode that was beneficial to the electron transport and avoided instable electron emission caused by thermal injury of CNTs.

  1. Copper chelators: chemical properties and bio-medical applications.

    Science.gov (United States)

    Tegoni, M; Valensin, D; Toso, L; Remelli, M

    2014-01-01

    Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined.

  2. Thermal Stability of Nanocrystalline Copper for Potential Use in Printed Wiring Board Applications

    Science.gov (United States)

    Woo, Patrick Kai Fai

    Copper is a widely used conductor in the manufacture of printed wiring boards (PWB). The trends in miniaturization of electronic devices create increasing challenges to all electronic industries. In particular PWB manufacturers face great challenges because the increasing demands in greater performance and device miniaturization pose enormous difficulties in manufacturing and product reliability. Nanocrystalline and ultra-fine grain copper can potentially offer increased reliability and functionality of the PWB due to the increases in strength and achievable wiring density by reduction in grain size. The first part of this thesis is concerned with the synthesis and characterization of nanocrystalline and ultra-fine grain-sized copper for potential applications in the PWB industry. Nanocrystalline copper with different amounts of sulfur impurities (25-230ppm) and grain sizes (31-49nm) were produced and their hardness, electrical resistivity and etchability were determined. To study the thermal stability of nanocrystalline copper, differential scanning calorimetry and isothermal heat treatments combined with electron microscopy techniques for microstructural analysis were used. Differential scanning calorimetry was chosen to continuously monitor the grain growth process in the temperature range from 40?C to 400?C. During isothermal annealing experiments samples were annealed at 23?C, 100?C and 300?C to study various potential thermal issues for these materials in PWB applications such as the long-term room temperature thermal stability as well as for temperature excursions above the operation temperature and peak temperature exposure during the PWB manufacturing process. From all annealing experiments the various grain growth events and the overall stability of these materials were analyzed in terms of driving and dragging forces. Experimental evidence is presented which shows that the overall thermal stability, grain boundary character and texture evolution of

  3. Copper Leaching from Copper-ethanolamine Treated Wood: Comparison of Field Test Studies and Laboratory Standard Procedures

    OpenAIRE

    Nejc Thaler; Miha Humar

    2014-01-01

    Copper-based compounds are some of the most important biocides for the protection of wood in heavy duty applications. In the past, copper was combined with chromium compounds to reduce copper leaching, but a recent generation of copper-based preservatives uses ethanolamine as a fixative. To elucidate the leaching of copper biocides from wood, Norway spruce (Picea abies) wood was treated with a commercial copper-ethanolamine solution with two different copper concentrations (cCu = 0.125% and 0...

  4. Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract

    Science.gov (United States)

    DeAlba-Montero, I.; Morales-Sánchez, Elpidio; Araujo-Martínez, Rene

    2017-01-01

    This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used. PMID:28286459

  5. Influence of Gate Dielectrics, Electrodes and Channel Width on OFET Characteristics

    International Nuclear Information System (INIS)

    Liyana, V P; Stephania, A M; Shiju, K; Predeep, P

    2015-01-01

    Organic Field Effect Transistors (OFET) possess wide applications in large area electronics owing to their attractive features like easy fabrication process, light weight, flexibility, cost effectiveness etc. But instability, high operational voltages and low carrier mobility act as inhibitors to commercialization of OFETs and various approaches were tried on a regular basis so as to make it viable. In this work, Poly 3-hexylthiophene-2,5diyl (P3HT) based OFETs with bottom-contact top-gate configuration using Poly vinyl alcohol (PVA) and Poly (methyl methacrylate) (PMMA) as gate dielectrics, aluminium and copper as source-drain electrodes are investigated. An effort is made to compare the effect of these dielectric materials and electrodes on the performance of OFET. Also, an attempt has been made to optimize the channel width of the device. These devices are characterised with mobility (μ), threshold voltage (V T ), on-off ratio (I on /I off ) and their comparative analysis is reported. (paper)

  6. Influence of Gate Dielectrics, Electrodes and Channel Width on OFET Characteristics

    Science.gov (United States)

    Liyana, V. P.; Stephania, A. M.; Shiju, K.; Predeep, P.

    2015-06-01

    Organic Field Effect Transistors (OFET) possess wide applications in large area electronics owing to their attractive features like easy fabrication process, light weight, flexibility, cost effectiveness etc. But instability, high operational voltages and low carrier mobility act as inhibitors to commercialization of OFETs and various approaches were tried on a regular basis so as to make it viable. In this work, Poly 3-hexylthiophene-2,5diyl (P3HT) based OFETs with bottom-contact top-gate configuration using Poly vinyl alcohol (PVA) and Poly (methyl methacrylate) (PMMA) as gate dielectrics, aluminium and copper as source-drain electrodes are investigated. An effort is made to compare the effect of these dielectric materials and electrodes on the performance of OFET. Also, an attempt has been made to optimize the channel width of the device. These devices are characterised with mobility (μ), threshold voltage (VT), on-off ratio (Ion/Ioff) and their comparative analysis is reported.

  7. Suspension Flame Spray Construction of Polyimide-Copper Layers for Marine Antifouling Applications

    Science.gov (United States)

    Liu, Yi; Xu, Xiaomin; Suo, Xinkun; Gong, Yongfeng; Li, Hua

    2018-01-01

    Individual capsule-like polyimide splats have been fabricated by suspension flame spray, and the polyimide splat exhibits hollow structure with an inner pore and a tiny hole on its top surface. Enwrapping of 200-1000-nm copper particles inside the splats is accomplished during the deposition for constrained release of copper for antifouling performances. Antifouling testing of the coatings by 24-h exposure to Escherichia coli-containing artificial seawater shows that the Cu-doped splat already prohibits effectively attachment of the bacteria. The prohibited adhesion of bacteria obviously impedes formation and further development of bacterial biofilm. This capsulated splat with releasing and loading of copper biocides results in dual-functional structures bearing both release-killing and contact-killing mechanisms. The suspension flame spray route and the encapsulated structure of the polyimide-Cu coatings would open a new window for designing and constructing marine antifouling layers for long-term applications.

  8. Effect of Post Treatment For Cu-Cr Source/Drain Electrodes on a-IGZO TFTs.

    Science.gov (United States)

    Hu, Shiben; Fang, Zhiqiang; Ning, Honglong; Tao, Ruiqiang; Liu, Xianzhe; Zeng, Yong; Yao, Rihui; Huang, Fuxiang; Li, Zhengcao; Xu, Miao; Wang, Lei; Lan, Linfeng; Peng, Junbiao

    2016-07-27

    We report a high-performance amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with new copper-chromium (Cu-Cr) alloy source/drain electrodes. The TFT shows a high mobility of 39.4 cm 2 ·V - 1 ·s - 1 a turn-on voltage of -0.8 V and a low subthreshold swing of 0.47 V/decade. Cu diffusion is suppressed because pre-annealing can protect a-IGZO from damage during the electrode sputtering and reduce the copper diffusion paths by making film denser. Due to the interaction of Cr with a-IGZO, the carrier concentration of a-IGZO, which is responsible for high mobility, rises.

  9. Scanning electrochemical microscopy for the fabrication of copper nanowires: Atomic contacts with quantized conductance, and molecular adsorption effect

    International Nuclear Information System (INIS)

    Janin, Marion; Ghilane, Jalal; Lacroix, Jean-Christophe

    2012-01-01

    Highlights: ► Electrochemistry and SECM to generate copper nanowires with quantized conductance. ► Stable atomic contacts lasting for several hundreds of seconds have been obtained. ► The quantized conductances are independent of the tip and gap size. ► The method allows contacts to be generated in the presence of chosen molecules. ► Four-electrode configuration opens the route to redox gated atomic contact. - Abstract: Scanning electrochemical microscopy, SECM, is proposed as a tool for the fabrication of copper nanowires. In a first step, configuration based on two electrodes, a platinum UME (cathode) and a copper substrate (anode), operating in the SECM configuration was employed. For nanowires generated in water the conductance changes stepwise and varies by integer values of the conductance quantum G 0 . The formation of atomic contacts is supported by the ohmic behavior of the I–V curve. It depends neither on the UME tip radius nor on the initial gap size between tip and substrate. Atomic contacts generated in aqueous solutions of sodium dodecyl sulfate (SDS) below the critical micellar concentration (CMC) have conductances below 1G 0 attributed to molecular adsorption on the contact. In some cases, the nanowires have low conductance, 0.01G 0 . The corresponding I–V curve shows tunneling rather than ohmic behavior, suggesting that molecular junctions are formed with a few surfactant molecules trapped between the two electrodes. Finally, copper nanowires with quantized conductance have been generated using the SECM operating in a four-electrode setup. Thanks to the reference electrode, this configuration leads to better control of the potential of each working electrode; this setup will make it possible to evaluate the conductance variation and/or modulation upon electrochemical stimuli.

  10. Ion-selective electrode reviews

    CERN Document Server

    Thomas, J D R

    1985-01-01

    Ion-Selective Electrode Reviews, Volume 7 is a collection of papers that covers the applications of electrochemical sensors, along with the versatility of ion-selective electrodes. The coverage of the text includes solid contact in membrane ion-selective electrodes; immobilized enzyme probes for determining inhibitors; potentiometric titrations based on ion-pair formation; and application of ion-selective electrodes in soil science, kinetics, and kinetic analysis. The text will be of great use to chemists and chemical engineers.

  11. Neutron activation analysis with a deuteron accelerator. Application to the determination of copper in a Cu-Sn mixture

    International Nuclear Information System (INIS)

    Kodia, A.A.

    1976-01-01

    Neutron activation analysis allows a rapid determination of trace elements. It has many applications in vegetal biology, agronomy, animal biology, medicine and industry. This report presents the different devices used (deuteron accelerator, 3 H-Ti/Zr target, NaI(Tl) scintillation counter, Li-drifted Ge detector), the theory of the method and an application to the determination of copper in a copper-mixture [fr

  12. Mechanical properties and microstructure of copper alloys and copper alloy-stainless steel laminates for fusion reactor high heat flux applications

    Science.gov (United States)

    Leedy, Kevin Daniel

    A select group of copper alloys and bonded copper alloy-stainless steel panels are under consideration for heat sink applications in first wall and divertor structures of a planned thermonuclear fusion reactor. Because these materials must retain high strengths and withstand high heat fluxes, their material properties and microstructures must be well understood. Candidate copper alloys include precipitate strengthened CuNiBe and CuCrZr and dispersion strengthened Cu-Alsb2Osb3 (CuAl25). In this study, uniaxial mechanical fatigue tests were conducted on bulk copper alloy materials at temperatures up to 500sp°C in air and vacuum environments. Based on standardized mechanical properties measurement techniques, a series of tests were also implemented to characterize copper alloy-316L stainless steel joints produced by hot isostatic pressing or by explosive bonding. The correlation between mechanical properties and the microstructure of fatigued copper alloys and the interface of copper alloy-stainless steel laminates was examined. Commercial grades of these alloys were used to maintain a degree of standardization in the materials testing. The commercial alloys used were OMG Americas Glidcop CuAl25 and CuAl15; Brush Wellman Hycon 3HP and Trefimetaux CuNiBe; and Kabelmetal Elbrodur and Trefimetaux CuCrZr. CuAl25 and CuNiBe alloys possessed the best combination of fatigue resistance and microstructural stability. The CuAl25 alloy showed only minimal microstructural changes following fatigue while the CuNiBe alloy consistently exhibited the highest fatigue strength. Transmission electron microscopy observations revealed that small matrix grain sizes and high densities of submicron strengthening phases promoted homogeneous slip deformation in the copper alloys. Thus, highly organized fatigue dislocation structure formation, as commonly found in oxygen-free high conductivity Cu, was inhibited. A solid plate of CuAl25 alloy hot isostatically pressed to a 316L stainless steel

  13. New Three-Dimensional Porous Electrode Concept: Vertically-Aligned Carbon Nanotubes Directly Grown on Embroidered Copper Structures

    Directory of Open Access Journals (Sweden)

    Noemí Aguiló-Aguayo

    2017-12-01

    Full Text Available New three-dimensional (3D porous electrode concepts are required to overcome limitations in Li-ion batteries in terms of morphology (e.g., shapes, dimensions, mechanical stability (e.g., flexibility, high electroactive mass loadings, and electrochemical performance (e.g., low volumetric energy densities and rate capabilities. Here a new electrode concept is introduced based on the direct growth of vertically-aligned carbon nanotubes (VA-CNTs on embroidered Cu current collectors. The direct growth of VA-CNTs was achieved by plasma-enhanced chemical vapor deposition (PECVD, and there was no application of any post-treatment or cleaning procedure. The electrochemical behavior of the as-grown VA-CNTs was analyzed by charge/discharge cycles at different specific currents and with electrochemical impedance spectroscopy (EIS measurements. The results were compared with values found in the literature. The as-grown VA-CNTs exhibit higher specific capacities than graphite and pristine VA-CNTs found in the literature. This together with the possibilities that the Cu embroidered structures offer in terms of specific surface area, total surface area, and designs provide a breakthrough in new 3D electrode concepts.

  14. A sensor for acetaminophen in a blood medium using a Cu(II)-conducting polymer complex modified electrode

    International Nuclear Information System (INIS)

    Boopathi, Mannan; Won, Mi-Sook; Shim, Yoon-Bo

    2004-01-01

    Complexation of Cu ions in a terthiophene carboxylic acid (TTCA) polymer film resulted an enhanced anodic current for acetaminophen oxidation when compared to polymer coated and bare glassy carbon electrodes in human blood and buffer media. Scanning electron microscopy (SEM) and ESCA experiments indicate the involvement of copper in the electrocatalytic oxidation of acetaminophen. No interference was observed from other biologically important and phenolic compounds used with this modified electrode. Especially, the non-interference from N-acetylcysteine, an antidote for the treatment of acetaminophen poisoning, reveals the proposed method's superiority in medicinal applications. In addition, the present modified electrode avoids surface fouling at higher concentrations of acetaminophen. The calibration range obtained with CV was based between 2.0x10 -5 and 5.0x10 -3 M [r 2 =0.997 (n=5, R.S.D.=2.5%); DL=5.0x10 -6 M (S/N=3)]. The analytical utility of the modified electrode was achieved by analyzing the content of acetaminophen in different drugs without pretreatment using CV and amperometric techniques

  15. Sensitive and selective determination of Cu2+ at D-penicillamine functionalized nano-cellulose modified pencil graphite electrode

    Science.gov (United States)

    Taheri, M.; Ahour, F.; Keshipour, S.

    2018-06-01

    A novel electrochemical sensor based on D-penicillamine anchored nano-cellulose (DPA-NC) modified pencil graphite electrode was fabricated and used for highly selective and sensitive determination of copper (II) ions in the picomolar concentration by square wave adsorptive stripping voltammetric (SWV) method. The modified electrode showed better and increased SWV response compared to the bare and NC modified electrodes which may be related to the porous structure of modifier along with formation of complex between Cu2+ ions and nitrogen or oxygen containing groups in DPA-NC. Optimization of various experimental parameters influence the performance of the sensor, were investigated. Under optimized condition, DPA-NC modified electrode was used for the analysis of Cu2+ in the concentration range from 0.2 to 50 pM, and a lower detection limit of 0.048 pM with good stability, repeatability, and selectivity. Finally, the practical applicability of DPA-NC-PGE was confirmed via measuring trace amount of Cu (II) in tap and river water samples.

  16. Fabricating Copper Nanotubes by Electrodeposition

    Science.gov (United States)

    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.

  17. Calculations of secondary electron yield of graphene coated copper for vacuum electronic applications

    Directory of Open Access Journals (Sweden)

    H. K. A. Nguyen

    2018-01-01

    Full Text Available The suppression of secondary electron yield (SEY which can possibly lead to multipactor is an important goal for several applications. Though some techniques have focused on geometric modifications to lower the SEY, the use of graphene coatings as thin as a few monolayers is a promising new development that deserves attention either as a standalone technique or in concert with geometric alterations. Here we report on Monte Carlo based numerical studies of SEY on graphene coated copper with comparisons to recent experimental data. Our predicted values are generally in good agreement with reported measurements. Suppression of the secondary electron yield by as much as 50 percent (over copper with graphene coating is predicted at energies below 125 eV, and bodes well for multipactor suppression in radio frequency applications.

  18. Copper-doped titanium dioxide nanoparticles as dual-functional labels for fabrication of electrochemical immunosensors.

    Science.gov (United States)

    Zhang, Sen; Ma, Hongmin; Yan, Liangguo; Cao, Wei; Yan, Tao; Wei, Qin; Du, Bin

    2014-09-15

    Constructions of versatile electroactive labels are key issues in the development of electrochemical immunosensors. In this study, copper-doped titanium dioxide nanoparticle (Cu@TiO2) was synthesized and used as labels for fabrication of sandwich-type electrochemical immunosensors on glassy carbon electrode (GCE). Due to the presence of copper ions, Cu@TiO2 shows a strong response current when coupled to an electrode. The prepared nanocomposite also shows high electrocatalytic activity towards reduction of hydrogen peroxide (H2O2). The dual functionality of Cu@TiO2 enables the fabrication of immunosensor using different detection modes, that is, square wave voltammetry (SWV) or chronoamperometry (CA). While Cu@TiO2 was used as labels of secondary antibodies (Ab2), carboxyl functionalized graphene oxide (CFGO) was used as electrode materials to immobilize primary antibodies (Ab1). Using human immunoglobulin G (IgG) as a model analyte, the immunosensor shows high sensitivity, acceptable stability and good reproducibility for both detection modes. Under optimal conditions, a linear range from 0.1 pg/mL to 100 ng/mL with a detection limit of 0.052 pg/mL was obtained for SWV analysis. For CA analysis, a wider linear range from 0.01 pg/mL to 100 ng/mL and a lower detection limit of 0.0043 pg/mL were obtained. The proposed metal ion-based enzyme-free and noble metal-free immunosensor may have promising applications in clinical diagnoses and many other fields. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Horseradish peroxidase immobilized on copper surfaces and applications in selective electrocatalysis of p-dihydroxybenzene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chuntao, E-mail: tsyj1992@126.com [Department of Chemistry, Taiyuan Normal University, Taiyuan 030031 (China); Institute of Energy and Environmental Electrochemistry, Taiyuan Normal University, Taiyuan 030031 (China); Luo, Xiaoxiao [Department of Natural Science, Michigan State University, MI 48823,USA (United States); Jia, Zehui [Department of Chemistry, Taiyuan Normal University, Taiyuan 030031 (China); Institute of Energy and Environmental Electrochemistry, Taiyuan Normal University, Taiyuan 030031 (China); Shi, Qinghua; Zhu, Ritao [Department of Chemistry, Taiyuan Normal University, Taiyuan 030031 (China)

    2017-06-01

    Abstract: Horseradish Peroxidase (HRP) was immobilized on copper surfaces with the linker of L-Cysteine (L-Cys) self-assembled films to form Cu/L-Cys/HRP electrodes. The activity of HRP can be preserved by the Cu/L-Cys self-assembled films. The Cu/L-Cys/HRP electrodes can be used for the selective electrocatalytic oxidase of p-dihydroxybenzen in absent of H{sub 2}O{sub 2}. The optimum pH for electrocatalyzing p-dihydroxybenzen was 5.5 or 7.0, which corresponds to the isoelectric points of L-Cys and HRP, respectively. X-ray photoelectron spectroscopy (XPS) provided the evidence that L-Cys linked with Cu surface by the Cu− S bond. Fourier transform infrared spectroscopy (FTIR) analyses indicated that aromatic plane of p-dihydroxybenzen was connected parallel to porphyrin ring of heme in HRP. Quantum chemical calculation of density functional theory (DFT) revealed that symmetry of molecular structure and minimum space steric hindrance for p-dihydroxybenzen were benefit to combination with HRP. Moreover, the lowest energy of LUMO and most negative charges of oxygen atom on hydroxyl group of p-dihydroxybenzen were advantage to lose the hydrogen atom of hydroxyl group to be oxided.

  20. Insight into the electroreduction of nitrate ions at a copper electrode, in neutral solution, after determination of their diffusion coefficient by electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Aouina, Nizar; Cachet, Hubert; Debiemme-chouvy, Catherine; Tran, Thi Tuyet Mai

    2010-01-01

    The electrochemical reduction of nitrate ions at a copper electrode in an unbuffered neutral aqueous solution is studied. Using a two compartment electrochemical cell, three stationary cathodic waves, noted P1, P2 and P3, were evidenced by cyclic voltammetry at -0.9, -1.2 and -1.3 V/SCE, respectively. By comparing the electrochemical response of nitrate and nitrite containing solutions, P1 was attributed to the reduction of nitrate to nitrite. In order to assign P2 and P3 features by determining the number of electrons involved at the corresponding potential, rotating disk electrode experiments at various rotation speeds, combined with linear sweep voltammetry, were performed. Current data analysis at a given potential was carried out using Koutecky-Levich treatment taking into account water reduction. Confident values of the diffusion coefficient D of nitrate ions were assessed by electrochemical impedance spectroscopy for nitrate concentrations of 10 -3 , 10 -2 and 10 -1 M. For a nitrate concentration of 10 -2 M, D was found to be 1.31 x 10 -5 cm 2 s -1 allowing the number of electrons to be determined as 6 for P2 and 8 for P3, in accordance with nitrate reduction into hydroxylamine and ammonia, respectively. The formation of hydroxylamine was confirmed by the observation of its reoxidation at a Pt microelectrode present at the Cu electrode/nitrate solution interface.

  1. Enzymatic electrodes nanostructured with functionalized carbon nanotubes for biofuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Nazaruk, E.; Bilewicz, R. [University of Warsaw, Faculty of Chemistry, Warsaw (Poland); Sadowska, K.; Biernat, J.F. [Gdansk University of Technology, Chemical Faculty, Gdansk (Poland); Rogalski, J. [Maria Curie Sklodowska University, Department of Biochemistry, Lublin (Poland); Ginalska, G. [Medical University of Lublin, Department of Biochemistry, Lublin (Poland)

    2010-10-15

    Nanostructured bioelectrodes were designed and assembled into a biofuel cell with no separating membrane. The glassy carbon electrodes were modified with mediator-functionalized carbon nanotubes. Ferrocene (Fc) and 2,2{sup '}-azino-bis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) bound chemically to the carbon nanotubes were found useful as mediators of the enzyme catalyzed electrode processes. Glucose oxidase from Aspergillus niger AM-11 and laccase from Cerrena unicolor C-139 were incorporated in a liquid-crystalline matrix-monoolein cubic phase. The carbon nanotubes-nanostructured electrode surface was covered with the cubic phase film containing the enzyme and acted as the catalytic surface for the oxidation of glucose and reduction of oxygen. Thanks to the mediating role of derivatized nanotubes the catalysis was almost ten times more efficient than on the GCE electrodes: catalytic current of glucose oxidation was 1 mA cm{sup -2} and oxygen reduction current exceeded 0.6 mA cm{sup -2}. The open circuit voltage of the biofuel cell was 0.43 V. Application of carbon nanotubes increased the maximum power output of the constructed biofuel cell to 100 {mu}W cm{sup -2} without stirring of the solution which was ca. 100 times more efficient than using the same bioelectrodes without nanotubes on the electrode surface. (orig.)

  2. Piercing by composite electrode tool

    International Nuclear Information System (INIS)

    Abdukarimov, Eh.T.; Krakov, B.G.; Saidinov, S.Ya.

    1990-01-01

    The construction of the electrode consisting of a dielectric shell, where a working liquid enters, and a metal rod is designed for precision super-deep piercing by the electroerosion treatment method. Technological parameters of piercing with small diameter (0.5-1.9 mm) for 12Kh18N10T steel, copper and tungsten are presented. A possibility to use a new tool for treating components of any form and sizes is marked

  3. Low-cost electrodes for stable perovskite solar cells

    Science.gov (United States)

    Bastos, João P.; Manghooli, Sara; Jaysankar, Manoj; Tait, Jeffrey G.; Qiu, Weiming; Gehlhaar, Robert; De Volder, Michael; Uytterhoeven, Griet; Poortmans, Jef; Paetzold, Ulrich W.

    2017-06-01

    Cost-effective production of perovskite solar cells on an industrial scale requires the utilization of exclusively inexpensive materials. However, to date, highly efficient and stable perovskite solar cells rely on expensive gold electrodes since other metal electrodes are known to cause degradation of the devices. Finding a low-cost electrode that can replace gold and ensure both efficiency and long-term stability is essential for the success of the perovskite-based solar cell technology. In this work, we systematically compare three types of electrode materials: multi-walled carbon nanotubes (MWCNTs), alternative metals (silver, aluminum, and copper), and transparent oxides [indium tin oxide (ITO)] in terms of efficiency, stability, and cost. We show that multi-walled carbon nanotubes are the only electrode that is both more cost-effective and stable than gold. Devices with multi-walled carbon nanotube electrodes present remarkable shelf-life stability, with no decrease in the efficiency even after 180 h of storage in 77% relative humidity (RH). Furthermore, we demonstrate the potential of devices with multi-walled carbon nanotube electrodes to achieve high efficiencies. These developments are an important step forward to mass produce perovskite photovoltaics in a commercially viable way.

  4. Virgin olive oil blended polyurethane micro/nanofibers ornamented with copper oxide nanocrystals for biomedical applications

    Directory of Open Access Journals (Sweden)

    Amna T

    2014-02-01

    Full Text Available Touseef Amna,1 M Shamshi Hassan,2 Jieun Yang,1 Myung-Seob Khil,2 Ki-Duk Song,3 Jae-Don Oh,3 Inho Hwang1 1Department of Animal Sciences and Biotechnology, 2Department of Organic Materials and Fiber Engineering, Chonbuk National University, Jeonju, South Korea; 3Genomic Informatics Center, Hankyong National University, Anseong, South Korea Abstract: Recently, substantial interest has been generated in using electrospun biomimetic nanofibers of hybrids, particularly organic/inorganic, to engineer different tissues. The present work, for the first time, introduced a unique natural and synthetic hybrid micronanofiber wound dressing, composed of virgin olive oil/copper oxide nanocrystals and polyurethane (PU, developed via facile electrospinning. The as-spun organic/inorganic hybrid micronanofibers were characterized by scanning electron microscopy (SEM, energy dispersive X-ray analysis, X-ray diffraction, electron probe microanalysis, and transmission electron microscopy. The interaction of cells with scaffold was studied by culturing NIH 3T3 fibroblasts on an as-spun hybrid micronanofibrous mat, and viability, proliferation, and growth were assessed. The 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay results and SEM observation showed that the hybrid micronanofibrous scaffold was noncytotoxic to fibroblast cell culture and was found to benefit cell attachment and proliferation. Hence our results suggest the potential utilization of as-spun micronanoscaffolds for tissue engineering. Copper oxide–olive oil/PU wound dressing may exert its positive beneficial effects at every stage during wound-healing progression, and these micronanofibers may serve diverse biomedical applications, such as tissue regeneration, damaged skin treatment, wound healing applications, etc. Conclusively, the fabricated olive oil–copper oxide/PU micronanofibers combine the benefits of virgin olive oil and copper oxide, and therefore hold great promise for

  5. Electrochemical and AFM characterization on gold and carbon electrodes of a high redox potential laccase from Fusarium proliferatum.

    Science.gov (United States)

    González Arzola, K; Gimeno, Y; Arévalo, M C; Falcón, M A; Hernández Creus, A

    2010-08-01

    The redox potential of the T1 copper site of laccase from Fusarium proliferatum was determined by titration to be about 510 mV vs. SCE (750 mV vs. NHE), which makes it a high redox potential enzyme. Anaerobic electron transfer reactions between laccase and carbon and gold electrodes were detected, both in solution and when the enzyme was adsorbed on these surfaces. In solution, a single high-potential signal (660 mV vs. SCE) was recorded at the carbon surfaces, attributable to the T1 copper site of the enzyme. However, a well-defined oxidative process at about 660 mV and an anodic wave at 350 mV vs. SCE were recorded at the gold electrode, respectively associated with the T1 and T2 copper sites. Laccase-modified carbon electrodes behaved analogously when the enzyme was in solution, unlike laccase adsorbed on gold, which showed only a low-potential signal. Laccase molecules were successfully imaged by AFM; obtaining a thick compact stable film on Au(111), and large aggregates forming a complex network of small branches leaving voids on the HOPG surface. Laccase-modified carbon electrodes retained significant enzymatic activity, efficiently oxidising violuric acid and reducing molecular oxygen. Explanations are proposed for how protein-film organisation affects the electrode function. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  6. Aerosol jet printed silver nanowire transparent electrode for flexible electronic application

    Science.gov (United States)

    Tu, Li; Yuan, Sijian; Zhang, Huotian; Wang, Pengfei; Cui, Xiaolei; Wang, Jiao; Zhan, Yi-Qiang; Zheng, Li-Rong

    2018-05-01

    Aerosol jet printing technology enables fine feature deposition of electronic materials onto low-temperature, non-planar substrates without masks. In this work, silver nanowires (AgNWs) are proposed to be printed into transparent flexible electrodes using a Maskless Mesoscale Material Deposition Aerosol Jet® printing system on a glass substrate. The influence of the most significant process parameters, including printing cycles, printing speed, and nozzle size, on the performance of AgNW electrodes was systematically studied. The morphologies of printed patterns were characterized by scanning electron microscopy, and the transmittance was evaluated using an ultraviolet-visible spectrophotometer. Under optimum conditions, high transparent AgNW electrodes with a sheet resistance of 57.68 Ω/sq and a linewidth of 50.9 μm were obtained, which is an important step towards a higher performance goal for flexible electronic applications.

  7. Removal of copper in leachate from mining residues using electrochemical technology.

    Science.gov (United States)

    Lambert, Andréa; Drogui, Patrick; Daghrir, Rimeh; Zaviska, François; Benzaazoua, Mostafa

    2014-01-15

    This research is related to a laboratory study on the performance of a successive mining residues leaching and electrochemical copper recovery process. To clearly define the experimental region for response surface methodology (RSM), a preliminary study was performed by applying a current intensity varying from 0.5 A to 4.0 A for 60 min. By decreasing the current intensity from 4.0 A to 0.5 A, a good adhesion and a very smooth and continuous interface of copper was formed and deposited on the cathode electrode. However, the removal rate of Cu decreased from 83.7% to 37.9% when the current intensity passed from 4.0 A to 0.5 A, respectively. Subsequently, the factorial design and central composite design methodologies were successively employed to define the optimal operating conditions for copper removal in the mining residues leachate. Using a 2(3) factorial matrix, the best performance for copper removal (97.7%) was obtained at a current intensity of 2.0 A during 100 min. The current intensity and electrolysis time were found to be the most influent parameters. The contribution of current intensity and electrolysis time was around 65.8% and 33.9%, respectively. The treatment using copper electrode and current intensity of 1.3 A during 80 min was found to be the optimal conditions in terms of cost/effectiveness. Under these conditions, 86% of copper can be recovered for a total cost of 0.56 $ per cubic meter of treated mining residues leachate. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Column study on electrochemical separation of cesium ions from wastewater using copper hexacyanoferrate film

    International Nuclear Information System (INIS)

    Chen, Rongzhi; Tanaka, Hisashi; Asai, Miyuki; Fukushima, Chikako; Kawamoto, Tohru; Kurihara, Masato; Ishizaki, Manabu; Arisaka, Makoto; Nankawa, Takuya; Watanabe, Masayuki

    2013-01-01

    We coated the copper hexacyanoferrate (CuHCF) on the gold electrodes, and then performed the Cs removal by electrochemical separation (ES). The prepared CuHCF nanoparticles can be simply and uniformly coated on electrodes by wet process like conventional printing methods, so any sizes or patterns are feasible at low cost, which indicated the potential as a promising sorption electrode of large size in the columns for sequential removal and recycle of Cs from wastewater. (author)

  9. Dechlorination of Trichloroacetic Acid Using a Noble Metal-Free Graphene-Cu Foam Electrode via Direct Cathodic Reduction and Atomic H.

    Science.gov (United States)

    Mao, Ran; Li, Ning; Lan, Huachun; Zhao, Xu; Liu, Huijuan; Qu, Jiuhui; Sun, Meng

    2016-04-05

    A three-dimensional graphene-copper (3D GR-Cu) foam electrode prepared by chemical vapor deposition method exhibited superior electrocatalytic activity toward the dechlorination of trichloroacetic acid (TCAA) as compared to the Cu foam electrode. The cyclic voltammetry and electrochemical impedance spectra analysis confirmed that GR accelerated the electron transfer from the cathode surface to TCAA. With the applied cathode potential of -1.2 V (vs SCE), 95.3% of TCAA (500 μg/L) was removed within 20 min at pH 6.8. TCAA dechlorination at the Cu foam electrode was enhanced at acidic pH, while a slight pH effect was observed at the GR-Cu foam electrode with a significant inhibition for Cu leaching. The electrocatalytic dechlorination of TCAA was accomplished via a combined stepwise and concerted pathway on both electrodes, whereas the concerted pathway was efficiently promoted on the GR-Cu foam electrode. The direct reduction by electrons was responsible for TCAA dechlorination at Cu foam electrode, while at GR-Cu foam electrode, the surface-adsorbed atomic H* also contributed to TCAA dechlorination owing to the chemical storage of hydrogen in the GR structure. Finally, the potential applicability of GR-Cu foam was revealed by its stability in the electrocatalytic dechlorination over 25 cycles.

  10. Sol-gel derived electrode materials for supercapacitor applications

    Science.gov (United States)

    Lin, Chuan

    1998-12-01

    Electrochemical capacitors have been receiving increasing interest in recent years for use in energy storage systems because of their high energy and power density and long cycle lifes. Possible applications of electrochemical capacitors include high power pulsed lasers, hybrid power system for electric vehicles, etc. In this dissertation, the preparation of electrode materials for use as electrochemical capacitors has been studied using the sol-gel process. The high surface area electrode materials explored in this work include a synthetic carbon xerogel for use in a double-layer capacitor, a cobalt oxide xerogel for use in a pseudocapacitor, and a carbon-ruthenium xerogel composite, which utilizes both double-layer and faradaic capacitances. The preparation conditions of these materials were investigated in detail to maximize the surface area and optimize the pore size so that more energy could be stored while minimizing mass transfer limitations. The microstructures of the materials were also correlated with their performance as electrochemical capacitors to improve their energy and power densities. Finally, an idealistic mathematical model, including both double-layer and faradaic processes, was developed and solved numerically. This model can be used to perform the parametric studies of an electrochemical capacitor so as to gain a better understanding of how the capacitor works and also how to improve cell operations and electrode materials design.

  11. Low Energy Desalination Using Battery Electrode Deionization

    KAUST Repository

    Kim, Taeyoung

    2017-09-21

    New electrochemical technologies that use capacitive or battery electrodes are being developed to minimize energy requirements for desalinating brackish waters. When a pair of electrodes is charged in capacitive deionization (CDI) systems, cations bind to the cathode and anions bind to the anode, but high applied voltages (>1.2 V) result in parasitic reactions and irreversible electrode oxidation. In the battery electrode deionization (BDI) system developed here, two identical copper hexacyanoferrate (CuHCF) battery electrodes were used that release and bind cations, with anion separation occurring via an anion exchange membrane. The system used an applied voltage of 0.6 V, which avoided parasitic reactions, achieved high electrode desalination capacities (up to 100 mg-NaCl/g-electrode, 50 mM NaCl influent), and consumed less energy than CDI. Simultaneous production of desalinated and concentrated solutions in two channels avoided a two-cycle approach needed for CDI. Stacking additional membranes between CuHCF electrodes (up to three anion and two cation exchange membranes) reduced energy consumption to only 0.02 kWh/m3 (approximately an order of magnitude lower than values reported for CDI), for an influent desalination similar to CDI (25 mM decreased to 17 mM). These results show that BDI could be effective as a very low energy method for brackish water desalination.

  12. Fabrication and electrochemical characterization of multi-walled carbon nanotube electrodes for applications to nano-electrochemical sensing

    International Nuclear Information System (INIS)

    Hwang, Sookhyun; Choi, Hyonkwang; Jeon, Minhyon; Vedala, Harindra; Kim, Taehyung; Choi, Wonbong

    2010-01-01

    In this study, we fabricated and electrochemically characterized two types of individual carbon nanotube electrodes: an as-produced multi-walled carbon nanotube (MWNT) electrode and a modified MWNT electrode. As-produced MWNTs were electrically contacted with Au/Ti layers by using nanolithography and RF magnetron sputtering. Open-ended modified MWNT electrodes were fabricated by using a reactive ion etching treatment under an oxygen atmosphere. We also performed cyclic voltammetry measurements to detect aqueous dopamine solutions with different concentrations. We found that an individual MWNT electrode, which had a small effective area, showed good electrochemical performance. The electrocatalytic behavior of the modified electrode, which had 'broken' open ends were better than that of the as-produced electrode with respect to sensitivity. The modified electrode was capable of detecting dopamine at the picomolar level. Therefore, an individual modified MWNT electrode has potential for applications to active components in nanobiosensors.

  13. Experimental study of the electrode material for electro-osmosis in mudflat sludge

    Science.gov (United States)

    Liu, Yi-min; Xu, Hao-feng

    2017-11-01

    In order to study the performance of electro-osmosis, several tests including indoor electro-osmosis experiments using copper, aluminum as the anode and cathode electrode materials, and Mercury Intrusion Porosimiter (MIP) were conducted. The results indicate that the drainage ratio using aluminum is faster than that of copper while the energy consumption per unit is lower, the effectiveness is better than that of copper. After electro-osmosis, the percentage of pore with large diameter shows a remarkable decrease comparing with the remolded soil which result in the increase of pore with small diameter. The reasons were discussed in this paper.

  14. Ni-BaTiO3-Based Base-Metal Electrode (BME) Ceramic Capacitors for Space Applications

    Science.gov (United States)

    Liu, Donhang; Fetter, Lula; Meinhold, Bruce

    2015-01-01

    A multi-layer ceramic capacitor (MLCC) is a high-temperature (1350C typical) co-fired ceramic monolithic that is composed of many layers of alternately stacked oxide-based dielectric and internal metal electrodes. To make the dielectric layers insulating and the metal electrode layers conducting, only highly oxidation-resistant precious metals, such as platinum, palladium, and silver, can be used for the co-firing of insulating MLCCs in a regular air atmosphere. MLCCs made with precious metals as internal electrodes and terminations are called precious-metal electrode (PME) capacitors. Currently, all military and space-level applications only address the use of PME capacitors.

  15. Development of high temperature reference electrodes for in-pile application: Part I. Feasibility study of the external pressure balanced Ag/AgCl reference electrode (EPBRE) and the cathodically charged Palladium hydrogen electrode

    International Nuclear Information System (INIS)

    Bosch, R.W.; Van Nieuwenhove, R.

    1998-10-01

    The main problems connected with corrosion potential measurements at elevated temperatures and pressures are related to the stability and lifetime of the reference electrode and the correct estimation of the potential related to the Standard Hydrogen Scale (SHE). Under Pressurised Water Reactor (PWR) conditions of 300 degrees Celsius and 150 bar, the choice of materials is also a limiting factor due to the influence of radiation. Investigations on two reference electrodes that can be used under PWR conditions are reported: the cathodically charged palladium hydrogen electrode, and the external pressure balanced silver/silver chloride electrode. Preliminary investigations with the Pd-electrode were focused on the calculation of the required charging time and the influence of dissolved oxygen. High temperature applications are discussed on the basis of results reported in the literature. Investigations with the silver/silver chloride reference electrode mainly dealt with the salt bridge which is necessary to connect the reference electrode with the testing solution. It is shown that the thermal junction potential is independent of the length of the salt bridge. In addition, the high temperature contributes to an increase of the conductivity of the solution, which is beneficial for the salt bridge connection

  16. REMOVAL OF COPPER ELECTROLYTE CONTAMINANTS BY ADSORPTION

    Directory of Open Access Journals (Sweden)

    B Gabai

    1997-09-01

    Full Text Available Abstract - Selective adsorbents have become frequently used in industrial processes. Recent studies have shown the possibility of using adsorption to separate copper refinery electrolyte contaminants, with better results than those obtained with conventional techniques. During copper electrorefinning, many impurities may be found as dissolved metals present in the anode slime which forms on the electrode surface, accumulated in the electrolyte or incorporated into the refined copper on the cathode by deposition. In this study, synthetic zeolites, chelating resins and activated carbons were tested as adsorbents to select the best adsorbent performance, as well as the best operating temperature for the process. The experimental method applied was the finite bath, which consists in bringing the adsorbent into contact with a finite volume of electrolyte while controlling the temperature. The concentration of metals in the liquid phase was continuously monitored by atomic absorption spectrophotometry (AAS

  17. Implementation of active electrodes on a brain-computer interface and its application as P300 speller

    International Nuclear Information System (INIS)

    Aguero Rojas, Eliecer

    2013-01-01

    A brain computer interface has implemented using open hardware called Modular EEG, created by The OpenEEG Project and distributed by the company Olimex Ltd. That hardware is modified to use active electrodes, instead of passive electrodes, for acquiring electroencephalographic signals. The application has been given to the interface has been a speller P300; for which has used the BC12000 open software that has the necessary configuration for the application. P300 speller has used a protocol in each session so that could be standardize the method to different users. Valuing the results with three neuropsychological tests, was within the objectives; however, has not been achieved by the limitation in time of project implementation. A brain computer interface has been used with passive electrodes; implemented in the same way that the BCI with active electrodes; and has worked better than the interface with active electrodes. One of the major advantages that has been observed of passive electrodes on the actives has been the size of the same, because the liabilities are smaller and therefore, easier to place preventing the hair of the user, which increases the noise in the signal. (author) [es

  18. Voltammetric paracetamole sensor using a gold electrode made from a digital versatile disc chip and modified with a hybrid material consisting of carbon nanotubes and copper nanoparticles

    International Nuclear Information System (INIS)

    Daneshvar, Leili; Rounaghi, Gholam Hossein; Tarahomi, Somayeh

    2016-01-01

    A composite consisting of carbon nanotubes (CNT) and copper nanoparticles (CuNPs) was prepared by a chemical reduction method, and its structure characterized by scanning electron microscopy, transmission electron microscopy energy dispersive spectroscopy and FT-IR spectrometry. The hybrid composite was deposited on the surface of a disposable gold electrode that was manufactured from a commercial digital versatile gold disc by a drop casting method. The electrochemical properties of the modified electrode were investigated by cyclic voltammetry and differential pulse voltammetry. The sensor showed an excellent electrocatalytic activity towards oxidation of paracetamole (PA). The calibration plot (with current typically measured at 0.41 V vs. Ag/AgCl) is linear in the 0.5 to 80 μM concentration range, and the detection limit is as low as 10 nM. The sensor was successfully applied to the determination of PA in spiked water and tablet samples where it gave recoveries ranging between 95.25 and 100.5 %. (author)

  19. Emerging Novel Metal Electrodes for Photovoltaic Applications.

    Science.gov (United States)

    Lu, Haifei; Ren, Xingang; Ouyang, Dan; Choy, Wallace C H

    2018-04-01

    Emerging novel metal electrodes not only serve as the collector of free charge carriers, but also function as light trapping designs in photovoltaics. As a potential alternative to commercial indium tin oxide, transparent electrodes composed of metal nanowire, metal mesh, and ultrathin metal film are intensively investigated and developed for achieving high optical transmittance and electrical conductivity. Moreover, light trapping designs via patterning of the back thick metal electrode into different nanostructures, which can deliver a considerable efficiency improvement of photovoltaic devices, contribute by the plasmon-enhanced light-mattering interactions. Therefore, here the recent works of metal-based transparent electrodes and patterned back electrodes in photovoltaics are reviewed, which may push the future development of this exciting field. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Study of the electroreduction of nitrate on copper in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Reyter, David [INRS Energie, Materiaux et Telecommunications, 1650 bd. Lionel Boulet, Varennes, Qc (Canada); Departement de Chimie, Universite du Quebec a Montreal, CP 8888, Montreal, Qc (Canada); Belanger, Daniel [Departement de Chimie, Universite du Quebec a Montreal, CP 8888, Montreal, Qc (Canada); Roue, Lionel [INRS Energie, Materiaux et Telecommunications, 1650 bd. Lionel Boulet, Varennes, Qc (Canada)

    2008-08-20

    The electrocatalytic activity of a Cu electrode for the electroreduction of nitrate in alkaline medium was investigated by linear sweep voltammetry at stationary and rotating disc electrodes. Nitrate-reduction products generated upon prolonged electrolyses at different potentials were quantified. In addition, adsorption phenomena associated with the nitrate electroreduction process were characterized by electrochemical quartz crystal microbalance (EQCM) experiments. This data revealed that nitrate electroreduction process strongly depends on the applied potential. Firstly, at ca. -0.9 V vs. Hg/HgO, the electroreduction of adsorbed nitrate anions to nitrite anions was identified as the rate-determining step of the nitrate electroreduction process. Between -0.9 and -1.1 V, nitrite is reduced to hydroxylamine. However, during long-term electrolyses, hydroxylamine is not detected and presumably because it is rapidly reduced to ammonia. At potential more negative than -1.1 V, nitrite is reduced to ammonia. At ca. -1.45 V, i.e. just before the hydrogen evolution reaction, the abrupt decrease of the cathodic current is due to the electrode poisoning by adsorbed hydrogen. In addition, during the first minutes of nitrate electrolysis, a decrease of the copper electrode activity was observed at the three investigated potentials (-0.9, -1.1 and -1.4 V). From polarization and EQCM measurements, this deactivation was attributed to the adsorption of nitrate-reduction products, blocking the electrode surface and slowing down the nitrate electroreduction rate. However, it was demonstrated that the Cu electrode can be reactivated by the periodic application of a square wave potential pulse at -0.5 V, which causes the desorption of poisoning species. (author)

  1. Potentiometric application of boron- and phosphorus-doped glassy carbon electrodes

    Directory of Open Access Journals (Sweden)

    ZORAN V. LAUSEVIC

    2001-03-01

    Full Text Available Acomparative study was carried out of the potentiometric application of boronand phosphorus-doped and undoped glassy carbon samples prepared at the same heat treatment temperature (HTT 1000°C. The electrochemical activities of the obtained electrode materials were investigated on the example of argentometric titrations. It was found that the electrochemical behaviour of the doped glassy carbon samples are very similar to a Sigri (undoped glassy carbon sample (HTT 2400°C. The experiments showed that the potentiometric response depends on the polarization mode, the nature of the sample, the pretreatment of the electrode surface, and the nature of the supporting electrolyte. The amounts of iodide, bromide, and of chloridewere determined to be 1.27 mg, 0.80 mg and 0.54 mg, respectively, with a maximum relative standard deviation of less than 1.1%. The obtained results are in good agreement with the results of comparative potentiometric titrations using a silver indicator electrode. The titrationmethod was applied to the indirect determination of pyridoxine hydrochloride, i.e., vitamin B6.

  2. Antagonistic effects of copper on the electrochemical performance of LiFePO4

    International Nuclear Information System (INIS)

    Morales, Julian; Santos-Pena, Jesus; Rodriguez-Castellon, Enrique; Franger, Sylvain

    2007-01-01

    In the last few years, several strategies towards boosting the electrochemical performance of LiFePO 4 cathodes have been envisaged. Copper addition to the phosphate seems to be a simple, inexpensive method for this purpose. However, it has a serious drawback: at voltages slightly higher than that required for lithium extraction from LiFePO 4 , the copper is oxidized to either Cu(I) or Cu(II) with partial decomposition of the electrolyte. XRD patterns are consistent with the disappearance of copper from pristine composites upon charging at up to 4.0 V. Moreover, a copper deposit is formed on the lithium surface in the discharged state that creates a barrier hindering the release of Li ion from the electrode. Therefore, copper electroactivity strongly influences the capacity and cycling life of the cell

  3. Bristle-sensors—low-cost flexible passive dry EEG electrodes for neurofeedback and BCI applications

    Science.gov (United States)

    Grozea, Cristian; Voinescu, Catalin D.; Fazli, Siamac

    2011-04-01

    In this paper, we present a new, low-cost dry electrode for EEG that is made of flexible metal-coated polymer bristles. We examine various standard EEG paradigms, such as capturing occipital alpha rhythms, testing for event-related potentials in an auditory oddball paradigm and performing a sensory motor rhythm-based event-related (de-) synchronization paradigm to validate the performance of the novel electrodes in terms of signal quality. Our findings suggest that the dry electrodes that we developed result in high-quality EEG recordings and are thus suitable for a wide range of EEG studies and BCI applications. Furthermore, due to the flexibility of the novel electrodes, greater comfort is achieved in some subjects, this being essential for long-term use.

  4. Electrode-electrolyte BIMEVOX system for moderate temperature oxygen separation

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, J.C.; Pirovano, C.; Nowogrocki, G.; Mairesse, G. [Laboratoire de Cristallochimie et Physicochimie du Solide, URA CNRS 452, USTL-ENSCL BP 108, 59652 Villeneuve d`Ascq (France); Labrune, Ph.; Lagrange, G. [Centre de recherches Claude Delorme, Air Liquide, Jouy en Josas (France)

    1998-12-01

    Electrochemical separation of oxygen from air is a promising application for oxide conductor solid electrolytes. However, several important specifications are required in order to obtain an efficient separation device. First of all, the electrolyte material must exhibit a high conductivity at moderate temperature. From this point of view, a new family of materials called BIMEVOX ideally fulfils this condition. Secondly, a typical separation device must comport two electrodes on opposite faces of the electrolyte. These electrodes must act as electronic collectors but also, at the cathodic side, as an oxygen dissociation catalyst. BIMEVOX electrolytes exhibit ionic conductivity values that can allow work at temperature below 500C. The classical electrode approach, like in solid oxide fuel cells, consists in using a specific mixed oxide, for instance strontium lanthanum manganite or cobaltite. However, the lower the temperature, the lower the efficiency of these electrodes which quickly appears as the limiting factor. In previous work on bismuth lead oxide electrolytes, we proposed a new approach that consists of using the surface of the bismuth-based electrolyte itself as the catalyst, the electron collection being then performed by a co-sintered metallic grid. This `in-situ` electrode system provides many advantages, particularly it eliminates the problem of the chemical compatibility between electrode and electrolyte materials. Taking into account the presence of both catalytic vanadium and bismuth cations in BIMEVOX, we checked under these conditions the separation of oxygen from air for different electrolytes (BICOVOX, BICUVOX, BIZNVOX) at various temperatures in the range 430-600C. For instance, using a BICOVOX pellet with a gold grid inserted on each side makes it possible to separate oxygen with nearly 100% efficiency for current density values up to 1000 mA/cm{sup -2}. For higher intensity values, the faradic efficiency progressively but reversibly decreases

  5. Electrochemical Comparison of the Interaction of 5-Nitrouracil with Single- or Double-Stranded DNA at mercury and glassy carbon electrodes

    OpenAIRE

    Ibrahim, Mohamed Sayed; Ibrahim, Hossieny Sameh Mohamed; Kamal, Moustafa Mohamed; Temerk, Yassin Mohamed

    2014-01-01

    The interaction of the 5-Nitrouracil (5NU), with ss-, and ds-DNA was investigated electrochemically in absence and presence of copper ions by using cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) at hanging mercury drop electrode (HMDE) and glassy carbon electrode (GCE) surfaces. It was found that, in absence of copper ions, the addition of ss- or ds-DNA to a buffered solution of 5NU results in a decrease on the 5NU redox peak current with a remarkable change in th...

  6. Copper corrosion in irradiated environments: The influence of H2O2 on the electrochemistry of copper dissolution in HCl electrolyte

    International Nuclear Information System (INIS)

    Smyrl, W.H.; Bell, B.T.; Atanasoski, R.T.; Glass, R.S.

    1986-12-01

    The anodic dissolution of copper was examined in deaerated, 0.1 M HCl aqueous solution in the presence of H 2 O 2 . Concentrations of H 2 O 2 up to 0.2 M were studied at a rotating copper disk-platinum ring electrode. The open circuit potential (OCP) of copper was found to depend on both peroxide concentration and rotation rate. The OCP shifts towards more positive values with increasing H 2 O 2 concentration (C) and decreasing rotation rate. The current-voltage curves for anodic dissolution of copper were also influenced by the presence of peroxide. The curves recorded with the potential scanned in the positive direction showed the expected 60 mV slope, but the reverse scans showed significant departures. At a given potential scan rate, hysteresis was observed which was larger for higher H 2 O 2 concentrations, lower rotation rates, and more positive anodic potential limits. Monitoring the cuprous ions at the outer Pt ring revealed that there was a complex set of events taking place at the copper surface, including film formation and the appearance of cupric ions. 13 refs., 7 figs

  7. Synthesis and Applications of Large Area Graphene-Based Electrode Systems

    Science.gov (United States)

    Paul, Rajat Kanti

    Graphene is a single sheet of carbon atoms with outstanding electrical and physical properties and being exploited for applications in electronics, sensors, fuel cells, photovoltaics and energy storage. However, practical designs of graphene-based electrode systems and related experimental implementations are required to realize their widespread applications in nano- to bioelectronics. In this dissertation, different graphene-based electrode systems having metallic and semiconducting properties are synthesized optimizing process conditions. Also realized is the potential of the fabricated electrode systems by applying them in practical applications such as sensor devices and fuel cells. The zero bandgap of semimetal graphene still limits its application as an effective field-effect transistor device or a chemiresistor sensor operating at room temperature. It has been shown theoretically and experimentally that graphene nanoribbons (GNRs) or nanomeshes (GNMs) can attain a bandgap that is large enough for a transistor device, and hence would show high sensitivity to various gaseous species or biomolecules. Large-area mono- and bilayer graphene films are synthesized by a simple chemical vapor deposition (CVD) technique depending on the carbon precursors such as methane, acetylene and ethanol, and the results are compared using optical microscopy (OM), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and x-ray photoelectron spectroscopy (XPS). A simple reactive ion etching (RIE) combined with well-established nanosphere lithography is performed on the synthesized CVD-grown monolayer graphene platform to fabricate large area GNMs with specific dimension and periodicity. The fabricated GNMs chemiresistor sensor devices show excellent sensitivity towards NO2 and NH 3, significantly higher than their film counterparts. The GNM sensor devices exhibit sensitivities of about 4.32%/ppm (parts-per-million) in NO 2 and 0.71%/ppm in NH3 with estimated

  8. Electroreduction of CO{sub 2} using copper-deposited on boron-doped diamond (BDD)

    Energy Technology Data Exchange (ETDEWEB)

    Panglipur, Hanum Sekar; Ivandini, Tribidasari A., E-mail: ivandini.tri@sci.ui.ac.id [Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Einaga, Yasuaki [Department of Chemistry, Keio University (Japan); Wibowo, Rahmat

    2016-04-19

    Electroreduction of CO{sub 2} was studied at copper-modified boron-doped diamond (Cu-BDD) electrodes as the working electrode. The Cu-BDD electrodes were prepared by electrochemical reduction with various concentrations of CuSO{sub 4} solutions. FE-SEM was utilized to characterize the electrodes. At Cu-BDD electrodes, a reduction peak at around -1.2 V (vs Ag/AgCl) attributtable to CO{sub 2} reductions could be observed by cyclic voltammetry technique of CO{sub 2} bubbled in water containing 0.1M NaCl. Accordingly, electroreduction of CO{sub 2} was conducted at -1.2 V (vs Ag/AgCl) using amperometry technique. The chemical products of the electroreduction analyzed by using HPLC showed the formation of formaldehyde, formic acid, and acetic acid at Cu-BDD electrodes.

  9. Anisotropic D-EAP Electrodes and their Application in Spring Roll Actuators

    Science.gov (United States)

    Fang, Xiaomeng

    Electroactive polymers (EAPs) exhibit shape change when subjected to an electric field. They are lightweight, soft, and inexpensive, while they are easy to process, shape, and tune to offer a broad range of mechanical and electrical properties. Dielectric electroactive polymers (DEAP) constitute a class of EAPs with great potential. D-EAPs consist of physically or chemically cross-linked macromolecular networks and are mechanically isotopic. Therefore, in most actuator applications that require directional electromechanical response, it is necessary to use other complex means to direct the stress/strain in the preferred direction. In this work, a simple carbon nanotube (CNT) based electrode for D-EAP actuators is demonstrated that vastly improves directional strain response originating from the mechanical anisotropy of the electrode material. Using this novel approach, the mechanical anisotropy, defined as the ratio of initial modulus in fiber direction and that in cross-fiber direction, of the CNT electroded VHB actuators, ranges from 7.9 to 11.2. Hence, the CNT-VHB flat film actuators show high directed linear actuation strain in cross-fiber direction of greater than 25% meanwhile almost no strain in fiber direction at a relatively low electric field (120 V mum-1). The morphology of the CNT sheets has critical influence on their mechanical properties and resultant actuator performance. The results demonstrate the efficacy of microcombing and selective laser etching processes to improve the CNT fiber alignment to produce pure unidirectional strain of 33% at a relatively moderate electric field. Unidirectional D-EAP composite laminates using polyurethane and polyamide monofilaments are also employed in spring roll actuators to investigate their directional mechanical and electromechanical properties. While CNT electroded D-EAP spring roll actuators were found to have about the same performance as actuators with carbon grease electrodes (6.5% strain in CNT

  10. Insight into the electroreduction of nitrate ions at a copper electrode, in neutral solution, after determination of their diffusion coefficient by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Aouina, Nizar; Cachet, Hubert [Laboratoire Interfaces et Systemes Electrochimiques - UPR15 du CNRS, Universite Pierre et Marie Curie - Paris 6, 4, place Jussieu, F-75005 Paris (France); Debiemme-chouvy, Catherine, E-mail: catherine.debiemme-chouvy@upmc.f [Laboratoire Interfaces et Systemes Electrochimiques - UPR15 du CNRS, Universite Pierre et Marie Curie - Paris 6, 4, place Jussieu, F-75005 Paris (France); Tran, Thi Tuyet Mai [Laboratoire Interfaces et Systemes Electrochimiques - UPR15 du CNRS, Universite Pierre et Marie Curie - Paris 6, 4, place Jussieu, F-75005 Paris (France)

    2010-10-01

    The electrochemical reduction of nitrate ions at a copper electrode in an unbuffered neutral aqueous solution is studied. Using a two compartment electrochemical cell, three stationary cathodic waves, noted P1, P2 and P3, were evidenced by cyclic voltammetry at -0.9, -1.2 and -1.3 V/SCE, respectively. By comparing the electrochemical response of nitrate and nitrite containing solutions, P1 was attributed to the reduction of nitrate to nitrite. In order to assign P2 and P3 features by determining the number of electrons involved at the corresponding potential, rotating disk electrode experiments at various rotation speeds, combined with linear sweep voltammetry, were performed. Current data analysis at a given potential was carried out using Koutecky-Levich treatment taking into account water reduction. Confident values of the diffusion coefficient D of nitrate ions were assessed by electrochemical impedance spectroscopy for nitrate concentrations of 10{sup -3}, 10{sup -2} and 10{sup -1} M. For a nitrate concentration of 10{sup -2} M, D was found to be 1.31 x 10{sup -5} cm{sup 2} s{sup -1} allowing the number of electrons to be determined as 6 for P2 and 8 for P3, in accordance with nitrate reduction into hydroxylamine and ammonia, respectively. The formation of hydroxylamine was confirmed by the observation of its reoxidation at a Pt microelectrode present at the Cu electrode/nitrate solution interface.

  11. Electronic transport properties of copper and gold at atomic scale

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadzadeh, Saeideh

    2010-11-23

    The factors governing electronic transport properties of copper and gold atomic-size contacts are theoretically examined in the present work. A two-terminal conductor using crystalline electrodes is adopted. The non-equilibrium Green's function combined with the density functional tight-binding method is employed via gDFTB simulation tool to calculate the transport at both equilibrium and non-equilibrium conditions. The crystalline orientation, length, and arrangement of electrodes have very weak influence on the electronic characteristics of the considered atomic wires. The wire width is found to be the most effective geometric aspect determining the number of conduction channels. The obtained conductance oscillation and linear current-voltage curves are interpreted. To analyze the conduction mechanism in detail, the transmission channels and their decomposition to the atomic orbitals are calculated in copper and gold single point contacts. The presented results offer a possible explanation for the relation between conduction and geometric structure. Furthermore, the results are in good agreement with available experimental and theoretical studies. (orig.)

  12. Effects of pulse ON and OFF time and electrode types on the material removal rate and tool wear rate of the Ti-6Al-4V Alloy using EDM machining with reverse polarity

    Science.gov (United States)

    Praveen, L.; Geeta Krishna, P.; Venugopal, L.; Prasad, N. E. C.

    2018-03-01

    Electrical Discharge Machining (EDM) is an unconventional metal removal process that is extensively used for removing the difficult-to-machine metal such as Ti alloys, super alloys and metal matrix composites. This paper investigates the effects of pulse (ON/OFF) time on EDM machining characteristics of Ti-6Al-4V alloy using copper and graphite as electrodes in reverse polarity condition. Full factorial design method was used to design the experiments. Two variables (Pulse On and OFF) with three levels are considered. The output variables are the tool wear rate and the material removal rate. The important findings from the present work are: (1) the material removal rate (MRR) increases gradually with an increase of the Pulse ON time whereas the change is insignificant with an increase of the Pulse OFF time, (2) Between copper and graphite electrodes, the copper electrode is proved to be good in terms of MRR, (3) a combination of high pulse ON time and OFF time is desirable for high MRR rate in the Cu electrode whereas for the graphite electrode, a combination of high pulse ON time and low pulse OFF time is desirable for high MRR rate, (4) the tool wear rate (TWR) reduces with the Pulse On or OFF time, the rate of TWR is uniform for the graphite electrode in contrast to abrupt decrease from 25 to 50 μs (pulse ON time) in the copper electrode, (5) In order to keep the TWR as minimum possible, it is desirable to have a combination of high pulse ON time and OFF time for both the copper and the graphite electrode.

  13. Application of N-doped graphene modified carbon ionic liquid electrode for direct electrochemistry of hemoglobin.

    Science.gov (United States)

    Sun, Wei; Dong, Lifeng; Deng, Ying; Yu, Jianhua; Wang, Wencheng; Zhu, Qianqian

    2014-06-01

    Nitrogen-doped graphene (NG) was synthesized and used for the investigation on direct electrochemistry of hemoglobin (Hb) with a carbon ionic liquid electrode as the substrate electrode. Due to specific characteristics of NG such as excellent electrocatalytic property and large surface area, direct electron transfer of Hb was realized with enhanced electrochemical responses appearing. Electrochemical behaviors of Hb on the NG modified electrode were carefully investigated with the electrochemical parameters calculated. The Hb modified electrode exhibited excellent electrocatalytic reduction activity toward different substrates, such as trichloroacetic acid and H2O2, with wider dynamic range and lower detection limit. These findings show that NG can be used for the preparation of chemically modified electrodes with improved performance and has potential applications in electrochemical sensing. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Copper sulphate poisoning in horses

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, M

    1975-01-01

    In the archives of the Clinic for Internal Diseases of Domestic Animals at the Veterinary Faculty of Zagreb University some thirty cases of horse disease diagnosed as copper sulphate poisoning were noted. The data correspond in many respects to the clinical findings of copper sulphate poisoning in other domestic animals. A series of experimental horse poisonings were undertaken in order to determine the toxicity of copper sulphate. The research results are as follows: Horses are sensitive to copper sulphate. Even a single application of 0.125 g/kg body weight in 1% concentration by means of incubation into the stomach causes stomach and gut disturbances and other poisoning symptoms. Poisoning occurs in two types: acute and chronic. The former appears after one to three applications of copper sulphate solution and is characterized by gastroenteritis, haemolysis, jaundice and haemoglobinuria with signs of consecutive damage of kidney, liver and other organs. The disease, from the first application to death lasts for two weeks. Chronic poisoning is caused by ingestion of dry copper sulphate in food (1% solution dried on hay or clover) for two or more months. There are chronic disturbances of stomach and gut and loss of weight, and consecutive (three to four) haemolytic crises similar to those of acute poisoning. From the beginning of poisoning to death six or more months can elapse.

  15. Industrial Tests to Modify Molten Copper Slag for Improvement of Copper Recovery

    Science.gov (United States)

    Guo, Zhengqi; Zhu, Deqing; Pan, Jian; Zhang, Feng; Yang, Congcong

    2018-04-01

    In this article, to improve the recovery of copper from copper slag by flotation process, industrial tests of the modification process involving addition of a composite additive into molten copper slag were conducted, and the modified slag was subjected to the flotation process to confirm the modification effect. The phase evolution of the slag in the modification process was revealed by thermodynamic calculations, x-ray diffraction, optical microscopy and scanning electron microscopy. The results show that more copper was transformed and enriched in copper sulfide phases. The magnetite content in the modified slag decreased, and that of "FeO" increased correspondingly, leading to a better fluidity of the molten slag, which improved the aggregation and growth of fine particles of the copper sulfide minerals. Closed-circuit flotation tests of the original and modified slags were conducted, and the results show that the copper recovery increased obviously from 69.15% to 73.38%, and the copper grade of concentrates was elevated slightly from 20.24% to 21.69%, further confirming that the industrial tests of the modification process were successful. Hence, the modification process has a bright future in industrial applications for enhancing the recovery of copper from the copper slag.

  16. Growth of a Copper-Gold Alloy Phase by Bulk Copper Electrodeposition on Gold Investigated by In Situ STM

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Møller, Per

    1995-01-01

    the potential in the double-layer charging region from 500 to -100 mV and back to 500 mV at a sweep rate of 1 mV/s in an acidified copper sulfate electrolyte (0.01M H2SO4, 0.01M CuSO4, and Millipore water). After completion of the first cycle the gold surface had recrystallized and nuclei of an alloy phase were...... in peak potential for the anodic current transient from E = 20 mV to E = -2 mV was observed after completion of four subsequent cycles of copper electrodeposition/dissolution. The shift is suggested to be equal to the change in potential of the working electrode owing to the formation of the alloy phase....

  17. Determinação voltamétrica do herbicida glifosato em águas naturais utilizando eletrodo de cobre Voltammetric determination of glyphosate in natural waters with a copper electrode

    Directory of Open Access Journals (Sweden)

    Andresa Fabiana Garcia

    2007-01-01

    Full Text Available The aim of this work was to investigate the copper electrode behavior in the voltammetric determination of glyphosate. The best conditions for this determination are phosphate buffer 0.05 mol L-1 and pH 7.3, and the peak potential is observed at 187 mV. LD and LQ values are 59 µg L-1 e 196 µg L-1, respectively. A water sample was analysed for glyphosate and identical results were obtained by using the analytical curve and the standard addition method. The comparison with a voltammetric method with Hg electrode, after a reaction with nitrite, showed quite concordant results for the analysis of the surface water sample. Therefore, the proposed method can be applied to direct determinations of the herbicide in waters, decreasing the time of analysis; besides, the method is in agreement with the "green chemistry" concept.

  18. The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Jokić Anja B.

    2013-01-01

    Full Text Available The application of the hydrogen-palladium electrode (H2/Pd as the indicator electrode for the determination of relative acidity scale (Es, mV of tetrahydrofuran (THF and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH, which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

  19. The industrial application of a uranium dioxide electrode

    International Nuclear Information System (INIS)

    Needes, C.R.S.; Nicol, M.J.; Finkelstein, N.P.; Ormrod, G.T.W.

    1975-01-01

    A correlation between the potential of a UO 2 electrode and the rate of recovery of uranium has been proved in laboratory and plant trials. When the recovery rates change because of variation in the concentrations of Fe(III), Fe(II), SO 2- 4 , and H + , a positive correlation is observed. However, an increase in the concentration of phosphate in solution produces an increase in the UO 2 electrode potential but a decrease in the rate of leaching of UO 2 . The correlation between the UO 2 electrode potential and the rate of leaching of UO 2 is then negative. It is concluded that, as a control device, the electrode cannot compete with the platinum electrode for use on certain plants. Nevertheless, the UO 2 electrode will act as a useful warning device if the total concentration of iron in solution decreases to below a level concomitant with the economic recovery of uranium. Furthermore, because of the positive correlation between the UO 2 electrode potential and the phosphate concentration, the electrode will also be of value in the detection of an increase in the phosphate level in solution. When it was incorporated in a suitable industrial probe, the electrode was found to be able to withstand the rigours of the leaching conditions in a large pilot-plant pachuca, and only failed after six weeks operation [af

  20. Nanostructured ternary electrodes for energy-storage applications

    KAUST Repository

    Baby, Rakhi Raghavan

    2012-02-13

    A three-component, flexible electrode is developed for supercapacitors over graphitized carbon fabric, utilizing γ-MnO 2 nanoflowers anchored onto carbon nanotubes (γ-MnO 2/CNT) as spacers for graphene nanosheets (GNs). The three-component, composite electrode doubles the specific capacitance with respect to GN-only electrodes, giving the highest-reported specific capacitance (308 F g -1) for symmetric supercapacitors containing MnO 2 and GNs using a two-electrode configuration, at a scan rate of 20 mV s -1. A maximum energy density of 43 W h kg -1 is obtained for our symmetric supercapacitors at a constant discharge-current density of 2.5 A g -1 using GN-(γ-MnO 2/CNT)-nanocomposite electrodes. The fabricated supercapacitor device exhibits an excellent cycle life by retaining ≈90% of the initial specific capacitance after 5000 cycles. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Impedimetric Thiourea Sensing in Copper Electrorefining Bath based on DC Magnetron Sputtered Nanosilver as Highly Uniform Transducer

    International Nuclear Information System (INIS)

    Mozaffari, S.A.; Amoli, H. Salar; Simorgh, S.; Rahmanian, R.

    2015-01-01

    Highlights: • Fabrication of a novel disposable impedimetric thiourea sensor based on nanostructured Ag film transducer. • Exploiting sputtering as a high-tech method for preparation of highly uniform nanostructured Ag film. • A wonderful combination of nanostructured Ag film and carbon paper substrate as remarkably stable and reproducible sensor for thiourea detection in copper electrorefining bath. • Application of impedimetric assessment for thiourea monitoring due to its rapidity, sensitivity, and repeatability. - Abstract: Highly uniform sputtered nanostructured silver (Nano-Ag) film on the conductive carbon paper (CP) substrate (Nano-Ag/CP) was applied as a novel approach for thiourea (TU) measurement in copper electrorefining bath. Nano-Ag film was achieved by direct current (DC) magnetron sputtering system at the optimized instrumental deposition conditions. Characterization of the surface structure of Nano-Ag film by field emission-scanning electron microscopy (FE-SEM), exhibits uniform Nano-Ag film as an effective transducer for TU sensing. Step by step monitoring of Nano-Ag/CP electrode fabrication were performed using electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Fabricated Nano-Ag/CP electrode was used for TU determination using EIS assessment. The impedimetric results show high sensitivity for TU sensing within 2.0–250 ppm.

  2. Diode-rectified multiphase AC arc for the improvement of electrode erosion characteristics

    Science.gov (United States)

    Tanaka, Manabu; Hashizume, Taro; Saga, Koki; Matsuura, Tsugio; Watanabe, Takayuki

    2017-11-01

    An innovative multiphase AC arc (MPA) system was developed on the basis of a diode-rectification technique to improve electrode erosion characteristics. Conventionally, electrode erosion in AC arc is severer than that in DC arc. This originated from the fact that the required properties for the cathode and anode are different, although an AC electrode works as the cathode and the anode periodically. To solve this problem, a separation of AC electrodes into pairs of thoriated tungsten cathode and copper anode by diode-rectification was attempted. A diode-rectified multiphase AC arc (DRMPA) system was then successfully established, resulting in a drastic improvement of the erosion characteristics. The electrode erosion rate in the DRMPA was less than one-third of that in the conventional MPA without the diode rectification. In order to clarify its erosion mechanism, electrode phenomena during discharge were visualized by a high-speed camera system with appropriate band-pass filters. Fluctuation characteristics of the electrode temperature in the DRMPA were revealed.

  3. Copper Bioleaching in China: Review and Prospect

    OpenAIRE

    Shenghua Yin; Leiming Wang; Eugie Kabwe; Xun Chen; Rongfu Yan; Kai An; Lei Zhang; Aixiang Wu

    2018-01-01

    The commercial application of copper bioleaching, an environmentally-friendly approach for low-grade and secondary mineral resources recycling, has increased worldwide since the 2000s. As the world’s second-largest economic entity and the largest developing country, China has the largest demand for metal resources, significantly advancing the theory and industrial technology of copper bioleaching. This paper reviews the exploration and application of copper bioleaching in China. Two typical b...

  4. Improving electrochemical performance of flexible thin film electrodes with micropillar array structures

    International Nuclear Information System (INIS)

    Myllymaa, Sami; Myllymaa, Katja; Lappalainen, Reijo; Pirinen, Sami; Pakkanen, Tapani A; Pakkanen, Tuula T; Suvanto, Mika

    2012-01-01

    For reliable function, bioelectrodes require a stable, low-impedance contact with the target tissue. In biosignal monitoring applications, in which low ion current densities are recorded, it is important to minimize electrode contact impedances. Recently, several flexible electrode concepts have been introduced for single-patient use. These electrodes conform well on the patient skin enabling an artifact-free, low-noise recording. In this study, polydimethylsiloxane (PDMS) elastomer was used as an electrode substrate material. One half of the substrates were surface-patterned with micropillars produced by using micro-working robot-made mold inserts and a replica molding technique. The substrates were subsequently coated with thin films of titanium (Ti), copper (Cu), silver (Ag) or silver–silver chloride (Ag/AgCl). Electrical impedance spectroscopy studies revealed that the micropillar structure caused statistically significant reductions in impedance modulus and phase for each coating candidate. The relative effect was strongest for pure Ag, for which the values of the real part (Z′) and the imaginary part (Z″) decreased to less than one tenth of the original (smooth) values. However, Ag/AgCl, as expected, proved to be a superior electrode material. Coating with chloride drastically reduced the interfacial impedance compared to pure Ag. Further significant reduction was achieved by the micropillars, since the phase angle declined from 10–13° (for smooth samples, f < 50 Hz) to a value as low as 5°. Equivalent circuit modeling was used to obtain a better understanding of phenomena occurring at various electrode–electrolyte interfaces. The knowledge obtained in this study will be exploited in the further development of flexible electrodes and miniaturized biointerfaces with improved electrochemical characteristics. (paper)

  5. Copper and brass aged at open circuit potential in slightly alkaline solutions

    International Nuclear Information System (INIS)

    Procaccini, R.; Vazquez, M.; Cere, S.

    2009-01-01

    Surface oxide films were grown on 99.99% copper and brass (copper-zinc alloy, Cu77Zn21Al2) in 0.1 mol L -1 borax solution at open circuit potential and were characterized using various experimental techniques. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. The thickness of the oxide layers on copper and brass was compared by chronopotentiometric curves and potentiodynamic reductions. The electrical properties of each oxide were analyzed by means of electrochemical impedance spectroscopy. Their influence on the oxygen reduction reaction was also investigated using voltammetry hydrodynamic tools such as the rotating disk electrode. The results show that the incorporation of Zn to Cu in brass changes the composition and the thickness of the surface film. The films grown on brass tend to be thicker but less resistive and Zn compounds incorporate to the film. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction is strongly inhibited on oxidized electrodes, particularly in the case of brass. The global number of exchanged electrons remains close to four and seems to be independent of the presence of surface oxides.

  6. Structure of Polymer Fibers Fabricated by Electrospinning Method Utilizing a Metal Wire Electrode in a Capillary Tube

    Science.gov (United States)

    Onozuka, Shintaro; Hoshino, Rikiya; Mizuno, Yoshinori; Shinbo, Kazunari; Ohdaira, Yasuo; Baba, Akira; Kato, Keizo; Kaneko, Futao

    We fabricated electrospun poly (vinylalcohol) (PVA) fibers using a copper wire electrode in Teflon capillary tube, and the SEM images were observed. The apparatus in this method is reasonable, and needed volume of polymer solution and distance between the electrodes can be largely reduced compared to conventional method. The wire electrode tip position in the capillary tube is also important in this method and should be close to the polymer solution surface.

  7. Voltammetric study of adenine complex with copper on mercury electrode

    Czech Academy of Sciences Publication Activity Database

    Jelen, František; Kouřilová, Alena; Hasoň, Stanislav; Kizek, R.; Trnková, L.

    2009-01-01

    Roč. 21, 3-5 (2009), s. 439-444 ISSN 1040-0397 R&D Projects: GA AV ČR(CZ) IAA100040602; GA AV ČR(CZ) IAA400040804; GA AV ČR(CZ) KAN200040651 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : cyclic voltammetry * elimination voltammetry * copper-adenine complex Subject RIV: BO - Biophysics Impact factor: 2.630, year: 2009

  8. Cytotoxicity evaluation of polymer-derived ceramics for pacemaker electrode applications.

    Science.gov (United States)

    Grossenbacher, Jonas; Gullo, Maurizio R; Dalcanale, Federico; Blugan, Gurdial; Kuebler, Jakob; Lecaudé, Stéphanie; Tevaearai Stahel, Hendrik; Brugger, Juergen

    2015-11-01

    Ceramics are known to be chemically stable, and the possibility to electrically dope polymer-derived ceramics makes it a material of interest for implantable electrode applications. We investigated cytotoxic characteristics of four polymer-derived ceramic candidates with either electrically conductive or insulating properties. Cytotoxicity was assessed by culturing C2C12 myoblast cells under two conditions: by exposing them to material extracts and by putting them directly in contact with material samples. Cell spreading was optically evaluated by comparing microscope observations immediately after the materials insertion and after 24 h culturing. Cell viability (MTT) and mortality (LDH) were quantified after 24-h incubation in contact with the materials. Comparison was made with biocompatible positive references (alumina, platinum, biocompatible stainless steel 1.4435), negative references (latex, stainless steel 1.4301) and controls (no material present in the culture wells). We found that the cytotoxic properties of tested ceramics are comparable to established reference materials. These ceramics, which are reported to be very stable, can be microstructured and electrically doped to a wide range of conductivity and are thus excellent candidates for implantable electrode applications including pacemakers. © 2015 Wiley Periodicals, Inc.

  9. Stress evolution in elastic-plastic electrodes during electrochemical processes: A numerical method and its applications

    Science.gov (United States)

    Wen, Jici; Wei, Yujie; Cheng, Yang-Tse

    2018-07-01

    Monitoring in real time the stress state in high capacity electrodes during charge-discharge processes is pivotal to the performance assessment and structural optimization of advanced batteries. The wafer curvature measurement technique broadly employed in thin-film industry, together with stress analysis using the Stoney equation, has been successfully adopted to measure in situ the stress in thin film electrodes. How large plastic deformation or interfacial delamination during electrochemical cycles in such electrodes affects the applicability of Stoney equation remains unclear. Here we develop a robust electrochemical-mechanical coupled numerical procedure to investigate the influence of large plastic deformation and interfacial failure on the measured stress in thin film electrodes. We identify how the constitutive behavior of electrode materials and film-substrate interfacial properties affect the measured stress-capacity curves of electrodes, and hence establish the relationship of electrode material parameters with the characteristics of stress-capacity curves. Using Li-ions batteries as examples, we show that plastic deformation and interfacial delamination account for the asymmetric stress-capacity loops seen in in situ stress measurements. The methods used here, along with the finite-element code in the supplementary material, may be used to model the electrode behavior as a function of the state of charge.

  10. Probing Electrode Heterogeneity Using Fourier-Transformed Alternating Current Voltammetry: Application to a Dual-Electrode Configuration.

    Science.gov (United States)

    Tan, Sze-Yin; Unwin, Patrick R; Macpherson, Julie V; Zhang, Jie; Bond, Alan M

    2017-03-07

    Quantitative studies of electron transfer processes at electrode/electrolyte interfaces, originally developed for homogeneous liquid mercury or metallic electrodes, are difficult to adapt to the spatially heterogeneous nanostructured electrode materials that are now commonly used in modern electrochemistry. In this study, the impact of surface heterogeneity on Fourier-transformed alternating current voltammetry (FTACV) has been investigated theoretically under the simplest possible conditions where no overlap of diffusion layers occurs and where numerical simulations based on a 1D diffusion model are sufficient to describe the mass transport problem. Experimental data that meet these requirements can be obtained with the aqueous [Ru(NH 3 ) 6 ] 3+/2+ redox process at a dual-electrode system comprised of electrically coupled but well-separated glassy carbon (GC) and boron-doped diamond (BDD) electrodes. Simulated and experimental FTACV data obtained with this electrode configuration, and where distinctly different heterogeneous charge transfer rate constants (k 0 values) apply at the individual GC and BDD electrode surfaces, are in excellent agreement. Principally, because of the far greater dependence of the AC current magnitude on k 0 , it is straightforward with the FTACV method to resolve electrochemical heterogeneities that are ∼1-2 orders of magnitude apart, as applies in the [Ru(NH 3 ) 6 ] 3+/2+ dual-electrode configuration experiments, without prior knowledge of the individual kinetic parameters (k 0 1 and k 0 2 ) or the electrode size ratio (θ 1 :θ 2 ). In direct current voltammetry, a difference in k 0 of >3 orders of magnitude is required to make this distinction.

  11. Electrodeposited reduced-graphene oxide/cobalt oxide electrodes for charge storage applications

    Energy Technology Data Exchange (ETDEWEB)

    García-Gómez, A. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Eugénio, S., E-mail: s.eugenio@tecnico.ulisboa.pt [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Duarte, R.G. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); ESTBarreiro, Instituto Politécnico de Setúbal, Setúbal (Portugal); Silva, T.M. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); ADEM, GI-MOSM, ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Lisboa (Portugal); Carmezim, M.J. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); ESTSetúbal, Instituto Politécnico de Setúbal, Setúbal (Portugal); Montemor, M.F. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal)

    2016-09-30

    Highlights: • Electrochemically reduced graphene/CoOx composites were successfully produced by electrodeposition. • The composite material presents a specific capacitance of about 430 F g{sup −1}. • After heat treatment, the capacitance retention of the composite was 76% after 3500 cycles. - Abstract: In the present work, electrochemically reduced-graphene oxide/cobalt oxide composites for charge storage electrodes were prepared by a one-step pulsed electrodeposition route on stainless steel current collectors and after that submitted to a thermal treatment at 200 °C. A detailed physico-chemical characterization was performed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Raman spectroscopy. The electrochemical response of the composite electrodes was studied by cyclic voltammetry and charge-discharge curves and related to the morphological and phase composition changes induced by the thermal treatment. The results revealed that the composites were promising materials for charge storage electrodes for application in redox supercapacitors, attaining specific capacitances around 430 F g{sup −1} at 1 A g{sup −1} and presenting long-term cycling stability.

  12. Electrochemical and electrophoretic deposition of enzymes : Principles, differences and application in miniaturized biosensor and biofuel cell electrodes

    NARCIS (Netherlands)

    Ammam, Malika

    2014-01-01

    Recent advances in nano-biotechnology have made it possible to realize a great variety of enzyme electrodes suitable for sensing and energy applications. In coating miniaturized electrodes with enzymes, there is no doubt that most of the available deposition processes suffer from the difficulty in

  13. Titanium electroplating of copper in molten salt media

    International Nuclear Information System (INIS)

    Renaud, Denis

    1985-01-01

    After a bibliographical survey on electroplating in molten salt media and on the electrolytic production of titanium, the author explains the reasons for the choice of the LiF-NaF-KF eutectic mix as solvent. He recalls the main properties which are used, and describes the conventional and convolutional processing of data obtained by linear volt-amperometry. He presents the electrolyte preparation mode which takes into account the existence of titanium ions with intermediate oxidation degree, and the reactivity of titanium with oxygenated species. Experimental results are discussed. Then, after the study of the mechanism of reduction of trivalent titanium into titanium on molybdenum (intermetallic diffusion is here negligible), he reports the study of this mechanism on copper (it is a more complicated situation, due to combinations between titanium and copper). The effect of different parameters (electrolyte purity, current density, electrode potential and temperature) is interpreted in order to identify optimal conditions for titanium electroplating of copper [fr

  14. Microfabricated Reference Electrodes and their Biosensing Applications

    Directory of Open Access Journals (Sweden)

    M. Jamal Deen

    2010-03-01

    Full Text Available Over the past two decades, there has been an increasing trend towards miniaturization of both biological and chemical sensors and their integration with miniaturized sample pre-processing and analysis systems. These miniaturized lab-on-chip devices have several functional advantages including low cost, their ability to analyze smaller samples, faster analysis time, suitability for automation, and increased reliability and repeatability. Electrical based sensing methods that transduce biological or chemical signals into the electrical domain are a dominant part of the lab-on-chip devices. A vital part of any electrochemical sensing system is the reference electrode, which is a probe that is capable of measuring the potential on the solution side of an electrochemical interface. Research on miniaturization of this crucial component and analysis of the parameters that affect its performance, stability and lifetime, is sparse. In this paper, we present the basic electrochemistry and thermodynamics of these reference electrodes and illustrate the uses of reference electrodes in electrochemical and biological measurements. Different electrochemical systems that are used as reference electrodes will be presented, and an overview of some contemporary advances in electrode miniaturization and their performance will be provided.

  15. Generation of copper, nickel, and CuNi alloy nanoparticles by spark discharge

    International Nuclear Information System (INIS)

    Muntean, Alex; Wagner, Moritz; Meyer, Jörg; Seipenbusch, Martin

    2016-01-01

    The generation of copper, nickel, and copper-nickel alloy nanoparticles by spark discharge was studied, using different bespoke alloy feedstocks. Roughly spherical particles with a primary particle Feret diameter of 2–10 nm were produced and collected in agglomerate form. The copper-to-nickel ratios determined by Inductively coupled plasma mass spectrometry (ICP-MS), and therefore averaged over a large number of particles, matched the nominal copper content quite well. Further investigations showed that the electrode compositions influenced the evaporation rate and the primary particle size. The evaporation rate decreased with increasing copper content, which was found to be in good accordance with the Llewellyn-Jones model. However, the particle diameter was increasing with an increasing copper content, caused by a decrease in melting temperature due to the lower melting point of copper. Furthermore, the alloy compositions on the nanoscale were investigated via EDX. The nanoparticles exhibited almost the same composition as the used alloy feedstock, with a deviation of less than 7 percentage points. Therefore, no segregation could be detected, indicating the presence of a true alloy even on the nanoscale.

  16. Copper Powder and Chemicals: edited proceedings of a seminar

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    Various papers are presented covering the following topics: Status of Copper Chemical Industry in India, Copper Powder from Industrial Wastes, Manufacture of Copper Hydroxide and High Grade Cement Copper from Low Grade Copper Ore, Manufacture of Copper Sulphate as a By-Product, Hydrometallurgical Treatments of Copper Converter and Smelter Slage for Recovering Copper and other Non-Ferrous Metals, Recovery of Copper from Dilute Solutions, Use of Copper Compounds as Fungicides in India, Copper in Animal Husbandry, and Use of Copper Powder and Chemicals for Marine Applications. The keynote paper given at the Seminar was on Conservation of Copper for Better Use.

  17. 3D Printed Dry EEG Electrodes.

    Science.gov (United States)

    Krachunov, Sammy; Casson, Alexander J

    2016-10-02

    Electroencephalography (EEG) is a procedure that records brain activity in a non-invasive manner. The cost and size of EEG devices has decreased in recent years, facilitating a growing interest in wearable EEG that can be used out-of-the-lab for a wide range of applications, from epilepsy diagnosis, to stroke rehabilitation, to Brain-Computer Interfaces (BCI). A major obstacle for these emerging applications is the wet electrodes, which are used as part of the EEG setup. These electrodes are attached to the human scalp using a conductive gel, which can be uncomfortable to the subject, causes skin irritation, and some gels have poor long-term stability. A solution to this problem is to use dry electrodes, which do not require conductive gel, but tend to have a higher noise floor. This paper presents a novel methodology for the design and manufacture of such dry electrodes. We manufacture the electrodes using low cost desktop 3D printers and off-the-shelf components for the first time. This allows quick and inexpensive electrode manufacturing and opens the possibility of creating electrodes that are customized for each individual user. Our 3D printed electrodes are compared against standard wet electrodes, and the performance of the proposed electrodes is suitable for BCI applications, despite the presence of additional noise.

  18. 3D Printed Dry EEG Electrodes

    Directory of Open Access Journals (Sweden)

    Sammy Krachunov

    2016-10-01

    Full Text Available Electroencephalography (EEG is a procedure that records brain activity in a non-invasive manner. The cost and size of EEG devices has decreased in recent years, facilitating a growing interest in wearable EEG that can be used out-of-the-lab for a wide range of applications, from epilepsy diagnosis, to stroke rehabilitation, to Brain-Computer Interfaces (BCI. A major obstacle for these emerging applications is the wet electrodes, which are used as part of the EEG setup. These electrodes are attached to the human scalp using a conductive gel, which can be uncomfortable to the subject, causes skin irritation, and some gels have poor long-term stability. A solution to this problem is to use dry electrodes, which do not require conductive gel, but tend to have a higher noise floor. This paper presents a novel methodology for the design and manufacture of such dry electrodes. We manufacture the electrodes using low cost desktop 3D printers and off-the-shelf components for the first time. This allows quick and inexpensive electrode manufacturing and opens the possibility of creating electrodes that are customized for each individual user. Our 3D printed electrodes are compared against standard wet electrodes, and the performance of the proposed electrodes is suitable for BCI applications, despite the presence of additional noise.

  19. A single-walled carbon nanotubes/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/copper hexacyanoferrate hybrid film for high-volumetric performance flexible supercapacitors

    Science.gov (United States)

    Li, Jianmin; Li, Haizeng; Li, Jiahui; Wu, Guiqing; Shao, Yuanlong; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

    2018-05-01

    Volumetric energy density is generally considered to be detrimental to the actual application of supercapacitors, which has provoked a range of research work on increasing the packing density of electrodes. Herein, we fabricate a free-standing single-walled carbon nanotubes (SWCNTs)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/copper hexacyanoferrate (CuHCF) nanoparticles (NPs) composite supercapacitor electrode, with a high packing density of 2.67 g cm-3. The pseudocapacitive CuHCF NPs are decorated onto the SWCNTs/PEDOT:PSS networks and filled in interspace to increase both of packing density and specific capacitance. This hybrid electrode exhibits a series of outstanding performances, such as high electric conductivity, ultrahigh areal and volumetric capacitances (969.8 mF cm-2 and 775.2 F cm-3 at scan rate of 5 mV s-1), long cycle life and superior rate capability. The asymmetric supercapacitor built by using the SWCNTs/PEDOT:PSS/CuHCF film as positive electrode and Mo-doped WO3/SWCNTs film as negative electrode, can deliver a high energy density of 30.08 Wh L-1 with a power density of 4.25 kW L-1 based on the total volume of the device. The approach unveiled in this study could provide important insights to improving the volumetric performance of energy storage devices and help to reach the critical targets for high rate and high power density demand applications.

  20. Solvent extraction and its practical application for the recovery of copper and uranium

    International Nuclear Information System (INIS)

    Reuter, J.

    1975-01-01

    In recent years solvent extraction has been developed to a stage that allows practical application first for the recovery of uranium and later also for winning copper from low-grade acid-soluble ores. By now it has been realized in several plants with great technical and ecomomic success. Solvent extraction includes the following essential operations: leaching, solvent extraction, back extraction of the organically bonded valuable mineral to an acid, aqueous solution and finally separation of the valuable metal from the final acid by precipitation or electrolytic procedures. Upon assessing the cost of the solvent extraction process for the recovery of copper it turns out that from an economic point of view it is significantly superior to the conventional cementation process. (orig.) [de

  1. Electrochemical capacitor behavior of copper sulfide (CuS) nanoplatelets

    Energy Technology Data Exchange (ETDEWEB)

    Justin Raj, C.; Kim, Byung Chul; Cho, Won-Je; Lee, Won-Gil; Seo, Yongseong; Yu, Kook-Hyun, E-mail: yukook@dongguk.edu

    2014-02-15

    Highlights: • The electrochemical supercapacitor electrode was fabricated using CuS nanoplatelets. • CuS electrodes shows better electrochemical properties in aqueous LiClO{sub 4} electrolyte. • The heat treated CuS electrode shows an excellent pseudocapacitance performance than bare CuS electrode. -- Abstract: Copper sulfide (CuS) nanoplatelets have been fabricated by simple low temperature chemical bath deposition technique for electrochemical supercapacitor electrodes. The morphology and structural properties of the electrodes were analyzed using scanning electron microscopy and X-ray diffraction. The effect of heat treatment on electrochemical properties of CuS electrodes were examined by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge tests. Results show that bare and heat treated CuS has pseudocapacitive characteristic within the potential range of −0.6 to 0.3 V (vs. Ag/AgCl) in aqueous 1 M LiClO{sub 4} solution. The pseudocapacitance is induced mainly by lithium ions insertion/extraction with the CuS electrodes. The specific capacitance of 72.85 F g{sup −1} was delivered by heat treated CuS film at a scan rate of 5 mV s{sup −1} with an energy and power density of 6.23 W h kg{sup −1} and 1.75 kW kg{sup −1} at 3 Ag{sup −1} constant discharge current which is comparatively higher than that of as deposited CuS electrode.

  2. Application of Heterogeneous Copper Catalyst in a Continuous Flow Process: Dehydrogenation of Cyclohexanol

    Science.gov (United States)

    Glin´ski, Marek; Ulkowska, Urszula; Iwanek, Ewa

    2016-01-01

    In this laboratory experiment, the synthesis of a supported solid catalyst (Cu/SiO2) and its application in the dehydrogenation of cyclohexanol performed under flow conditions was studied. The experiment was planned for a group of two or three students for two 6 h long sessions. The copper catalyst was synthesized using incipient wetness…

  3. Silicon-embedded copper nanostructure network for high energy storage

    Science.gov (United States)

    Yu, Tianyue

    2016-03-15

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  4. Silicon-embedded copper nanostructure network for high energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Tianyue

    2018-01-23

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  5. Transparent Electrodes for Efficient Optoelectronics

    KAUST Repository

    Morales-Masis, Monica

    2017-03-30

    With the development of new generations of optoelectronic devices that combine high performance and novel functionalities (e.g., flexibility/bendability, adaptability, semi or full transparency), several classes of transparent electrodes have been developed in recent years. These range from optimized transparent conductive oxides (TCOs), which are historically the most commonly used transparent electrodes, to new electrodes made from nano- and 2D materials (e.g., metal nanowire networks and graphene), and to hybrid electrodes that integrate TCOs or dielectrics with nanowires, metal grids, or ultrathin metal films. Here, the most relevant transparent electrodes developed to date are introduced, their fundamental properties are described, and their materials are classified according to specific application requirements in high efficiency solar cells and flexible organic light-emitting diodes (OLEDs). This information serves as a guideline for selecting and developing appropriate transparent electrodes according to intended application requirements and functionality.

  6. Transparent Electrodes for Efficient Optoelectronics

    KAUST Repository

    Morales-Masis, Monica; De Wolf, Stefaan; Woods-Robinson, Rachel; Ager, Joel W.; Ballif, Christophe

    2017-01-01

    With the development of new generations of optoelectronic devices that combine high performance and novel functionalities (e.g., flexibility/bendability, adaptability, semi or full transparency), several classes of transparent electrodes have been developed in recent years. These range from optimized transparent conductive oxides (TCOs), which are historically the most commonly used transparent electrodes, to new electrodes made from nano- and 2D materials (e.g., metal nanowire networks and graphene), and to hybrid electrodes that integrate TCOs or dielectrics with nanowires, metal grids, or ultrathin metal films. Here, the most relevant transparent electrodes developed to date are introduced, their fundamental properties are described, and their materials are classified according to specific application requirements in high efficiency solar cells and flexible organic light-emitting diodes (OLEDs). This information serves as a guideline for selecting and developing appropriate transparent electrodes according to intended application requirements and functionality.

  7. An improved amperometric L-lactate biosensor based on covalent immobilization of microbial lactate oxidase onto carboxylated multiwalled carbon nanotubes/copper nanoparticles/polyaniline modified pencil graphite electrode.

    Science.gov (United States)

    Dagar, Kusum; Pundir, C S

    2017-01-01

    An improved amperometric l-lactate biosensor was constructed based on covalent immobilization of lactate oxidase (LOx) from Pediococcus species onto carboxylated multiwalled carbon nanotubes (cMWCNT)/copper nanoparticles (CuNPs)/polyaniline (PANI) hybrid film electrodeposited on the surface of a pencil graphite electrode (PGE). The enzyme electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS), while CuNPs synthesized by chemical reduction method, were characterized by transmission electron microscopy (TEM), UV spectrascopy and X-ray diffraction (XRD). The biosensor showed maximum response within 5s at pH 8.0 in 0.05M sodium phosphate buffer and 37°C, when operated at 20mVs -1 . The biosensor had a detection limit of 0.25μM with a wide working range between 1μM-2500μM. The biosensor was employed for measurement of l-lactic acid level in plasma of apparently healthy and diseased persons. Analytical recovery of added lactic acid in plasma was 95.5%. Within- and between-batch coefficients of variations were 6.24% and 4.19% respectively. There was a good correlation (R 2 =0.97) between plasma lactate values as measured by standard enzymatic spectrophotometric method and the present biosensor. The working enzyme electrode was used 180 times over a period of 140 days, when stored at 4°C. Copyright © 2016. Published by Elsevier Inc.

  8. ISO 14001 Environmental Management System and The Application to The Copper Sector

    Directory of Open Access Journals (Sweden)

    İrfan ERTUĞRUL

    2013-12-01

    Full Text Available This study presents firstly Environmental Management and Environmental Management Systems (EMS. The certification process of ISO 14001 EMS is described in the Copper Industry that begin the environmental activities by completely considering environment. Evaluating the environmental impacts of business, it is presented the process including EMS so as to dispose of waste, the creation of process, the application difficulties and the benefits of EMS.

  9. Patterned self-assembled monolayers of alkanethiols on copper nanomembranes by submerged laser ablation

    Science.gov (United States)

    Rhinow, Daniel; Hampp, Norbert A.

    2012-06-01

    Self-assembled monolayers (SAMs) of alkanethiols are major building blocks for nanotechnology. SAMs provide a functional interface between electrodes and biomolecules, which makes them attractive for biochip fabrication. Although gold has emerged as a standard, copper has several advantages, such as compatibility with semiconductors. However, as copper is easily oxidized in air, patterning SAMs on copper is a challenging task. In this work we demonstrate that submerged laser ablation (SLAB) is well-suited for this purpose, as thiols are exchanged in-situ, avoiding air exposition. Using different types of ω-substituted alkanethiols we show that alkanethiol SAMs on copper surfaces can be patterned using SLAB. The resulting patterns were analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Both methods indicate that the intense laser beam promotes the exchange of thiols at the copper surface. Furthermore, we present a procedure for the production of free-standing copper nanomembranes, oxidation-protected by alkanethiol SAMs. Incubation of copper-coated mica in alkanethiol solutions leads to SAM formation on both surfaces of the copper film due to intercalation of the organic molecules. Corrosion-protected copper nanomembranes were floated onto water, transferred to electron microscopy grids, and subsequently analyzed by electron energy loss spectroscopy (EELS).

  10. Analytical Applications of Solid and Paste Amalgam Electrodes

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Barek, J.

    2009-01-01

    Roč. 39, č. 3 (2009), s. 189-203 ISSN 1040-8347 R&D Projects: GA ČR GA203/07/1195; GA AV ČR IAA400400806; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z40400503 Keywords : solid amalgam electrodes * voltammetry * paste amalgam electrodes * reference amalgam electrodes Subject RIV: CG - Electrochemistry Impact factor: 2.621, year: 2009

  11. Copper Nanowire Production for Interconnect Applications

    Science.gov (United States)

    Han, Jin-Woo (Inventor); Meyyappan, Meyya (Inventor)

    2014-01-01

    A method of fabricating metallic Cu nanowires with lengths up to about 25 micrometers and diameters in a range 20-100 nanometers, or greater if desired. Vertically oriented or laterally oriented copper oxide structures (CuO and/or Cu2O) are grown on a Cu substrate. The copper oxide structures are reduced with 99+ percent H or H2, and in this reduction process the lengths decrease (to no more than about 25 micrometers), the density of surviving nanostructures on a substrate decreases, and the diameters of the surviving nanostructures have a range, of about 20-100 nanometers. The resulting nanowires are substantially pure Cu and can be oriented laterally (for local or global interconnects) or can be oriented vertically (for standard vertical interconnects).

  12. Preparation, characterization and application of nanosized copper ferrite photocatalysts for dye degradation under UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zaharieva, Katerina, E-mail: zaharieva@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Rives, Vicente, E-mail: vrives@usal.es [GIR-QUESCAT, Dpto. Química Inorgánica, Universidad de Salamanca, 37008 Salamanca (Spain); Tsvetkov, Martin, E-mail: mptsvetkov@gmail.com [Faculty of Chemistry and Pharmacy, St. Kliment Ohridski University of Sofia, 1 J. Bourchier Blvd., 1164 Sofia (Bulgaria); Cherkezova-Zheleva, Zara, E-mail: zzhel@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Kunev, Boris, E-mail: bkunev@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Trujillano, Raquel, E-mail: rakel@usal.es [GIR-QUESCAT, Dpto. Química Inorgánica, Universidad de Salamanca, 37008 Salamanca (Spain); Mitov, Ivan, E-mail: mitov@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Milanova, Maria, E-mail: nhmm@wmail.chem.uni-sofia.bg [Faculty of Chemistry and Pharmacy, St. Kliment Ohridski University of Sofia, 1 J. Bourchier Blvd., 1164 Sofia (Bulgaria)

    2015-06-15

    {sup −3} min{sup −1}) for degradation of organic dye Malachite green under UV irradiation. - Highlights: • Copper ferrites via co-precipitation, mechanochemical and/or thermal treatment. • Nano ferrites show a superparamagnetic and collective magnetic excitations nature. • The co-precipitated Cu{sub 0.25}Fe{sub 2.75}O{sub 4} posses the highest photocatalytic activity. • The amount adsorbed Malachite Green by catalyst depends on the preparation method. • The prepared copper ferrites can be applicable as cheap adsorbents and catalysts.

  13. Preparation, characterization and application of nanosized copper ferrite photocatalysts for dye degradation under UV irradiation

    International Nuclear Information System (INIS)

    Zaharieva, Katerina; Rives, Vicente; Tsvetkov, Martin; Cherkezova-Zheleva, Zara; Kunev, Boris; Trujillano, Raquel; Mitov, Ivan; Milanova, Maria

    2015-01-01

    Malachite green under UV irradiation. - Highlights: • Copper ferrites via co-precipitation, mechanochemical and/or thermal treatment. • Nano ferrites show a superparamagnetic and collective magnetic excitations nature. • The co-precipitated Cu 0.25 Fe 2.75 O 4 posses the highest photocatalytic activity. • The amount adsorbed Malachite Green by catalyst depends on the preparation method. • The prepared copper ferrites can be applicable as cheap adsorbents and catalysts

  14. Cold spray copper coatings for used fuel containers

    Energy Technology Data Exchange (ETDEWEB)

    Keech, P. [Nuclear Waste Management Organization, Toronto, ON (Canada); Vo, P.; Poirier, D.; Legoux, J-G [National Research Council, Boucherville QC, (Canada)

    2015-07-01

    Recently, the Nuclear Waste Management Organization has been developing copper coatings as a method of protecting steel used fuel containers (UFCs) from corrosion within a deep geological repository. The corrosion barrier design is based on the application of a copper coating bonded directly to the exterior surface of the UFC structural core. Copper coating technologies amendable to supply of pre-coated UFC vessel components and application to the weld zone following UFC closure within the radiological environment have been investigated. Copper cold spray has been assessed for both operations; this paper outlines the research and development to date of this technique. (author)

  15. Voltammetry at micro-mesh electrodes

    Directory of Open Access Journals (Sweden)

    Wadhawan Jay D.

    2003-01-01

    Full Text Available The voltammetry at three micro-mesh electrodes is explored. It is found that at sufficiently short experimental durations, the micro-mesh working electrode first behaves as an ensemble of microband electrodes, then follows the behaviour anticipated for an array of diffusion-independent micro-ring electrodes of the same perimeter as individual grid-squares within the mesh. During prolonged electrolysis, the micro-mesh electrode follows that behaviour anticipated theoretically for a cubically-packed partially-blocked electrode. Application of the micro-mesh electrode for the electrochemical determination of carbon dioxide in DMSO electrolyte solutions is further illustrated.

  16. Flexible electrode belt for EIT using nanofiber web dry electrodes.

    Science.gov (United States)

    Oh, Tong In; Kim, Tae Eui; Yoon, Sun; Kim, Kap Jin; Woo, Eung Je; Sadleir, Rosalind J

    2012-10-01

    Efficient connection of multiple electrodes to the body for impedance measurement and voltage monitoring applications is of critical importance to measurement quality and practicality. Electrical impedance tomography (EIT) experiments have generally required a cumbersome procedure to attach the multiple electrodes needed in EIT. Once placed, these electrodes must then maintain good contact with the skin during measurements that may last several hours. There is usually also the need to manage the wires that run between the electrodes and the EIT system. These problems become more severe as the number of electrodes increases, and may limit the practicality and portability of this imaging method. There have been several trials describing human-electrode interfaces using configurations such as electrode belts, helmets or rings. In this paper, we describe an electrode belt we developed for long-term EIT monitoring of human lung ventilation. The belt included 16 embossed electrodes that were designed to make good contact with the skin. The electrodes were fabricated using an Ag-plated PVDF nanofiber web and metallic threads. A large contact area and padding were used behind each electrode to improve subject comfort and reduce contact impedances. The electrodes were incorporated, equally spaced, into an elasticated fabric belt. We tested the electrode belt in conjunction with the KHU Mark1 multi-frequency EIT system, and demonstrate time-difference images of phantoms and human subjects during normal breathing and running. We found that the Ag-plated PVDF nanofiber web electrodes were suitable for long-term measurement because of their flexibility and durability. Moreover, the contact impedance and stability of the Ag-plated PVDF nanofiber web electrodes were found to be comparable to similarly tested Ag/AgCl electrodes.

  17. Highly stable supercapacitors with conducting polymer core-shell electrodes for energy storage applications

    KAUST Repository

    Xia, Chuan; Chen, Wei; Wang, Xianbin; Hedhili, Mohamed N.; Wei, Nini; Alshareef, Husam N.

    2015-01-01

    commercial application. Here, the development of nanostructured PAni-RuO2 core-shell arrays as electrodes for highly stable pseudocapacitors with excellent energy storage performance is reported. A thin layer of RuO2 grown by atomic layer deposition (ALD

  18. Development of highly transparent Pd-coated Ag nanowire electrode for display and catalysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Canlier, Ali, E-mail: ali.canlier@agu.edu.tr [Department of Materials Science and Nanotechnology Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Ucak, Umit Volkan, E-mail: sirvolkan@gmail.com [Department of Materials Science and Nanotechnology Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), P.O. Box 305-701, Daejeon (Korea, Republic of); Usta, Hakan, E-mail: husta38@gmail.com [Department of Materials Science and Nanotechnology Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Cho, Changsoon, E-mail: cscho@kaist.ac.kr [Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), P.O. Box 305-701, Daejeon (Korea, Republic of); Lee, Jung-Yong, E-mail: jungyong.lee@kaist.ac.kr [Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), P.O. Box 305-701, Daejeon (Korea, Republic of); Sen, Unal, E-mail: senunal@gmail.com [Department of Mechanical Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey); Citir, Murat, E-mail: muratcitir@gmail.com [Department of Chemical Engineering, Abdullah Gul University, P.O. Box 38080, Kayseri (Turkey)

    2015-09-30

    Highlights: • Highly uniform thin-layer coating of Pd onto Ag nanowire surface was accomplished. • A transparent electrode of Pd-coated Ag nanowire was uniformly deposited on flexible substrate. • 95% of optical transmittance and 175 Ω/sq sheet resistance were obtained. • Extremely low haze of 1.9% and high oxidation stability proved an efficient transparent electrode. • This electrode can be used as Pd-catalyst for synthesis reactions and fuel cell electrode applications. - Abstract: Ag nanowire transparent electrode has excellent transmittance (90%) and sheet resistance (20 Ω/sq), yet there are slight drawbacks such as optical haze and chemical instability against aerial oxidation. Chemical stability of Ag nanowires needs to be improved in order for it to be suitable for electrode applications. In our recent article, we demonstrated that coating Ag nanowires with a thin layer of Au through galvanic exchange reactions enhances the chemical stability of Ag nanowire films highly and also helps to obtain lower haze. In this study, coating of a thin Pd layer has been applied successfully onto the surface of Ag nanowires. A mild Pd complex oxidant [Pd(en){sub 2}](NO{sub 3}){sub 2} was prepared in order to oxidize Ag atoms partially on the surface via galvanic displacement. The mild galvanic exchange allowed for a thin layer (1–2 nm) of Pd coating on the Ag nanowires with minimal truncation of the nanowire, where the average length and the diameter were 12.5 μm and 59 nm, respectively. The Pd-coated Ag nanowires were suspended in methanol and then electrostatically sprayed on flexible polycarbonate substrates. It has been revealed that average total transmittance remain around 95% within visible spectrum region (400–800 nm) whereas sheet resistance rises up to 175 Ω/sq. To the best of our knowledge, for the first time in the literature, Pd coating was employed on Ag nanowires in order to design transparent electrodes for high transparency and strong

  19. A benchmark study of commercially available copper nanoparticle inks for application in organic electronic devices

    NARCIS (Netherlands)

    Polino, G.; Abbel, R.; Shanmugam, S.; Bex, G.J.P.; Hendriks, R.; Brunetti, F.; Di Carlo, A.; Andriessen, R.; Galagan, Y.

    2016-01-01

    A set of three commercial copper nanoparticle based inkjet inks has been benchmarked with respect to their potential to form conducting printed structures for future applications in organic electronic devices. Significant differences were observed in terms of jetting properties, spreading behaviour

  20. Highly stable supercapacitors with conducting polymer core-shell electrodes for energy storage applications

    KAUST Repository

    Xia, Chuan

    2015-01-14

    Conducting polymers such as polyaniline (PAni) show a great potential as pseudocapacitor materials for electrochemical energy storage applications. Yet, the cycling instability of PAni resulting from structural alteration is a major hurdle to its commercial application. Here, the development of nanostructured PAni-RuO2 core-shell arrays as electrodes for highly stable pseudocapacitors with excellent energy storage performance is reported. A thin layer of RuO2 grown by atomic layer deposition (ALD) on PAni nanofibers plays a crucial role in stabilizing the PAni pseudocapacitors and improving their energy density. The pseudocapacitors, which are based on optimized PAni-RuO2 core-shell nanostructured electrodes, exhibit very high specific capacitance (710 F g-1 at 5 mV s-1) and power density (42.2 kW kg-1) at an energy density of 10 Wh kg-1. Furthermore, they exhibit remarkable capacitance retention of ≈88% after 10 000 cycles at very high current density of 20 A g-1, superior to that of pristine PAni-based pseudocapacitors. This prominently enhanced electrochemical stability successfully demonstrates the buffering effect of ALD coating on PAni, which provides a new approach for the preparation of metal-oxide/conducting polymer hybrid electrodes with excellent electrochemical performance.

  1. High stored-energy breakdown tests on electrodes made of stainless steel, copper, titanium and molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Esch, H. P. L. de, E-mail: hubert.de-esch@cea.fr; Simonin, A.; Grand, C. [CEA-Cadarache, IRFM, F-13108 St. Paul-lez-Durance (France)

    2015-04-08

    IRFM have conducted resilience tests on electrodes made of Cu, stainless steel 304L, Ti and Mo against breakdowns up to 170 kV and 300 J. The tests of the 10×10 cm{sup 2} electrodes have been performed at an electrode distance d=11 mm under vacuum (P∼5×10{sup −6} mbar). No great difference in voltage holding between the materials could be identified; all materials could reach a voltage holding between 140 and 170 kV over the 11 mm gap, i.e. results scatter within a ±10% band. After exposure to ∼10000 seconds of high-voltage (HV) on-time, having accumulated ∼1000 breakdowns, the electrodes were inspected. The anodes were covered with large and small craters. The rugosity of the anodes had increased substantially, that of the cathodes to a lesser extent. The molybdenum electrodes are least affected, but this does not show in their voltage holding capability. It is hypothesized that penetrating high-energy electrons from the breakdown project heat below the surface of the anode and cause a micro-explosion of material when melting point is exceeded. Polished electrodes have also been tested. The polishing results in a substantially reduced breakdown rate in the beginning, but after having suffered a relatively small number (∼100) of breakdowns, the polished electrodes behaved the same as the unpolished ones.

  2. A low-power bio-potential acquisition system with flexible PDMS dry electrodes for portable ubiquitous healthcare applications.

    Science.gov (United States)

    Chen, Chih-Yuan; Chang, Chia-Lin; Chang, Chih-Wei; Lai, Shin-Chi; Chien, Tsung-Fu; Huang, Hong-Yi; Chiou, Jin-Chern; Luo, Ching-Hsing

    2013-03-04

    This work describes a bio-potential acquisition system for portable ubiquitous healthcare applications using flexible polydimethylsiloxane dry electrodes (FPDEs) and a low-power recording circuit. This novel FPDE used Au as the skin contact layer, which was made using a CO2 laser and replica method technology. The FPDE was revised from a commercial bio-potential electrode with a conductive snap using dry electrodes rather than wet electrodes that proposed reliable and robust attachment for the purpose of measurement, and attaching velcro made it wearable on the forearm for bio-potential applications. Furthermore, this study proposes a recording device to store bio-potential signal data and provides portability and low-power consumption for the proposed acquisition system. To acquire differential bio-potentials, such as electrocardiogram (ECG) signals, the proposed recording device includes a low-power front-end acquisition chip fabricated using a complementary metal-oxide-semiconductor (CMOS) process, a commercial microcontroller (MSP430F149), and a secure digital (SD) card for portable healthcare applications. The proposed system can obtain ECG signals efficiently and are comfortable to the skin. The power consumption of the system is about 85 mW for continuous working over a 3 day period with two AA batteries. It can also be used as a compact Holter ECG system.

  3. Direct detection of ammonium ion by means of oxygen electrocatalysis at a copper-polyaniline composite on a screen-printed electrode

    International Nuclear Information System (INIS)

    Zhybak, Mykhailo T.; Vagin, Mikhail Yu.; Beni, Valerio; Liu, Xianjie; Turner, Anthony P. F.; Dempsey, Eithne; Korpan, Yaroslav I.

    2016-01-01

    We describe a composite material for use in electrochemical oxygen reduction. A screen-printed electrode (SPE) was consecutively modified with electrodeposited copper, a Nafion membrane and electropolymerized polyaniline (PANi) to give an electrocatalytic composite of type PANi/Nafion/Cu_2O/SPE that displays good electrical conductivity at neutral pH values. It is found that the presence of ammonia causes complex formation with Cu(I), and this causes electroreduction of oxygen to result in an increased cathodic current. The finding was applied to the quantification of ammonium ions in the 1 to 1000 μM concentration range by amperometry at −0.45 V (vs. Ag/AgCl). This Faradaic phenomenon offers the advantage of direct voltammetric detection, one of the lowest known limits of detection (0.5 μM), and high sensitivity (250 mA∙M"−"1∙cm"−"2). It was applied to the determination of ammonium ion in human serum where it compared well with the photometric routine approach for clinical analysis using glutamate dehydrogenase. (author)

  4. ELECTROCHEMICAL STUDY OF RHENIUM-TELLURIUM-COPPER SYSTEM

    OpenAIRE

    E.A.Salakhova*1, D.B.Tagiyev2, P.E.Kalantarova3 and A.M.Askerova4

    2017-01-01

    The formation of the triple alloys Re-Te-Cu on the platinum electrode at volt amperemetric cycling has been studied. The investigation was carried out from chloride acidic solution containing tellurium acid, potassium perrhenate, chloride copper. The kinetics of the processes was controlled using the measurements by the method of cyclic volt-amperometry on the device İVİUMSTAT. For the analysis of composition and structure the methods of XRD (X-ray diffraction analysis) were used, and the inv...

  5. Structural Engineering of Metal-Mesh Structure Applicable for Transparent Electrodes Fabricated by Self-Formable Cracked Template

    Directory of Open Access Journals (Sweden)

    Yeong-gyu Kim

    2017-08-01

    Full Text Available Flexible and transparent conducting electrodes are essential for future electronic devices. In this study, we successfully fabricated a highly-interconnected metal-mesh structure (MMS using a self-formable cracked template. The template—fabricated from colloidal silica—can be easily formed and removed, presenting a simple and cost-effective way to construct a randomly and uniformly networked MMS. The structure of the MMS can be controlled by varying the spin-coating speed during the coating of the template solution or by stacking of metal-mesh layers. Through these techniques, the optical transparency and sheet resistance of the MMS can be designed for a specific purpose. A double-layered Al MMS showed high optical transparency (~80% in the visible region, low sheet resistance (~20 Ω/sq, and good flexibility under bending test compared with a single-layered MMS, because of its highly-interconnected wire structure. Additionally, we identified the applicability of the MMS in the case of practical devices by applying it to electrodes of thin-film transistors (TFTs. The TFTs with MMS electrodes showed comparable electrical characteristics to those with conventional film-type electrodes. The cracked template can be used for the fabrication of a mesh structure consisting of any material, so it can be used for not only transparent electrodes, but also various applications such as solar cells, sensors, etc.

  6. X-ray spectrum microanalysis of copper and stainless steel surface layer after electroerosion machining

    International Nuclear Information System (INIS)

    Abdukarimov, Eh.T.; Saidinov, S.Ya.

    1989-01-01

    The results of experimental investigations of the surface layer of copper and steel 12Kh18N10T after electroerrosion treatment by a rotating tungsten electrode in natural and distilled water are presented. It is established that the quantity of electrode material transferred to the surface of the steel treated grows with the spark discharge energy increase. Tungsten concentration in the surface layer reaches 5-10% with the average depth of penetration 40-50 μm

  7. Effect of multipactor conditioning on technical electrode surfaces

    International Nuclear Information System (INIS)

    Graves, T. P.; Spektor, R.; Stout, P.

    2009-01-01

    Historically, multipactor conditioning has been utilized to remove surface contaminants from rf electrodes by electron-stimulated gas desorption, and such conditioning has been shown to reduce multipactor susceptibility. Multipactor threshold improvements are due to increasing E 1 , the minimum energy for the secondary electron coefficient, δ>1, such that resonant electrons are incapable of producing discharge-sustaining secondary emission. Using an rf amplitude sweep technique, the evolution of the multipactor threshold is measured as a function of multipactor conditioning time for a series of technical electrode surfaces. Results show over +3 dB of threshold improvement in copper and gold electrodes, while the aluminum threshold actually decreases with conditioning exposure. Additionally, these conditioning results indicate the possible voltage region for transient-mode multipaction (TMM), which can cause significant risk to rf systems such as space satellite components for which in-situ conditioning is generally not possible. Experimental results and supporting Monte Carlo particle tracking simulation results are presented.

  8. Technical note 2. A review of the creep ductility of copper for nuclear waste canister application

    International Nuclear Information System (INIS)

    Pettersson, Kjell

    2011-03-01

    Background: The Swedish Radiation Safety Authority (SSM) reviews the Swedish Nuclear Fuel Company's (SKB) applications under the Act on Nuclear Activities (SFS 1984:3) for the construction and operation of a repository for spent nuclear fuel and for an encapsulation facility. As part of the review, SSM commissions consultants to carry out work in order to obtain information on specific issues. The results from the consultants' tasks are reported in SSM's Technical Note series. Objectives of the project: This project is part of SSM:s review of SKB:s license application for final disposal of spent nuclear fuel. The assignment concerns review of creep mechanisms for copper material used as a corrosion barrier in canisters for nal disposal of nuclear fuel in Sweden. Summary by the author: SKB has presented insufficient evidence to justify their position that the OFP copper has an adequate creep ductility during long term storage. Their large body of experiments only serves to prove that the creep ductility is sufficient for much shorter time spans than the intended storage times. There is a clear need for a credible theory of creep brittleness of OFP copper which will permit extrapolations to long term storage. The theory presented by SKB does not in its present state permit credible extrapolations. Alternatively SKB needs to find an explanation to the effect of phosphorus on the creep ductility and that it ensures the absence of creep brittleness in OFP copper. It is interesting to note that SKB has presented experimental evidence that intergranular cracks can form in OFP material tested in cracked specimens. Perhaps it is possible to more systematically study formation and growth of intergranular cracks in specimens of OFP copper with cracks

  9. Non-invasive method for selection of electrodes and stimulus parameters for FES applications with intrafascicular arrays

    Science.gov (United States)

    Dowden, B. R.; Frankel, M. A.; Normann, R. A.; Clark, G. A.

    2012-02-01

    High-channel-count intrafascicular electrode arrays provide comprehensive and selective access to the peripheral nervous system. One practical difficulty in using several electrode arrays to evoke coordinated movements in paralyzed limbs is the identification of the appropriate stimulation channels and stimulus parameters to evoke desired movements. Here we present the use of a six degree-of-freedom load cell placed under the foot of a feline to characterize the muscle activation produced by three 100-electrode Utah Slanted Electrode Arrays (USEAs) implanted into the femoral nerves, sciatic nerves, and muscular branches of the sciatic nerves of three cats. Intramuscular stimulation was used to identify the endpoint force directions produced by 15 muscles of the hind limb, and these directions were used to classify the forces produced by each intrafascicular USEA electrode as flexion or extension. For 451 USEA electrodes, stimulus intensities for threshold and saturation muscle forces were identified, and the 3D direction and linearity of the force recruitment curves were determined. Further, motor unit excitation independence for 198 electrode pairs was measured using the refractory technique. This study demonstrates the utility of 3D endpoint force monitoring as a simple and non-invasive metric for characterizing the muscle-activation properties of hundreds of implanted peripheral nerve electrodes, allowing for electrode and parameter selection for neuroprosthetic applications.

  10. Machining of AISI D2 Tool Steel with Multiple Hole Electrodes by EDM Process

    Science.gov (United States)

    Prasad Prathipati, R.; Devuri, Venkateswarlu; Cheepu, Muralimohan; Gudimetla, Kondaiah; Uzwal Kiran, R.

    2018-03-01

    In recent years, with the increasing of technology the demand for machining processes is increasing for the newly developed materials. The conventional machining processes are not adequate to meet the accuracy of the machining of these materials. The non-conventional machining processes of electrical discharge machining is one of the most efficient machining processes is being widely used to machining of high accuracy products of various industries. The optimum selection of process parameters is very important in machining processes as that of an electrical discharge machining as they determine surface quality and dimensional precision of the obtained parts, even though time consumption rate is higher for machining of large dimension features. In this work, D2 high carbon and chromium tool steel has been machined using electrical discharge machining with the multiple hole electrode technique. The D2 steel has several applications such as forming dies, extrusion dies and thread rolling. But the machining of this tool steel is very hard because of it shard alloyed elements of V, Cr and Mo which enhance its strength and wear properties. However, the machining is possible by using electrical discharge machining process and the present study implemented a new technique to reduce the machining time using a multiple hole copper electrode. In this technique, while machining with multiple holes electrode, fin like projections are obtained, which can be removed easily by chipping. Then the finishing is done by using solid electrode. The machining time is reduced to around 50% while using multiple hole electrode technique for electrical discharge machining.

  11. Handbook of reference electrodes

    CERN Document Server

    Inzelt, György; Scholz, Fritz

    2013-01-01

    Reference Electrodes are a crucial part of any electrochemical system, yet an up-to-date and comprehensive handbook is long overdue. Here, an experienced team of electrochemists provides an in-depth source of information and data for the proper choice and construction of reference electrodes. This includes all kinds of applications such as aqueous and non-aqueous solutions, ionic liquids, glass melts, solid electrolyte systems, and membrane electrodes. Advanced technologies such as miniaturized, conducting-polymer-based, screen-printed or disposable reference electrodes are also covered. Essen

  12. Square-wave voltammetric determination of rutin in pharmaceutical formulations using a carbon composite electrode modified with copper (II phosphate immobilized in polyester resin

    Directory of Open Access Journals (Sweden)

    Kellen Heloizy Garcia Freitas

    2012-12-01

    Full Text Available A carbon composite electrode modified with copper (II phosphate immobilized in a polyester resin (Cu3(PO42-Poly for the determination of rutin in pharmaceutical samples by square-wave voltammetry is described herein. The modified electrode allows the determination of rutin at a potential (0.20 V vs. Ag/AgCl (3.0 mol L-1 KCl lower than that observed at an unmodified electrode. The peak current was found to be linear to the rutin concentration in the range from 9.9 × 10-8 to 2.5 × 10-6 mol L-1, with a detection limit of 1.2×10-8 mol L-1. The response of the electrode was stable, with no variation in baseline levels within several hours of continuous operation. The surface morphology of the modified electrode was characterized by scanning electron microscopy (SEM and energy dispersive X-ray (EDX system. The results obtained are precise and accurate. In addition, these results are in agreement with those obtained by the chromatographic method at a 95% confidence level.Descreve-se um eletrodo de carbono modificado com fosfato de cobre (II imobilizado em uma resina de poliéster (Cu3(PO42-Poly para a determinação de rutina em amostras farmacêuticas por voltametria de onda quadrada. O eletrodo modificado permite a determinação de rutina em potencial (0.20 V vs Ag / AgCl (3,0 mol L-1 KCl menor que o observado em um eletrodo não modificado. Verificou-se que a corrente de pico foi linear com a concentração de rutina na faixa de 9,9 × 10-8 a 2,5 × 10-6 mol L-1, com um limite de detecção de 1,2 × 10-8 mol L¹. A resposta do eletrodo foi estável, sem variação significativa dentro de várias horas de operação contínua. A morfologia da superfície do eletrodo modificado foi caracterizada por microscopia eletrônica de varredura (MEV e pelo sistema de energia dispersiva de raios-X (EDX. Os resultados obtidos foram precisos e exatos. Ademais, estes resultados estão de acordo com aqueles obtidos pelo método cromatográfico a um nível de

  13. Multimaterial 3D Printing of Graphene-Based Electrodes for Electrochemical Energy Storage Using Thermoresponsive Inks.

    Science.gov (United States)

    Rocha, Victoria G; García-Tuñón, Esther; Botas, Cristina; Markoulidis, Foivos; Feilden, Ezra; D'Elia, Eleonora; Ni, Na; Shaffer, Milo; Saiz, Eduardo

    2017-10-25

    The current lifestyles, increasing population, and limited resources result in energy research being at the forefront of worldwide grand challenges, increasing the demand for sustainable and more efficient energy devices. In this context, additive manufacturing brings the possibility of making electrodes and electrical energy storage devices in any desired three-dimensional (3D) shape and dimensions, while preserving the multifunctional properties of the active materials in terms of surface area and conductivity. This paves the way to optimized and more efficient designs for energy devices. Here, we describe how three-dimensional (3D) printing will allow the fabrication of bespoke devices, with complex geometries, tailored to fit specific requirements and applications, by designing water-based thermoresponsive inks to 3D-print different materials in one step, for example, printing the active material precursor (reduced chemically modified graphene (rCMG)) and the current collector (copper) for supercapacitors or anodes for lithium-ion batteries. The formulation of thermoresponsive inks using Pluronic F127 provides an aqueous-based, robust, flexible, and easily upscalable approach. The devices are designed to provide low resistance interface, enhanced electrical properties, mechanical performance, packing of rCMG, and low active material density while facilitating the postprocessing of the multicomponent 3D-printed structures. The electrode materials are selected to match postprocessing conditions. The reduction of the active material (rCMG) and sintering of the current collector (Cu) take place simultaneously. The electrochemical performance of the rCMG-based self-standing binder-free electrode and the two materials coupled rCMG/Cu printed electrode prove the potential of multimaterial printing in energy applications.

  14. Electrokinetic remediation of a copper contaminated clay: 2-D experiments

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Maroto, J.M.; Garcia Delgado, R.A.; Gomez Lahoz, C.; Garcia Herruzo, F. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain); Vereda Alonso, C. [Dept. de Ingenieria Quimica, Univ. de Malaga (Spain)]|[Inst. for Geologi and Geoteknik, Danmarks Tekniske Univ., Lyngby (Denmark)

    2001-07-01

    The in-situ electrokinetic soil remediation technique was used to clean-up a commercial standard kaolin that had been contaminated with copper. A number of experiments were carried out at a lab scale with the purpose of testing the performance of this technique in a 2 dimensional arrangement and establishing the base for future studies on the distribution of electrodes. (orig.)

  15. Trajectory Analysis of Copper and Glass Particles in Electrostatic Separation for the Recycling of ASR

    Directory of Open Access Journals (Sweden)

    Beom-uk Kim

    2017-10-01

    Full Text Available Automobile-shredder-residue (ASR recycling techniques have been widely applied for improving the total recycling rate of end-of-life vehicles. In this study, to obtain useful information for predicting or improving ASR-separation efficiency, trajectory analyses of conductors (copper and non-conductors (glass were performed using a lab-scale induction electrostatic separator. The copper-wire trajectories obtained showed a good agreement depending significantly on the electric field strength and particle size. The observed copper-wire trajectories showed consistent congruity with the coarse-particles simulation (0.5 and 0.25 mm. The observed fine-particles (0.06 mm trajectory was deflected toward the (− attractive electrode, owing to the charge density effects due to the particle characteristics and relative humidity. This results in superior separation performance because more copper enters the conductor products bin. The actual dielectric-glass trajectory was deflected toward the (− attractive electrode, thus showing characteristics similar to conductive-particle characteristics. Through analyses conducted using a stereoscopic microscope, scanning electron microscope, and energy dispersive spectroscope, we found heterogeneous materials (fine ferrous particles and conductive organics on the glass surface. This demonstrates the separation-efficiency decrease for non-ferrous metals during electrostatic separation in the recycling of ASR. Future work should include a pretreatment process for eliminating impurities from the glass and advanced trajectory-simulation processes.

  16. Measurement of the specific surface area of loose copper deposit by electrochemical methods

    Directory of Open Access Journals (Sweden)

    E. A. Dolmatova

    2016-07-01

    Full Text Available In the work the surface area of the electrode with dispersed copper deposit obtained within 30 seconds was evaluated by techniques of chronopotentiometry (CPM and impedance spectroscopy. In method CPM the electrode surface available for measurement depends on the value of the polarizing current. At high currents during the transition time there is a change of surface relief that can not determine the full surface of loose deposit. The electrochemical impedance method is devoid of this shortcoming since the measurements are carried out in indifferent electrolyte in the absence of current. The area measured by the impedance is tens of times higher than the value obtained by chronopotentiometry. It is found that from a solution containing sulfuric acid the deposits form with a high specific surface area. Based on these data it was concluded that the method of impedance spectroscopy can be used to measure in situ the surface area of the dispersed copper deposits.

  17. Flash light sintered copper precursor/nanoparticle pattern with high electrical conductivity and low porosity for printed electronics

    International Nuclear Information System (INIS)

    Chung, Wan-Ho; Hwang, Hyun-Jun; Kim, Hak-Sung

    2015-01-01

    In this work, the hybrid copper inks with precursor and nanoparticles were fabricated and sintered via flash light irradiation to achieve highly conductive electrode pattern with low porosity. The hybrid copper ink was made of copper nanoparticles and various copper precursors (e.g., copper(II) chloride, copper(II) nitrate trihydrate, copper(II) sulfate pentahydrate and copper(II) trifluoroacetylacetonate). The printed hybrid copper inks were sintered at room temperature and under ambient conditions using an in-house flash light sintering system. The effects of copper precursor weight fraction and the flash light irradiation conditions (light energy and pulse duration) were investigated. Surfaces of the sintered hybrid copper patterns were analyzed using a scanning electron microscope. Also, spectroscopic characterization techniques such as Fourier transform infrared spectroscopy and X-ray diffraction were used to investigate the crystal phases of the flash light sintered copper precursors. High conductivity hybrid copper patterns (27.3 μΩ cm), which is comparable to the resistivity of bulk copper (1.68 μΩ cm) were obtained through flash light sintering at room temperature and under ambient conditions. - Highlights: • The hybrid copper inks with precursor and nanoparticles were fabricated. • The hybrid copper ink was sintered via flash light irradiation. • The resistivity of sintered hybrid copper ink was 27.3 μΩ cm. • Highly conductive copper film with low porosity could be achieved

  18. Flash light sintered copper precursor/nanoparticle pattern with high electrical conductivity and low porosity for printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Wan-Ho; Hwang, Hyun-Jun [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-04-01

    In this work, the hybrid copper inks with precursor and nanoparticles were fabricated and sintered via flash light irradiation to achieve highly conductive electrode pattern with low porosity. The hybrid copper ink was made of copper nanoparticles and various copper precursors (e.g., copper(II) chloride, copper(II) nitrate trihydrate, copper(II) sulfate pentahydrate and copper(II) trifluoroacetylacetonate). The printed hybrid copper inks were sintered at room temperature and under ambient conditions using an in-house flash light sintering system. The effects of copper precursor weight fraction and the flash light irradiation conditions (light energy and pulse duration) were investigated. Surfaces of the sintered hybrid copper patterns were analyzed using a scanning electron microscope. Also, spectroscopic characterization techniques such as Fourier transform infrared spectroscopy and X-ray diffraction were used to investigate the crystal phases of the flash light sintered copper precursors. High conductivity hybrid copper patterns (27.3 μΩ cm), which is comparable to the resistivity of bulk copper (1.68 μΩ cm) were obtained through flash light sintering at room temperature and under ambient conditions. - Highlights: • The hybrid copper inks with precursor and nanoparticles were fabricated. • The hybrid copper ink was sintered via flash light irradiation. • The resistivity of sintered hybrid copper ink was 27.3 μΩ cm. • Highly conductive copper film with low porosity could be achieved.

  19. Influence of the lithium salt electrolyte on the electrochemical performance of copper/LiFePO4 composites

    International Nuclear Information System (INIS)

    Trócoli, Rafael; Morales, Julián; Franger, Sylvain; Santos-Peña, Jesús

    2012-01-01

    In this work, we studied the influence of the electrolyte salt, LiPF 6 or LiClO 4 , on the electrochemical properties of copper/LiFePO 4 composites. We found a different stability voltage window for the two electrolytes that was remarkably wide for LiPF 6 . Also, copper addition is commonly accepted to increase electrode conductivity, which is beneficial for electrochemical purposes. However, copper is always oxidised to a variable extent depending on the particular electrolyte during the charge phase. Oxidation of the electrolyte solvent (especially with LiClO 4 ) was also observed during the first charge. In the first cycle, copper was more or less efficiently removed from the electrode surface. In subsequent cycles, however, these phenomena failed to occur (LiPF 6 ) or were weaker (LiClO 4 ). In all these configurations, iron is partially dissolved, to an extent dependent on the amount of copper present in the composite and differing with the particular electrolyte used. Electrochemical impedance spectroscopy allowed us to identify the process taking place close to 3.6 V in LiPF 6 configuration: Fe(II) from the composites are oxidised and irreversibly complexed by the joint action of HF formed from LiPF 6 and water traces and Cu(I) formed upon charging. Our hypothesis accurately explains the results observed in terms of charge/discharge profiles, capacities provided and capacities evolution upon cycling. Also, our test results testify to the importance of using low contents of copper in the composites and the good properties of LiPF 6 as electrolyte solvent.

  20. High reproducibility and sensitivity of bifacial copper nanowire array for detection of glucose

    Directory of Open Access Journals (Sweden)

    Hanqing Zhang

    2017-06-01

    Full Text Available The ordered bifacial copper nanowire array (Cu BNWA was synthesized by a template assisted electrochemical deposition method. The morphology and structure of the as-prepared samples were investigated by field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. The results show that the ordered Cu nanowire array with uniform geometrical dimensions covered both side of the Cu substrate. When used as the electrode for glucose detection, the minimum detectable concentration of glucose can be reached as low as 0.2 mM. Impressively, the sample still showed high sensitivity and stability for glucose detection after two months placement in ambient environment. These excellent performances of the Cu BNWA make it a promising non-enzyme glucose detection sensor for various applications.

  1. Poly(o-aminophenol) film electrodes synthesis, transport properties and practical applications

    CERN Document Server

    Tucceri, Ricardo

    2014-01-01

    This review book is concerned with the synthesis, charge transport properties and practical applications of poly (o-aminophenol) (POAP) film electrodes. It is divided into three parts. The first one has a particular emphasis on problems of synthesis and structure of POAP. The second part deals with the mechanism of charge transfer and charge transport processes occurring in the course of the redox reactions of POAP. The third part describes the promising applications of POAP in the different fields of sensors, electrocatalysis, bioelectrochemistry, corrosion protection, among others. This review covers the literature on POAP in the time period comprised between 1987 and 2013.

  2. Photoelectrochemical detection of copper ions by modulating the growth of CdS quantum dots.

    Science.gov (United States)

    Grinyte, Ruta; Barroso, Javier; Díez-Buitrago, Beatriz; Saa, Laura; Möller, Marco; Pavlov, Valeri

    2017-09-15

    We discovered that copper ions (Cu 2+ ) catalyze the oxidation of cysteine (CSH) by oxygen (O 2 ) to modulate the growth of CSH-capped cadmium sulfide (CdS) nanoparticles (NPs). This new chemical process was applied to sensitive fluorogenic and photoelectrochemical (PEC) detection of Cu 2+ ions in real samples of mineral and tap water using the photocatalytic activity of the resulting NPs. Disposable screen-printed electrodes (SPCEs) modified with electroactive polyvinylpyridine bearing osmium complex (Os-PVP) by cyclic voltammetry (CV) were employed for PEC analytical system. CdS NPs formed during the assay photocatalyze oxidation of 1-thioglycerol (TG) upon application of 0.3 V vs. Ag/AgCl to SPCEs. Os-PVP complex mediated the electron transfer between the electrode surface and CdS NPs. We proved that our assays did not suffer from interference from other ions accompanying Cu 2+ and the sensitivity of our assays covers the European Union standard limit of Cu 2+ ions in drinking water. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Functionalized polypyrrole nanotube arrays as electrochemical biosensor for the determination of copper ions

    International Nuclear Information System (INIS)

    Lin Meng; Hu Xiaoke; Ma Zhaohu; Chen Lingxin

    2012-01-01

    Highlights: ► PPy nanotube arrays were electropolymerized using ZnO nanowire arrays as templates. ► PPy nanotube arrays were anchored onto ITO glass without any chemical linker. ► Using SWV, the biosensor was found to be highly sensitive and selective to Cu 2+ . ► The biosensor was successfully applied for the determination of Cu 2+ in drinking water. - Abstract: A novel electrochemical biosensor based on functionalized polypyrrole (PPy) nanotube arrays modified with a tripeptide (Gly-Gly-His) proved to be highly effective for electrochemical analysis of copper ions (Cu 2+ ). The vertically oriented PPy nanotube arrays were electropolymerized by using modified zinc oxide (ZnO) nanowire arrays as templates which were electrodeposited on indium–tin oxide (ITO) coated glass substrates. The electrodes were functionalized by appending pyrrole-α-carboxylic acid onto the surface of polypyrrole nanotube arrays by electrochemical polymerization. The carboxylic groups of the polymer were covalently coupled with the amine groups of the tripeptide, and its structural features were confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy. The tripeptide modified PPy nanotube arrays electrode was used for the electrochemical analysis of various trace copper ions by square wave voltammetry. The electrode was found to be highly sensitive and selective to Cu 2+ in the range of 0.1–30 μM. Furthermore, the developed biosensor exhibited a high stability and reproducibility, despite the repeated use of the biosensor electrode.

  4. Technology ready use of single layer graphene as a transparent electrode for hybrid photovoltaic devices

    OpenAIRE

    Wang, Zhibing; Puls, Conor P.; Staley, Neal E.; Zhang, Yu; Todd, Aaron; Xu, Jian; Howsare, Casey A.; Hollander, Matthew J.; Robinson, Joshua A.; Liu, Ying

    2011-01-01

    Graphene has been used recently as a replacement for indium tin oxide (ITO) for the transparent electrode of an organic photovoltaic device. Due to its limited supply, ITO is considered as a limiting factor for the commercialization of organic solar cells. We explored the use of large-area graphene grown on copper by chemical vapor deposition (CVD) and then transferred to a glass substrate as an alternative transparent electrode. The transferred film was shown by scanning Raman spectroscopy m...

  5. Molecular Dynamics Study of the Separation Behavior at the Interface between PVDF Binder and Copper Current Collector

    Directory of Open Access Journals (Sweden)

    Seungjun Lee

    2016-01-01

    Full Text Available In Li-ion batteries, the mechanical strengths at the interfaces of binder/particle and binder/current collector play an important role in maintaining the mechanical integrity of the composite electrode. In this work, the separation behaviors between polyvinylidene fluoride (PVDF binders and copper current collectors are studied in the opening and sliding modes using molecular dynamics (MD simulations. The simulation shows that the separation occurs inside the PVDF rather than at the interface due to the strong adhesion between PVDF and copper. This fracture behavior is different from the behavior of the PVDF/graphite basal plane that shows a clear separation at the interface. The results suggest that the adhesion strength of the PVDF/copper is stronger than that of the PVDF/graphite basal plane. The methodology used in MD simulation can directly evaluate the adhesion strength at the interfaces of various materials between binders, substrates, and particles at the atomic scales. The proposed method can therefore provide a guideline for the design of the electrode in order to enhance the mechanical integrity for better battery performance.

  6. Solid state bonding of beryllium-copper for an ITER first wall application

    International Nuclear Information System (INIS)

    Odegard, B.C. Jr.; Cadden, C.H.

    1998-02-01

    Several different joint assemblies were evaluated in support of a manufacturing technology for diffusion bonding a beryllium armor tile to a copper alloy heat sink for fusion reactor applications. Because beryllium reacts with all but a few elements to form intermetallic compounds, this study considered several different surface treatments as a means of both inhibiting these reactions and promoting a good diffusion bond between the two substrates. A diffusion bonded assemblies used aluminum or an aluminum-beryllium composite (AlBeMet-150) as the interfacial material in contact with beryllium. In most cases, explosive bonding was utilized as a technique for joining the copper alloy heat sink to an aluminum or AlBeMet-150 substrate, which was subsequently diffusion bonded to an aluminum coated beryllium tile. In this approach, a 250 microm thick titanium foil was used as a diffusion barrier between the copper and aluminum to prevent the formation of Cu-Al intermetallic phases. In all cases, a hot isostatic pressing (HIP) furnace was used in conjunction with canned assemblies in order to minimize oxidation and apply sufficient pressure on the assembly for excellent metal-to-metal contact and subsequent bonding. Several different processing schedules were evaluated during the course of this study; bonded assemblies were produced that failed outside the bond area indicating a 100% joint efficiency

  7. Solid state bonding of beryllium-copper for an ITER first wall application

    Energy Technology Data Exchange (ETDEWEB)

    Odegard, B.C. Jr.; Cadden, C.H. [Sandia National Labs., Livermore, CA (United States)

    1998-01-01

    Several different joint assemblies were evaluated in support of a manufacturing technology for diffusion bonding a beryllium armor tile to a copper alloy heat sink for fusion reactor applications. Because beryllium reacts with all but a few elements to form intermetallic compounds, this study considered several different surface treatments as a means of both inhibiting these reactions and promoting a good diffusion bond between the two substrates. All diffusion bonded assemblies used aluminum or an aluminum-beryllium composite (AlBeMet-150) as the interfacial material in contact with beryllium. In most cases, explosive bonding was utilized as a technique for joining the copper alloy heat sink to an aluminum or AlBeMet-150 substrate, which was subsequently diffusion bonded to an aluminum coated beryllium tile. In this approach, a 250 {mu}m thick titanium foil was used as a diffusion barrier between the copper and aluminum to prevent the formation of Cu-Al intermetallic phases. In all cases, a hot isostatic pressing (HIP) furnace was used in conjunction with canned assemblies in order to minimize oxidation and apply sufficient pressure on the assembly for excellent metal-to-metal contact and subsequent bonding. Several different processing schedules were evaluated during the course of this study; bonded assemblies were produced that failed outside the bond area indicating a 100% joint efficiency. (author)

  8. Preparation and electrochemical performance of copper foam-supported amorphous silicon thin films for rechargeable lithium-ion batteries

    International Nuclear Information System (INIS)

    Li Haixia; Cheng Fangyi; Zhu Zhiqiang; Bai Hongmei; Tao Zhanliang; Chen Jun

    2011-01-01

    Research highlights: → Amorphous Si thin films have been deposited on copper foam substrate by radio-frequency (rf) magnetron sputtering. → The as-prepared Si/Cu films with interconnected 3-dimensional structure are employed as anode materials of rechargeable lithium-ion batteries, showing that the electrode properties are greatly affected by the deposition temperature. → The film electrode deposited at an optimum temperature of 300 deg. C delivers a specific capacity of ∼2900 mAh/g and a coulombic efficiency above 95% at charge/discharge current density of 0.2C after 30 cycles. → The Li + diffusion coefficiency in copper foam-supported Si thin films is determined to be 2.36 x 10 -9 cm 2 /s. → The combination of rf magnetron sputtering and cooper foam substrate is an efficient route to prepare amorphous Si films with high capacity and cyclability due to the efficient ionic diffusion and interface contact with a good conductive current collector. - Abstract: Amorphous Si thin films, which have been deposited on copper foam by radio-frequency (rf) magnetron sputtering, are employed as anode materials of rechargeable lithium-ion batteries. The morphologies and structures of the as-prepared Si thin films are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). Electrochemical performance of lithium-ion batteries with the as-prepared Si films as the anode materials is investigated by cyclic voltammetry and charge-discharge measurements. The results show that the electrode properties of the prepared amorphous Si films are greatly affected by the deposition temperature. The film electrode deposited at an optimum temperature of 300 deg. C can deliver a specific capacity of ∼2900 mAh/g and a coulombic efficiency above 95% at charge/discharge current density of 0.2C after 30 cycles. The Li + diffusion coefficiency in copper foam-supported Si thin films is determined to be 2.36 x 10 -9 cm

  9. Electrodeposited Reduced Graphene Oxide Films on Stainless Steel, Copper, and Aluminum for Corrosion Protection Enhancement

    Directory of Open Access Journals (Sweden)

    Abdulkareem Mohammed Ali Al-Sammarraie

    2017-01-01

    Full Text Available The enhancement of corrosion protection of metals and alloys by coating with simple, low cost, and highly adhered layer is still a main goal of many workers. In this research graphite flakes converted into graphene oxide using modified Hammers method and then reduced graphene oxide was electrodeposited on stainless steel 316, copper, and aluminum for corrosion protection application in seawater at four temperatures, namely, 20, 30, 40, and 50°C. All corrosion measurements, kinetics, and thermodynamics parameters were established from Tafel plots using three-electrode potentiostat. The deposited films were examined by FTIR, Raman, XRD, SEM, and AFM techniques; they revealed high percentages of conversion to the few layers of graphene with confirmed defects.

  10. Acetaldehyde as an Intermediate in the Electroreduction of Carbon Monoxide to Ethanol on Oxide-Derived Copper

    DEFF Research Database (Denmark)

    Bertheussen, Erlend; Verdaguer Casadevall, Arnau; Ravasio, Davide

    2016-01-01

    Oxide-derived copper (OD-Cu) electrodes exhibit unprecedented CO reduction performance towards liquid fuels, producing ethanol and acetate with >50 % Faradaic efficiency at −0.3 V (vs. RHE). By using static headspace-gas chromatography for liquid phase analysis, we identify acetaldehyde as a mino...... solutions using NMR spectroscopy, requiring alternative methods for detection and quantification. Our results represent an important step towards understanding the CO reduction mechanism on OD-Cu electrodes....

  11. Surface-modified electrodes (SME)

    NARCIS (Netherlands)

    Schreurs, J.P.G.M.; Barendrecht, E.

    1984-01-01

    This review deals with the literature (covered up to August 1983), the characterization and the applications of Surface-Modified Electrodes (SME). As a special class of SME's, the Enzyme-Modified Electrode (EME) is introduced. Three types of modification procedures are distinguished; i.e. covalent

  12. Vanadium oxide (VO) based low cost counter electrode in dye sensitized solar cell (DSSC) applications

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, P.; Pandian, Muthu Senthil; Ramasamy, P., E-mail: ramasamyp@ssn.edu.in [SSN Research Centre, SSN College of Engineering, Kalavakkam-603 110, Chennai, Tamilnadu (India)

    2015-06-24

    Vanadium oxide nanostars were synthesized by chemical method. The prepared Vanadium oxide nanostars are introduced into dye sensitized solar cell (DSSC) as counter electrode (CE) catalyst to replace the expensive platinum (Pt). The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) method. The photovoltaic performance of the VO as counter electrode based DSSC was evaluated under simulated standard global AM 1.5G sunlight (100 mW/cm{sup 2}). The solar to electrical energy conversion efficiency (η) of the DSSC was found to be 0.38%.This work expands the Counter electrode catalyst, which can help to reduce the cost of DSSC and thereby encourage their fundamental research and commercial application.

  13. Analysis of polypyrrole-coated stainless steel electrodes

    Indian Academy of Sciences (India)

    Analysis of polypyrrole-coated stainless steel electrodes - Estimation of specific ... is carried out on stainless steel electrodes using -toluene sulphonic acid. ... The feasibility of the electrode for supercapacitor applications is investigated.

  14. Development of powder diffraction anomalous fine structure method and applications to electrode materials for rechargeable batteries

    International Nuclear Information System (INIS)

    Kawaguchi, Tomoya; Fukuda, Katsutoshi; Oishi, Masatsugu; Ichitsubo, Tetsu; Matsubara, Eiichiro; Mizuki, Jun'ichiro

    2015-01-01

    A powder diffraction anomalous fine structure (P-DAFS) method is developed both in analytical and experimental techniques and applied to cathode materials for lithium ion batteries. The DAFS method, which is an absorption spectroscopic technique through a scattering measurement, enables us to analyze the chemical states and the local structures of a certain element at different sites, thanks to the nature of x-ray diffraction, where the contributions from each site are different at each diffraction. Electrode materials for rechargeable batteries frequently exhibit the interchange between Li and a transition metal, which is known as the cation mixing phenomena. This cation mixing significantly affects the whole electrode properties; therefore, the site-distinguished understanding of the roles of the transition metal is essential for further material design by controlling and positively utilizing this cation mixing phenomenon. However, the developments of the P-DAFS method are required for the applications to the practical materials such as the electrode materials. In the present study, a direct analysis technique to extract the absorption spectrum from the scattering without using the conventional iterative calculations, fast and accurate measurement techniques of the P-DAFS method, and applications to a typical electrode material of Li 1-x Ni 1+x O 2 , which exhibits the significant cation mixing, are described. (author)

  15. Corrosion of aluminium in copper-aluminium couples under a marine environment: Influence of polyaniline deposited onto copper

    International Nuclear Information System (INIS)

    Vera, Rosa; Verdugo, Patricia; Orellana, Marco; Munoz, Eduardo

    2010-01-01

    Research highlights: → The presence of Polyaniline in the Al-Cu system produces a decrease in the oxygen reduction reaction. → In the marine enviroment, aluminium in Al-Cu couples, suffers pitting and exfoliation. → The aluminium deterioration increases with chloride and enviromental sulphur dioxide presence, mainly when it is united to bare copper. - Abstract: In this study, we examined how aluminium corrosion in Al-Cu/PANI galvanic couples in a marine environment is influenced by deposition of polyaniline (PANI) on copper. Polarization curves and immersion assays in 0.1 M NaCl were performed. The morphologies of etched Al and corrosion products were observed by SEM, and the Al ions in solution were quantified by atomic absorption spectroscopy. A reduction in aluminium damage due to galvanic corrosion was observed as a result of decreased effective area for the oxygen reduction reaction on Cu/PANI electrode. Furthermore, an electrochemical reduction of PANI from leucoemeraldine to emeraldine base is proposed.

  16. Screen-printed carbon-containing electrode modified with formazan for determining copper, lead, cadmium, and zinc

    International Nuclear Information System (INIS)

    Stozhko, N.Yu.; Aleshina, L.V.; Brajnina, Kh.Z.; Lipunova, G.N.; Maslakova, T.I.

    2004-01-01

    The electrochemical behavior of some hetarylated formazans introduced into the bulk of carbon-containing inks of screen-printed electrodes was studied. The compositions of complexes formed at the electrode surface were found, and their stability constants were estimated. It was shown that the modification of carbon-containing screen-printed electrode with 1-(o-chlorophenyl-3-phenyl-5-(6-methyl-4-oxo-pyrimidinyl-2)formazan improves its sensitivity, lowers detection limits for Pb(II), Cu(II), Cd(II), and Zn(II), and ensures high precision of the results of voltammetric analysis [ru

  17. Synthesis and Microstructural Characterization of Manganese Oxide Electrodes for Application as Electrochemical Supercapacitors

    Science.gov (United States)

    Babakhani, Banafsheh

    The aim of this thesis work was to synthesize Mn-based oxide electrodes with high surface area structures by anodic electrodeposition for application as electrochemical capacitors. Rod-like structures provide large surface areas leading to high specific capacitances. Since templated electrosynthesis of rods is not easy to use in practical applications, it is more desirable to form rod-like structures without using any templates. In this work, Mn oxide electrodes with rod-like structures (˜1.5 µm in diameter) were synthesized from a solution of 0.01 M Mn acetate under galvanostatic control without any templates, on Au coated Si substrates. The electrochemical properties of the synthesized nanocrystalline electrodes were investigated to determine the effect of morphology, chemistry and crystal structure on the corresponding electrochemical behavior of Mn oxide electrodes. Mn oxides prepared at different current densities showed a defective antifluoritetype crystal structure. The rod-like Mn oxide electrodes synthesized at low current densities (5 mAcm.2) exhibited a high specific capacitance due to their large surface areas. Also, specific capacity retention after 250 cycles in an aqueous solution of 0.5 M Na2SO4 at 100 mVs -1 was about 78% of the initial capacity (203 Fg-1 ). To improve the electrochemical capacitive behavior of Mn oxide electrodes, a sequential approach and a one-step method were adopted to synthesize Mn oxide/PEDOT electrodes through anodic deposition on Au coated Si substrates from aqueous solutions. In the former case, free standing Mn oxide rods (about 10 µm long and less than 1.5 µm in diameter) were first synthesized, then coated by electro-polymerization of a conducting polymer (PEDOT) giving coaxial rods. The one-step, co-electrodeposition method produced agglomerated Mn oxide/PEDOT particles. The electrochemical behavior of the deposits depended on the morphology and crystal structure of the fabricated electrodes, which were affected

  18. Study on oxidization of Ru and its application as electrode of PZT capacitor for FeRAM

    International Nuclear Information System (INIS)

    Jia Ze; Ren Tianling; Liu Tianzhi; Hu Hong; Zhang Zhigang; Xie Dan; Liu Litian

    2007-01-01

    Oxidization for Ru through anneal with plenteous oxygen atmosphere and its application as the top electrode of sol-gel PZT capacitor are investigated in this study. PZT capacitor with RuO 2 or oxygen-doped Ru as top electrode can be obtained from Ru/PZT/Pt capacitor through slow-rate anneal at 650 deg. C for 20 min in cannulation furnace. It has larger remanent polarization, better rectangle shape, better fatigue properties and lower leakage current than the other capacitors with PZT film prepared by the same process and different top electrodes in this study. Plenteous oxygen atmosphere and 650 deg. C in cannulation furnace are important conditions for the oxidation of Ru and renewed crystallization of PZT in this capacitor. Plenteous oxygen at interface can compensate the oxygen vacancies at PZT/electrode interface, which results in the above good characteristics

  19. Ultrathin nickel hydroxide on carbon coated 3D-porous copper structures for high performance supercapacitors.

    Science.gov (United States)

    Kang, Kyeong-Nam; Kim, Ik-Hee; Ramadoss, Ananthakumar; Kim, Sun-I; Yoon, Jong-Chul; Jang, Ji-Hyun

    2018-01-03

    An ultrathin nickel hydroxide layer electrodeposited on a carbon-coated three-dimensional porous copper structure (3D-C/Cu) is suggested as an additive and binder-free conductive electrode with short electron path distances, large electrochemical active sites, and improved structural stability, for high performance supercapacitors. The 3D-porous copper structure (3D-Cu) provides high electrical conductivity and facilitates electron transport between the Ni(OH) 2 active materials and the current collector of the Ni-plate. A carbon coating was applied to the 3D-Cu to prevent the oxidation of Cu, without degrading the electron transport behavior of the 3D-Cu. The 3D-Ni(OH) 2 /C/Cu exhibited a high specific capacitance of 1860 F g -1 at 1 A g -1 , and good cycling performance, with an 86.5% capacitance retention after 10 000 cycles. When tested in a two-electrode system, an asymmetric supercapacitor exhibited an energy density of 147.9 W h kg -1 and a power density of 37.0 kW kg -1 . These results open a new area of ultrahigh-performance supercapacitors, supported by 3D-Cu electrodes.

  20. Electrochemical Synthesis of Graphene/MnO2 Nano-Composite for Application to Supercapacitor Electrode.

    Science.gov (United States)

    Jeong, Kwang Ho; Lee, Hyeon Jeong; Simpson, Michael F; Jeong, Mun

    2016-05-01

    Graphene/MnO2 nano-composite was electrochemically synthesized for application to an electrode material for electrochemical supercapacitors. The nanosized needle-like MnO2 was obtained by use of a graphene substrate. The prepared composite exhibited an ideal supercapacitive behavior. A capacitance retention of 94% was achieved with a 4 h deposition time (an initial capacitance of 574 mF/cm2 at a scan rate of 20 mV/s) and the retention declined with further deposition time. The results demonstrate enhanced contact between the electrode and electrolyte and improved power density as an electrochemical capacitor.

  1. An insight into the adsorption and electrochemical processes occurring during the analysis of copper and lead in wines, using an electrochemical quartz crystal nanobalance.

    Science.gov (United States)

    Yamasaki, Alzira; Oliveira, João A B P; Duarte, Armando C; Gomes, M Teresa S R

    2012-08-30

    Copper and lead in wine were quantified by anodic stripping voltammetry (ASV), performed onto the gold electrode of a piezoelectric quartz crystal. Both current or mass changes could be used as analytical signals, without a statistical difference in the results (α=0.05). However, the plot of mass vs. potential provided an in depth understanding of the electrochemical processes and allowed studying adsorption phenomena. Copper interaction with fructose is an example of a process which was not possible to ignore by observing the mass change on the gold electrode of the piezoelectric quartz crystal. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. The investigation of movement dynamics of an AC electric arc attachment along the working surface of a hollow cylindrical electrode under the action of gas-dynamic and electromagnetic forces

    International Nuclear Information System (INIS)

    Surov, A V; Popov, S D; Serba, E O; Nakonechny, G V; Spodobin, V A; Ovchinnikov, R V; Kumkova, I I; Shabalin, S A

    2012-01-01

    Stationary electric arc alternating current plasma torches are used today for realization of plasma chemical technologies requiring relatively high energy input. Waste treatment is one these directions. The paper reports on experiment results directed towards the increase in the lifetime characteristics of electrode units of the powerful high-voltage electric-arc AC plasma torches. The solution to the problem of obtainment the uniform wear of a copper hollow cylindrical electrode achieved by the controlled movement of the arc attachment along the working surface was offered. Organization of gas supply in the near electrode area and application of alternating magnetic field ensured movement of arc attachment along the surface with average speed from 2 to 14 m/s. Arc current was about 47 A and 84 A, gas flow rate in near electrode area was about 5 and 4.5 g/s. Due to researches on the experimental prototype of a hollow cylindrical electrode, the erosion of its material reached only 3 μg/C, that enables production of the electrode assembly with life time above 1000 hours at currents in the arc up to 100–200 A.

  3. Preparation of the spacer for narrow electrode gap configuration in ionization-based gas sensor

    International Nuclear Information System (INIS)

    Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif

    2012-01-01

    Carbon nanotubes (CNTs) have started to be developed as the sensing element for ionization-based gas sensors due to the demand for improved sensitivity, selectivity, stability and other sensing properties beyond what can be offered by the conventional ones. Although these limitations have been overcome, the problems still remain with the conventional ionization-based gas sensors in that they are bulky and operating with large breakdown voltage and high temperature. Recent studies have shown that the breakdown voltage can be reduced by using nanostructured electrodes and narrow electrode gap. Nanostructured electrode in the form of aligned CNTs array with evenly distributed nanotips can enhance the linear electric field significantly. The later is attributed to the shorter conductivity path through narrow electrode gap. The paper presents the study on the design consideration in order to realize ionization based gas sensor using aligned carbon nanotubes array in an optimum sensor configuration with narrow electrode gap. Several deposition techniques were studied to deposit the spacer, the key component that can control the electrode gap. Plasma spray deposition, electron beam deposition and dry oxidation method were employed to obtain minimum film thickness around 32 μm. For plasma spray method, sand blasting process is required in order to produce rough surface for strong bonding of the deposited film onto the surface. Film thickness, typically about 39 μm can be obtained. For the electron beam deposition and dry oxidation, the film thickness is in the range of nanometers and thus unsuitable to produce the spacer. The deposited multilayer film consisting of copper, alumina and ferum on which CNTs array will be grown was found to be removed during the etching process. This is attributed to the high etching rate on the thin film which can be prevented by reducing the rate and having a thicker conductive copper film.

  4. Preparation of the spacer for narrow electrode gap configuration in ionization-based gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif [Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh, Perak. (Malaysia); Fundamental and Applied Science, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh, Perak. (Malaysia); Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh, Perak. (Malaysia)

    2012-09-26

    Carbon nanotubes (CNTs) have started to be developed as the sensing element for ionization-based gas sensors due to the demand for improved sensitivity, selectivity, stability and other sensing properties beyond what can be offered by the conventional ones. Although these limitations have been overcome, the problems still remain with the conventional ionization-based gas sensors in that they are bulky and operating with large breakdown voltage and high temperature. Recent studies have shown that the breakdown voltage can be reduced by using nanostructured electrodes and narrow electrode gap. Nanostructured electrode in the form of aligned CNTs array with evenly distributed nanotips can enhance the linear electric field significantly. The later is attributed to the shorter conductivity path through narrow electrode gap. The paper presents the study on the design consideration in order to realize ionization based gas sensor using aligned carbon nanotubes array in an optimum sensor configuration with narrow electrode gap. Several deposition techniques were studied to deposit the spacer, the key component that can control the electrode gap. Plasma spray deposition, electron beam deposition and dry oxidation method were employed to obtain minimum film thickness around 32 {mu}m. For plasma spray method, sand blasting process is required in order to produce rough surface for strong bonding of the deposited film onto the surface. Film thickness, typically about 39 {mu}m can be obtained. For the electron beam deposition and dry oxidation, the film thickness is in the range of nanometers and thus unsuitable to produce the spacer. The deposited multilayer film consisting of copper, alumina and ferum on which CNTs array will be grown was found to be removed during the etching process. This is attributed to the high etching rate on the thin film which can be prevented by reducing the rate and having a thicker conductive copper film.

  5. Influence of Electrodes Characteristics on The Performance of a Microbial Fuel Cell

    Directory of Open Access Journals (Sweden)

    Muhammad Hadi Radi

    2017-07-01

    Full Text Available A single chamber microbial fuel cell is designed incorporating microorganism as catalyst with Escherichia coli, Staphylococcus, Kelbssila bacteria as an electrolyte at pH =7 and an operating temperature of 30 C0 in batch mode. The electrodes are made of three different types of materials, namely; aluminum, copper and zinc. Each material is configurated at three different shape (circle, rectangle and square in three different cross sectional areas of (3.14,7.065and 12.56cm2. The distance between anode and cathode is fixed at different values of 0.5,1,2,4 and 6cm. Results indicate that electrodes of circular shape show the best performance among other shapes investigated in this study, however the area of the anode is found to affect the cell performance more than its shape. Using zinc as an anode material and copper as a cathode in circular shape with cross sectional area of 12.56 cm2 and a 2 cm distance between them output the best performance in comparison to other combinations investigated in this study.

  6. Photo-induced changes in nano-copper oxide for optoelectronic applications

    Science.gov (United States)

    Hendi, A. A.; Rashad, M.

    2018-06-01

    Copper oxide (CuO) nanoparticles (NPs) have been prepared using microwave irradiation. A mother material was copper nitrate in distilled water. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used for characterizing the NPs powders. Thermal Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) were measured for as-prepared CuO NPs. The obtained oxides NPs were confirmed produced during chemical precipitation by these characterizions. These NPs were dropped on top of glass substrate for measuring the optical characterizions. Both linear and nonlinear optical properties of the as-prepared CuO NP films were studied. The optical energy gap of the as-prepared CuO NP films is equal to 3.98 eV, which is higher than that of the bulk material. The effect of ultraviolet (UV) light irradiation on the CuO NP films was investigated at 2 and 5 h for study the photo-induced effect. The optical properties of CuO NP films were measured as a function of these UV irradiation time. The optical constants for as-prepared and irradiated CuO NP films were calculated which reflect the affect of UV irradiation time. As observed from these optical results, a highly forced for optoelectronic applications.

  7. Enzyme electrode configurations : for application in biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaoju

    2012-07-01

    ; their effects on the electrode performance were then investigated. It is proposed that the {eta}-{eta} interaction between the PSS{sup -} and the hydrophobic substrate-binding pocket in the vicinity of the T1 Cu site results in a favorable location of the conducting polymer chain of PEDOT-PSS close to the T1 Cu site and thus facilitates the DET of ThL within this particular architecture. The flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase from Glomerella cingulata (GcGDH) and cellobiose dehydrogense from Corynascus thermophuilus (CtCDH) have been studied to construct different enzyme electrode configurations as bioanodes towards biofuel cell applications. For GcGDH, six Os-containing polymers, whose redox potentials range across a broad potential window between +15 and +489 mV vs. NHE, were used to 'wire' the GcGDH on the graphite electrodes to catalyze the oxidation of glucose. The ratio of GcGDH:Os-polymer in the overall loading onto the electrode surface significantly affected the catalytic performance of the enzyme electrode on the glucose oxidation. Both the Os-polymer and the GcGDH:Os-polymer ratio were optimized for obtaining the maximum current density; a high current density of 493 {mu}A/cm{sup 2} for 30 mM glucose was produced by a GcGDH/Os c modified electrode. DET type biocatalysis of CtCDH on lactose (and glucose) oxidation was accomplished on Au nanoparticle (AuNP) structured electrode. The haem site in the CtCDH enzyme functions as a 'built-in' mediator for communicating the electron transfer between the FAD site and the AuNP surface. The redox potential of the haem site in CtCDH was determined to be E{sub 1/2} = -122 mV vs. Ag/AgCl/KCl(s) (75 mV vs. NHE). The CtCDH/AuNP/Au bioanode can generate a maximum current response for lactose with I{sub max} = 43.3{+-}1.5 ({mu}A/cm{sup 2}) or for glucose with I{sub max} = 31.2{+-}2.3 ({mu}A/cm{sup 2}). The DET type biocatalysis of CtCDH works most efficiently in a more neutral

  8. Reliability of copper based alloys for electric resistance spot welding

    International Nuclear Information System (INIS)

    Jovanovicj, M.; Mihajlovicj, A.; Sherbedzhija, B.

    1977-01-01

    Durability of copper based alloys (B-5 and B-6) for electric resistance spot-welding was examined. The total amount of Be, Ni and Zr was up to 2 and 1 wt.% respectively. Good durability and satisfactory quality of welded spots were obtained in previous laboratory experiments carried out on the fixed spot-welding machine of an industrial type (only B-5 alloy was examined). Electrodes made of both B-5 and B-6 alloy were tested on spot-welding grips and fixed spot-welding machines in Tvornica automobila Sarajevo (TAS). The obtained results suggest that the durability of electrodes made of B-5 and B-6 alloys is more than twice better than of that used in TAS

  9. Preparation of a Counter Electrode with P-Type NiO and Its Applications in Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Chuen-Shii Chou

    2010-01-01

    Full Text Available This study investigates the applicability of a counter electrode with a P-type semiconductor oxide (such as NiO on a dye-sensitized solar cell (DSSC. The counter electrode is fabricated by depositing an NiO film on top of a Pt film, which has been deposited on a Fluorine-doped tin oxide (FTO glass using an ion-sputtering coater (or E-beam evaporator, using a simple spin coating method. This study also examines the effect of the average thickness of TiO2 film deposited on a working electrode upon the power conversion efficiency of a DSSC. This study shows that the power conversion efficiency of a DSSC with a Pt(E/NiO counter electrode (4.28% substantially exceeds that of a conventional DSSC with a Pt(E counter electrode (3.16% on which a Pt film was deposited using an E-beam evaporator. This result is attributed to the fact that the NiO film coated on the Pt(E counter electrode improves the electrocatalytic activity of the counter electrode.

  10. Applicability of copper alloys for DEMO high heat flux components

    Science.gov (United States)

    Zinkle, Steven J.

    2016-02-01

    The current state of knowledge of the mechanical and thermal properties of high-strength, high conductivity Cu alloys relevant for fusion energy high heat flux applications is reviewed, including effects of thermomechanical and joining processes and neutron irradiation on precipitation- or dispersion-strengthened CuCrZr, Cu-Al2O3, CuNiBe, CuNiSiCr and CuCrNb (GRCop-84). The prospects for designing improved versions of wrought copper alloys and for utilizing advanced fabrication processes such as additive manufacturing based on electron beam and laser consolidation methods are discussed. The importance of developing improved structural materials design criteria is also noted.

  11. Electrodes for bio-application: recording and stimulation

    International Nuclear Information System (INIS)

    Fontes, M B A

    2013-01-01

    Recording and stimulation electrodes applied on excitable tissue are the basis of electrophysiological research, such as brain, muscles, peripheral nerves or sensory systems. Electrode-electrolyte impedance is one of the important characteristics due to its influence on the signal/noise ratio, signal distortion and built-up voltage. Strategies to lowering and tuning the impedance are achieved by biasing iridium oxide modified platinum microelectrodes. Surface and impedance analysis after pulse stimulation are also addressed.

  12. Copper induced oxidative stresses, antioxidant responses and phytoremediation potential of Moso bamboo (Phyllostachys pubescens)

    Science.gov (United States)

    Chen, Junren; Shafi, Mohammad; Li, Song; Wang, Ying; Wu, Jiasen; Ye, Zhengqian; Peng, Danli; Yan, Wenbo; Liu, Dan

    2015-09-01

    Moso bamboo is recognized as phytoremediation plant due to production of huge biomass and high tolerance in stressed environment. Hydroponics and pot experiments were conducted to investigate mechanism of copper tolerance and to evaluate copper accumulation capacity of Moso bamboo. In hydroponics experiment there was non significant variation in MDA contents of leaves compared with control. SOD and POD initially indicated enhancing trend with application of 5 μM Cu and then decreased consistently with application of 25 and 100 μM Cu. Application of each additional increment of copper have constantly enhanced proline contents while maximum increase of proline was observed with application of 100 μM copper. In pot experiment chlorophyll and biomass initially showed increasing tendency and decreased gradually with application of each additional increment of Cu. Normal growth of Moso bamboo was observed with application of 100 mg kg-1 copper. However, additional application of 300 or 600 mg kg-1 copper had significantly inhibited growth of Moso bamboo. The concentration of Cu in Moso bamboo has attained the levels of 340, 60, 23 mg kg-1 in roots, stems and leaves respectively. The vacuoles were the main organs which accumulated copper and reduced toxicity of copper as studied by TEM-DEX technology.

  13. Cold cap subsidence for in situ vitrification and electrodes therefor

    Science.gov (United States)

    Buelt, James L.; Carter, John G.; Eschbach, Eugene A.; FitzPatrick, Vincent F.; Koehmstedt, Paul L.; Morgan, William C.; Oma, Kenton H.; Timmerman, Craig L.

    1992-01-01

    An electrode for use in in situ vitrification of soil comprises a molybdenum rod received within a conductive sleeve or collar formed of graphite. Electrodes of this type are placed on either side of a region containing buried waste material and an electric current is passed therebetween for vitrifying the soil between the electrodes. The graphite collar enhances the thermal conductivity of the electrode, bringing heat to the surface, and preventing the formation of a cold cap of material above the ground surface. The annulus between the molybdenum rod electrode and the graphite collar is filled with a conductive ceramic powder of a type that sinters upon the molybdenum rod, protecting the same from oxidation as the graphite material is consumed, or a metal powder which liquifies at operating temperatures. The molybdenum rod in the former case may be coated with an oxidation protectant, e.g. of molybdenum disilicide. As insulative blanket is suitably placed on the surface of the soil during processing to promote subsidence by allowing off-gassing and reducing surface heat loss. In other embodiments, connection to vitrification electrodes is provided below ground level to avoid loss of connection due to electrodes deterioration, or a sacrificial electrode may be employed when operation is started. Outboard electrodes can be utilized to square up the vitrified area. Further, the center of the molybdenum rod can be made hollow and filled with a powdered metal, such as copper, which liquifies at operating temperatures. In one embodiment, the molybdenum rod and the graphite collar are physically joined at the bottom.

  14. Body of Knowledge (BOK) for Copper Wire Bonds

    Science.gov (United States)

    Rutkowski, E.; Sampson, M. J.

    2015-01-01

    Copper wire bonds have replaced gold wire bonds in the majority of commercial semiconductor devices for the latest technology nodes. Although economics has been the driving mechanism to lower semiconductor packaging costs for a savings of about 20% by replacing gold wire bonds with copper, copper also has materials property advantages over gold. When compared to gold, copper has approximately: 25% lower electrical resistivity, 30% higher thermal conductivity, 75% higher tensile strength and 45% higher modulus of elasticity. Copper wire bonds on aluminum bond pads are also more mechanically robust over time and elevated temperature due to the slower intermetallic formation rate - approximately 1/100th that of the gold to aluminum intermetallic formation rate. However, there are significant tradeoffs with copper wire bonding - copper has twice the hardness of gold which results in a narrower bonding manufacturing process window and requires that the semiconductor companies design more mechanically rigid bonding pads to prevent cratering to both the bond pad and underlying chip structure. Furthermore, copper is significantly more prone to corrosion issues. The semiconductor packaging industry has responded to this corrosion concern by creating a palladium coated copper bonding wire, which is more corrosion resistant than pure copper bonding wire. Also, the selection of the device molding compound is critical because use of environmentally friendly green compounds can result in internal CTE (Coefficient of Thermal Expansion) mismatches with the copper wire bonds that can eventually lead to device failures during thermal cycling. Despite the difficult problems associated with the changeover to copper bonding wire, there are billions of copper wire bonded devices delivered annually to customers. It is noteworthy that Texas Instruments announced in October of 2014 that they are shipping microcircuits containing copper wire bonds for safety critical automotive applications

  15. Electrocatalytic reduction of nitrate at low concentration on coinage and transition-metal electrodes in acid solutions

    NARCIS (Netherlands)

    Dima, G.E.; Vooys, de A.C.A.; Koper, M.T.M.

    2003-01-01

    A comparative study was performed to determine the reactivity of nitrate ions at 0.1 M on eight different polycrystalline electrodes (platinum, palladium, rhodium, ruthenium, iridium, copper, silver and gold) in acidic solution using cyclic voltammetry (CV), chronoamperometry and differential

  16. Synthesis of new copper nanoparticle-decorated anchored type ligands: Applications as non-enzymatic electrochemical sensors for hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ensafi, Ali A., E-mail: Ensafi@cc.iut.ac.ir; Zandi-Atashbar, N.; Ghiaci, M.; Taghizadeh, M.; Rezaei, B.

    2015-02-01

    In this work, copper nanoparticles (CuNPs) decorated on two new anchored type ligands were utilized to prepare two electrochemical sensors. These ligands are made from bonding amine chains to silica support including SiO{sub 2}–pro–NH{sub 2} (compound I) and SiO{sub 2}–pro–NH–cyanuric–NH{sub 2} (compound II). The morphology of synthesized CuNPs was characterized by transmission electron microscopy (TEM). The nano-particles were in the range of 13–37 nm with the average size of 23 nm. These materials were used to modify carbon paste electrode. Different electrochemical techniques, including cyclic voltammetry, electrochemical impedance spectroscopy and hydrodynamic chronoamperometry, were used to study the sensor behavior. These electrochemical sensors were used as a model for non-enzymatic detection of hydrogen peroxide (H{sub 2}O{sub 2}). To evaluate the abilities of the modified electrodes for H{sub 2}O{sub 2} detection, the electrochemical signals were compared in the absence and presence of H{sub 2}O{sub 2}. From them, two modified electrodes showed significant responses vs. H{sub 2}O{sub 2} addition. The amperograms illustrated that the sensors were selective for H{sub 2}O{sub 2} sensing with linear ranges of 5.14–1250 μmol L{sup −1} and 1.14–1120 μmol L{sup −1} with detection limits of 0.85 and 0.27 μmol L{sup −1} H{sub 2}O{sub 2}, sensitivities of 3545 and 11,293 μA mmol{sup −1} L and with response times less than 5 s for I/CPE and II/CPE, respectively. As further verification of the selected sensor, H{sub 2}O{sub 2} contained in milk sample was analyzed and the obtained results were comparable with the ones from classical control titration method. - Highlights: • Copper nanoparticles decorating on two new anchored type ligands were prepared. • Ligands are bonding to silica support as SiO{sub 2}–pro–NH{sub 2} and SiO{sub 2}–pro–NH–cyanuric–NH{sub 2}. • These materials were used as electrochemical sensors for H

  17. Novel synthesis of Ni-ferrite (NiFe2O4) electrode material for supercapacitor applications

    International Nuclear Information System (INIS)

    Venkatachalam, V.; Jayavel, R.

    2015-01-01

    Novel nanocrystalline NiFe 2 O 4 has been synthesized through combustion route using citric acid as a fuel. Phase of the synthesized material was analyzed using powder X-ray diffraction. The XRD study revealed the formation of spinel phase cubic NiFe 2 O 4 with high crystallinity. The average crystallite size of NiFe 2 O 4 nanomaterial was calculated from scherrer equation. The electrochemical properties were realized by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The electrode material shows a maximum specific capacitance of 454 F/g with pseudocapacitive behavior. High capacitance retention of electrode material over 1000 continuous charging-discharging cycles suggests its excellent electrochemical stability. The results revealed that the nickel ferrite electrode is a potential candidate for energy storage applications in supercapacitor

  18. Silver-nickel oxide core-shell nanoparticle array electrode with enhanced lithium-storage performance

    International Nuclear Information System (INIS)

    Zhao, Wenjia; Du, Ning; Zhang, Hui; Yang, Deren

    2015-01-01

    We demonstrate the synthesis of Ag-NiO core-shell nanoparticle arrays via a one-step solution-immersion process and subsequent RF-sputtering technique. The Ag nanoparticle arrays on copper substrate are firstly prepared by a displacement reaction at mild temperature of 303K. Then, a NiO layer is deposited onto the surface of the Ag nanoparticles via RF-sputtering technique. When evaluated as an anode for lithium-ion batteries, the Ag-NiO core-shell electrode shows higher capacity and better cycling performance than the planar NiO electrode. The in-situ synthesized Ag nanoparticles can enhance the interfacial strength between the active material and substrate, andimprove the electrical conductivity of the electrode, which may be responsible for the enhanced performance

  19. Micromachining with copper lasers

    Science.gov (United States)

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  20. Selective electrochemical sensor for copper (II) ion based on chelating ionophores

    International Nuclear Information System (INIS)

    Singh, Ashok Kumar; Mehtab, Sameena; Jain, Ajay Kumar

    2006-01-01

    Plasticized membranes using 3-(2-pyridinyl)-2H-pyrido[1,2,-a]-1,3,5-triazine-2,4(3H)-dithione (L 1 ) and acetoacetanilide (L 2 ) have been prepared and explored as Cu 2+ -selective sensors. Effect of various plasticizers, viz. chloronaphthalene (China), benzyl acetate (BA), o-nitrophenyloctyl ether (o-NPOE), and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied in detail and improved performance was observed at several instances. Optimum performance was observed with dithione derivative (L 1 ) having a membrane composition of L 1 (5):PVC (120):o-NPOE (240):OA (10). The sensor works satisfactorily in the concentration range 5.0 x 10 -8 to 1.0 x 10 -2 M (detection limit 4.0 x 10 -8 M) with a Nernstian slope of 29.5 mV decade -1 of activity. Wide pH range (3.0-9.5), fast response time (12 s), non-aqueous tolerance (up to 20%) and adequate shelf life (4 months) indicate the vital utility of the proposed sensor. The potentiometric selectivity coefficient values as determined by match potential method (MPM) indicate good response for Cu 2+ in presence of interfering ions. The proposed electrode comparatively shows good selectivity with respect to alkali, alkaline earth, transition and some rare earth metals ions. The electrode was used for the determination of copper in different milk powder, water samples and as indicator electrode in potentiometric titration of copper ion with EDTA

  1. Copper corrosion in irradiated environments. The influence of H2O2 on the electrochemistry of copper dissolution in HC1 electrolyte

    International Nuclear Information System (INIS)

    Smyrl, W.H.; Bell, B.T.; Atanasoski, R.T.; Glass, R.S.

    1987-01-01

    The anodic dissolution of copper has been examined in deaerated, 0.1 M HCl aqueous solution in the presence of H 2 O 2 . Concentrations of H 2 O 2 up to 0.2 M were studied at a rotating copper disk-platinum ring electrode. The open circuit potential (OCP) of copper was found to depend on both peroxide concentration and rotation rate. The OCP shifts towards more positive values with increasing H 2 O 2 concentration (C) and decreasing rotation rate (Omega). The dependence of OCP on (C/Omega/sup 1/2/) was the same as for oxygenated solutions reported earlier [1], at small values of (C/Omega/sup 1/2/). At higher values of (C/Omega/sup 1/2/), departure from the expected behavior was observed. The current-voltage curves for anodic dissolution of copper were also influenced by the presence of peroxide. The curves recorded with the potential scanned in the positive direction showed the expected 60 mV slope, but the reverse scans showed significant departures. At a given potential scan rate, hysteresis was observed which was larger for higher H 2 O 2 concentrations, lower rotation rates, and more positive anodic potential limits. Monitoring the cuprous ions at the outer Pt ring revealed that there was a complex set of events taking place at the copper surface, including film formation and the appearance of cupric ions. 13 references, 7 figures

  2. Properties of experimental copper-aluminium-nickel alloys for dental post-and-core applications.

    Science.gov (United States)

    Rittapai, Apiwat; Urapepon, Somchai; Kajornchaiyakul, Julathep; Harniratisai, Choltacha

    2014-06-01

    This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost. Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (α=0.05). The alloy toxicity was evaluated according to the ISO standard. The solidus and liquidus points of experimental alloys ranged from 1023℃ to 1113℃ and increased as the nickel content increased. The highest ultimate tensile strength (595.9 ± 14.2 MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity (113.9 ± 8.0 and 122.8 ± 11.3 GPa, respectively), but also had a value of 0.2% proof strength (190.8 ± 4.8 and 198.2 ± 3.4 MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control. The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications.

  3. Efficiency of Nb-Doped ZnO Nanoparticles Electrode for Dye-Sensitized Solar Cells Application

    Science.gov (United States)

    Anuntahirunrat, Jirapat; Sung, Youl-Moon; Pooyodying, Pattarapon

    2017-09-01

    The technological of Dye-sensitized solar cells (DSSCs) had been improved for several years. Due to its simplicity and low cost materials with belonging to the part of thin films solar cells. DSSCs have numerous advantages and benefits among the other types of solar cells. Many of the DSSC devices had use organic chemical that produce by specific method to use as thin film electrodes. The organic chemical that widely use to establish thin film electrodes are Zinc Oxide (ZnO), Titanium Dioxide (TiO2) and many other chemical substances. Zinc oxide (ZnO) nanoparticles had been used in DSSCs applications as thin film electrodes. Nanoparticles are a part of nanomaterials that are defined as a single particles 1-100 nm in diameter. From a few year ZnO widely used in DSSC applications because of its optical, electrical and many others properties. In particular, the unique properties and utility of ZnO structure. However the efficiency of ZnO nanoparticles based solar cells can be improved by doped various foreign impurity to change the structures and properties. Niobium (Nb) had been use as a dopant of metal oxide thin films. Using specification method to doped the ZnO nanoparticles thin film can improved the efficiencies of DSSCs. The efficiencies of Nb-doped ZnO can be compared by doping 0 at wt% to 5 at wt% in ZnO nanoparticles thin films that prepared by the spin coating method. The thin film electrodes doped with 3 at wt% represent a maximum efficiencies with the lowest resistivity of 8.95×10-4 Ω·cm.

  4. Sorption of polluting metal ions on a palm tree frond sawdust studied by the means of modified carbon paste electrodes.

    Science.gov (United States)

    Nouacer, Sana; Hazourli, Sabir; Despas, Christelle; Hébrant, Marc

    2015-11-01

    Water remediation by adsorption of the metal ions on a low cost sorbent is the frame of the present study. The metal ions adsorption properties of sawdust of palm tree fronds (PTF sawdust) are investigated by both equilibrium measurements and modified carbon paste electrode. The ability to adsorb Cu(II), Cr(VI) and As(III) in significant quantities is demonstrated. Carbon paste electrodes modified by incorporation of PTF sawdust (PTF-CPE) or, for comparison, an organically modified silica for the detection of copper(II) are investigated in term of sensitivity, estimation of number of possible reuses, repeatability and interference effect. A detection limit for Cu(II) analysis of 1.0×10(-8) M has been achieved after 5 min preconcentration and a single PTF-CPE can be used for up to 10 preconcentration-analysis-regeneration cycles. The relative standard deviation (n=9) for the determination of a 10(-6) M Cu(II) solution (pH=5) was about 26%. The effects of Ca(II), As(III) and Cr(VI) on the copper detection are investigated: calcium ions were shown to compete with copper on the same adsorption sites, arsenic(III) has no effect on the copper detection whereas chromium(VI) was shown to enhance the copper detection. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Arcing time analysis of liquid nitrogen with respect to electrode materials

    Science.gov (United States)

    Junaid, Muhammad; Yang, Kun; Ge, Hanming; Wang, Jianhua

    2018-03-01

    Unlike sulphur hexafluoride (SF6), liquid nitrogen (LN2) is cost effective, environment friendly and cryogenic dielectric. It has astounding insulating properties with the potential to decrease power loss in switchgear applications due to its remarkably low temperatures. The basic research is however a necessity to observe the performance of LN2 subjected to high luminance arcs. So far, there are no findings that refer to the arcing time inside the LN2 environment. The objective of this work was to investigate the arcing times in LN2 and compare the results with open air conditions using different electrode materials. Experiments were conducted on different DC voltages and their arcing times were measured. Three different kinds of electrode materials, namely: pure copper (Cu), stainless used steel (SUS) and aluminium alloy (Al 6061) were tested under 1 atmospheric pressure. The results revealed that LN2 extinguishes arc in almost half the amount of time required by the open air insulation. With Al 6061 has the shortest arcing time, whilst Cu, the second best choice and SUS places last in the evaluation. It was encapsulated from the findings that LN2 is a better choice than air insulation in terms of arc quenching and a better alternative to SF6 when environment is the priority.

  6. A potentiodynamic study of the reduction of oxygen on copper

    International Nuclear Information System (INIS)

    King, F.; Litke, C.D.

    1994-07-01

    The reduction of oxygen on copper has been studied in 0.1 mol·dm -3 NaCl solutions using potentiodynamic techniques. Experiments were carried out in unbuffered and phosphate-buffered solutions at pH 7. Additional experiments in NaCl solution were performed at pH 10, with the bulk pH adjusted by adding NaOH. Some voltammetric studies in deaerated electrolytes were carried out to examine the nature of the surface films formed on the electrode. The reduction of oxygen on copper is dominated by the 4-electron reduction to OH - . Limited quantities of peroxide were detected by the ring electrode at disc potentials in the joint- and kinetic-control regions. No peroxide was detected in the transport-limiting region. The rate of reduction of oxygen is influenced by the nature of the surface film on the electrode. At interfacial pH values of ∼10, a catalytic surface film forms, thought to be submonolayer Cu(OH) ads or submonolayer Cu 2 O. simultaneously, a peak is observed on the current-potential curve. This peak is observed in neutral solutions with atmospheres of 50% O 2 /N 2 and 100% O 2 and in pH 10 solution with atmospheres >∼10% O 2 /N 2 . The peak is not observed in phosphate-buffered solution because of the buffering action on the interfacial pH. At potentials positive of the peak potential, a thin Cu 2 O layer forms in unbuffered solutions on which the rate of oxygen reduction is partially inhibited. (author). 44 refs., 17 figs

  7. First prototype Copper-Niobium RF Superconducting Cavity

    CERN Multimedia

    1983-01-01

    This is the first RF superconducting cavity made of copper with a very thin layer of pure niobium deposited on the inner wall by sputtering. This new developpment lead to a considerable increase of performance and stability of superconducting cavities and to non-negligible economy. The work was carried out in the ISR workshop. This technique was adopted for the LEP II accelerating cavities. At the centre is Cristoforo Benvenuti, inventor of this important technology, with his assistants, Nadia Circelli and Max Hauer, carrying the sputtering electrode. See also 8209255, 8312339.

  8. Growth of TiO2-ZrO2 Binary Oxide Electrode for Dye Sensitized Solar Cell Application

    International Nuclear Information System (INIS)

    Than Than Win; Aye Myint Myat Kywe; Shwe Yee Win; Honey Thaw; Yin Maung Maung; Ko Ko Kyaw Soe

    2011-12-01

    TiO2-ZrO2 fine binary oxide was prepared by mechanochemical milling process to be homogeneous binary oxide powder. TiO2-ZrO2 paste was deposited on microscopic glass slide by rolling. It was immersed in the henna solution and annealed at 100C for 2h. It was deposited onto another glass slide and used as counter electrode (second electrode). Two glass slides were offset and two binder clips were used to hold the electrodes together. Photovoltaic properties of TiO2-ZrO2 cell were measured and it was expected to utilize the dye sensitized solar cells application.

  9. Copper-catalyzed azide–alkyne cycloaddition (CuAAC) and beyond: new reactivity of copper(i) acetylides†

    OpenAIRE

    Hein, Jason E.; Fokin, Valery V.

    2010-01-01

    Copper-catalyzed azide–alkyne cycloaddition (CuAAC) is a widely utilized, reliable, and straightforward way for making covalent connections between building blocks containing various functional groups. It has been used in organic synthesis, medicinal chemistry, surface and polymer chemistry, and bioconjugation applications. Despite the apparent simplicity of the reaction, its mechanism involves multiple reversible steps involving coordination complexes of copper(i) acetylides of varying nucle...

  10. Electrochemical determination of 2,4,6-trinitrophenol using a hybrid film composed of a copper-based metal organic framework and electroreduced graphene oxide.

    Science.gov (United States)

    Wang, Yong; Cao, Wei; Wang, Luyao; Zhuang, Qianfen; Ni, Yongnian

    2018-06-04

    A metal organic framework (MOF) of the type copper(II)-1,3,5-benzenetricarboxylic acid (Cu-BTC) was electrodeposited on electroreduced graphene oxide (ERGO) placed on a glassy carbon electrode (GCE). The modified GCE was used for highly sensitive electrochemical determination of 2,4,6-trinitrophenol (TNP). The fabrication process of the modified electrode was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. Differential pulse voltammetry (DPV) demonstrates that the Cu-BTC/ERGO/GCE gives stronger signals for TNP reduction than Cu-BTC/GCE or ERGO/GCE alone. DPV also shows TNP to exhibit three reduction peaks, the first at a potential of -0.42 V (vs. SCE). This potential was selected because the other three similarly-structured compounds (2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol) do not give a signal at this potential. Response is linear in the 0.2 to 10 μM TNP concentration range, with a 0.1 μM detection limit (at S/N = 3) and a 15.98 μA∙μM -1 ∙cm -2 sensitivity under optimal conditions. The applicability of the sensor was evaluated by detecting TNP in spiked tap water and lake water samples. Recoveries ranged between 95 and 101%. Graphical abstract Schematic presentation of an electrochemical sensor that was fabricated by electrodeposition of the metal-organic framework (MOF) of copper(II)-1,3,5-benzenetricarboxylic acid (Cu-BTC) onto the surface of electroreduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). It was applied to sensitive and selective detection of 2,4,6-trinitrophenol (TNP).

  11. Chemical synthesis of α-La{sub 2}S{sub 3} thin film as an advanced electrode material for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Patil, S.J.; Kumbhar, V.S.; Patil, B.H.; Bulakhe, R.N.; Lokhande, C.D., E-mail: l_chandrakant@yahoo.com

    2014-10-25

    Highlights: • The simple, chemical method used for synthesis of lanthanum sulphide thin films. • The lanthanum sulphide thin film surface exhibited porous microstructure. • The lanthanum sulphide thin film electrode is used for supercapacitor application. - Abstract: α-La{sub 2}S{sub 3} thin films have been synthesized for the first time by successive ionic layer adsorption and reaction (SILAR) method and used for supercapacitor application. These films are characterized for crystal structure, surface morphology and wettability studies using X-ray diffraction (XRD), Fourier Transform-Raman (FT-Raman) spectroscopy, scanning electron microscopy (SEM) and contact angle measurements. The electrochemical supercapacitive performance of α-La{sub 2}S{sub 3} electrode is evaluated by cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. From the electrochemical study, it is seen that α-La{sub 2}S{sub 3} electrode delivers high specific capacitance of 256 F g{sup −1} at scan rate of 5 mV s{sup −1} with cycling stability of 85% over 1000 cycles. Such La{sub 2}S{sub 3} electrode has great application in supercapacitor device for energy storage.

  12. Nano-sized copper tungstate thin films as positive electrodes for rechargeable Li batteries

    International Nuclear Information System (INIS)

    Li Chilin; Fu Zhengwen

    2008-01-01

    Nano-sized CuWO 4 thin films have been fabricated by radio-frequency (R.F.) sputtering deposition, and are used as positive electrode with both LiClO 4 liquid electrolyte and LiPON solid electrolyte in rechargeable lithium batteries. An initial discharge capacity of 192 and 210 mAh/g is obtainable for CuWO 4 film electrode with and without coated LiPON in liquid electrolyte, respectively. An all-solid-state cell with Li/LiPON/CuWO 4 layers shows a high-volume rate capacity of 145 μAh/cm 2 μm in first discharge, and overcomes the unfavorable electrochemical degradation observed in liquid electrolyte system. A two-step reactive mechanism is investigated by both transmission electron microscopy and selected area electron diffraction techniques. Apart from the extrusion and injection of Cu 2+ /Cu 0 , additional capacity can be achieved by the reversible reactivity of (WO 4 ) 2- framework. The chemical diffusion coefficients of Li intercalation/deintercalation are estimated by cyclic voltammetry. Nano-CuWO 4 thin film is expected to be a promising positive electrode material for high-performance rechargeable thin-film lithium batteries

  13. Synthesis of TiO2 Nanoparticle and its Application to Graphite Composite Electrode for Hydroxylamine Oxidation

    Directory of Open Access Journals (Sweden)

    M. Mazloum-Ardakani

    2013-09-01

    Full Text Available In this work, sol-gel method was used tosynthesize titanium dioxide nanoparticles (TiO2. The TiO2nanoparticles was characterized by Scanning Electron Microscopy (SEM, x-ray diffraction (XRD and BET technique.The TiO2 and coumarin derivative (7-(1,3-dithiolan-2-yl-9, 10-dihydroxy-6H-benzofuro [3,2-c] chromen-6-on were incorporated in a graphite composite electrode. The resulting modified electrode displayed a good electrocatalytic activity for the oxidation of hydroxylamine, which leads to a reduction in its overpotential by more than 520 mV. Differential pulse voltammetry (DPV of hydroxylamine at the modified electrode exhibited a linear dynamic range (between 0.5 and 500.0 µM with a detection limit (3σ of 0.133 μM. The high sensitivity, ease of fabrication and low cost of this modified electrode for the detection of hydroxylamine demonstrate its potential sensing applications.

  14. Design of lithium cobalt oxide electrodes with high thermal conductivity and electrochemical performance using carbon nanotubes and diamond particles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eungje; Salgado, Ruben Arash; Lee, Byeongdu; Sumant, Anirudha V.; Rajh, Tijana; Johnson, Christopher; Balandin, Alexander A.; Shevchenko, Elena V.

    2018-04-01

    Thermal management remains one of the major challenges in the design of safe and reliable Li-ion batteries. We show that composite electrodes assembled from commercially available 100 μm long carbon nanotubes (CNTs) and LiCoO2 (LCO) particles demonstrate the in-plane thermal conductivity of 205.8 W/m*K. This value exceeds the thermal conductivity of dry conventional laminated electrodes by about three orders of magnitude. The cross-plane thermal conductivity of CNT-based electrodes is in the same range as thermal conductivities of conventional laminated electrodes. The CNT-based electrodes demonstrate a similar capacity to conventional laminated design electrodes, but revealed a better rate performance and stability. The introduction of diamond particles into CNT-based electrodes further improves the rate performance. Our lightweight, flexible electrode design can potentially be a general platform for fabricating polymer binder- and aluminum and copper current collector- free electrodes from a broad range of electrochemically active materials with efficient thermal management.

  15. Sonochemical synthesis of nanostructured nickel hydroxide as an electrode material for improved electrochemical energy storage application

    Directory of Open Access Journals (Sweden)

    Arshid Numan

    2017-08-01

    Full Text Available A facile and fast approach for the synthesis of a nanostructured nickel hydroxide (Ni(OH2 via sonochemical technique is reported in the present study. The X-ray diffraction results confirmed that the synthesized Ni(OH2 was oriented in β-phase of hexagonal brucite structure. The nanostructured Ni(OH2 electrode exhibited the maximum specific capacitance of 1256 F/g at a current density of 200 mA/g in 1 M KOH(aq. Ni(OH2 electrodes exhibited the pseudocapacitive behavior due to the presence of redox reaction. It also exhibited long-term cyclic stability of 85% after 2000 cycles, suggesting that the nanostructured Ni(OH2 electrode will play a promising role for high performance supercapacitor application.

  16. EFFECTS OF ELECTRODE DEFORMATION OF RESISTANCE SPOT WELDING ON 304 AUSTENITIC STAINLESS STEEL WELD GEOMETRY

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2012-12-01

    Full Text Available The resistance spot welding process is accomplished by forcing huge amounts of current flow from the upper electrode tip through the base metals to the lower electrode tip, or vice versa or in both directions. A weld joint is established between the metal sheets through fusion, resulting in a strong bond between the sheets without occupying additional space. The growth of the weld nugget (bond between sheets is therefore determined from the welding current density; sufficient time for current delivery; reasonable electrode pressing force; and the area provided for current delivery (electrode tip. The welding current and weld time control the root penetration, while the electrode pressing force and electrode tips successfully accomplish the connection during the welding process. Although the welding current and weld time cause the heat generation at the areas concerned (electrode tip area, the electrode tips’ diameter and electrode pressing forces also directly influence the welding process. In this research truncated-electrode deformation and mushrooming effects are observed, which result in the welded areas being inconsistent due to the expulsion. The copper to chromium ratio is varied from the tip to the end of the electrode whilst the welding process is repeated. The welding heat affects the electrode and the electrode itself influences the shape of the weld geometry.

  17. Application of the modulated temperature differential scanning calorimetry technique for the determination of the specific heat of copper nanofluids

    International Nuclear Information System (INIS)

    De Robertis, E.; Cosme, E.H.H.; Neves, R.S.; Kuznetsov, A.Yu.; Campos, A.P.C.; Landi, S.M.; Achete, C.A.

    2012-01-01

    The purpose of this work is to investigate the applicability of the modulated temperature differential scanning calorimetry technique to measure specific heat of copper nanofluids by using the ASTM E2719 standard procedure, which is generally applied to thermally stable solids and liquids. The one-step method of preparation of copper nanofluid samples is described. The synthesized nanoparticles were separated from the base fluid and examined by X-ray diffraction and transmission electron microscopy in order to evaluate their structure, morphology and chemical nature. The presence of copper nanoparticles in the base fluid alters the characteristics of crystallization and melting processes and reduces the specific heat values of nanofluids in the whole studied temperature range. - Highlights: ► Copper nanofluids prepared by one-step method. ► Methodology of synthesis improved nanofluid stability. ► Specific heat determinations using modulated temperature differential scanning calorimetry. ► Good agreement between theoretical and experimental values.

  18. Graphene-protected copper and silver plasmonics

    DEFF Research Database (Denmark)

    Kravets, V. G.; Jalil, R.; Kim, Y. J.

    2014-01-01

    suitable for plasmonic applications. To this end, there has been a continuous search for alternative plasmonic materials that are also compatible with complementary metal oxide semiconductor technology. Here we show that copper and silver protected by graphene are viable candidates. Copper films covered...... with one to a few graphene layers show excellent plasmonic characteristics. They can be used to fabricate plasmonic devices and survive for at least a year, even in wet and corroding conditions. As a proof of concept, we use the graphene-protected copper to demonstrate dielectric loaded plasmonic...

  19. Multi-wavelength copper vapour lasers for novel materials processing application

    International Nuclear Information System (INIS)

    Knowles, M.; Foster-Turner, R.; Kearsley, A.; Evans, J.

    1995-01-01

    The copper vapour laser (CVL) is a high average power, short pulse laser with a multi-kilohertz pulse repetition rate. The CVL laser lines (511 nm and 578 nm) combined with the good beam quality and high peak power available from these lasers allow it to operate in a unique parameter space. Consequently, it has demonstrated many unique and advantageous machining characteristics. We have also demonstrated efficient conversion of CVL radiation to other wavelengths using non-linear frequency conversion, dye lasers and Ti:AL 2 O 3 . Output powers of up to 4 W at 255 nm have been achieved by frequency doubling. The frequency doubled CVL is inherently narrow linewidth and frequency locked making it a suitable source for UV photolithography. Slope efficiencies in excess of 25 % have been achieved with CVL pumped Ti:Al 2 O 3 and dye lasers. These laser extend the wavelengths options into the red and infrared regions of the spectrum. The near diffraction limited beams from these tunable lasers can be efficiently frequency doubled into the blue and near UV. The wide range of wavelength options from the CVL enable a wide variety of materials processing and material interactions to be explored. A European consortium for Copper Laser Applications in Manufacture and Production (CLAMP) has been set up under the EUREKA scheme to coordinate the commercial and technical expertise currently available in Europe. (author)

  20. Effects of stimulation of copper bioleaching on microbial community in vineyard soil and copper mining waste.

    Science.gov (United States)

    Andreazza, Robson; Okeke, Benedict C; Pieniz, Simone; Bortolon, Leandro; Lambais, Márcio R; Camargo, Flávio A O

    2012-04-01

    Long-term copper application in vineyards and copper mining activities cause heavy metal pollution sites. Such sites need remediation to protect soil and water quality. Bioremediation of contaminated areas through bioleaching can help to remove copper ions from the contaminated soils. Thus, the aim of this work was to evaluate the effects of different treatments for copper bioleaching in two diverse copper-contaminated soils (a 40-year-old vineyard and a copper mining waste) and to evaluate the effect on microbial community by applying denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA amplicons and DNA sequence analysis. Several treatments with HCl, H(2)SO(4), and FeSO(4) were evaluated by stimulation of bioleaching of copper in the soils. Treatments and extractions using FeSO(4) and H(2)SO(4) mixture at 30°C displayed more copper leaching than extractions with deionized water at room temperature. Treatment with H(2)SO(4) supported bioleaching of as much as 120 mg kg(-1) of copper from vineyard soil after 115 days of incubation. DGGE analysis of the treatments revealed that some treatments caused greater diversity of microorganisms in the vineyard soil compared to the copper mining waste. Nucleotide Blast of PCR-amplified fragments of 16S rRNA gene bands from DGGE indicated the presence of Rhodobacter sp., Silicibacter sp., Bacillus sp., Paracoccus sp., Pediococcus sp., a Myxococcales, Clostridium sp., Thiomonas sp., a firmicute, Caulobacter vibrioides, Serratia sp., and an actinomycetales in vineyard soil. Contrarily, Sphingomonas was the predominant genus in copper mining waste in most treatments. Paracoccus sp. and Enterobacter sp. were also identified from DGGE bands of the copper mining waste. Paracoccus species is involved in the copper bioleaching by sulfur oxidation system, liberating the copper bounded in the soils and hence promoting copper bioremediation. Results indicate that stimulation of bioleaching with a combination of FeSO(4

  1. Ni-Based Solid Oxide Cell Electrodes

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Holtappels, Peter

    2013-01-01

    This paper is a critical review of the literature on nickel-based electrodes for application in solid oxide cells at temperature from 500 to 1000 _C. The applications may be fuel cells or electrolyser cells. The reviewed literature is that of experimental results on both model electrodes...... and practical composite cermet electrodes. A substantially longer three-phase boundary (TPB) can be obtained per unit area of cell in such a composite of nickel and electrolyte material, provided that two interwoven solid networks of the two solid and one gaseous phases are obtained to provide a three...

  2. Method for uniformly distributing carbon flakes in a positive electrode, the electrode made thereby and compositions. [Patent application

    Science.gov (United States)

    Mrazek, F.C.; Smaga, J.A.; Battles, J.E.

    1981-01-19

    A positive electrode for a secondary electrochemical cell is described wherein an electrically conductive current collector is in electrical contact with a particulate mixture of gray cast iron and an alkali metal sulfide and an electrolyte including alkali metal halides or alkaline earth metal halides. Also present may be a transition metal sulfide and graphite flakes from the conversion of gray cast iron to iron sulfide. Also disclosed is a method of distributing carbon flakes in a cell wherein there is formed an electrochemical cell of a positive electrode structure of the type described and a suitable electrolyte and a second electrode containing a material capable of alloying with alkali metal ions. The cell is connected to a source of electrical potential to electrochemically convert gray cast iron to an iron sulfide and uniformly to distribute carbon flakes formerly in the gray cast iron throughout the positive electrode while forming an alkali metal alloy in the negative electrode. Also disclosed are compositions useful in preparing positive electrodes.

  3. Stimulation and recording electrodes for neural prostheses

    CERN Document Server

    Pour Aryan, Naser; Rothermel, Albrecht

    2015-01-01

    This book provides readers with basic principles of the electrochemistry of the electrodes used in modern, implantable neural prostheses. The authors discuss the boundaries and conditions in which the electrodes continue to function properly for long time spans, which are required when designing neural stimulator devices for long-term in vivo applications. Two kinds of electrode materials, titanium nitride and iridium are discussed extensively, both qualitatively and quantitatively. The influence of the counter electrode on the safety margins and electrode lifetime in a two electrode system is explained. Electrode modeling is handled in a final chapter.

  4. Electrochemical synthesis of highly crystalline copper nanowires

    International Nuclear Information System (INIS)

    Kaur, Amandeep; Gupta, Tanish; Kumar, Akshay; Kumar, Sanjeev; Singh, Karamjeet; Thakur, Anup

    2015-01-01

    Copper nanowires were fabricated within the pores of anodic alumina template (AAT) by template synthesis method at pH = 2.9. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to investigate the structure, morphology and composition of fabricated nanowires. These characterizations revealed that the deposited copper nanowires were highly crystalline in nature, dense and uniform. The crystalline copper nanowires are promising in application of future nanoelectronic devices and circuits

  5. Application of Vertical Electrodes in Microfluidic Channels for Impedance Analysis

    Directory of Open Access Journals (Sweden)

    Qiang Li

    2016-05-01

    Full Text Available This paper presents a microfluidic device with electroplated vertical electrodes in the side walls for impedance measurement. Based on the proposed device, the impedance of NaCl solutions with different concentrations and polystyrene microspheres with different sizes was measured and analyzed. The electroplating and SU-8-PDMS (SU-8-poly(dimethylsiloxane bonding technologies were firstly integrated for the fabrication of the proposed microfluidic device, resulting in a tightly three-dimensional structure for practical application. The magnitude of impedance of the tested solutions in the frequency range of 1 Hz to 100 kHz was analyzed by the Zennium electrochemical workstation. The results show that the newly designed microfluidic device has potential for impedance analysis with the advantages of ease of fabrication and the integration of 3D electrodes in the side walls. The newly designed impedance sensor can distinguish different concentrations of polystyrene microspheres and may have potential for cell counting in biological areas. By integrating with other techniques such as dielectrophoresis (DEP and biological recognition technology, the proposed device may have potential for the assay to identify foodborne pathogen bacteria.

  6. Time-dependent simulation of plasma and electrodes in high-intensity discharge lamps with different electrode shapes

    CERN Document Server

    Flesch, P

    2003-01-01

    The subject of this paper is the modelling of d.c. and a.c. high-intensity Hg-discharge lamps with differently shaped electrodes. Different arc attachments on the electrodes are studied and insight for the development of new electrodes is gained. The model includes the entire discharge plasma (plasma column, hot plasma spots in front of electrodes, near-electrode non-LTE-plasma) as well as anode and cathode. No subdivision of the discharge space into different regions is necessary (like space charge layer, ionization zone, plasma column). This is achieved by using a differential equation for a non-LTE electrical conductivity which is applicable for local thermal equilibrium (LTE-)regions as well as for non-LTE plasma regions close to the electrodes in a high pressure plasma. Modelling results for a 0.6 MPa mercury discharge considering six different electrode shapes (anode and cathode) are presented and compared with experimental results. The electrodes have different diameters and different electrode tips, s...

  7. Radioisotope application to studies of copper electrolytic refining

    International Nuclear Information System (INIS)

    Shul'ts, U.; Lange, Kh.; Gajdel', B.

    1976-01-01

    Silver and selenium behaviour was studied using sup(110m)Ag and 75 Se radioisotopes in the copper electrolysis process. sup(110m)Ag and 75 Se distribution in the electrorefining products was also studied. It was found that Ag/Se mass ratio affected greatly the silver content in the copper cathode. It was found that the tracer technique made it possible to determine 0,1gSe/tCu and 1gAg/t Cu simultaneously and accurately with small material and time expenses. Using sup(110m)Ag radioisotope, the reduction in electrolyte silver content dependent on time may be determined quickly and accurately

  8. Development of innovative micro-pattern gaseous detectors with resistive electrodes and first results of their applications

    CERN Document Server

    Di Mauro, A; Martinengo, P; Nappi, E; Oliveira, R; Peskov, Vladimir; Periale, L; Picchi, P; Pietropaolo, F; Rodionov, I; Santiard, Jean-Claude

    2007-01-01

    The paper summarizes our latest progress in the development of newly introduced micro pattern gaseous detectors with resistive electrodes. These resistive electrodes protect the detector and the front-end electronics in case of occasional discharges and thus make the detectors very robust and reliable in operation. As an example, we describe in greater detail a new recently developed GEM-like detector, fully spark-protected with electrodes made of resistive kapton. We discovered that all resistive layers used in these studies (including kapton), that are coated with photosensitive layers, such as CsI, can be used as efficient photo cathodes for detectors operating in a pulse counting mode. We describe the first applications of such detectors combined with CsI or SbCs photo cathodes for the detection of UV photons at room and cryogenic temperatures.

  9. Acetaldehyde as an Intermediate in the Electroreduction of Carbon Monoxide to Ethanol on Oxide-Derived Copper

    DEFF Research Database (Denmark)

    Bertheussen, Erlend; Verdaguer Casadevall, Arnau; Ravasio, Davide

    2016-01-01

    Oxide-derived copper (OD-Cu) electrodes exhibit unprecedented CO reduction performance towards liquid fuels, producing ethanol and acetate with >50 % Faradaic efficiency at −0.3 V (vs. RHE). By using static headspace-gas chromatography for liquid phase analysis, we identify acetaldehyde as a minor...

  10. The role of adsorbates in the electrochemical oxidation of ammonia on noble and transition metal electrodes

    NARCIS (Netherlands)

    Vooys, de A.C.A.; Koper, M.T.M.; Santen, van R.A.; Veen, van J.A.R.

    2001-01-01

    The activity for ammonia oxidation and the intermediates formed during the reaction have been studied on platinum, palladium, rhodium, ruthenium, iridium, copper, silver and gold electrodes. The activity in the selective oxidation to N-2 is related directly to the nature of the species at the

  11. Silane pre-treatments on copper and aluminium

    International Nuclear Information System (INIS)

    Deflorian, F.; Rossi, S.; Fedrizzi, L.

    2006-01-01

    A large part of aluminium products are coated with an organic layer in order to improve the corrosion resistance. Copper surfaces are also sometimes protected with an organic coating to improve the durability or the aesthetic properties. Examples of industrial applications are household appliances and heat exchanger components. For these applications it is not rare to have the industrial need to treat at the same time components made of aluminium and copper. In order to extend the service life of the organic coated copper a specific surface pre-treatment is often required. Nevertheless, probably because of the limited market of this application, no specific pre-treatments for copper are industrially developed, with the exception of cleaning procedures, but simply extensions of existing pre-treatments optimised for other metals (aluminium, zinc) are used. The application of silane pre-treatments as adhesion promoters for organic coated metals is remarkably increasing in the last decade, because silanes offer very good performance together with high environmental compatibility. The idea is therefore to try to develop a specific silane based pre-treatment for copper. The starting point is the existing silane products for aluminium, optimising the composition and the application conditions (concentration, temperature, pH of the bath, etc.) in order to develop a high performance copper alloy pre-treatment increasing the protective properties and the adhesion of a successively applied organic coating. Moreover these pre-treatments could be used for aluminium alloys too and therefore could be suggested for multi-metals components. The deposits were analysed using FTIR spectroscopy and optical and electron microscopic observations. A careful electrochemical characterisation, mainly by electrochemical impedance spectroscopy measurements (EIS) was carried out to highlight the presence of silane and to evaluate the performance of the different deposits. In order to study an

  12. A Cooperative Copper Metal-Organic Framework-Hydrogel System Improves Wound Healing in Diabetes

    OpenAIRE

    Xiao, Jisheng; Chen, Siyu; Yi, Ji; Zhang, Hao; Ameer, Guillermo A.

    2016-01-01

    Chronic non-healing wounds remain a major clinical challenge that would benefit from the development of advanced, regenerative dressings that promote wound closure within a clinically relevant time frame. The use of copper ions has shown promise in wound healing applications possibly by promoting angiogenesis. However, reported treatments that use copper ions require multiple applications of copper salts or oxides to the wound bed, exposing the patient to potentially toxic levels of copper io...

  13. Application of a multiwalled carbon nanotube-chitosan composite as an electrode in the electrosorption process for water purification.

    Science.gov (United States)

    Ma, Chih-Yu; Huang, Shih-Ching; Chou, Pei-Hsin; Den, Walter; Hou, Chia-Hung

    2016-03-01

    In this study, a multiwalled carbon nanotubes-chitosan (CNTs-CS) composite electrode was fabricated to enable water purification by electrosorption. The CNTs-CS composite electrode was shown to possess excellent capacitive behaviors and good pore accessibility by electrochemical impedance spectroscopy, galvanostatic charge-discharge, and cyclic voltammetry measurements in 1 M H2SO4 electrolyte. Moreover, the CNTs-CS composite electrode showed promising performance for capacitive water desalination. At an electric potential of 1.2 V, the electrosorption capacity and electrosorption rate of NaCl ions on the CNTs-CS composite electrode were determined to be 10.7 mg g(-1) and 0.051 min(-1), respectively, which were considerably higher than those of conventional activated electrodes. The improved electrosorption performance could be ascribed to the existence of mesopores. Additionally, the feasibility of electrosorptive removal of aniline from an aqueous solution has been demonstrated. Upon polarization at 0.6 V, the CNTs-CS composite electrode had a larger electrosorption capacity of 26.4 mg g(-1) and a higher electrosorption rate of 0.006 min(-1) for aniline compared with the open circuit condition. The enhanced adsorption resulted from the improved affinity between aniline and the electrode under electrochemical assistance involving a nonfaradic process. Consequently, the CNT-CS composite electrode, exhibiting typical double-layer capacitor behavior and a sufficient potential range, can be a potential electrode material for application in the electrosorption process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. 76 FR 18542 - Copper Valley Electric Association; Notice of Scoping Document 2 and Soliciting Scoping Comments...

    Science.gov (United States)

    2011-04-04

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-002] Copper Valley.... Applicant: Copper Valley Electric Association (Copper Valley) d. Name of Project: Allison Creek Project. e.... 791(a)-825(r). g. Applicant Contact: Robert A. Wilkinson, CEO, Copper Valley Electric Association, P.O...

  15. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Waechtler, Thomas

    2010-05-25

    Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent

  16. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Waechtler, Thomas

    2010-05-25

    Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent

  17. Synthesis and Biomedical Applications of Copper Sulfide Nanoparticles: From Sensors to Theranostics

    Science.gov (United States)

    Goel, Shreya; Chen, Feng; Cai, Weibo

    2013-01-01

    Copper sulfide (CuS) nanoparticles have attracted increasing attention from biomedical researchers across the globe, because of their intriguing properties which have been mainly explored for energy- and catalysis-related applications to date. This focused review article aims to summarize the recent progress made in the synthesis and biomedical applications of various CuS nanoparticles. After a brief introduction to CuS nanoparticles in the first section, we will provide a concise outline of the various synthetic routes to obtain different morphologies of CuS nanoparticles, which can influence their properties and potential applications. CuS nanoparticles have found broad applications in vitro, especially in the detection of biomolecules, chemicals, and pathogens which will be illustrated in detail. The in vivo uses of CuS nanoparticles have also been investigated in preclinical studies, including molecular imaging with various techniques, cancer therapy based on the photothermal properties of CuS, as well as drug delivery and theranostic applications. Research on CuS nanoparticles will continue to thrive over the next decade, and tremendous opportunities lie ahead for potential biomedical/clinical applications of CuS nanoparticles. PMID:24106015

  18. Bilayered Oxide thin films for transparent electrode application

    Science.gov (United States)

    Dutta, Titas; Narayan, Jagdish

    2008-10-01

    Ga doped ZnO films with electrical and optical properties comparable to indium tin oxide (ITO) is a promising candidate for transparent conducting oxides (TCOs) because of its superior stability in hydrogen environment, benign nature and relatively inexpensive supply. However, ZnO based TCO films suffer from low work function, which is a critical parameter for device applications. We report here the growth of a novel bilayered structure consisting of very thin (few monolayers) ITO, MoOx layer on Zn0.95Ga0.05O film for transparent electrode applications by using pulsed laser deposition technique at different temperatures and oxygen partial pressure. The characteristics of the ITO film and the heterostructure have been investigated in detail using XRD, TEM, XPS, and electrical and optical property measurements. It is envisaged that the overall transmittance and the resistivity are dictated by the thicker layer of ZnGa0.05O beneath the ITO layer. Hence, this study is aimed to improve the surface characteristics without affecting the overall transmittance and sheet resistance. This will enhance the transport of the carriers across the heterojunction in the device, thus, resulting in the increase in device efficiency.

  19. 77 FR 42722 - Copper Valley Electric Association; Notice of Updated Environmental Analysis Preparation Schedule

    Science.gov (United States)

    2012-07-20

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-002] Copper Valley...: Original License Application. b. Project No.: 13124-002. c. Applicant: Copper Valley Electric Association (Copper Valley). d. Name of Project: Allison Creek Project. e. Location: On the south side of Port Valdez...

  20. Manganese oxide-based materials as electrochemical supercapacitor electrodes.

    Science.gov (United States)

    Wei, Weifeng; Cui, Xinwei; Chen, Weixing; Ivey, Douglas G

    2011-03-01

    Electrochemical supercapacitors (ECs), characteristic of high power and reasonably high energy densities, have become a versatile solution to various emerging energy applications. This critical review describes some materials science aspects on manganese oxide-based materials for these applications, primarily including the strategic design and fabrication of these electrode materials. Nanostructurization, chemical modification and incorporation with high surface area, conductive nanoarchitectures are the three major strategies in the development of high-performance manganese oxide-based electrodes for EC applications. Numerous works reviewed herein have shown enhanced electrochemical performance in the manganese oxide-based electrode materials. However, many fundamental questions remain unanswered, particularly with respect to characterization and understanding of electron transfer and atomic transport of the electrochemical interface processes within the manganese oxide-based electrodes. In order to fully exploit the potential of manganese oxide-based electrode materials, an unambiguous appreciation of these basic questions and optimization of synthesis parameters and material properties are critical for the further development of EC devices (233 references).

  1. Tunable Reaction Potentials in Open Framework Nanoparticle Battery Electrodes for Grid-Scale Energy Storage

    KAUST Repository

    Wessells, Colin D.

    2012-02-28

    The electrical energy grid has a growing need for energy storage to address short-term transients, frequency regulation, and load leveling. Though electrochemical energy storage devices such as batteries offer an attractive solution, current commercial battery technology cannot provide adequate power, and cycle life, and energy efficiency at a sufficiently low cost. Copper hexacyanoferrate and nickel hexacyanoferrate, two open framework materials with the Prussian Blue structure, were recently shown to offer ultralong cycle life and high-rate performance when operated as battery electrodes in safe, inexpensive aqueous sodium ion and potassium ion electrolytes. In this report, we demonstrate that the reaction potential of copper-nickel alloy hexacyanoferrate nanoparticles may be tuned by controlling the ratio of copper to nickel in these materials. X-ray diffraction, TEM energy dispersive X-ray spectroscopy, and galvanostatic electrochemical cycling of copper-nickel hexacyanoferrate reveal that copper and nickel form a fully miscible solution at particular sites in the framework without perturbing the structure. This allows copper-nickel hexacyanoferrate to reversibly intercalate sodium and potassium ions for over 2000 cycles with capacity retentions of 100% and 91%, respectively. The ability to precisely tune the reaction potential of copper-nickel hexacyanoferrate without sacrificing cycle life will allow the development of full cells that utilize the entire electrochemical stability window of aqueous sodium and potassium ion electrolytes. © 2012 American Chemical Society.

  2. The natural diatomite from caldiran-van (Turkey): electroanalytical application to antimigraine compound naratriptan at modified carbon paste electrode.

    Science.gov (United States)

    Calışkan, Necla; Sögüt, Eda; Saka, Cafer; Yardım, Yavuz; Sentürk, Zuhre

    2010-09-01

    This paper is the first report describing the characterization of local diatomite of Caldiran-Van region (Eastern Anatolia, Turkey). Special attention was paid to the ability of its electroanalytical performance at modified electrodes and to the potential application of diatomite-modified electrode. For this purpose, the determination of Naratriptan which is a novel oral triptan (5-hydroxytryptamine receptor agonist) in migraine treatment, by means of a carbon paste electrode modified with 10% (w/w) of diatomite was studied using cyclic and square-wave voltammetry. The experimental conditions that affect the electrode reaction process were studied in terms of pH of the supporting electrolyte, scan rate, accumulation variables, modifier composition and square-wave parameters. Using square-wave stripping mode, the drug yielded a well-defined voltammetric response in Britton-Robinson buffer, pH 4.0 at 0.84 V (vs. Ag/AgCl) (a pre-concentration step being carried out with an open circuit at 120 s). The process could be used to determine Naratriptan concentrations in the range 5x10(-7)-9x10(-7) M, with a detection limit of 1.25x10(-7) M (46.5 mug L(-1)). The applicability of the method to spiked human urine samples was illustrated.

  3. Facile 3D Metal Electrode Fabrication for Energy Applications via Inkjet Printing and Shape Memory Polymer

    International Nuclear Information System (INIS)

    Roberts, R C; Wu, J; Li, D C; Hau, N Y; Chang, Y H; Feng, S P

    2014-01-01

    This paper reports on a simple 3D metal electrode fabrication technique via inkjet printing onto a thermally contracting shape memory polymer (SMP) substrate. Inkjet printing allows for the direct patterning of structures from metal nanoparticle bearing liquid inks. After deposition, these inks require thermal curing steps to render a stable conductive film. By printing onto a SMP substrate, the metal nanoparticle ink can be cured and substrate shrunk simultaneously to create 3D metal microstructures, forming a large surface area topology well suited for energy applications. Polystyrene SMP shrinkage was characterized in a laboratory oven from 150-240°C, resulting in a size reduction of 1.97-2.58. Silver nanoparticle ink was patterned into electrodes, shrunk, and the topology characterized using scanning electron microscopy. Zinc-Silver Oxide microbatteries were fabricated to demonstrate the 3D electrodes compared to planar references. Characterization was performed using 10M potassium hydroxide electrolyte solution doped with zinc oxide (57g/L). After a 300s oxidation at 3Vdc, the 3D electrode battery demonstrated a 125% increased capacity over the reference cell. Reference cells degraded with longer oxidations, but the 3D electrodes were fully oxidized for 4 hours, and exhibited a capacity of 5.5mA-hr/cm 2 with stable metal performance

  4. Nanotribology at single crystal electrodes: Influence of ionic adsorbates on friction forces studied with AFM

    Energy Technology Data Exchange (ETDEWEB)

    Hausen, Florian; Nielinger, Michael; Ernst, Siegfried [Institut fuer Physikalische und Theoretische Chemie, Universitaet Bonn, Roemerstrasse 164, D-53117 Bonn (Germany); Baltruschat, Helmut [Institut fuer Physikalische und Theoretische Chemie, Universitaet Bonn, Roemerstrasse 164, D-53117 Bonn (Germany)], E-mail: baltruschat@uni-bonn.de

    2008-09-01

    We present friction force measurements on Au(1 1 1) single crystal electrode surfaces performed under electrochemical conditions using an atomic force microscope (AFM). At monoatomic steps friction is increased in both scan directions. In 0.05 M sulfuric acid an increase of friction is observed with the increase of adsorbed sulfate. Friction force increases non-linearly with load. Cu UPD also increases friction in presence of sulfate. However, in presence of 4 x 10{sup -4} M chloride friction is much smaller for all deposited Cu coverages - ranging from a submonolayer up to bulk copper compared to the solution without chloride. After dissolution of bulk copper clusters deposited on Au(1 1 1) we observed an area with higher friction forces due to the formation of an alloy between gold and copper.

  5. Measurements of copper corrosion in the LOT Project at the Aespoe Hard Rock Laboratory

    International Nuclear Information System (INIS)

    Rosborg, B.; Karnland, O.; Quirk, G.; Werme, L.

    2003-01-01

    Real-time monitoring, of corrosion by means of electrochemical noise and other electrochemical techniques may offer interesting possibilities to estimate the kind and degree of corrosion in a sample or component, and further visualize the corrosion resistance of pure copper in repository environments. As a pilot effort, three cylindrical copper electrodes for such measurements, each of about 100 cm 2 surface area, have been installed in a test parcel in the Aespoe Hard Rock Laboratory and electrochemical measurements using InterCorr's SmartCET system were initiated in May 2001. The first results from real-time monitoring of copper corrosion in the Aespoe HRL under actual repository environment conditions by means of linear polarisation resistance, harmonic distortion analysis and electrochemical noise techniques are presented, and compared with the results obtained from one of the retrieved test parcels. (authors)

  6. Chemical synthesis of flower-like hybrid Cu(OH)2/CuO electrode: Application of polyvinyl alcohol and triton X-100 to enhance supercapacitor performance.

    Science.gov (United States)

    Shinde, S K; Fulari, V J; Kim, D-Y; Maile, N C; Koli, R R; Dhaygude, H D; Ghodake, G S

    2017-08-01

    In this research article, we report hybrid nanomaterials of copper hydroxide/copper oxide (Cu(OH) 2 /CuO). A thin films were prepared by using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method. As-synthesized and hybrid Cu(OH) 2 /CuO with two different surfactants polyvinyl alcohol (PVA) and triton-X 100 (TRX-100) was prepared having distinct morphological, structural, and supercapacitor properties. The surface of the thin film samples were examined by scanning electron microscopy (SEM). A nanoflower-like morphology of the Cu(OH) 2 /CuO nanostructures arranged vertically was evidenced on the stainless steel substrate. The surface was well covered by nanoflake-like morphology and formed a uniform Cu(OH) 2 /CuO nanostructures after treating with surfactants. X-ray diffraction patterns were used to confirm the hybrid phase of Cu(OH) 2 /CuO materials. The electrochemical properties of the pristine Cu(OH) 2 /CuO, PVA:Cu(OH) 2 /CuO, TRX-100:Cu(OH) 2 /CuO films were observed by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy technique. The electrochemical examination reveals that the Cu(OH) 2 /CuO electrode has excellent specific capacitance, 292, 533, and 443Fg -1 with pristine, PVA, and TRX-100, respectively in 1M Na 2 SO 4 electrolyte solution. The cyclic voltammograms (CV) of Cu(OH) 2 /CuO electrode shows positive role of the PVA and TRX-100 to enhance supercapacitor performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Thermophysical properties and microstructure of graphite flake/copper composites processed by electroless copper coating

    International Nuclear Information System (INIS)

    Liu, Qian; He, Xin-Bo; Ren, Shu-Bin; Zhang, Chen; Ting-Ting, Liu; Qu, Xuan-Hui

    2014-01-01

    Highlights: • GF–copper composites were fabricated using a sparking plasma sintering, which involves coating GF with copper, using electroless plating technique. • The oriented graphite flake distributed homogeneously in matrix. • With the increase of flake graphite from 44 to 71 vol.%, the basal plane thermal conductivity of composites increases from 445 to 565 W m −1 K −1 and the thermal expansion of composites decreases from 8.1 to 5.0. • The obtained composites are suitable for electronic packaging materials. -- Abstract: This study focuses on the fabrication of thermal management material for power electronics applications using graphite flake reinforced copper composites. The manufacturing route involved electroless plating of copper on the graphite flake and further spark plasma sintering of composite powders. The relative density of the composites with 44–71 vol.% flakes achieved up to 98%. Measured thermal conductivities and coefficients of thermal expansion of composites ranged from 455–565 W m −1 K −1 and 8 to 5 ppm K −1 , respectively. Obtained graphite flake–copper composites exhibit excellent thermophysical properties to meet the heat dispersion and matching requirements of power electronic devices to the packaging materials

  8. The development of a micropatterned electrode for studies of zinc electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Sutija, Dave P. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States); Tobias, Charles W. [Univ. of California, Berkeley, CA (United States)

    1986-12-01

    A micropatterned electrode was prepared for the study of electrocrystallization. Using microphotolithography, in conjunction with evaporation and pulse electrodeposition of thin films, a set of artificially roughened electrodes with hemispherical surface features five microns in diameter was developed. Voltammetric studies were conducted to determine the best electrode material. Gold, platinum, and various carbon surfaces were evaluated for zinc nucleation density and hydrogen overpotential. Surface homogeneity was examined by both light and scanning electron microscopy. Gold was determined to possess the best combination of material properties: chemical inertness, low melting point, and a high work function allowing underpotential deposition of zinc which reduces the rate of hydrogen evolution. Stripping coulometry was employed to determine zinc limiting currents, and evaluate effective diffusion coefficients in concentrated zinc chloride solutions. Although the method worked well for dilute zinc chloride and copper sulfate solutions, it failed at higher current densities; the emergence of surface roughness obscured actual limiting current plateaus.

  9. Adsorption behavior of caffeine as a green corrosion inhibitor for copper

    International Nuclear Information System (INIS)

    Souza, Fernando Sílvio de; Giacomelli, Cristiano; Gonçalves, Reinaldo Simões; Spinelli, Almir

    2012-01-01

    Electrochemical and impedance experiments were carried out to evaluate the corrosion behavior of copper in aerated 0.1 mol L −1 H 2 SO 4 solutions in the presence of three xanthine derivatives with similar chemical structures. The corrosion rate of copper was found to increase in the presence of theophylline and theobromine and decrease in the presence of caffeine. The adsorption and inhibitory effect of caffeine on copper surfaces in aerated 0.1 mol L −1 H 2 SO 4 solutions were then investigated in detail by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), contact angle measurements, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and fluorescence experiments. The data obtained indicate that caffeine behaves as a cathodic-type inhibitor adsorbing onto the copper surface according to the Temkin isotherm, with the negative ∆G° ads value of − 31.1 kJ mol −1 signifying a spontaneous adsorption process. The corrosion inhibition efficiency increased with caffeine concentration in the range of 1.0–10.0 mmol L −1 . Furthermore, the EIS results obtained at the open-circuit potential and surface analysis (SEM, EDS and fluorescence) clearly demonstrated the adsorption of the organic compound onto the copper electrode. The contact angle measurements revealed the formation of a hydrophobic protective film. This film covers up to 72% of the total active surface, acts as a protective barrier and prevents interaction between the metal, water and oxygen molecules. - Highlights: ► We have investigated the adsorption and corrosion inhibition of caffeine on copper surfaces. ► Caffeine behaves as a cathodic-type inhibitor. ► Caffeine adsorbs onto copper surface according to Temkin isotherm. ► There exists the formation of a hydrophobic film that acts as a protective barrier. ► This corrosion inhibitor covers up to 72% of the total active surface of copper.

  10. Development, production, and application of sealed-off copper and gold vapour lasers

    International Nuclear Information System (INIS)

    Lyabin, Nikolai A; Chursin, A D; Ugol'nikov, S A; Koroleva, M E; Kazaryan, M A

    2001-01-01

    An analysis is made of the current state of the art of scientific and engineering advances in the field of repetitively pulsed self-heating metal vapour (copper and gold) lasers based on industrial, sealed-off, high-temperature, metalceramic and metal-glass active elements. The major applications of these lasers are discussed. The energy, spatial, and time characteristics of the lasers and their dependence on the parameters and construction of the laser active elements (tubes) and optical resonators are considered. The ways for the development of new high-power industrial laser active elements with a high efficiency (1 - 2%) and a service life of 500 - 1000 h are analysed. An average output power of 80 W was realised with a laser tube 150 cm in length and 32 mm in diameter. When the pumping efficiency is improved by raising the voltage to 30 - 35 kV, this system in a copper vapour laser will allow an output power of 100 W to be obtained with one active element. The characteristics of industrial versions of metal vapour lasers manufactured in different countries are compared and discussed. (invited paper)

  11. Copper and Copper Proteins in Parkinson's Disease

    Science.gov (United States)

    Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo

    2014-01-01

    Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology. PMID:24672633

  12. Biomedical Applications of Modified Carbon Glassy Electrode Sensor with Nanoparticles and Dendrimers

    Directory of Open Access Journals (Sweden)

    Solomon W. LEUNG

    2011-04-01

    Full Text Available We previously reported the development of a biosensor platform that is capable of measuring biometabolites and environmental sensitive species, such as peroxide and nitrate/nitrate, to concentrations in the order of ppb (parts per billion or lower. In this investigation, we modified our platform with dendrimers to enhance its performance. Zero and second generation of dendrimers were coated on the surface of a carbon glassy electrode which was then modified with l-glutamate dehydrogenase (GDH and α-keto glutarate. The resulting electrode was tested with ammonium solutions, concentrations ranged from 2 to 300 nM at pH 7.4; the results were satisfactory. Measurements at lower concentrations had better resolution than at higher concentrations and it is believed that the measurement limit can be lower than 2 nM. This biosensor platform was proven to be versatile and can be employed as a platform for ultrasensitive detecting devices in many biomedical and environmental applications.

  13. Review of iron oxide for photo electrode application in water splitting

    International Nuclear Information System (INIS)

    Amir Memar; Mohammad Kassim

    2009-01-01

    Full text: The use of the photoelectrochemical (PEC) route in hydrogen production is a promising, valuable, clean and efficient way of storing solar energy for use in hydrogen-powered fuel cells. Iron oxide (α-Fe 2 O 3 ) is an attractive photo electrode in PEC cell due to its constructive bandgap of ∼ 2.2 eV, lying in the visible region. This paper presents a review of the different methods of Fe2O3 thin film production and the characterization of the thin film and its application for photo-electrochemical hydrogen production. (author)

  14. Role of polymeric binders on mechanical behavior and cracking resistance of silicon composite electrodes during electrochemical cycling

    Science.gov (United States)

    Li, Dawei; Wang, Yikai; Hu, Jiazhi; Lu, Bo; Dang, Dingying; Zhang, Junqian; Cheng, Yang-Tse

    2018-05-01

    This work focuses on understanding the role of various binders, including sodium alginate (SA), Nafion, and polyvinylidene fluoride (PVDF), on the mechanical behavior and cracking resistance of silicon composite electrodes during electrochemical cycling. In situ curvature measurement of bilayer electrodes, consisting of a silicon-binder-carbon black composite layer on a copper foil, is used to determine the effects of binders on bending deformation, elastic modulus, and stress on the composite electrodes. It is found that the lithiation induced curvature and the modulus of the silicon/SA electrodes are larger than those of electrodes with Nafion and PVDF as binders. Although the modulus of Nafion is smaller than that of PVDF, the curvature and the modulus of silicon/Nafion composite are larger than those of silicon/PVDF electrodes. The moduli of all three composites decrease not only during lithiation but also during delithiation. Based on the measured stress and scanning electron microscopy observations of cracking in the composite electrodes, we conclude that the stress required to crack the composite electrodes with SA and Nafion binders is considerably higher than that of the silicon/PVDF electrode during electrochemical cycling. Thus, the cracking resistance of silicon/SA and silicon/Nafion composite electrodes is higher than that of silicon/PVDF electrodes.

  15. COPPER CABLE RECYCLING TECHNOLOGY

    International Nuclear Information System (INIS)

    Chelsea Hubbard

    2001-01-01

    The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D and D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D and D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D and D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D and D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness

  16. A copper-based layered coordination polymer: synthesis, magnetic properties and electrochemical performance in supercapacitors.

    Science.gov (United States)

    Liu, Qi; Liu, Xiuxiu; Shi, Changdong; Zhang, Yanpeng; Feng, Xuejun; Cheng, Mei-Ling; Su, Seng; Gu, Jiande

    2015-11-28

    A copper-based layered coordination polymer ([Cu(hmt)(tfbdc)(H2O)]; hmt = hexamethylenetetramine, tfbdc = 2,3,5,6-tetrafluoroterephthalate; Cu-LCP) has been synthesized, and it has been structurally and magnetically characterized. The Cu-LCP shows ferromagnetic interactions between the adjacent copper(II) ions. Density functional theory calculations on the special model of Cu-LCP support the occurrence of ferromagnetic interactions. As an electrode material for supercapacitors, Cu-LCP exhibits a high specific capacitance of 1274 F g(-1) at a current density of 1 A g(-1) in 1 M LiOH electrolyte, and the capacitance retention is about 88% after 2000 cycles.

  17. CueO-immobilized porous carbon electrode exhibiting improved performance of electrochemical reduction of dioxygen to water

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Seiya [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake cho, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: seiya@kais.kyoto-u.ac.jp; Miura, Yuko; Kano, Kenji [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2008-07-20

    We report the electro-enzymatic reduction of O{sub 2} to water at a current density controlled by the diffusion of the dissolved O{sub 2} in rotating disk electrode experiments under a broad pH range between 2 and 8. The electrocatalyst is CueO from Escherichia coli, which belongs to the family of multi-copper oxidases, immobilized on mesoporous carbon supports. The electrons are transferred from the electrode to CueO without an electron transfer mediator. The current density reached a value as high as 12 mA cm{sup -2} at 1 atm O{sub 2}, 25 deg. C, and 10,000 rpm on the CueO-modified electrodes. The CueO-modified mesoporous carbon cathode is quite superior to the smooth CueO cathode in the current density, electrode kinetics, pH tolerance, and thermal stability.

  18. Separation of copper-64 from copper phthalocyanine

    International Nuclear Information System (INIS)

    Battaglin, R.I.M.

    1979-01-01

    The separation of copper-64 from irradiated copper phthalocyanine by Szilard-Chalmers effect is studied. Two methods of separation are used: one of them is based on the dissolution of the irradiated dry compound in concentrated sulfuric acid following its precipitation in water. In the other one the compound is irradiated with water in paste form following treatment with water and hydrochloric acid. The influence of the crystal form of the copper phthalocyanine on the separation yield of copper-64 is shown. Preliminary tests using the ionic exchange technique for purification and changing of copper-64 sulfate to chloride form are carried out. The specific activity using the spectrophotometric technique, after the determination of the copper concentration in solution of copper-64, is calculated. (Author) [pt

  19. Sensing of volatile organic compounds by copper phthalocyanine thin films

    Science.gov (United States)

    Ridhi, R.; Saini, G. S. S.; Tripathi, S. K.

    2017-02-01

    Thin films of copper phthalocyanine have been deposited by thermal evaporation technique. We have subsequently exposed these films to the vapours of methanol, ethanol and propanol. Optical absorption, infrared spectra and electrical conductivities of these films before and after exposure to chemical vapours have been recorded in order to study their sensing mechanisms towards organic vapours. These films exhibit maximum sensing response to methanol while low sensitivities of the films towards ethanol and propanol have been observed. The changes in sensitivities have been correlated with presence of carbon groups in the chemical vapours. The effect of different types of electrodes on response-recovery times of the thin film with organic vapours has been studied and compared. The electrodes gap distance affects the sensitivity as well as response-recovery time values of the thin films.

  20. Applications of Silver Nanowires on Transparent Conducting Film and Electrode of Electrochemical Capacitor

    Directory of Open Access Journals (Sweden)

    Yuan-Jun Song

    2014-01-01

    Full Text Available Silver nanowire has potential applications on transparent conducting film and electrode of electrochemical capacitor due to its excellent conductivity. Transparent conducting film (G-film was prepared by coating silver nanowires on glass substrate using Meyer rod method, which exhibited better performance than carbon nanotube and graphene. The conductivity of G-film can be improved by increasing sintering temperature. Electrode of electrochemical capacitor (I-film was fabricated through the same method with G-film on indium tin oxide (ITO. CV curves of I-film under different scanning rates had obvious redox peaks, which indicated that I-film exhibited excellent electrochemical pseudocapacitance performance and good reversibility during charge/discharge process. In addition, the specific capacitance of I-film was measured by galvanostatic charge/discharge experiments, indicating that I-film exhibits high special capacitance and excellent electrochemical stability.

  1. Plasmatron with expanding channel of outlet electrode and its applications

    International Nuclear Information System (INIS)

    Chinnov, V.F.; Isakajev, E.Kh.; Ivanov, P.P.; Sinkevich, O.A.; Tyuftyaev, A.S.

    2000-01-01

    A serious industrial application is found for the plasmatron with expanding channel of outlet electrode - hardening and nitriding surface treatment of railway wheels. Several plasma installations are under operation at the engine houses of Moscow Railways. More than 12 000 wheel sets have been treated up to now. Results are evident: wheel life doubles due to plasma treatment. The plasmatron developed essentially in an empiric way is now under heavy investigation both theoretically and experimentally. High precision measurements of nitrogen emission spectra are expected to be used directly for accurate calculation of radiation heat loss term in a quasi-one dimensional flow code. (Authors)

  2. Exogenous salicylate application affects the lead and copper accumulation characteristics of Lemna gibba L.

    Energy Technology Data Exchange (ETDEWEB)

    Duman, Fatih; Aksoy, Ahmet; Ozturk, Fatma; Ceylan, Ahmet [Erciyes Univ., Kayseri (Turkey). Dept. of Biology

    2010-11-15

    Previous studies have shown that salicylates can change the ion permeability of root cells. Therefore the possible effects of exogenous salicylate application on lead (Pb) and copper (Cu) accumulation and its protective role against DNA damage due to metal exposure in Lemna gibba were studied. L. gibba was exposed to 5, 10, and 25 {mu}M Pb and Cu for six days in the presence and absence of sodium salicylate (SA) (0.1, 0.5, and 1 mM). At all concentrations tested, SA application decreased Pb accumulation. On the other hand, application of 0.5 mM SA increased Cu accumulation. SA did not reduce DNA damage resulting from Pb and Cu toxicity. In summary, SA may be useful for reducing Pb accumulation, and application of SA at 0.5 mM may be useful for the phytoextraction of Cu. (orig.)

  3. Templated synthesis, characterization, and sensing application of macroscopic platinum nanowire network electrodes

    DEFF Research Database (Denmark)

    Wang, D. H.; Kou, R.; Gil, M. P.

    2005-01-01

    properties of the electrodes, such as electrochemical active area and methanol oxidation, have also been studied. Compared with conventional polycrystalline Pt electrodes, these novel nanowire network electrodes possess high electrochemical active areas and demonstrate higher current densities and a lower...... onset potential for methanol electro-oxidation. Enzymatic Pt nanowire-network-based sensors show higher sensitivity for glucose detection than that using conventional polycrystalline Pt electrode. Such macroscopic nanowire network electrodes provide ideal platforms for sensing and other device......Abstract: Novel platinum nanowire network electrodes have been fabricated through electrodeposition using mesoporous silica thin films as templates. These electrodes were characterized by X-ray diffraction, transmission electron microscope, and scanning electron microscope. The electrochemical...

  4. Porous Fe-Mn-O nanocomposites: Synthesis and supercapacitor electrode application

    Directory of Open Access Journals (Sweden)

    Guoxing Zhu

    2016-06-01

    Full Text Available Transition metal oxide micro-/nanostructures demonstrate high potential applications in energy storage devices. Here, we report a facile synthesis of highly homogeneous oxide composites with porous structure via a coordination polymer precursor, which was prepared with the assistance of tartaric acid. The typical product, Fe-Mn-O composite was demonstrated here. The obtained Fe-Mn-O product was systemically characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, elemental mapping analysis, and X-ray photoelectron spectroscopy. It was demonstrated that the Fe-Mn-O nanocomposite shows interconnected porous structure, in which iron, manganese, and oxygen are uniformly distributed. In addition, the Fe-Mn-O nanocomposite was then fabricated as capacitor electrodes. Operating in an aqueous neutral solution, the Fe-Mn-O composite electrodes showed an wide working potential window from −0.2 to 1.0 V (vs. SCE, and a specific capacitance of 86.7 Fg−1 or 0.4 Fcm−2 at a constant current density of 1 Ag−1 with good cycle life. This study offers a new precursor approach to prepare porous metal oxide composites, which would be applied in energy-storage/conversion devices, catalysts, sensors, and so on.

  5. Corrosive effect of the type of soil in the systems of grounding more used (copper and stainless steel) for local soil samples from the city of Tunja (Colombia), by means of electrochemical techniques

    Science.gov (United States)

    Guerrero, L.; Salas, Y.; Blanco, J.

    2016-02-01

    In this work electrochemical techniques were used to determine the corrosion behaviour of copper and stainless steel electrodes, used in grounding varying soil type with which they react. A slight but significant change in the corrosion rate, linear polarization resistance and equivalent parameters in the technique of electrochemical impedance spectroscopy circuit was observed. Electrolytes in soils are slightly different depending on laboratory study, but the influence was noted in the retention capacity of water, mainly due to clays, affecting ion mobility and therefore measures such as the corrosion rate. Behaviour was noted in lower potential for copper corrosion, though the corrosion rate regardless of the type of soil, was much higher for electrodes based on copper, by several orders of magnitude.

  6. A selective potentiometric copper (II) ion sensor based on the functionalized ZnO nanorods.

    Science.gov (United States)

    Khun, K; Ibupoto, Z H; Liu, X; Nur, O; Willander, M; Danielsson, B

    2014-09-01

    In this work, ZnO nanorods were hydrothermally grown on the gold-coated glass substrate and characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The ZnO nanorods were functionalized by two different approaches and performance of the sensor electrode was monitored. Fourier transform infrared spectroscopy (FTIR) was carried out for the confirmation of interaction between the ionophore molecules and ZnO nanorods. In addition to this, the surface of the electrode was characterized by X-ray photoelectron spectroscopy (XPS) showing the chemical and electronic state of the ionophore and ZnO nanorod components. The ionophore solution was prepared in the stabilizer, poly vinyl chloride (PVC) and additives, and then functionalized on the ZnO nanorods that have shown the Nernstian response with the slope of 31 mV/decade. However, the Cu2+ ion sensor was fabricated only by immobilizing the selective copper ion ionophore membrane without the use of PVC, plasticizers, additives and stabilizers and the sensor electrode showed a linear potentiometric response with a slope of 56.4 mV/decade within a large dynamic concentration range (from 1.0 x 10(-6) to 1.0 x 10(-1) M) of copper (II) nitrate solutions. The sensor showed excellent repeatability and reproducibility with response time of less than 10 s. The negligible response to potentially interfering metal ions such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe3+), zinc (Zn2+), and sodium (Na+) allows this sensor to be used in biological studies. It may also be used as an indicator electrode in the potentiometric titration.

  7. Application of graphene oxide/lanthanum-modified carbon paste electrode for the selective determination of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Fengying; Feng, Chenqi; Fu, Ning; Wu, Huihui; Jiang, Jibo, E-mail: jibojiang0506@163.com; Han, Sheng, E-mail: hansheng654321@sina.com

    2015-12-01

    Highlights: • The effective surface area of the modified CPE has been expanded after self-assembly. • The GO–La composite exhibited excellent electrocatalytic activity toward DA. • The GO–La/CPE presented high selectivity, sensitivity, excellent stability and repeatability. - Abstract: A home-made carbon paste electrode (CPE) was reformed by graphene oxide (GO)/lanthanum (La) complexes, and a modified electrode, called GO–La/CPE, was fabricated for the selective determination of dopamine (DA) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Several factors affecting the electrocatalytic performance of the modified sensor were investigated. Owning to the combination of GO and La ions, the GO–La/CPE sensor exhibited large surface area, well selectivity, good repeatability and stability in the oxidation reaction of DA. At optimal conditions, the response of the GO–La/CPE electrode for determining DA was linear in the region of 0.01–0.1 μM and 0.1–400.0 μM. The limit of detection was down to 0.32 nM (S/N = 3). In addition, this modified electrode was successfully applied to the detection of DA in real urine and serum samples by using standard adding method, showing its promising application in the electroanalysis of real samples.

  8. Review of Fabrication Methods, Physical Properties, and Applications of Nanostructured Copper Oxides Formed via Electrochemical Oxidation

    Directory of Open Access Journals (Sweden)

    Wojciech J. Stepniowski

    2018-05-01

    Full Text Available Typically, anodic oxidation of metals results in the formation of hexagonally arranged nanoporous or nanotubular oxide, with a specific oxidation state of the transition metal. Recently, the majority of transition metals have been anodized; however, the formation of copper oxides by electrochemical oxidation is yet unexplored and offers numerous, unique properties and applications. Nanowires formed by copper electrochemical oxidation are crystalline and composed of cuprous (CuO or cupric oxide (Cu2O, bringing varied physical and chemical properties to the nanostructured morphology and different band gaps: 1.44 and 2.22 eV, respectively. According to its Pourbaix (potential-pH diagram, the passivity of copper occurs at ambient and alkaline pH. In order to grow oxide nanostructures on copper, alkaline electrolytes like NaOH and KOH are used. To date, no systemic study has yet been reported on the influence of the operating conditions, such as the type of electrolyte, its temperature, and applied potential, on the morphology of the grown nanostructures. However, the numerous reports gathered in this paper will provide a certain view on the matter. After passivation, the formed nanostructures can be also post-treated. Post-treatments employ calcinations or chemical reactions, including the chemical reduction of the grown oxides. Nanostructures made of CuO or Cu2O have a broad range of potential applications. On one hand, with the use of surface morphology, the wetting contact angle is tuned. On the other hand, the chemical composition (pure Cu2O and high surface area make such materials attractive for renewable energy harvesting, including water splitting. While compared to other fabrication techniques, self-organized anodization is a facile, easy to scale-up, time-efficient approach, providing high-aspect ratio one-dimensional (1D nanostructures. Despite these advantages, there are still numerous challenges that have to be faced, including the

  9. One-pot hydrothermal synthesis, characterization and electrochemical properties of CuS nanoparticles towards supercapacitor applications

    International Nuclear Information System (INIS)

    Krishnamoorthy, Karthikeyan; Rao, Alluri Nagamalleswara; Jae Kim, Sang; Kumar Veerasubramani, Ganesh

    2014-01-01

    In this article, we have investigated the electrochemical properties of CuS nanoparticles for supercapacitor applications. The CuS nanoparticles are prepared by a facile one-pot hydrothermal approach using copper nitrate and thiourea as starting materials. The x-ray diffraction study revealed the formation of covellite CuS. The field-emission scanning electron microscope studies suggested the formation of cubic shaped CuS nanoparticles. The electrochemical studies such as cyclic voltammetry, galvanostatic charge-discharge analysis and electrochemical impedance spectroscopy confirmed the pseudocapacitive nature of the CuS electrodes. The CuS electrode shows a specific capacitance of about 101.34 F g −1 from the cyclic voltammetry at a scan rate of 5 mV s −1 . The electrochemical impedance spectra analyzed using Nyquist plot confirmed the pseudocapacitive behavior of the CuS electrodes. (paper)

  10. The electrochemical behaviour of copper in aerated 1 mol·dm-3 NaCl at room temperature: Pt. 2

    International Nuclear Information System (INIS)

    King, F.; Litke, C.D.

    1989-05-01

    Uniform corrosion will be an important process in determining the lifetime of a copper nuclear fuel waste container. We need to know the mechanism of the corrosion reaction if we are to make reliable predictions about the long-term corrosion behaviour. This series of reports summarizes the results of an electrochemical investigation of the corrosion of copper in aerated 1 mol·dm -3 NaCl at room temperature. In part 2 we discuss the cathodic reduction of oxygen on a copper rotating disc electrode. The anodic dissolution of copper and the behaviour under freely corroding conditions are considered in Parts 1 and 3, respectively. The mechanism of the oxygen reduction reaction has been studied over a wide range of applied potentials. At potentials close to the corrosion potential, the mechanism is complicated and not fully understood. It is possible that in this potential region, oxygen is reduced to peroxide. At more negative applied potentials, between -0.50 and -0.90 V sce , the predominant process is the 4-electron reduction of oxygen to hydroxide. In this potential region, the rate is controlled jointly by the interfacial reaction and the rate of supply of oxygen to the electrode surface. At an applied potential of about -1.0 V sce , the rate of reduction is almost totally controlled by the rate of transport of oxygen. Values for the kinetic parameters for the 4-electron reaction have been determined. In addition, the diffusion coefficient of oxygen was found to be 1.7 3 ± 0.0 5 x 10 -5 cm 2 ·s -1 . These data, along with the results on the anodic dissolution of copper, will be used to explain the behaviour of copper under freely corroding conditions

  11. Role of electrodes in ambient electrolytic decomposition of hydroxylammonium nitrate (HAN) solutions

    OpenAIRE

    Koh, Kai Seng; Chin, Jitkai; Wahida Ku Chik, Tengku F.

    2013-01-01

    Decomposition of hydroxylammonium nitrate (HAN) solution with electrolytic decomposition method has attracted much attention in recent years due to its efficiencies and practicability. However, the phenomenon has not been well-studied till now. By utilizing mathematical model currently available, the effect of water content and power used for decomposition was studied. Experiment data shows that sacrificial material such as copper or aluminum outperforms inert electrodes in the decomposition ...

  12. Rare-earth hafnium oxide materials for magnetohydrodynamic (MHD) generator application

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, D. D; Bates, J. L.

    1979-01-01

    Several ceramic materials based on rare-earth hafnium oxides have been identified as potential high-temperature electrodes and low-temperature current leadouts for open cycle coal-fired MHD generator channels. The electrode-current leadouts combination must operate at temperatures between 400 and 2000K with an electrical conductivity greater than 10/sup -2/ ohm/sup -1/ cm/sup -1/. The electrodes will be exposed to flowing (linear flow rates up to 100 m/s) potassium seeded coal combustion gases (plasma core temperatures between 2400 to 3200/sup 0/K) and coal slag. During operation the electrodes must conduct direct electric current at densities near 1.5 amp/cm/sup 2/. Consequently, the electrodes must be resistant to electrochemical decompositions and interactions with both the coal slag and potassium salts (e.g., K/sub 2/SO/sub 4/, K/sub 2/CO/sub 3/). The current leadout materials are placed between the hot electrodes and the water-cooled copper structural members and must have electrical conductivities greater than 10/sup -2/ ohm/sup -1/ cm/sup -1/ between 1400 and 400/sup 0/K. The current leadouts must be thermally and electrochemically compatible with the electrode, copper, and potassium salts. Ideally, the electrodes and current leadouts should exhibit minimal ionic conductivity. The fabrication, electrical conductivity, and electrochemical corrosion of rare-earth hafnium oxide materials are discussed. (WHK)

  13. Testing the Underlying Chemical Principles of the Biotic Ligand Model (BLM) to Marine Copper Systems: Measuring Copper Speciation Using Fluorescence Quenching.

    Science.gov (United States)

    Tait, Tara N; McGeer, James C; Smith, D Scott

    2018-01-01

    Speciation of copper in marine systems strongly influences the ability of copper to cause toxicity. Natural organic matter (NOM) contains many binding sites which provides a protective effect on copper toxicity. The purpose of this study was to characterize copper binding with NOM using fluorescence quenching techniques. Fluorescence quenching of NOM with copper was performed on nine sea water samples. The resulting stability constants and binding capacities were consistent with literature values of marine NOM, showing strong binding with [Formula: see text] values from 7.64 to 10.2 and binding capacities ranging from 15 to 3110 nmol mg [Formula: see text] Free copper concentrations estimated at total dissolved copper concentrations corresponding to previously published rotifer effect concentrations, in the same nine samples, were statistically the same as the range of free copper calculated for the effect concentration in NOM-free artificial seawater. These data confirms the applicability of fluorescence spectroscopy techniques for NOM and copper speciation characterization in sea water and demonstrates that such measured speciation is consistent with the chemical principles underlying the biotic ligand model approach for bioavailability-based metals risk assessment.

  14. Copper and copper-nickel alloys as zebra mussel antifoulants

    Energy Technology Data Exchange (ETDEWEB)

    Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

    1996-04-01

    Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

  15. The effects of a magnetic field on the morphologies of nickel and copper deposits: the concept of “effective overpotential”

    Directory of Open Access Journals (Sweden)

    NEBOJSA D. NIKOLIC

    2007-08-01

    Full Text Available The morphologies of nickel and copper deposits obtained without applied magnetic fields, and with both parallel and perpendicular applied magnetic fields were examined by the scanning electron microscopy (SEM technique. Changes in the morphologies of the metals caused by the effect of the magnetic fields are explained by the concept of “effective overpotential”. The morphologies of the nickel and copper deposits obtained under parallelly oriented magnetic fields were similar to those obtained at some lower cathodic potentials without an applied magnetic field. The magnetic field with a perpendicular orientation to the electrode surface increased the dispersity of the nickel and copper deposits. Nickel and copper deposits obtained under this orientation of the magnetic field were similar to those obtained at some higher cathodic potentials without an applied magnetic field.

  16. Characterization and electrocatalytic application of silver modified polypyrrole electrodes

    Directory of Open Access Journals (Sweden)

    A. DEKANSKI

    2005-02-01

    Full Text Available Silver modified polypyrrole electrodeswere preparedwith the aim of testing them for the electrooxidation of formaldehyde in alkaline solution. The modification of polypyrrole by immersion in aqueous AgNO3 solution was studied by cyclic voltammetry and vacuum techniques (AES and XPS. The influence of time of immersion and the thickness of the polypyrrole film, prepared by electrochemical polymerization, on the modification of the polymer were examined. The results acquired from both electrochemical and spectroscopic examinations show that immersion of a polypyrrole electrode in a AgNO3 solution results in its modificationwith silver, which is deposited in the elemental state on the surface. The quantity of silver deposited depends not only on the immersion time but also on the thickness of the polymer film. A modified PPy/Ag electrode exhibits catalytic activity for the electrooxidation of CH2O in NaOH. In spite of the low quantity of silver, the activity of the electrode for this reaction is comparable to that of a polycrystalline silver electrode.

  17. Studying the Technology of Creating Cortical Electrode Instruments using the Rapid Prototyping Technology

    Directory of Open Access Journals (Sweden)

    Ablyaz T. R.

    2017-06-01

    Full Text Available This paper shows the results of studying the technology of manufacturing cortical electrode-instruments (EI with the use of indirect methods of the Rapid Prototyping technology. Functional EI prototypes were made by layered synthesis of the photopolymer material with the use of the stereolithography technology (SLA - Stereo Lithography Apparatus. The article is focused on two methods of indirect EI manufacturing. One of the EI prototypes was used for making a molded wax model for hot investment casting, followed by applying copper coating. The second prototype was used for applying copper plating to a prepared current-conductive layer. As a result of EDMing a steel workpiece, both EIs reached the desired depth, which is 1 mm. The copper plating applied to the EI preserves its integrity. Through the use of the casting technology, there is a possibility to cut the economic costs by 35%. Using a prototype with preliminarily applied conductive coating makes it possible to make geometrically-complex EIs.

  18. The corrosion rate of copper in a bentonite test package measured with electric resistance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Rosborg, Bo [Division of Surface and Corrosion Science, KTH, Stockholm (Sweden); Kosec, Tadeja; Kranjc, Andrej; Kuhar, Viljem; Legat, Andraz [Slovenian National Building and Civil Engineering Institute, Ljubljana (Slovenia)

    2012-12-15

    LOT1 test parcel A2 was exposed for six years in the Aespoe Hard Rock Laboratory, which offers a realistic environment for the conditions that will prevail in a deep repository for high-level radioactive waste disposal in Sweden. The test parcel contained copper electrodes for real-time corrosion monitoring in bentonite ring 36, where the temperature was 24 deg C, and copper coupons in bentonite rings 22 and 30, where the temperature was higher. After retrieval of the test parcel in January 2006, a bentonite test package consisting of bentonite rings 35 - 37 was placed in a container and sealed with a thick layer of paraffin. Later the same year new copper electrodes were installed in the test package. In January 2007 electric resistance (ER) sensors of pure copper with a thickness of 35 {mu}m were also installed in the test package mainly to facilitate the interpretation of the results from the real-time corrosion monitoring with electrochemical techniques. The ER measurements have shown that the corrosion rate of pure copper exposed in an oxic bentonite/ saline groundwater environment at room temperate decreases slowly with time to low but measurable values. The corrosion rates estimated from the regularly performed EIS measurements replicate the ER data. Thus, for this oxic environment in which copper acquires corrosion potentials of the order of 200 mV (SHE) or higher, electrochemical measurements provide believable data. Comparing the recorded ER data with an estimate of the average corrosion rate based on comparing cross-sections from exposed and protected sensor elements, it is obvious that the former overestimates the actual corrosion rate, which is understandable. It seems as if electrochemical measurements can provide a better estimate of the corrosion rate; however, this is quite dependent on the use of proper measuring frequencies and evaluation methods. In this respect ER measurements are more reliable. It has been shown that real-time corrosion

  19. The corrosion rate of copper in a bentonite test package measured with electric resistance sensors

    International Nuclear Information System (INIS)

    Rosborg, Bo; Kosec, Tadeja; Kranjc, Andrej; Kuhar, Viljem; Legat, Andraz

    2012-12-01

    LOT1 test parcel A2 was exposed for six years in the Aespoe Hard Rock Laboratory, which offers a realistic environment for the conditions that will prevail in a deep repository for high-level radioactive waste disposal in Sweden. The test parcel contained copper electrodes for real-time corrosion monitoring in bentonite ring 36, where the temperature was 24 deg C, and copper coupons in bentonite rings 22 and 30, where the temperature was higher. After retrieval of the test parcel in January 2006, a bentonite test package consisting of bentonite rings 35 - 37 was placed in a container and sealed with a thick layer of paraffin. Later the same year new copper electrodes were installed in the test package. In January 2007 electric resistance (ER) sensors of pure copper with a thickness of 35 μm were also installed in the test package mainly to facilitate the interpretation of the results from the real-time corrosion monitoring with electrochemical techniques. The ER measurements have shown that the corrosion rate of pure copper exposed in an oxic bentonite/ saline groundwater environment at room temperate decreases slowly with time to low but measurable values. The corrosion rates estimated from the regularly performed EIS measurements replicate the ER data. Thus, for this oxic environment in which copper acquires corrosion potentials of the order of 200 mV (SHE) or higher, electrochemical measurements provide believable data. Comparing the recorded ER data with an estimate of the average corrosion rate based on comparing cross-sections from exposed and protected sensor elements, it is obvious that the former overestimates the actual corrosion rate, which is understandable. It seems as if electrochemical measurements can provide a better estimate of the corrosion rate; however, this is quite dependent on the use of proper measuring frequencies and evaluation methods. In this respect ER measurements are more reliable. It has been shown that real-time corrosion

  20. Thermally modified bentonite clay for copper removal

    International Nuclear Information System (INIS)

    Bertagnolli, C.; Kleinübing, S.J.; Silva, M.G.C.

    2011-01-01

    Bentonite clay coming from Pernambuco was thermally modified in order to increase its affinity and capacity in the copper removal in porous bed. The application of this procedure is justified by the low cost of clay, their abundance and affinity for various metal ions. Thermally treatment modifies the clay adsorption properties enables its use in porous bed system, with the increase in surface area and mechanical strength. The material was characterized by x-ray diffraction, thermogravimetric analysis and N_2 physisorption. Then tests were carried out for adsorption of copper in various experimental conditions and evaluated the mass transfer zone, useful and total adsorbed removal amounts and total copper removal percentage. The results showed that the clay treated at higher temperature showed higher copper removal. (author)