Electrosynthesis and catalytic activity of polymer-nickel particles composite electrode materials

Energy Technology Data Exchange (ETDEWEB)

Melki, Tahar; Zouaoui, Ahmed; Bendemagh, Barkahoum [Universite Ferhat Abbas, Setif (Algeria). Faculte des Sciences de l' Ingenieur. Dept. du Tronc Commun; Oliveira, Ione M.F. de; Oliveira, Gilver F. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Lepretre, Jean-Claude [UMR-5631 CNRS-INPG-UJF, St. Martin d' Heres Cedex (France). Lab. d' Electrochimie et de Physicochimie des Materiaux et Interfaces; Bucher, Christophe; Mou tet, Jean-Claude [Universite Joseph Fourier Grenoble 1 (France). Dept. de Chimie Moleculaire], e-mail: Jean-Claude.Moutet@ujf-grenoble.fr

2009-07-01

Nickel-polymer composite electrode materials have been synthesized using various strategies, all comprising the electrochemical reduction of nickel(II) cations or complexes, incorporated by either ion-exchange or complexation into various poly(pyrrole-carboxylate) thin films coated by oxidative electropolymerization onto carbon electrodes. The electrocatalytic activity and the stability of the different composites have been then evaluated in the course of the electrocatalytic hydrogenation of ketones and enones in aqueous electrolytes. The best results were obtained using nickel-polymer composites synthesized by electroreduction of nickel(II) ions complexed into polycarboxylate films, which are characterized by a high catalytic activity and a good operational stability. (author)

High-performance binder-free supercapacitor electrode by direct growth of cobalt-manganese composite oxide nansostructures on nickel foam

OpenAIRE

Jiang, Shulan; Shi, Tielin; Long, Hu; Sun, Yongming; Zhou, Wei; Tang, Zirong

2014-01-01

A facile approach composed of hydrothermal process and annealing treatment is proposed to directly grow cobalt-manganese composite oxide ((Co,Mn)3O4) nanostructures on three-dimensional (3D) conductive nickel (Ni) foam for a supercapacitor electrode. The as-fabricated porous electrode exhibits excellent rate capability and high specific capacitance of 840.2 F g-1 at the current density of 10 A g-1, and the electrode also shows excellent cycling performance, which retains 102% of its initial d...

Supercapacitive properties of symmetry and the asymmetry two electrode coin type supercapacitor cells made from MWCNTS/nickel oxide nanocomposite

CSIR Research Space (South Africa)

Adekunle, AS

2011-10-01

Full Text Available Supercapacitive properties of synthesised nickel oxides (NiO) nanoparticles integrated with multi-walled carbon nanotubes (MWCNT) in a two-electrode coin cell type supercapacitor were investigated. Successful formation of the MWCNT-NiO nanocomposite...

Study on the influences of reduction temperature on nickel-yttria-stabilized zirconia solid oxide fuel cell anode using nickel oxide-film electrode

Science.gov (United States)

Jiao, Zhenjun; Ueno, Ai; Suzuki, Yuji; Shikazono, Naoki

2016-10-01

In this study, the reduction processes of nickel oxide at different temperatures were investigated using nickel-film anode to study the influences of reduction temperature on the initial performances and stability of nickel-yttria-stabilized zirconia anode. Compared to conventional nickel-yttria-stabilized zirconia composite cermet anode, nickel-film anode has the advantage of direct observation at nickel-yttria-stabilized zirconia interface. The microstructural changes were characterized by scanning electron microscopy. The reduction process of nickel oxide is considered to be determined by the competition between the mechanisms of volume reduction in nickel oxide-nickel reaction and nickel sintering. Electrochemical impedance spectroscopy was applied to analyze the time variation of the nickel-film anode electrochemical characteristics. The anode performances and microstructural changes before and after 100 hours discharging and open circuit operations were analyzed. The degradation of nickel-film anode is considered to be determined by the co-effect between the nickel sintering and the change of nickel-yttria-stabilized zirconia interface bonding condition.

Disposable Non-Enzymatic Glucose Sensors Using Screen-Printed Nickel/Carbon Composites on Indium Tin Oxide Electrodes

Directory of Open Access Journals (Sweden)

Won-Yong Jeon

2015-12-01

Full Text Available Disposable screen-printed nickel/carbon composites on indium tin oxide (ITO electrodes (DSPNCE were developed for the detection of glucose without enzymes. The DSPNCE were prepared by screen-printing the ITO substrate with a 50 wt% nickel/carbon composite, followed by curing at 400 °C for 30 min. The redox couple of Ni(OH2/NiOOH was deposited on the surface of the electrodes via cyclic voltammetry (CV, scanning from 0–1.5 V for 30 cycles in 0.1 M NaOH solution. The DSPNCE were characterized by field-emission scanning electron microscopy (FE-SEM, X-ray photoelectron spectroscopy (XPS, and electrochemical methods. The resulting electrical currents, measured by CV and chronoamperometry at 0.65 V vs. Ag/AgCl, showed a good linear response with glucose concentrations from 1.0–10 mM. Also, the prepared electrodes showed no interference from common physiologic interferents such as uric acid (UA or ascorbic acid (AA. Therefore, this approach allowed the development of a simple, disposable glucose biosensor.

Disposable Non-Enzymatic Glucose Sensors Using Screen-Printed Nickel/Carbon Composites on Indium Tin Oxide Electrodes.

Science.gov (United States)

Jeon, Won-Yong; Choi, Young-Bong; Kim, Hyug-Han

2015-12-10

Disposable screen-printed nickel/carbon composites on indium tin oxide (ITO) electrodes (DSPNCE) were developed for the detection of glucose without enzymes. The DSPNCE were prepared by screen-printing the ITO substrate with a 50 wt% nickel/carbon composite, followed by curing at 400 °C for 30 min. The redox couple of Ni(OH)₂/NiOOH was deposited on the surface of the electrodes via cyclic voltammetry (CV), scanning from 0-1.5 V for 30 cycles in 0.1 M NaOH solution. The DSPNCE were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. The resulting electrical currents, measured by CV and chronoamperometry at 0.65 V vs. Ag/AgCl, showed a good linear response with glucose concentrations from 1.0-10 mM. Also, the prepared electrodes showed no interference from common physiologic interferents such as uric acid (UA) or ascorbic acid (AA). Therefore, this approach allowed the development of a simple, disposable glucose biosensor.

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...

Modified cermet fuel electrodes for solid oxide electrochemical cells

Science.gov (United States)

Ruka, Roswell J.; Spengler, Charles J.

1991-01-01

An exterior porous electrode (10), bonded to a solid oxygen ion conducting electrolyte (13) which is in contact with an interior electrode (14), contains coarse metal particles (12) of nickel and/or cobalt, having diameters from 3 micrometers to 35 micrometers, where the coarse particles are coated with a separate, porous, multiphase layer (17) containing fine metal particles of nickel and/or cobalt (18), having diameters from 0.05 micrometers to 1.75 micrometers and conductive oxide (19) selected from cerium oxide, doped cerium oxide, strontium titanate, doped strontium titanate and mixtures thereof.

Analysis of the dynamic behavior of porous nickel electrodes in alkaline solutions

International Nuclear Information System (INIS)

Real, Silvia G; Visintin, Arnaldo; Castro, Elida B

2004-01-01

The nickel electrode is important for its electrocatalytic properties, when it is used in water electrolysis, and for use as a positive terminal in alkaline nickel-cadmium, nickel-iron, nickel-zinc, nickel-hydrogen and nickel-metal hydride batteries. Since there are many factors related to the functioning of these batteries that have still not been clarified, such as the memory effect associated with the change in structure of the nickel hydroxide and the phenomenon of 'battery sudden death', that produce serious problems mostly in spaces uses, this work discusses the dynamic behavior of the porous nickel hydroxide electrode. This electrode possesses outstanding properties such as high power density, good cyclability and elevated specific energy, which make it unique for the above-mentioned applications. The electrochemical storage of energy in this electrode is based on the reversible characteristics of nickel hydroxide/oxhydroxide redox coupling. The reversibility of the process is an important factor in battery materials. In the case of the Ni oxide, during the electrode discharge H + is inserted and this process inverts during the charging. This work presents the results obtained with the use of impedance spectroscopy for different discharge states of the electrode material in order to correlate its electrochemical properties according to the development of physical chemical models. These models include the charging and discharging processes, the process of proton diffusion in the solid and the porous nature of the material. Knowledge about the functioning of the electrode material is obtained by adjusting the experimental data according to the model and the parametric identification to determine values associated with such variables as area of active material, diffusion coefficient of the H + , conductivity of the solid as a function of the discharge state and kinetic constants of the charge transfer process (CW)

High-performance binder-free supercapacitor electrode by direct growth of cobalt-manganese composite oxide nansostructures on nickel foam

Science.gov (United States)

Jiang, Shulan; Shi, Tielin; Long, Hu; Sun, Yongming; Zhou, Wei; Tang, Zirong

2014-09-01

A facile approach composed of hydrothermal process and annealing treatment is proposed to directly grow cobalt-manganese composite oxide ((Co,Mn)3O4) nanostructures on three-dimensional (3D) conductive nickel (Ni) foam for a supercapacitor electrode. The as-fabricated porous electrode exhibits excellent rate capability and high specific capacitance of 840.2 F g-1 at the current density of 10 A g-1, and the electrode also shows excellent cycling performance, which retains 102% of its initial discharge capacitance after 7,000 cycles. The fabricated binder-free hierarchical composite electrode with superior electrochemical performance is a promising candidate for high-performance supercapacitors.

High-performance Electrochemical Energy Storage Electrodes Based on Nickel Oxide-coated Nickel Foam Prepared by Sparking Method

International Nuclear Information System (INIS)

Chuminjak, Yaowamarn; Daothong, Suphaporn; Kuntarug, Aekapong; Phokharatkul, Ditsayut; Horprathum, Mati; Wisitsoraat, Anurat; Tuantranont, Adisorn; Jakmunee, Jaroon; Singjai, Pisith

2017-01-01

Highlights: • NiO particles (3-10 nm) were sparked on Ni foams with varying times (45-180 min). • Larger NiO nanoparticles were aggregated to foam-like structure at a longer time. • The optimal time of 45 min led to a high specific capacity of 920 C/g at 1 A/g. • The specific capacity remained as high as 699 (76% of 920) C/g at 20 A/g. • The optimal electrode exhibited 96% capacity retention after 1000 cycles at 4 A/g. - Abstract: In this work, high-performance electrochemical energy storage electrodes were developed based on nickel oxide (NiO)-coated nickel (Ni) foams prepared by a sparking method. NiO nanoparticles deposited on Ni foams with varying sparking times from 45 to 180 min were structurally characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. In addition, the electrochemical energy storage characteristics of the electrodes were evaluated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. It was found that NiO nanoparticles sparked on Ni foam with a longer time would be agglomerated and formed a foam-like network with large pore sizes and a lower surface area, leading to inferior charge storage behaviors. The NiO/Ni foam electrode prepared with the shortest sparking of 45 min displayed high specific capacities of 920 C g"-"1 (1840 F g"-"1) at 1 A g"-"1 and 699 (76% of 920) C g"-"1 at 20 A g"-"1 in a potential window of 0-0.5 V vs. Ag/AgCl as well as a good cycling performance with 96% capacity retention at 4 A g"-"1 after 1000 cycles and a low equivalent series resistance of 0.4 Ω. Therefore, NiO/Ni foam electrodes prepared by the sparking method are highly promising for high-capacity energy storage applications.

Development of a Micro-Fiber Nickel Electrode for Nickel-Hydrogen Cell

Science.gov (United States)

Britton, Doris L.

1996-01-01

The development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (NiH2) program at the NASA Lewis Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a more efficient and lighter weight electrode for the nickel-hydrogen fuel cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active materials. Initial tests include activation and capacity measurements at different discharge levels followed by half-cell cycle testing at 80 percent depth-of-discharge in a low Earth orbit regime. The electrodes that pass the initial tests are life cycle tested in a boiler plate nickel-hydrogen cell before flightweight designs are built and tested.

Nickel oxide electrode interlayer in CH3 NH3 PbI3 perovskite/PCBM planar-heterojunction hybrid solar cells.

Science.gov (United States)

Jeng, Jun-Yuan; Chen, Kuo-Cheng; Chiang, Tsung-Yu; Lin, Pei-Ying; Tsai, Tzung-Da; Chang, Yun-Chorng; Guo, Tzung-Fang; Chen, Peter; Wen, Ten-Chin; Hsu, Yao-Jane

2014-06-25

This study successfully demonstrates the application of inorganic p-type nickel oxide (NiOx ) as electrode interlayer for the fabrication of NiOx /CH3 NH3 PbI3 perovskite/PCBM PHJ hybrid solar cells with a respectable solar-to-electrical PCE of 7.8%. The better energy level alignment and improved wetting of the NiOx electrode interlayer significantly enhance the overall photovoltaic performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electroactive mesoporous yttria stabilized zirconia containing platinum or nickel oxide nanoclusters: a new class of solid oxide fuel cell electrode materials

Energy Technology Data Exchange (ETDEWEB)

Mamak, M.; Coombs, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Dept. of Chemistry

2001-02-01

The electroactivity of surfactant-templated mesoporous yttria stabilized zirconia, containing nanoclusters of platinum or nickel oxide, is explored by alternating current (AC) complex impedance spectroscopy. The observed oxygen ion and mixed oxygen ion-electron charge-transport behavior for these materials, compared to the sintered-densified non-porous crystalline versions, is ascribed to the unique integration of mesoporosity and nanocrystallinity within the binary and ternary solid solution microstructure. These attributes inspire interest in this new class of materials as candidates for the development of improved performance solid oxide fuel cell electrodes. (orig.)

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.

Progress in the Development of Lightweight Nickel Electrode for Nickel-Hydrogen Cell

Science.gov (United States)

Britton, Doris L.

1999-01-01

Development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (Ni-H2) program at the NASA Glenn Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a lighter weight electrode for the nickel-hydrogen cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active material. Initial tests include activation and capacity measurements at five different discharge levels, C/2, 1.0 C, 1.37 C, 2.0 C, and 2.74 C. The electrodes are life cycle tested using a half-cell configuration at 40 and 80% depths-of-discharge (DOD) in a low-Earth-orbit regime. The electrodes that pass the initial tests are life cycle-tested in a boiler plate nickel-hydrogen cell before flight weight design are built and tested.

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

Directory of Open Access Journals (Sweden)

Hae-Min Lee

2014-01-01

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

Ir-Ni oxide as a promising material for nerve and brain stimulating electrodes

Directory of Open Access Journals (Sweden)

Joan Stilling

2014-09-01

Full Text Available Tremendous potential for successful medical device development lies in both electrical stimulation therapies and neuronal prosthetic devices, which can be utilized in an extensive number of neurological disorders. These technologies rely on the successful electrical stimulation of biological tissue (i.e. neurons through the use of electrodes. However, this technology faces the principal problem of poor stimulus selectivity due to the currently available electrode’s large size relative to its targeted population of neurons. Irreversible damage to both the stimulated tissue and electrode are limiting factors in miniaturization of this technology, as charge density increases with decreasing electrode size. In an attempt to find an equilibrium between these two opposing constraints (electrode size and charge density, the objective of this work was to develop a novel iridium-nickel oxide (Ir0.2-Ni0.8-oxide coating that could intrinsically offer high charge storage capacity. Thermal decomposition was used to fabricate titanium oxide, iridium oxide, nickel oxide, and bimetallic iridium-nickel oxide coatings on titanium electrode substrates. The Ir0.2-Ni0.8-oxide coating yielded the highest intrinsic (material property and extrinsic (material property + surface area charge storage capacity (CSC among the investigated materials, exceeding the performance of the current state-of-the-art neural stimulating electrode, Ir-oxide. This indicates that the Ir0.2-Ni0.8-oxide material is a promising alternative to currently used Ir-oxide, Pt, Au and carbon-based stimulating electrodes.

Carbon deposition and sulfur poisoning during CO2 electrolysis in nickel-based solid oxide cell electrodes

Science.gov (United States)

Skafte, Theis Løye; Blennow, Peter; Hjelm, Johan; Graves, Christopher

2018-01-01

Reduction of CO2 to CO and O2 in the solid oxide electrolysis cell (SOEC) has the potential to play a crucial role in closing the CO2 loop. Carbon deposition in nickel-based cells is however fatal and must be considered during CO2 electrolysis. Here, the effect of operating parameters is investigated systematically using simple current-potential experiments. Due to variations of local conditions, it is shown that higher current density and lower fuel electrode porosity will cause local carbon formation at the electrochemical reaction sites despite operating with a CO outlet concentration outside the thermodynamic carbon formation region. Attempts at mitigating the issue by coating the composite nickel/yttria-stabilized zirconia electrode with carbon-inhibiting nanoparticles and by sulfur passivation proved unsuccessful. Increasing the fuel electrode porosity is shown to mitigate the problem, but only to a certain extent. This work shows that a typical SOEC stack converting CO2 to CO and O2 is limited to as little as 15-45% conversion due to risk of carbon formation. Furthermore, cells operated in CO2-electrolysis mode are poisoned by reactant gases containing ppb-levels of sulfur, in contrast to ppm-levels for operation in fuel cell mode.

Performance improvement of pasted nickel electrodes with multi-wall carbon nanotubes for rechargeable nickel batteries

International Nuclear Information System (INIS)

Song, Q.S.; Aravindaraj, G.K.; Sultana, H.; Chan, S.L.I.

2007-01-01

Carbon nanotubes (CNTs) were employed as a functional additive to improve the electrochemical performance of pasted nickel-foam electrodes for rechargeable nickel-based batteries. The nickel electrodes were prepared with spherical β-Ni(OH) 2 powder as the active material and various amounts of CNTs as additives. Galvanostatic charge/discharge cycling tests showed that in comparison with the electrode without CNTs, the pasted nickel electrode with added CNTs exhibited better electrochemical properties in the chargeability, specific discharge capacity, active material utilization, discharge voltage, high-rate capability and cycling stability. Meanwhile, the CNT addition also lowered the packing density of Ni(OH) 2 particles in the three-dimensional porous nickel-foam substrate, which could lead to the decrease in the active material loading and discharge capacity of the electrode. Hence, the amount of CNTs added to Ni(OH) 2 should be optimized to obtain a high-performance nickel electrode, and an optimum amount of CNT addition was found to be 3 wt.%. The superior electrochemical performance of the nickel electrode with CNTs could be attributed to lower electrochemical impedance and less γ-NiOOH formed during charge/discharge cycling, as indicated by electrochemical impedance spectroscopy and X-ray diffraction analyses. Thus, it was an effective method to improve the electrochemical properties of pasted nickel electrodes by adding an appropriate amount of CNTs to spherical Ni(OH) 2 as the active material

Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol

International Nuclear Information System (INIS)

Liu, Yong; Liu, Lan; Shan, Jun; Zhang, Jingdong

2015-01-01

Highlights: • Pd and reduced graphene oxide are deposited on foam-Ni via electrodeposition. • Pd particles supported on RGO possess large active surface area. • Pd/RGO/foam-Ni shows high electrocatalytic activity for dechlorination of 4-CP. • 100% 4-CP can be removed on Pd/RGO/foam-Ni under optimum ECH conditions. - Abstract: A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na 2 SO 4 concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96 kJ mol −1 . Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP

The electrocatalytic oxidation of carbohydrates at a nickel/carbon paper electrode fabricated by the filtered cathodic vacuum arc technique

International Nuclear Information System (INIS)

Fu, Yingyi; Wang, Tong; Su, Wen; Yu, Yanan; Hu, Jingbo

2015-01-01

The direct electrochemical behaviour of carbohydrates at a nickel/carbon paper electrode with a novel fabrication method is investigated. The investigation is used for verification the feasibility of using monosaccharides and disaccharides in the application of fuel cell. The selected monosaccharides are glucose, fructose and galactose; the disaccharides are sucrose, maltose and lactose. The modified nickel/carbon paper electrode was prepared using a filtered cathodic vacuum arc technique. The morphology image of the nickel thin film on the carbon paper surface was characterized by scanning electron microscopy (SEM). The existence of nickel was verified by X-ray photoelectron spectroscopy (XPS). The contact angle measurement was also used to characterize the modified electrode. Cyclic voltammetry (CV) was employed to evaluate the electrochemical behaviour of monosaccharides and disaccharides in an alkaline aqueous solution. The modified electrode exhibits good electrocatalytic activities towards carbohydrates. In addition, the stability of the nickel/carbon paper electrode with six sugars was also investigated. The good catalytic effects of the nickel/carbon paper electrode allow for the use of carbohydrates as fuels in fuel cell applications

Chemically grown, porous, nickel oxide thin-film for electrochemical supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Inamdar, A.I.; Kim, YoungSam; Im, Hyunsik [Department of Semiconductor Science, Dongguk University, Seoul 100-715 (Korea, Republic of); Pawar, S.M.; Kim, J.H. [Department of Materials Science and Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Kim, Hyungsang [Department of Physics, Dongguk University, Seoul 100-715 (Korea, Republic of)

2011-02-15

A porous nickel oxide film is successfully synthesized by means of a chemical bath deposition technique from an aqueous nickel nitrate solution. The formation of a rock salt NiO structure is confirmed with XRD measurements. The electrochemical supercapacitor properties of the nickel oxide film are examined using cyclic voltammetery (CV), galvanostatic and impedance measurements in two different electrolytes, namely, NaOH and KOH. A specific capacitance of {proportional_to}129.5 F g{sup -1} in the NaOH electrolyte and {proportional_to}69.8 F g{sup -1} in the KOH electrolyte is obtained from a cyclic voltammetery study. The electrochemical stability of the NiO electrode is observed for 1500 charge-discharge cycles. The capacitative behaviour of the NiO electrode is confirmed from electrochemical impedance measurements. (author)

Nickel cobalt oxide nanowire-reduced graphite oxide composite material and its application for high performance supercapacitor electrode material.

Science.gov (United States)

Wang, Xu; Yan, Chaoyi; Sumboja, Afriyanti; Lee, Pooi See

2014-09-01

In this paper, we report a facile synthesis method of mesoporous nickel cobalt oxide (NiCo2O4) nanowire-reduced graphite oxide (rGO) composite material by urea induced hydrolysis reaction, followed by sintering at 300 degrees C. P123 was used to stabilize the GO during synthesis, which resulted in a uniform coating of NiCo2O4 nanowire on rGO sheet. The growth mechanism of the composite material is discussed in detail. The NiCo2O4-rGO composite material showed an outstanding electrochemical performance of 873 F g(-1) at 0.5 A g(-1) and 512 F g(-1) at 40 A g(-1). This method provides a promising approach towards low cost and large scale production of supercapacitor electrode material.

Porous nickel hydroxide-manganese dioxide-reduced graphene oxide ternary hybrid spheres as excellent supercapacitor electrode materials.

Science.gov (United States)

Chen, Hao; Zhou, Shuxue; Wu, Limin

2014-06-11

This paper reports the first nickel hydroxide-manganese dioxide-reduced graphene oxide (Ni(OH)2-MnO2-RGO) ternary hybrid sphere powders as supercapacitor electrode materials. Due to the abundant porous nanostructure, relatively high specific surface area, well-defined spherical morphology, and the synergetic effect of Ni(OH)2, MnO2, and RGO, the electrodes with the as-obtained Ni(OH)2-MnO2-RGO ternary hybrid spheres as active materials exhibited significantly enhanced specific capacitance (1985 F·g(-1)) and energy density (54.0 Wh·kg(-1)), based on the total mass of active materials. In addition, the Ni(OH)2-MnO2-RGO hybrid spheres-based asymmetric supercapacitor also showed satisfying energy density and electrochemical cycling stability.

Facilely scraping Si nanoparticles@reduced graphene oxide sheets onto nickel foam as binder-free electrodes for lithium ion batteries

International Nuclear Information System (INIS)

Li, Suyuan; Xie, Wenhe; Gu, Lili; Liu, Zhengjiao; Hou, Xiaoyi; Liu, Boli; Wang, Qi; He, Deyan

2016-01-01

Binder-free electrodes of Si nanoparticles@reducedgrapheneoxidesheets(Si@rGO) for lithium ion batteries were facilely fabricated by scraping the mixture of commercial Si powder, graphene oxide and poly(vinyl pyrrolidone) (PVP) onto nickel foam and following a heat treatment. It was shown that the Si@rGO electrode performs an excellent electrochemical behavior. Even at a current density as high as 4 A/g, a reversible capacity of 792 mAh/g was obtained after 100 cycles. A small amount of PVP additive plays important roles, it not only increases the viscosity of the mixture paint in the coating process, but also improves the conductivity of the overall electrode after carbonization.

Deactivation of nickel hydroxide-gold modified electrodes

OpenAIRE

Caram, Bruno; Tucceri, Ricardo

2013-01-01

The aim of the present work was to study how the charge-transport process of a nickel hydroxide film electrochemically synthesized on a gold substrate is modified when the electrode is stored for a long time. It was found that nickel hydroxide films are deactivated under storage, that is, films became less conductive than films immediately prepared (nondeactivated). This study was carried out in the context of the rotating disc electrode voltammetry when the modified electrode contacts an ele...

A highly efficient microfluidic nano biochip based on nanostructured nickel oxide.

Science.gov (United States)

Ali, Md Azahar; Solanki, Pratima R; Patel, Manoj K; Dhayani, Hemant; Agrawal, Ved Varun; John, Renu; Malhotra, Bansi D

2013-04-07

We present results of the studies relating to fabrication of a microfluidic biosensor chip based on nickel oxide nanorods (NRs-NiO) that is capable of directly measuring the concentration of total cholesterol in human blood through electrochemical detection. Using this chip we demonstrate, with high reliability and in a time efficient manner, the detection of cholesterol present in buffer solutions at clinically relevant concentrations. The microfluidic channel has been fabricated onto a nickel oxide nanorod-based electrode co-immobilized with cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) that serves as the working electrode. Bare indium tin oxide served as the counter electrode. A Ag/AgCl wire introduced to the outlet of the microchannel acts as a reference electrode. The fabricated NiO nanorod-based electrode has been characterized using X-ray diffraction, Raman spectroscopy, HR-TEM, FT-IR, UV-visible spectroscopy and electrochemical techniques. The presented NRs-NiO based microfluidic sensor exhibits linearity in the range of 1.5-10.3 mM, a high sensitivity of 0.12 mA mM(-1) cm(-2) and a low value of 0.16 mM of the Michaelis-Menten constant (Km).

Synthesis of CoO/Reduced Graphene Oxide Composite as an Alternative Additive for the Nickel Electrode in Alkaline Secondary Batteries

International Nuclear Information System (INIS)

Fu, Gaoliang; Chang, Kun; Shangguan, Enbo; Tang, Hongwei; Li, Bao; Chang, Zhaorong; Yuan, Xiao-Zi; Wang, Haijiang

2015-01-01

Highlights: • CoO/RGO nanosheets with sandwiched structures were synthesized by hydrothermal method. • CoO/RGO composite can be as a good additive for Ni-MH battery. • Using CoO/RGO as the additive can greatly reduce the utilization of CoO in the commercial battery. • Particularly, the high rate capability of the electrode was enhanced significantly. - Abstract: A series of CoO/reduced graphene oxide (CoO/RGO) composites with different proportions are successfully synthesized via a hydrothermal method. As an additive for the nickel-based alkaline secondary battery cathode, the electrochemical performances of the proposed CoO/RGO composite are systematically investigated on its cyclic stability, rate capability, capacity recovery performance, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), in comparison with commercial CoO. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images show that the CoO nanoparticles are in-situ anchored on the surface of soft and flexible graphene sheets. Electrochemical results indicate that the CoO/RGO composites exhibite the highest performance when the weight ratio of CoO and RGO is 5:5. The optimized CoO/RGO composites as an additive for the nickel electrode not only can substantially reduce the CoO additive but also possess good electrochemical performances, especially for the high-rate capability. The discharge capacity of the nickel electrode with 5 wt% of CoO/RGO (5:5) addition deliver a high discharge capacity of 284.3, 264.6,235.4 and 208.6 mAh g"−"1 at 0.2, 1.0, 5.0 and 10.0 C, respectively. The capacity recovery rate at 0.2 C can reach 98.4%. CV and EIS test indicate that the incorporation of RGO can significantly enhance the reversible property, current density of cathodic peak, proton diffusion and conductivity of the nickel electrode.

Long life nickel electrodes for a nickel-hydrogen cell: Cycle life tests

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1985-01-01

In order to develop a long life nickel electrode for a Ni/H2 cell, the cycle life of nickel electrodes was tested in Ni/H2 boiler plate cells. A 19 test cell matrix was made of various nickel electrode designs including three levels each of plaque mechanical strength, median pore size of the plaque, and active material loading. Test cells were cycled to the end of their life (0.5v) in a 45 minute low Earth orbit cycle regime at 80% depth-of-discharge. It is shown that the active material loading level affects the cycle life the most with the optimum loading at 1.6 g/cc void. Mechanical strength does not affect the cycle life noticeably in the bend strength range of 400 to 700 psi. It is found that the best plaque is made of INCO nickel powder type 287 and has median pore size of 13 micron.

Synthesis, spectroscopic analysis and electrochemical performance of modified β-nickel hydroxide electrode with CuO

Directory of Open Access Journals (Sweden)

B. Shruthi

2017-03-01

Full Text Available In the present work, a modified β-nickel hydroxide (β-Ni(OH2 electrode material with CuO has been prepared using a co-precipitation method. The structure and property of the modified β-Ni(OH2 with CuO were characterized by X-ray diffraction (XRD, Fourier Transform infra-red (FT-IR, Raman and thermal gravimetric-differential thermal analysis (TG-DTA techniques. The results of the FT-IR spectroscopy and TG-DTA indicate that the modified β-Ni(OH2 electrode materials contain intercalated water molecules and anions. A pasted–type electrode was prepared using nickel hydroxide powder as the main active material on a nickel sheet as a current collector. Cyclic voltammetry (CV and Electrochemical impedance spectroscopy (EIS studies were undertaken to assess the electrochemical behavior of pure β-Ni(OH2 and modified β-Ni(OH2 electrode with CuO in a 6 M KOH electrolyte. The addition of CuO into β-nickel hydroxide was found to enhance the reversibility of the electrode reaction and also increase the separation of the oxidation current peak of the active material from the oxygen evolution current. The modified nickel hydroxide with CuO was also found to exhibit a higher proton diffusion coefficient and a lower charge transfer resistance. These findings suggest that the modified β-Ni(OH2 with CuO possesses an enhanced electrochemical response and thus can be recognized as a promising candidate for battery electrode applications.

Ex-situ tracking solid oxide cell electrode microstructural evolution in a redox cycle by high resolution ptychographic nanotomography

DEFF Research Database (Denmark)

De Angelis, Salvatore; Jørgensen, Peter Stanley; Esposito, Vincenzo

2017-01-01

, the nickel and pore networks undergo major reorganization and the formation of internal voids is observed in the nickel-oxide particles after the oxidation. These observations are discussed in terms of reaction kinetics, electrode mechanical stress and the consequences of redox cycling on electrode...... towards this aim by visualizing a complete redox cycle in a solid oxide cell (SOC) electrode. The experiment demonstrates synchrotron-based ptychography as a method of imaging SOC electrodes, providing an unprecedented combination of 3D image quality and spatial resolution among non-destructive imaging...

Long Life Nickel Electrodes for Nickel-Hydrogen Cells: Fiber Substrates Nickel Electrodes

Science.gov (United States)

Rogers, Howard H.

2000-01-01

Samples of nickel fiber mat electrodes were investigated over a wide range of fiber diameters, electrode thickness, porosity and active material loading levels. Thickness' were 0.040, 0.060 and 0.080 inches for the plaque: fiber diameters were primarily 2, 4, and 8 micron and porosity was 85, 90, and 95%. Capacities of 3.5 in. diameter electrodes were determined in the flooded condition with both 26 and 31% potassium hydroxide solution. These capacity tests indicated that the highest capacities per unit weight were obtained at the 90% porosity level with a 4 micron diameter fiber plaque. It appeared that the thinner electrodes had somewhat better performance, consistent with sintered electrode history. Limited testing with two-positive-electrode boiler plate cells was also carried out. Considerable difficulty with constructing the cells was encountered with short circuits the major problem. Nevertheless, four cells were tested. The cell with 95% porosity electrodes failed during conditioning cycling due to high voltage during charge. Discharge showed that this cell had lost nearly all of its capacity. The other three cells after 20 conditioning cycles showed capacities consistent with the flooded capacities of the electrodes. Positive electrodes made from fiber substrates may well show a weight advantage of standard sintered electrodes, but need considerably more work to prove this statement. A major problem to be investigated is the lower strength of the substrate compared to standard sintered electrodes. Problems with welding of leads were significant and implications that the electrodes would expand more than sintered electrodes need to be investigated. Loading levels were lower than had been expected based on sintered electrode experiences and the lower loading led to lower capacity values. However, lower loading causes less expansion and contraction during cycling so that stress on the substrate is reduced.

Nickel and cobalt bimetallic hydroxide catalysts for urea electro-oxidation

International Nuclear Information System (INIS)

Yan Wei; Wang Dan; Botte, Gerardine G.

2012-01-01

Nickel–Cobalt bimetallic hydroxide electrocatalysts, synthesized through a one-step electrodeposition method, were evaluated for the oxidation of urea in alkaline conditions with the intention of reducing the oxidation overpotential for this reaction. The Nickel–Cobalt bimetallic hydroxide catalysts were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), Raman spectroscopy, cyclic voltammetry (CV), and polarization techniques. A significant reduction in the overpotential (150 mV) of the reaction was observed with the Nickel–Cobalt bimetallic hydroxide electrode (ca. 43% Co content) when compared to a nickel hydroxide electrode. The decrease of the urea oxidation potential on the Nickel–Cobalt bimetallic hydroxide electrodes reveals great potential for future applications of urea electro-oxidation, including wastewater remediation, hydrogen production, sensors, and fuel cells.

A Highly Sensitive Electrochemical Glucose Sensor By Nickel-Epoxy Electrode With Non-Enzymatic Sensor

Directory of Open Access Journals (Sweden)

Riyanto Riyanto

2016-03-01

Full Text Available The preparation of new sensor for glucose was based on the fact that glucose can be determined by non-enzymatic glucose oxidase. The Ni metals (99.98% purity, 0.5 mm thick, Aldrich Chemical Company was used to prepare Ni-Epoxy electrode. The Ni-epoxy electrodes were prepared in square cut of 1 cm and 1 mm by length and wide respectively. The Ni metal electrodes were connected to silver wire with silver conducting paint prior covered with epoxy gum. The prepared of nickel-epoxy modified electrode showed outstanding electro catalytic activity toward the oxidation of glucose in alkaline solution. The result from this research are correlation of determination using Nickel-Epoxyelectrode for electroanalysis of glucose in NaOH was R2 = 0.9984. LOQ, LOD and recovery of the Nickel-Epoxy electrode towards glucose were found to be 4.4 μM, 1.48 μM and 98.19%, respectively. The Nickel-Epoxy wire based electrochemical glucose sensor demonstrates good sensitivity, wide linear range, outstanding detection limit, attractive selectivity, good reproducibility, high stability as well as prominent feasibility use of non-enzymatic sensor for monitoring glucose in human urine owing to its advantages of low cost, simple preparation and excellent properties for glucose detection.

Low temperature formation of electrode having electrically conductive metal oxide surface

Science.gov (United States)

Anders, Simone; Anders, Andre; Brown, Ian G.; McLarnon, Frank R.; Kong, Fanping

1998-01-01

A low temperature process is disclosed for forming metal suboxides on substrates by cathodic arc deposition by either controlling the pressure of the oxygen present in the deposition chamber, or by controlling the density of the metal flux, or by a combination of such adjustments, to thereby control the ratio of oxide to metal in the deposited metal suboxide coating. The density of the metal flux may, in turn, be adjusted by controlling the discharge current of the arc, by adjusting the pulse length (duration of on cycle) of the arc, and by adjusting the frequency of the arc, or any combination of these parameters. In a preferred embodiment, a low temperature process is disclosed for forming an electrically conductive metal suboxide, such as, for example, an electrically conductive suboxide of titanium, on an electrode surface, such as the surface of a nickel oxide electrode, by such cathodic arc deposition and control of the deposition parameters. In the preferred embodiment, the process results in a titanium suboxide-coated nickel oxide electrode exhibiting reduced parasitic evolution of oxygen during charging of a cell made using such an electrode as the positive electrode, as well as exhibiting high oxygen overpotential, resulting in suppression of oxygen evolution at the electrode at full charge of the cell.

Hydrothermal synthesis of nickel oxide nanosheets for lithium-ion batteries and supercapacitors with excellent performance.

Science.gov (United States)

Mondal, Anjon Kumar; Su, Dawei; Wang, Ying; Chen, Shuangqiang; Wang, Guoxiu

2013-11-01

Nickel oxide nanosheets have been successfully synthesized by a facile ethylene glycol mediated hydrothermal method. The morphology and crystal structure of the nickel oxide nanosheets were characterized by X-ray diffraction, field-emission SEM, and TEM. When applied as electrode materials for lithium-ion batteries and supercapacitors, nickel oxide nanosheets exhibited a high, reversible lithium storage capacity of 1193 mA h g(-1) at a current density of 500 mA g(-1), an enhanced rate capability, and good cycling stability. Nickel oxide nanosheets also demonstrated a superior specific capacitance of 999 F g(-1) at a current density of 20 A g(-1) in supercapacitors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-templated Synthesis of Nickel Silicate Hydroxide/Reduced Graphene Oxide Composite Hollow Microspheres as Highly Stable Supercapacitor Electrode Material.

Science.gov (United States)

Zhang, Yanhua; Zhou, Wenjie; Yu, Hong; Feng, Tong; Pu, Yong; Liu, Hongdong; Xiao, Wei; Tian, Liangliang

2017-12-01

Nickel silicate hydroxide/reduced graphene oxide (Ni 3 Si 2 O 5 (OH) 4 /RGO) composite hollow microspheres were one-pot hydrothermally synthesized by employing graphene oxide (GO)-wrapped SiO 2 microspheres as the template and silicon source, which were prepared through sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO 2 substrate microspheres. The composition, morphology, structure, and phase of Ni 3 Si 2 O 5 (OH) 4 /RGO microspheres as well as their electrochemical properties were carefully studied. It was found that Ni 3 Si 2 O 5 (OH) 4 /RGO microspheres featured distinct hierarchical porous morphology with hollow architecture and a large specific surface area as high as 67.6 m 2  g -1 . When utilized as a supercapacitor electrode material, Ni 3 Si 2 O 5 (OH) 4 /RGO hollow microspheres released a maximum specific capacitance of 178.9 F g -1 at the current density of 1 A g -1 , which was much higher than that of the contrastive bare Ni 3 Si 2 O 5 (OH) 4 hollow microspheres and bare RGO material developed in this work, displaying enhanced supercapacitive behavior. Impressively, the Ni 3 Si 2 O 5 (OH) 4 /RGO microsphere electrode exhibited outstanding rate capability and long-term cycling stability and durability with 97.6% retention of the initial capacitance after continuous charging/discharging for up to 5000 cycles at the current density of 6 A g -1 , which is superior or comparable to that of most of other reported nickel-based electrode materials, hence showing promising application potential in the energy storage area.

Three dimensional characterization of nickel coarsening in solid oxide cells via ex-situ ptychographic nano-tomography

Science.gov (United States)

De Angelis, Salvatore; Jørgensen, Peter Stanley; Tsai, Esther Hsiao Rho; Holler, Mirko; Kreka, Kosova; Bowen, Jacob R.

2018-04-01

Nickel coarsening is considered a significant cause of solid oxide cell (SOC) performance degradation. Therefore, understanding the morphological changes in the nickel-yttria stabilized zirconia (Ni-YSZ) fuel electrode is crucial for the wide spread usage of SOC technology. This paper reports a study of the initial 3D microstructure evolution of a SOC analyzed in the pristine state and after 3 and 8 h of annealing at 850 °C, in dry hydrogen. The analysis of the evolution of the same location of the electrode shows a substantial change of the nickel and pore network during the first 3 h of treatment, while only negligible changes are observed after 8 h. The nickel coarsening results in loss of connectivity in the nickel network, reduced nickel specific surface area and decreased total triple phase boundary density. For the condition of this experiment, nickel coarsening is shown to be predominantly curvature driven, and changes in the electrode microstructure parameters are discussed in terms of local microstructural evolution.

Nickel Oxide and Nickel Co-doped Graphitic Carbon Nitride Nanocomposites and its Octylphenol Sensing Application

KAUST Repository

Gong, Wanyun; Zou, Jing; Zhang, Sheng; Zhou, Xin; Jiang, Jizhou

2015-01-01

Nickel oxide and nickel co-doped graphitic carbon nitride (NiO-Ni-GCN) nanocomposites were successfully prepared by thermal treatment of melamine and NiCl2 6H2O. NiO-Ni-GCN nanocomposites showed superior electrochemical catalytic activity for the oxidation of octylphenol to pure GCN. A detection method of octylphenol in environmental water samples was developed based at NiO-Ni-GCN nanocomposites modified electrode under infrared light irradiation. Differential pulse voltammetry was used as the analytic technique of octylphenol, exhibiting stable and specific concentration-dependent oxidation signal in the presence of octylphenol in the range of 10nM to 1μM and 1μM to 50μM, with a detection limit of 3.3nM (3S/N). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nickel Oxide and Nickel Co-doped Graphitic Carbon Nitride Nanocomposites and its Octylphenol Sensing Application

KAUST Repository

Gong, Wanyun

2015-11-16

Nickel oxide and nickel co-doped graphitic carbon nitride (NiO-Ni-GCN) nanocomposites were successfully prepared by thermal treatment of melamine and NiCl2 6H2O. NiO-Ni-GCN nanocomposites showed superior electrochemical catalytic activity for the oxidation of octylphenol to pure GCN. A detection method of octylphenol in environmental water samples was developed based at NiO-Ni-GCN nanocomposites modified electrode under infrared light irradiation. Differential pulse voltammetry was used as the analytic technique of octylphenol, exhibiting stable and specific concentration-dependent oxidation signal in the presence of octylphenol in the range of 10nM to 1μM and 1μM to 50μM, with a detection limit of 3.3nM (3S/N). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

International Nuclear Information System (INIS)

Anon.

1983-01-01

This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes normally are used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium-nickel steels in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

International Nuclear Information System (INIS)

Anon.

1981-01-01

This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0% and nickel does not exceed 50.0%

Synthesis of bacteria promoted reduced graphene oxide-nickel sulfide networks for advanced supercapacitors.

Science.gov (United States)

Zhang, Haiming; Yu, Xinzhi; Guo, Di; Qu, Baihua; Zhang, Ming; Li, Qiuhong; Wang, Taihong

2013-08-14

Supercapacitors with potential high power are useful and have attracted much attention recently. Graphene-based composites have been demonstrated to be promising electrode materials for supercapacitors with enhanced properties. To improve the performance of graphene-based composites further and realize their synthesis with large scale, we report a green approach to synthesize bacteria-reduced graphene oxide-nickel sulfide (BGNS) networks. By using Bacillus subtilis as spacers, we deposited reduced graphene oxide/Ni3S2 nanoparticle composites with submillimeter pores directly onto substrate by a binder-free electrostatic spray approach to form BGNS networks. Their electrochemical capacitor performance was evaluated. Compared with stacked reduced graphene oxide-nickel sulfide (GNS) prepared without the aid of bacteria, BGNS with unique nm-μm structure exhibited a higher specific capacitance of about 1424 F g(-1) at a current density of 0.75 A g(-1). About 67.5% of the capacitance was retained as the current density increased from 0.75 to 15 A g(-1). At a current density of 75 A g(-1), a specific capacitance of 406 F g(-1) could still remain. The results indicate that the reduced graphene oxide-nickel sulfide network promoted by bacteria is a promising electrode material for supercapacitors.

High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode.

Science.gov (United States)

Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao-Xia; Li, Yat

2013-09-07

Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm(-2) (specific capacitance of 50 F g(-1)) at a charge/discharge current density of 1 mA cm(-2) and a maximum energy density of 39.9 W h kg(-1) (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm(-2), with a capacitance retention of 95% after 3000 cycles.

High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode

Science.gov (United States)

Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao-Xia; Li, Yat

2013-08-01

Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm-2 (specific capacitance of 50 F g-1) at a charge/discharge current density of 1 mA cm-2 and a maximum energy density of 39.9 W h kg-1 (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm-2, with a capacitance retention of 95% after 3000 cycles.

Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

International Nuclear Information System (INIS)

Anon.

1981-01-01

This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

Three dimensional characterization of nickel coarsening in solid oxide cells via ex-situ ptychographic nano-tomography

DEFF Research Database (Denmark)

De Angelis, Salvatore; Jørgensen, Peter Stanley; Tsai, Esther Hsiao Rho

2018-01-01

Nickel coarsening is considered a significant cause of solid oxide cell (SOC) performance degradation. Therefore, understanding the morphological changes in the nickel-yttria stabilized zirconia (Ni-YSZ) fuel electrode is crucial for the wide spread usage of SOC technology. This paper reports...... a study of the initial 3D microstructure evolution of a SOC analyzed in the pristine state and after 3 and 8 h of annealing at 850 °C, in dry hydrogen. The analysis of the evolution of the same location of the electrode shows a substantial change of the nickel and pore network during the first 3 h...... of treatment, while only negligible changes are observed after 8 h. The nickel coarsening results in loss of connectivity in the nickel network, reduced nickel specific surface area and decreased total triple phase boundary density. For the condition of this experiment, nickel coarsening is shown...

Fabrication of Nickel/nanodiamond/boron-doped diamond electrode for non-enzymatic glucose biosensor

International Nuclear Information System (INIS)

Dai, Wei; Li, Mingji; Gao, Sumei; Li, Hongji; Li, Cuiping; Xu, Sheng; Wu, Xiaoguo; Yang, Baohe

2016-01-01

Highlights: • Nanodiamonds (NDs) were electrophoretically deposited on the BDD film. • The NDs significantly extended the potential window. • Ni/NDs/BDD electrode was prepared by electrodeposition. • The electrode shows good catalytic activity for glucose oxidation. - Abstract: A stable and sensitive non-enzymatic glucose sensor was prepared by modifying a boron-doped diamond (BDD) electrode with nickel (Ni) nanosheets and nanodiamonds (NDs). The NDs were electrophoretically deposited on the BDD surface, and acted as nucleation sites for the subsequent electrodeposition of Ni. The morphology and composition of the modified BDD electrodes were characterized by field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The Ni nanosheet-ND modified BDD electrode exhibited good current response towards the non-enzymatic oxidation of glucose in alkaline media. The NDs significantly extended the potential window. The response to glucose was linear over the 0.2–1055.4-μM range. The limit of detection was 0.05 μM, at a signal-to-noise ratio of 3. The Ni nanosheet-ND/BDD electrode exhibited good selectivity, reproducibility and stability. Its electrochemical performance, low cost and simple preparation make it a promising non-enzymatic glucose sensor.

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

International Nuclear Information System (INIS)

Jinlong, Lv; Tongxiang, Liang; Chen, Wang

2016-01-01

Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H_2SO_4 solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H_2SO_4 solution at room temperature. A large number of gaps between ‘cauliflower’ like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

Energy Technology Data Exchange (ETDEWEB)

Jinlong, Lv, E-mail: ljlbuaa@126.com [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Tongxiang, Liang; Chen, Wang [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China)

2016-03-15

Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H{sub 2}SO{sub 4} solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H{sub 2}SO{sub 4} solution at room temperature. A large number of gaps between ‘cauliflower’ like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

Science.gov (United States)

Ovshinsky, Stanford R.; Corrigan, Dennis; Venkatesan, Srini; Young, Rosa; Fierro, Christian; Fetcenko, Michael A.

1994-01-01

A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

Nickel Inhibits Mitochondrial Fatty Acid Oxidation

Science.gov (United States)

Uppala, Radha; McKinney, Richard W.; Brant, Kelly A.; Fabisiak, James P.; Goetzman, Eric S.

2015-01-01

Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation—the pathway by which fatty acids are catabolized for energy—in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with L-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 hr), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis. PMID:26051273

Oxidation of methanol on perovskite-type La{sub 2-x}Sr{sub x}NiO{sub 4} (0 {<=} x {<=} 1) film electrodes modified by dispersed nickel in 1 M KOH

Energy Technology Data Exchange (ETDEWEB)

Singh, R.N.; Singh, A.; Mishra, D.; Anindita [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005 (India); Chartier, P. [Laboratoire d' Electrochimie et Chimie Physique du Corps Solide, Institut de Chimie LC3-UMR7177 CNRS/ULP, Universite Louis Pasteur, 67000, Strasbourg (France)

2008-12-01

Finely-dispersed nickel particles are electrodeposited on high surface-area perovskite-type La{sub 2-x}Sr{sub x}NiO{sub 4} (0 {<=} x {<=} 1) electrodes for possible use in a direct methanol fuel cell (DMFC). The study is conducted by cyclic voltammetry, chronoamperometry, impedance spectroscopy and anodic Tafel polarization techniques. The results show that the apparent electrocatalytic activities of the modified oxide electrodes are much higher than those of unmodified electrodes under similar experimental conditions; the observed activity is the greatest with the modified La{sub 1.5}Sr{sub 0.5}NiO{sub 4} electrode. At 0.550 V (vs. Hg vertical stroke HgO) in 1 M KOH + 1 M CH{sub 3}OH at 25 C, the latter electrode delivers a current density of over 200 mA cm{sup -2}, whereas other electrodes of the series produce relatively low values (65-117 mA cm{sup -2}). To our knowledge, such high methanol oxidation current densities have not been reported on any other non-platinum electrode in alkaline solution. Further, the modified electrodes are not poisoned by methanol oxidation intermediates/products. (author)

Carbon and Redox Tolerant Infiltrated Oxide Fuel-Electrodes for Solid Oxide Cells

DEFF Research Database (Denmark)

Skafte, Theis Løye; Sudireddy, Bhaskar Reddy; Blennow, P.

2016-01-01

To solve issues of coking and redox instability related to the presence of nickel in typical fuel electrodes in solid oxide cells,Gd-doped CeO2 (CGO) electrodes were studied using symmetriccells. These electrodes showed high electro-catalytic activity, butlow electronic conductivity. When...... infiltrated with Sr0.99Fe0.75Mo0.25O3-δ (SFM), the electronic conductivity wasenhanced. However, polarization resistance of the cells increased,suggesting that the infiltrated material is less electro-catalyticallyactive and was partly blocking the CGO surface reaction sites. Theactivity could be regained...... by infiltrating nano-sized CGO orNiCGO on top of SFM, while still sustaining the high electronicconductivity. Ohmic resistance of the electrodes was thuspractically eliminated and performance comparable to, or betterthan, state-of-the-art fuel electrodes was achieved. The Nicontaining cells were damaged by carbon...

Nickel-based anodic electrocatalysts for fuel cells and water splitting

Science.gov (United States)

Chen, Dayi

Our world is facing an energy crisis, so people are trying to harvest and utilize energy more efficiently. One of the promising ways to harvest energy is via solar water splitting to convert solar energy to chemical energy stored in hydrogen. Another of the options to utilize energy more efficiently is to use fuel cells as power sources instead of combustion engines. Catalysts are needed to reduce the energy barriers of the reactions happening at the electrode surfaces of the water-splitting cells and fuel cells. Nickel-based catalysts happen to be important nonprecious electrocatalysts for both of the anodic reactions in alkaline media. In alcohol fuel cells, nickel-based catalysts catalyze alcohol oxidation. In water splitting cells, they catalyze water oxidation, i.e., oxygen evolution. The two reactions occur in a similar potential range when catalyzed by nickel-based catalysts. Higher output current density, lower oxidation potential, and complete substrate oxidation are preferred for the anode in the applications. In this dissertation, the catalytic properties of nickel-based electrocatalysts in alkaline medium for fuel oxidation and oxygen evolution are explored. By changing the nickel precursor solubility, nickel complex nanoparticles with tunable sizes on electrode surfaces were synthesized. Higher methanol oxidation current density is achieved with smaller nickel complex nanoparticles. DNA aggregates were used as a polymer scaffold to load nickel ion centers and thus can oxidize methanol completely at a potential about 0.1 V lower than simple nickel electrodes, and the methanol oxidation pathway is changed. Nickel-based catalysts also have electrocatalytic activity towards a wide range of substrates. Experiments show that methanol, ethanol, glycerol and glucose can be deeply oxidized and carbon-carbon bonds can be broken during the oxidation. However, when comparing methanol oxidation reaction to oxygen evolution reaction catalyzed by current nickel

Nickel Nanowire@Porous NiCo2O4 Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

Directory of Open Access Journals (Sweden)

Houzhao Wan

2017-12-01

Full Text Available A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo2O4 nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo2O4 nanorods and construct the well-defined NiCo2O4 nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo2O4/Ni foam electrode shows a high areal specific capacitance (7.4 F cm−2 at 5 mA cm−2, excellent rate capability (88.04% retained at 100 mA cm−2, and good cycling stability (74.08% retained after 1,500 cycles. The superior electrochemical properties made it promising as electrode for supercapacitors.

Potassium Sodium Niobate-Based Lead-Free Piezoelectric Multilayer Ceramics Co-Fired with Nickel Electrodes

Directory of Open Access Journals (Sweden)

Shinichiro Kawada

2015-11-01

Full Text Available Although lead-free piezoelectric ceramics have been extensively studied, many problems must still be overcome before they are suitable for practical use. One of the main problems is fabricating a multilayer structure, and one solution attracting growing interest is the use of lead-free multilayer piezoelectric ceramics. The paper reviews work that has been done by the authors on lead-free alkali niobate-based multilayer piezoelectric ceramics co-fired with nickel inner electrodes. Nickel inner electrodes have many advantages, such as high electromigration resistance, high interfacial strength with ceramics, and greater cost effectiveness than silver palladium inner electrodes. However, widely used lead zirconate titanate-based ceramics cannot be co-fired with nickel inner electrodes, and silver palladium inner electrodes are usually used for lead zirconate titanate-based piezoelectric ceramics. A possible alternative is lead-free ceramics co-fired with nickel inner electrodes. We have thus been developing lead-free alkali niobate-based multilayer ceramics co-fired with nickel inner electrodes. The normalized electric-field-induced thickness strain (Smax/Emax of a representative alkali niobate-based multilayer ceramic structure with nickel inner electrodes was 360 pm/V, where Smax denotes the maximum strain and Emax denotes the maximum electric field. This value is about half that for the lead zirconate titanate-based ceramics that are widely used. However, a comparable value can be obtained by stacking more ceramic layers with smaller thicknesses. In the paper, the compositional design and process used to co-fire lead-free ceramics with nickel inner electrodes are introduced, and their piezoelectric properties and reliabilities are shown. Recent advances are introduced, and future development is discussed.

Exploring Lithium-Cobalt-Nickel Oxide Spinel Electrodes for ≥3.5 V Li-Ion Cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Eungje; Blauwkamp, Joel; Castro, Fernando C.; Wu, Jinsong; Dravid, Vinayak P.; Yan, Pengfei; Wang, Chongmin; Kim, Soo; Wolverton, Christopher; Benedek, Roy; Dogan, Fulya; Park, Joong Sun; Croy, Jason R.; Thackeray, Michael M.

2016-10-19

Recent reports have indicated that a manganese oxide spinel component, when embedded in a relatively small concentration in layered xLi2MnO3(1-x)LiMO2 (M=Ni, Mn, Co) electrode systems, can act as a stabilizer that increases their capacity, rate capability, cycle life, and first-cycle efficiency. These findings prompted us to explore the possibility of exploiting lithiated cobalt oxide spinel stabilizers by taking advantage of (1) the low mobility of cobalt ions relative to manganese and nickel ions in close-packed oxides and (2) their higher potential (~3.6 V vs. Li0) relative to manganese oxide spinels (~2.9 V vs. Li0) for the spinel-to-lithiated spinel electrochemical reaction. In particular, we have revisited the structural and electrochemical properties of lithiated spinels in the LiCo1-xNixO2 (0x0.2) system, first reported almost 25 years ago, by means of high-resolution (synchrotron) X-ray diffraction, transmission electron microscopy, nuclear magnetic resonance spectroscopy, electrochemical cell tests, and theoretical calculations. The results provide a deeper understanding of the complexity of intergrown layered/lithiated spinel LiCo1-xNixO2 structures, when prepared in air between 400 and 800 C, and the impact of structural variations on their electrochemical behavior. These structures, when used in low concentration, offer the possibility of improving the cycling stability, energy, and power of high energy (≥3.5 V) lithium-ion cells.

Recovery Of Electrodic Powder From Spent Nickel-Metal Hydride Batteries (NiMH

Directory of Open Access Journals (Sweden)

Shin S.M.

2015-06-01

Full Text Available This study was focused on recycling process newly proposed to recover electrodic powder enriched in nickel (Ni and rare earth elements (La and Ce from spent nickel-metal hydride batteries (NiMH. In addition, this new process was designed to prevent explosion of batteries during thermal treatment under inert atmosphere. Spent nickel metal hydride batteries were heated over range of 300°C to 600°C for 2 hours and each component was completely separated inside reactor after experiment. Electrodic powder was successfully recovered from bulk components containing several pieces of metals through sieving operation. The electrodic powder obtained was examined by X-ray diffraction (XRD and energy dispersive X-ray spectroscopy (EDX and image of the powder was taken by scanning electron microscopy (SEM. It was finally found that nickel and rare earth elements were mainly recovered to about 45 wt.% and 12 wt.% in electrodic powder, respectively.

High power nickel - cadmium cells with fiber electrodes (FNC)

International Nuclear Information System (INIS)

Haschka, F.; Schlieck, D.

1986-01-01

Nickel cadmium batteries differ greatly in their mechanical design and construction of the electrodes. Using available electrode constructions, batteries are designed which meet the requirements of specific applications and offer optimum performance. Pocket- and tubular cells are basically developed with the technology of the year 1895. Since then some improvements with todays technology have been made. The sintered cells use the technology of the 1930's and they are still limited to high power application. With this knowledge and the technology of today the fiber-structured nickel electrode (FNC) was developed at DAUG laboratory, a subsidiary company of Mercedes-Benz and Volkswagen. After ten years of experience in light weight prototype batteries for electric vehicles (1-2), the system was brought into production by a new company, DAUG-HOPPECKE. Characteristics of fiber electrodes: thickness and size can be easily changed; pure active materials are used; high conductor density; high elasticity of the structure; high porosity. Since 1983 NiCd-batteries with fiber-structured nickel electrodes (FNC) have been in production. Starting with the highly demanded cell-types for low, medium and high performance called L, M and H according to IEC 623 for low, medium and high performance applications, the program was recently completed with the X-type cell for very high power, as an alternative to sintered cells

Combination of Asymmetric Supercapacitor Utilizing Activated Carbon and Nickel Oxide with Cobalt Polypyridyl-Based Dye-Sensitized Solar Cell

International Nuclear Information System (INIS)

Bagheri, Narjes; Aghaei, Alireza; Ghotbi, Mohammad Yeganeh; Marzbanrad, Ehsan; Vlachopoulos, Nick; Häggman, Leif; Wang, Michael; Boschloo, Gerrit; Hagfeldt, Anders; Skunik-Nuckowska, Magdalena; Kulesza, Pawel J.

2014-01-01

Highlights: • Dye Solar Cell and supercapacitor are integrated into a single device capable of generation and storage of energy. • The solar cell part of the device utilizes the Co-based electrolyte and nickel/PEDOT counter electrode. • A cobalt-doped nickel oxide together with activated carbon is used in the capacitor part of the device. • The integrated photocapacitor is characterized by the capacitance of 32 F g −1 and the total efficiency of 0.6%. - Abstract: A dye-sensitized solar cell (DSC) based on the metal-free organic sensitizer and the cobalt (II, III) polypyridyl electrolyte was integrated here within an asymmetric supercapacitor utilizing cobalt-doped nickel oxide and activated carbon as positive and negative electrodes, respectively. A low cost nickel foil served as intermediate (auxiliary) bifunctional electrode separating two parts of the device and permitting the DSC electrolyte regeneration at one side and charge storage within cobalt-doped nickel oxide at the other. The main purpose of the research was to develop an integrated photocapacitor system capable of both energy generation and its further storage. Following irradiation at the 100 mW cm −2 level, the solar cell generated an open-circuit voltage of 0.8 V and short-circuit current of 8 mA cm −2 which corresponds to energy conversion efficiency of 4.9%. It was further shown that upon integration with asymmetric supercapacitor, the photogenerated energy was directly injected into porous charge storage electrodes thus resulting in specific capacitance of 32 F g −1 and energy density of 2.3 Wh kg −1 . The coulumbic and total (energy conversion and charge storage) efficiency of photocapacitor were equal to 54% and 0.6%, respectively

Metal Oxide/Graphene Composites for Supercapacitive Electrode Materials.

Science.gov (United States)

Jeong, Gyoung Hwa; Baek, Seungmin; Lee, Seungyeol; Kim, Sang-Wook

2016-04-05

Graphene composites with metal or metal oxide nanoparticles have been extensively investigated owing to their potential applications in the fields of fuel cells, batteries, sensing, solar cells, and catalysis. Among them, much research has focused on supercapacitor applications and have come close to realization. Composites include monometal oxides of cobalt, nickel, manganese, and iron, as well as their binary and ternary oxides. In addition, their morphological control and hybrid systems of carbon nanotubes have also been investigated. This review presents the current trends in research on metal oxide/graphene composites for supercapacitors. Furthermore, methods are suggested to improve the properties of electrochemical capacitor electrodes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon-encapsulated nickel-iron nanoparticles supported on nickel foam as a catalyst electrode for urea electrolysis

International Nuclear Information System (INIS)

Wu, Mao-Sung; Jao, Chi-Yu; Chuang, Farn-Yih; Chen, Fang-Yi

2017-01-01

Highlights: • Electrochemical process can purify the urea-rich wastewater, producing hydrogen gas. • Carbon-encapsulated nickel iron nanoparticles (CE-NiFe) are prepared by pyrolysis. • An ultra-thin layer of CE-NiFe nanoparticles is attached to the 3D Ni foam. • CE-NiFe nanoparticles escalate both the urea electrolysis and hydrogen evolution. - Abstract: A cyanide-bridged bimetallic coordination polymer, nickel hexacyanoferrate, could be pyrolyzed to form carbon-encapsulated nickel-iron (CE-NiFe) nanoparticles. The formation of nitrogen-doped spherical carbon shell with ordered mesoporous structure prevented the structural damage of catalyst cores and allowed the migration and diffusion of electrolyte into the hollow carbon spheres. An ultra-thin layer of CE-NiFe nanoparticles could be tightly attached to the three-dimensional macroporous nickel foam (NF) by electrophoretic deposition. The CE-NiFe nanoparticles could lower the onset potential and increase the current density in anodic urea electrolysis and cathodic hydrogen production as compared with bare NF. Macroporous NF substrate was very useful for the urea electrolysis and hydrogen production, which allowed for fast transport of electron, electrolyte, and gas products. The superior electrocatalytic ability of CE-NiFe/NF electrode in urea oxidation and water reduction made it favorable for versatile applications such as water treatment, hydrogen generation, and fuel cells.

Nickel exposure and plasma levels of biomarkers for assessing oxidative stress in nickel electroplating workers.

Science.gov (United States)

Tsao, Yu-Chung; Gu, Po-Wen; Liu, Su-Hsun; Tzeng, I-Shiang; Chen, Jau-Yuan; Luo, Jiin-Chyuan John

2017-07-01

The mechanism of nickel-induced pathogenesis remains elusive. To examine effects of nickel exposure on plasma oxidative and anti-oxidative biomarkers. Biomarker data were collected from 154 workers with various levels of nickel exposure and from 73 controls. Correlations between nickel exposure and oxidative and anti-oxidative biomarkers were determined using linear regression models. Workers with a exposure to high nickel levels had significantly lower levels of anti-oxidants (glutathione and catalase) than those with a lower exposure to nickel; however, only glutathione showed an independent association after multivariable adjustment. Exposure to high levels of nickel may reduce serum anti-oxidative capacity.

Controlled electroplating and electromigration in nickel electrodes for nanogap formation

Energy Technology Data Exchange (ETDEWEB)

De Los Santos Valladares, Luis; Mitrelias, Thanos; Sfigakis, Francois; Barnes, Crispin H W [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Leon Felix, Lizbet; Bustamante Dominguez, Angel [Laboratorio de Ceramicos y Nanomateriales, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Khondaker, Saiful I [NanoScience Technology Center and Department of Physics, University of Central Florida, Orlando, FL 32826 (United States); Majima, Yutaka, E-mail: ld301@cam.ac.uk, E-mail: luisitodv@yahoo.es [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

2010-11-05

We report the fabrication of nickel nanospaced electrodes by electroplating and electromigration for nanoelectronic devices. Using a conventional electrochemical cell, nanogaps can be obtained by controlling the plating time alone and after a careful optimization of electrodeposition parameters such as electrolyte bath, applied potential, cleaning, etc. During the process, the gap width decreases exponentially with time until the electrode gaps are completely bridged. Once the bridge is formed, the ex situ electromigration technique can reopen the nanogap. When the gap is {approx} 1 nm, tunneling current-voltage characterization shows asymmetry which can be corrected by an external magnetic field. This suggests that charge transfer in the nickel electrodes depends on the orientation of magnetic moments.

Controlled electroplating and electromigration in nickel electrodes for nanogap formation

International Nuclear Information System (INIS)

De Los Santos Valladares, Luis; Mitrelias, Thanos; Sfigakis, Francois; Barnes, Crispin H W; Leon Felix, Lizbet; Bustamante Dominguez, Angel; Khondaker, Saiful I; Majima, Yutaka

2010-01-01

We report the fabrication of nickel nanospaced electrodes by electroplating and electromigration for nanoelectronic devices. Using a conventional electrochemical cell, nanogaps can be obtained by controlling the plating time alone and after a careful optimization of electrodeposition parameters such as electrolyte bath, applied potential, cleaning, etc. During the process, the gap width decreases exponentially with time until the electrode gaps are completely bridged. Once the bridge is formed, the ex situ electromigration technique can reopen the nanogap. When the gap is ∼ 1 nm, tunneling current-voltage characterization shows asymmetry which can be corrected by an external magnetic field. This suggests that charge transfer in the nickel electrodes depends on the orientation of magnetic moments.

Effects of cadmium electrode properties on nickel-cadmium cell performance

International Nuclear Information System (INIS)

Zimmerman, A.H.

1986-01-01

Tests have been conducted on a number of nickel-cadmium cells that have exhibited a variety of performance problems, ranging from high voltages and pressures during overcharge to low capacity. The performance problems that have been specifically linked to the cadmium electrode are primarily related to two areas, poor sinter and the buildup of excessive pressure during overcharge. A number of specific nickel-cadmium cell and cadmium electrode characterists have been studied in this work to determine what the effects of poor sinter are, and to determine what factors are important in causing excessive pressures during overcharge in cells that otherwise appear normal. Several of the tests appear suitable for screening cells and electrodes for such problems

In situ fabrication of nickel based oxide on nitrogen-doped graphene for high electrochemical performance supercapacitors

Science.gov (United States)

Pan, Denghui; Zhang, Mingmei; Wang, Ying; Yan, Zaoxue; Jing, Junjie; Xie, Jimin

2017-10-01

In this article, we synthesize Ni(OH)2 homogeneous grown on nitrogen-doped graphene (Ni(OH)2/NG), subsequently, small and uniform nickel oxide nanoparticle (NiO/NG) is also successfully obtained through tube furnace calcination method. The high specific capacitance of the NiO/NG electrode can reach to 1314.1 F/g at a charge and discharge current density of 2 A/g, meanwhile the specific capacitance of Ni(OH)2/NG electrode is also 1350 F/g. The capacitance of NiO/NG can remain 93.7% of the maximum value after 1000 cycles, while the Ni(OH)2/NG electrode losses 16.9% of the initial capacitance after 1000 cycles. It can be attributed to nickel hydroxide instability during charge-discharge cycles.

Cermet electrode

Science.gov (United States)

Maskalick, Nicholas J.

1988-08-30

Disclosed is a cermet electrode consisting of metal particles of nickel, cobalt, iron, or alloys or mixtures thereof immobilized by zirconia stabilized in cubic form which contains discrete deposits of about 0.1 to about 5% by weight of praseodymium, dysprosium, terbium, or a mixture thereof. The solid oxide electrode can be made by covering a substrate with particles of nickel, cobalt, iron, or mixtures thereof, growing a stabilized zirconia solid oxide skeleton around the particles thereby immobilizing them, contacting the skeleton with a compound of praseodymium, dysprosium, terbium, or a mixture thereof, and heating the skeleton to a temperature of at least 500.degree. C. The electrode can also be made by preparing a slurry of nickel, cobalt, iron, or mixture and a compound of praseodymium, dysprosium, terbium, or a mixture thereof, depositing the slurry on a substrate, heating the slurry to dryness, and growing a stabilized zirconia skeleton around the metal particles.

Plastic-bonded electrodes for nickel-cadmium accumulators. IV - Some specific problems of the positive active layer

Science.gov (United States)

Micka, K.; Mrha, J.; Klapste, B.

1980-06-01

The active layer of plastic-bonded nickel oxide electrodes undergoes expansion during discharging and contraction during charging; the latter however does not fully compensate for the expansion. These volume changes can be made reversible by the action of an external pressure. The electro-chemical behavior of the conductive components, carbon black and graphite, shows more or less severe corrosion during anodic current loading.

Nickel Nanowire@Porous NiCo{sub 2}O{sub 4} Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

Energy Technology Data Exchange (ETDEWEB)

Wan, Houzhao; Li, Lang; Zhang, Jun; Liu, Xiang; Wang, Hanbin; Wang, Hao, E-mail: nanoguy@126.com [Faculty of Physics and Electronic Science, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Laboratory of Ferro & Piezoelectric Materials and Devices, Hubei University, Wuhan (China)

2017-12-13

A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo{sub 2}O{sub 4} nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo{sub 2}O{sub 4} nanorods and construct the well-defined NiCo{sub 2}O{sub 4} nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo{sub 2}O{sub 4}/Ni foam electrode shows a high areal specific capacitance (7.4 F cm{sup −2} at 5 mA cm{sup −2}), excellent rate capability (88.04% retained at 100 mA cm{sup −2}), and good cycling stability (74.08% retained after 1,500 cycles). The superior electrochemical properties made it promising as electrode for supercapacitors.

Amperometric detection of hydrogen peroxide at nano-nickel oxide/thionine and celestine blue nanocomposite-modified glassy carbon electrodes

International Nuclear Information System (INIS)

Noorbakhsh, Abdollah; Salimi, Abdollah

2009-01-01

A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with nickel oxide (NiOx) nanoparticles and water-soluble dyes. By immersing the GC/NiOx modified electrode into thionine (TH) or celestine blue (CB) solutions for a short period of time (5-120 s), a thin film of the proposed molecules was immobilized onto the electrode surface. The modified electrodes showed stable and a well-defined redox couples at a wide pH range (2-12), with surface confined characteristics. In comparison to usual methods for the immobilization of dye molecules, such as electropolymerization or adsorption on the surface of preanodized electrodes, the electrochemical reversibility and stability of these modified electrodes have been improved. The surface coverage and heterogeneous electron transfer rate constants (k s ) of thionin and celestin blue immobilized on a NiOx-GC electrode were approximately 3.5 x 10 -10 mol cm -2 , 6.12 s -1 , 5.9 x 10 -10 mol cm -2 and 6.58 s -1 , respectively. The results clearly show the high loading ability of the NiOx nanoparticles and great facilitation of the electron transfer between the immobilized TH, CB and NiOx nanoparticles. The modified electrodes show excellent electrocatalytic activity toward hydrogen peroxide reduction at a reduced overpotential. The catalytic rate constants for hydrogen peroxide reduction at GC/NiOx/CB and GC/NiOx/TH were 7.96 (±0.2) x 10 3 M -1 s -1 and 5.5 (±0.2) x 10 3 M -1 s -1 , respectively. The detection limit, sensitivity and linear concentration range for hydrogen peroxide detection were 1.67 μM, 4.14 nA μM -1 nA μM -1 and 5 μM to 20 mM, and 0.36 μM, 7.62 nA μM -1 , and 1 μM to 10 mM for the GC/NiOx/TH and GC/NiOx/CB modified electrodes, respectively. Compared to other modified electrodes, these modified electrodes have many advantages, such as remarkable catalytic activity, good reproducibility, simple preparation procedures and long-term stabilities of signal responses during

Photoelectrochemical characterization of squaraine-sensitized nickel oxide cathodes deposited via screen-printing for p-type dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Naponiello, Gaia; Venditti, Iole [Department of Chemistry, Sapienza University of Rome P.le A. Moro 5, 00185 Rome (Italy); Zardetto, Valerio [Centre for Hybrid and Organic Solar Energy, Department of Electronic Engineering, University of Rome - Tor Vergata, via del Politecnico 1, 00133 Rome (Italy); Saccone, Davide [Department of Chemistry and NIS, Interdepartmental Centre of Excellence, University of Torino, via Pietro Giuria 7, I-10125 Torino (Italy); Di Carlo, Aldo [Centre for Hybrid and Organic Solar Energy, Department of Electronic Engineering, University of Rome - Tor Vergata, via del Politecnico 1, 00133 Rome (Italy); Fratoddi, Ilaria [Department of Chemistry, Sapienza University of Rome P.le A. Moro 5, 00185 Rome (Italy); Center for Nanotechnology for Engineering (CNIS), Sapienza University of Rome P.le A. Moro 5, 00185 Rome (Italy); Barolo, Claudia [Department of Chemistry and NIS, Interdepartmental Centre of Excellence, University of Torino, via Pietro Giuria 7, I-10125 Torino (Italy); Dini, Danilo, E-mail: danilo.dini@uniroma1.it [Department of Chemistry, Sapienza University of Rome P.le A. Moro 5, 00185 Rome (Italy)

2015-11-30

Graphical abstract: Screen-printing method has been adopted for the deposition of nickel oxide thin film electrodes with mesoporous features. Nickel oxide was sensitized with three newly synthesized squaraines (VG1C8,VG10C8 and DS2/35) and employed as photoelectroactive cathode of p-type dye-sensitized solar cells. Colorant erythrosine b (EB) was taken as commercial benchmark for comparative purposes. Sensitization was successful with the attainment of overall conversion efficiencies in the order of 0.025% when the mesoporous surface of nickel oxide was alkali treated. The prolongation of nickel oxide sensitization time up to 16 h led to a general increase of the open circuit voltage in the corresponding solar cells. - Highlights: • We deposited nickel oxide with screen-printing technique utilizing nickel oxide nanoparticles. • We employed screen-printed nickel oxide as cathodes of p-DSCs. • We employed new squaraine as sensitizers of screen-printed nickel oxide. • Further progress is expected when the formulation of the screen-printing paste will be optimized. - Abstract: In the present paper we report on the employment of the screen-printing method for the deposition of nickel oxide (NiO{sub x}) layers when preformed nanoparticles of the metal oxide (diameter < 50 nm) constitute the precursors in the paste. The applicative purpose of this study is the deposition of mesoporous NiO{sub x} electrodes in the configuration of thin films (thickness, l ≤ 4 μm) for the realization of p-type dye-sensitized solar cells (p-DSCs). Three different squaraine-based dyes (here indicated with VG1C8, VG10C8 and DS2/35), have been used for the first time as sensitizers of a p-type DSC electrode. VG1C8 and VG10C8 present two carboxylic groups as anchoring moieties, whereas DS2/35 sensitizer possesses four acidic anchoring groups. All three squaraines are symmetrical and differ mainly for the extent of electronic conjugation. The colorant erythrosine b (ERY B) was taken as

Microwave-assisted synthesis of metal oxide/hydroxide composite electrodes for high power supercapacitors - A review

Science.gov (United States)

Faraji, Soheila; Ani, Farid Nasir

2014-10-01

Electrochemical capacitors (ECs), also known as pseudocapacitors or supercapacitors (SCs), is receiving great attention for its potential applications in electric and hybrid electric vehicles because of their ability to store energy, alongside with the advantage of delivering the stored energy much more rapidly than batteries, namely power density. To become primary devices for power supply, supercapacitors must be developed further to improve their ability to deliver high energy and power simultaneously. In this concern, a lot of effort is devoted to the investigation of pseudocapacitive transition-metal-based oxides/hydroxides such as ruthenium oxide, manganese oxide, cobalt oxide, nickel oxide, cobalt hydroxide, nickel hydroxide, and mixed metal oxides/hydroxides such as nickel cobaltite and nickel-cobalt oxy-hydroxides. This is mainly due to the fact that they can produce much higher specific capacitances than typical carbon-based electric double-layer capacitors and electronically conducting polymers. This review presents supercapacitor performance data of metal oxide thin film electrodes by microwave-assisted as an inexpensive, quick and versatile technique. Supercapacitors have established the specific capacitance (Cs) principles, therefore, it is likely that metal oxide films will continue to play a major role in supercapacitor technology and are expected to considerably increase the capabilities of these devices in near future.

ELECTROCHEMICAL OXIDATION OF ETHANOL USING Ni-Co-PVC COMPOSITE ELECTRODE

Directory of Open Access Journals (Sweden)

Riyanto Riyanto

2011-07-01

Full Text Available The morphological characteristics and electrochemical behavior of nickel metal foil (Ni, nickel-polyvinyl chloride (Ni-PVC and nickel-cobalt-polyvinyl chloride (Ni-Co-PVC electrodes in alkaline solution has been investigated. The morphological characteristics of the electrode surface were studied using SEM and EDS, while the electrochemical behavior of the electrodes was studied using cyclic voltammetry (CV. It was found that composite electrodes (Ni-PVC and Ni-Co-PVC have a porous, irregular and rough surface. In situ studies using electrochemical technique using those three electrodes exhibited electrochemical activity for redox system, as well as selectivity in the electrooxidation of ethanol to acetic acid. The studies also found that an electrokinetics and electrocatalytic activity behaviors of the electrodes prepared were Ni metal foil

The fabrication of graphene/polydopamine/nickel foam composite material with excellent electrochemical performance as supercapacitor electrode

Science.gov (United States)

Zheng, Yu; Lu, Shixiang; Xu, Wenguo; He, Ge; Cheng, Yuanyuan; Yu, Tianlong; Zhang, Yan

2018-02-01

A three dimensional composite electrode consisted of reduced graphene oxide (rGO), polydopamine (PDA) and nickel foam (NF) (rGO/PDA/NF) was fabricated by immersing NF into PDA aqueous solution and then graphene oxide (GO) suspension solution respectively, and followed by annealing treatment. During the procedure, GO was coated on NF with assistance of cohesive effect of the PDA middle film, and the reduction of GO and nitrogen doping occurred simultaneously while annealing. Through XRD analyzing, the composites GO/PDA and rGO/PDA treated in experiment are amorphous. The resulted rGO/PDA/NF composite electrode was directly applied as a supercapacitor electrode and showed excellent electrochemical performance, with a high specific capacitance of 566.9 F g-1 at 1 A g-1, the maximum energy density of 172.7 W h kg-1 and a power density of 27.2 kW kg-1 in 1 mol L-1 Na2SO4 electrolyte.

Catalytic properties of nickel ferrites for oxidation of glucose, β-nicotiamide adenine dinucleotide (NADH) and methanol

Energy Technology Data Exchange (ETDEWEB)

Galindo, R. [Departamento de Química, Universidad de Guanajuato, Cerro de la Venada s/n, Pueblito de Rocha, C.P. 36040 Guanajuato, Gto (Mexico); Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco s/n, C.P. 28049 Madrid (Spain); Gutiérrez, S. [Departamento de Química, Universidad de Guanajuato, Cerro de la Venada s/n, Pueblito de Rocha, C.P. 36040 Guanajuato, Gto (Mexico); Menéndez, N. [Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco s/n, C.P. 28049 Madrid (Spain); Herrasti, P., E-mail: pilar.herrasti@uam.es [Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco s/n, C.P. 28049 Madrid (Spain)

2014-02-15

Highlights: ► NiFe{sub 2}O{sub 4} nanoparticles obtained by electrochemical method are effective catalyst. ► A partially inverse spinel was obtained with 57% Fe{sup 3+} in tetrahedral position. ► A non-enzymatic electrode using NiFe{sub 2}O{sub 4} nanoparticles has been manufactured. -- Abstract: Nickel ferrite nanoparticles (NiFe{sub 2}O{sub 4}) were synthesized by electrochemical method and used as catalyst for direct oxidation of glucose, NADH and methanol. Characterization of these nanoparticles was carried out by X-ray diffraction, Mössbauer spectroscopy, and colloidal properties such as hydrodynamic radius and Zeta potential. To evaluate the catalytic properties of these nanoparticles against the oxidation process, paste graphite electrodes mixing nickel ferrites and different conductive materials (graphite, carbon nanotubes) and binders agents (mineral oil, 1-octylpyridinium hexafluorophosphate (nOPPF6)) were used. The results prove good catalytic properties of these materials, with an oxidation potential around 0.75, 0.5 and 0.8 V for glucose, NADH, and methanol, respectively.

Preparation and supercapacitor application of the single crystal nickel hydroxide and oxide nanosheets

Energy Technology Data Exchange (ETDEWEB)

Li, Qing [Department of Materials Science and Engineering, Yunnan University, 650091 Kunming (China); Ni, Haifang [Institute of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Cai, Yun; Cai, Xiaoyan [Department of Materials Science and Engineering, Yunnan University, 650091 Kunming (China); Liu, Yongjun [Advanced Analysis and Measurement Center, Yunnan University, 650091 Kunming (China); Chen, Gang [Department of Materials Science and Engineering, Yunnan University, 650091 Kunming (China); Fan, Li-Zhen, E-mail: fanlizhen@ustb.edu.cn [Institute of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Wang, Yude, E-mail: ydwang@ynu.edu.cn [Department of Materials Science and Engineering, Yunnan University, 650091 Kunming (China)

2013-09-01

Graphical abstract: The nickel hydroxide and nickel oxide nanosheets prepared using CTAB at room temperature exhibit a high specific capacitance, prompt charge/discharge rate. - Highlights: • The nickel hydroxide nanosheets were prepared using CTAB at room temperature. • Ni(OH){sub 2} nanosheet can be successfully converted to NiO nanosheet via calcination. • The NiO nanosheet has a specific capacitance of 388 F g{sup −1} at 5 A g{sup −1} in KOH solution. • Anneal temperature impacts capacitive properties as electrode. - Abstract: The single crystalline Ni(OH){sub 2} nanosheets were synthesized by a simple chemical precipitation method using nickel chloride as precursors and ammonia as precipitating agent. The Ni(OH){sub 2} nanosheets were successfully converted to NiO nanosheets via calcination under appropriate conditions. Analytical methods such as X-ray diffraction (XRD) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and Fourier transformed infrared (FTIR) spectra were employed to characterize the morphology and microstructure of the final products. The experimental results revealed that Ni(OH){sub 2} nanosheets were shape-preserved transformed to NiO nanosheets at 250 °C for 24 h. Ni(OH){sub 2} and NiO nanosheets were directly functionalized as supercapacitor electrodes for potential energy storage applications, whose charge–discharge properties, electrochemical impedance spectra, cyclic voltammetry, and cycle performance were examined. The experimental results show that the single-crystalline NiO nanosheets are a promising candidate for the supercapacitor electrode. They exhibit a high specific capacitance, prompt charge/discharge rate.

Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

International Nuclear Information System (INIS)

Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral; Florio, Daniel Zanetti de

2017-01-01

Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral, E-mail: shaynnedn@hotmail.com, E-mail: nataliakm@usp.br, E-mail: fntabuti@ipen.br, E-mail: fabiocf@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Florio, Daniel Zanetti de, E-mail: daniel.florio@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

2017-01-15

Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

Mesoporous nickel oxide nanowires: hydrothermal synthesis, characterisation and applications for lithium-ion batteries and supercapacitors with superior performance.

Science.gov (United States)

Su, Dawei; Kim, Hyun-Soo; Kim, Woo-Seong; Wang, Guoxiu

2012-06-25

Mesoporous nickel oxide nanowires were synthesized by a hydrothermal reaction and subsequent annealing at 400 °C. The porous one-dimensional nanostructures were analysed by field-emission SEM, high-resolution TEM and N(2) adsorption/desorption isotherm measurements. When applied as the anode material in lithium-ion batteries, the as-prepared mesoporous nickel oxide nanowires demonstrated outstanding electrochemical performance with high lithium storage capacity, satisfactory cyclability and an excellent rate capacity. They also exhibited a high specific capacitance of 348 F g(-1) as electrodes in supercapacitors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Specification for corrosion-resisting chromium and chromium-nickel steel welding rods and bare electrodes - approved 1969

International Nuclear Information System (INIS)

Anon.

1975-01-01

This specification covers corrosion-resisting chromium and chromium-nickel steel welding rods for use with the atomic hydrogen and gas-tungsten-arc welding processes and bare electrodes for use with the submerged arc and gas metal-arc welding processes. These welding rods and electrodes include those alloy steels designated as corrosion- or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4% and nickel does not exceed 50%

One-pot electrochemical growth of sponge-like polyaniline-intercalated phosphorous-doped graphene oxide on nickel foam as binder-free electrode material of supercapacitor

Science.gov (United States)

Bigdeli, Hadise; Moradi, Morteza; Borhani, Saeid; Jafari, Elnaz Abbasi; Hajati, Shaaker; Kiani, Mohammad Ali

2018-06-01

In this work, phosphor-doped graphene oxide (PGO) was synthesized by chemical technique. Also, the sponge-like PGO@polyaniline nanocomposite (PGO@PANI) film was coated on the nickel foam by one-step electropolymerization. The active materials were then characterized by Fourier transforms infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller technique. When PANI/PGO was used as supercapacitor electrode, under current density of 1 A/g, the specific capacitance of the prepared PGO@PANI was measured as 603 F/g, which is 6.0 times higher than that of pure PANI (102 F/g). Moreover, capacity stability of the PANI/PGO increased significantly as compared to PANI (65% vs. 44%) after increasing the current density from 1 to 15 A/g. The clear electrochemical performance of PANI/PGO was enhanced owing to the synergistic effect of PGO and PANI. Our results demonstrate that PANI/PGO nanosheet arrays are promising candidate for electrode supercapacitor applications.

Erosion on spark plug electrodes; Funkenerosion an Zuendkerzenelektroden

Energy Technology Data Exchange (ETDEWEB)

Rager, J.

2006-07-01

Durability of spark plugs is mainly determined by spark gap widening, caused by electrode wear. Knowledge about the erosion mechanisms of spark plug materials is of fundamental interest for the development of materials with a high resistance against electrode erosion. It is therefore crucial to identify those parameters which significantly influence the erosion behaviour of a material. In this work, a reliable and reproducible testing method is presented which produces and characterizes electrode wear under well-defined conditions and which is capable of altering parameters specifically. Endurance tests were carried out to study the dependence of the wear behaviour of pure nickel and platinum on the electrode temperature, gas, electrode gap, electrode diameter, atmospheric pressure, and partial pressure of oxygen. It was shown that erosion under nitrogen is negligible, irrespective of the material. This disproves all common mechanism discussed in the literature explaining material loss of spark plug electrodes. Based on this observation and the variation of the mentioned parameters a new erosion model was deduced. This relies on an oxidation of the electrode material and describes the erosion of nickel and platinum separately. For nickel, electrode wear is caused by the removal of an oxide layer by the spark. In the case of platinum, material loss occurs due to the plasma-assisted formation and subsequent evaporation of volatile oxides in the cathode spot. On the basis of this mechanism a new composite material was developed whose erosion resistance is superior to pure platinum. Oxidation resistant metal oxide particles were added to a platinum matrix, thus leading to a higher erosion resistance of the composite. However, this can be decreased by a side reaction, the separation of oxygen from the metal oxides, which effectively assists the oxidation of the matrix. This reaction can be suppressed by using highly stable oxides, characterized by a large negative Gibbs

Electrochemical investigation of nickel pattern electrodes in H₂/H₂O and CO/CO₂ atmospheres

DEFF Research Database (Denmark)

Ehn, A.; Høgh, Jens Valdemar Thorvald; Graczyk, M.

2010-01-01

performance. Both dense and porous nickel pattern electrodes were formed by heating. Holes appeared in the nickel layer of the porous pattern electrodes, where the open cavity triple phase boundaries exhibited different limiting processes than open triple phase boundary electrodes of the dense electrode...... and the partial pressure of CO was determined for the dense nickel pattern electrode, which agrees with previous results using nickel point electrodes. © 2010 The Electrochemical Society....

Hydrogen-water deuterium exchange over metal oxide promoted nickel catalysts

Energy Technology Data Exchange (ETDEWEB)

Sagert, N H; Shaw-Wood, P E; Pouteau, R M.L. [Atomic Energy of Canada Ltd., Pinawa, Manitoba. Whiteshell Nuclear Research Establishment

1975-11-01

Specific rates have been measured for hydrogen-water deuterium isotope exchange over unsupported nickel promoted with about 20% of various metal oxides. The oxides used were Cr/sub 2/O/sub 3/, MoO/sub 2/, MnO, WO/sub 2/-WO/sub 3/, and UO/sub 2/. Nickel surface areas, which are required to measure the specific rates, were determined by hydrogen chemisorption. Specific rates were measured as a function of temperature in the range 353 to 573 K and as a function of the partial pressure of hydrogen and water over a 10-fold range of partial pressure. The molybdenum and tungsten oxides gave the highest specific rates, and manganese and uranium oxides the lowest. Chromium oxide was intermediate, although it gave the highest rate per gram of catalyst. The orders with respect to hydrogen and water over molybdenum oxide and tungsten oxide promoted nickel were consistent with a mechanism in which nickel oxide is formed from the reaction of water with the catalyst, and then is reduced by hydrogen. Over manganese and uranium oxide promoted catalysts, these orders are consistent with a mechanism in which adsorbed water exchanges with chemisorbed hydrogen atoms on the nickel surface. Chromium oxide is intermediate. It was noted that those oxides which favored the nickel oxide route had electronic work functions closest to those of metallic nickel and nickel oxide.

Ultrasensitive electrospun nickel-doped carbon nanofibers electrode for sensing paracetamol and glucose

International Nuclear Information System (INIS)

Li, Lili; Zhou, Tingting; Sun, Guoying; Li, Zhaohui; Yang, Wenxiu; Jia, Jianbo; Yang, Guocheng

2015-01-01

The long, uniform and smooth Ni(NO 3 ) 2 -loaded polyvinyl alcohol nanofibers were prepared via electrospinning on a nonconductive quartz plate. The nanofibers were stabilized at 300 °C for 3 h in nitrogen atmosphere, and then the continuous heating to 800 °C at the rate of 2 °C min −1 keeping 3 h was used to prepare nickel-doped carbon nanofibers (Ni:CNFs). The composites were characterized with Raman spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The Ni:CNFs were used as the working electrode to sense paracetamol (PCT) and glucose (GLU), respectively. When sensing PCT, the Ni:CNFs electrode showed an electrochemical behavior like on macroelectrode; but for GLU, it displayed an electrochemical behavior like on microelectrode. For both of the species, higher sensitivities on the Ni:CNFs electrodes were obtained than those on bulk glassy carbon and nickel electrodes

Porous electrode preparation method

Science.gov (United States)

Arons, R.M.; Dusek, J.T.

1983-10-18

A porous sintered plaque is provided with a bimodal porosity that is especially well suited for use as an electrode within a molten carbonate fuel cell. The coarse porosity is sufficient for admitting gases into contact with the reaction surfaces while the fine porosity is wetted with and retains molten electrolyte on the reaction sites. The electrode structure is prepared by providing a very fine powder of such as nickel oxide and blending the powder with a suitable decomposable binder to form a solid mass. The mass is comminuted into agglomerate size particles substantially larger than the fine oxide particles and formed into a cohesive compact for subsequent sintering. Sintering is carried out at sufficient conditions to bind the agglomerates together into a porous structure having both coarse and fine porosity. Where lithiated nickel oxide cathodes are prepared, the sintering conditions can be moderate enough to retain substantial quantities of lithium within the electrode for adequate conductivity. 2 figs.

Nanoroses of nickel oxides: Synthesis, electron tomography study, and application in CO oxidation and energy storage

KAUST Repository

Fihri, Aziz; Sougrat, Rachid; Baby, Rakhi Raghavan; Rahal, Raed; Cha, Dong Kyu; Hedhili, Mohamed N.; Bouhrara, Mohamed; Alshareef, Husam N.; Polshettiwar, Vivek

2012-01-01

Nickel oxide and mixed-metal oxide structures were fabricated by using microwave irradiation in pure water. The nickel oxide self-assembled into unique rose-shaped nanostructures. These nickel oxide roses were studied by performing electron

Ultra High Electrical Performance of Nano Nickel Oxide and Polyaniline Composite Materials

Directory of Open Access Journals (Sweden)

Xiaomin Cai

2017-07-01

Full Text Available The cooperative effects between the PANI (polyaniline/nano-NiO (nano nickel oxide composite electrode material and redox electrolytes (potassium iodide, KI for supercapacitor applications was firstly discussed in this article, providing a novel method to prepare nano-NiO by using β-cyelodextrin (β-CD as the template agent. The experimental results revealed that the composite electrode processed a high specific capacitance (2122.75 F·g−1 at 0.1 A·g−1 in 0.05 M KI electrolyte solution, superior energy density (64.05 Wh·kg−1 at 0.2 A·g−1 in the two-electrode system and excellent cycle performance (86% capacitance retention after 1000 cycles at 1.5 A·g−1. All those ultra-high electrical performances owe to the KI active material in the electrolyte and the PANI coated nano-NiO structure.

Improvement of the process for electrochemical impregnation of nickel hydroxide electrodes

Science.gov (United States)

Comtat, M.; Lafage, B.; Leonardi, J.

1986-01-01

Nickel hydroxide electrodes containing 11g/dsqm hydroxide, with capacities of 3.6 to 3.8 Ah/dsqm were prepared at 353 K by electrochemical impregnation. The reproducibility of the results is obtained by readjusting the pH before each preparation. The control of each electrode is done during two cycles of charge and discharge following the manufacture by a potential relaxation method.

Effect of rare earth oxide additives on the performance of NiMH batteries

International Nuclear Information System (INIS)

Tanaka, Toshiki; Kuzuhara, Minoru; Watada, Masaharu; Oshitani, Masahiko

2006-01-01

To date, we have performed research on nickel-metal hydride (NiMH) batteries used in many applications and have found that addition of rare earth oxides to the nickel electrode and the hydrogen-storage alloy (MH) electrode improves battery performance significantly. Because heavy rare earth oxides of such as Er, Tm, Yb and Lu have remarkable properties that shift the oxygen evolution overpotentials of nickel electrodes to more noble potentials, it is possible to improve high-temperature charge efficiency of nickel-metal hydride secondary batteries by adding them to nickel electrodes. Furthermore, addition of heavy rare earth oxides to MH electrodes depresses an acceleration of the alloy corrosion and improves service life of the battery at high temperatures. Accordingly, addition of heavy rare earth oxides is effective for NiMH batteries used in high-temperature applications such as electric vehicles (EVs), hybrid vehicles (HEVs) and rapid charge devices. In this study, we discussed how the addition of heavy rare earth oxides affects NiMH battery characteristics

Nickel electrodes as a cheap and versatile platform for studying structure and function of immobilized redox proteins

Energy Technology Data Exchange (ETDEWEB)

Han, Xiao Xia [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Li, Junbo [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Öner, Ibrahim Halil [Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Zhao, Bing [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Leimkühler, Silke [Institut für Biochemie und Biologie, Universität Potsdam, Karl-Liebknecht Straße 24-25, H. 25, Golm D-14476 (Germany); Hildebrandt, Peter [Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Weidinger, Inez M., E-mail: i.weidinger@mailbox.tu-berlin.de [Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany)

2016-10-19

Practical use of many bioelectronic and bioanalytical devices is limited by the need of expensive materials and time consuming fabrication. Here we demonstrate the use of nickel electrodes as a simple and cheap solid support material for bioelectronic applications. The naturally nanostructured electrodes showed a surprisingly high electromagnetic surface enhancement upon light illumination such that immobilization and electron transfer reactions of the model redox proteins cytochrome b{sub 5} (Cyt b{sub 5}) and cytochrome c (Cyt c) could be followed via surface enhanced resonance Raman spectroscopy. It could be shown that the nickel surface, when used as received, promotes a very efficient binding of the proteins upon preservation of their native structure. The immobilized redox proteins could efficiently exchange electrons with the electrode and could even act as an electron relay between the electrode and solubilized myoglobin. Our results open up new possibility for nickel electrodes as an exceptional good support for bioelectronic devices and biosensors on the one hand and for surface enhanced spectroscopic investigations on the other hand. - Highlights: • Nickel electrodes were used without further functionalization as supports for various redox proteins. • It was possible to monitor the immobilized proteins via surface enhanced Raman spectroscopy. • The native structure of the immobilized proteins was preserved and they could exchange electrons with the Ni electrode. • The immobilized redox proteins worked as an electron relay between electrode and solubilized myoglobin.

Oxidation mechanism and passive behaviour of nickel in molten carbonate

Energy Technology Data Exchange (ETDEWEB)

Vossen, J.P.T. (ECN Fossil Fuels, Petten (Netherlands)); Ament, P.C.H.; De Wit, J.H.W. (Div. of Corrosion, Lab. for Maaterials Sceince, Delft Univ. of Technology, Delft (Netherlands))

1994-07-01

The oxidation and passivation mechanism and the passive behaviour of nickel in molten carbonate have been investigated with impedance measurements. The oxidation of nickel proceeds according to a dissolution and reprecipitation process. The slowest steps in the reaction sequence are the dissociation reaction of the carbonate and the diffusion of the formed NiO to the metal surface. In the passive range, dissolution of Ni[sup 2+] proceeds after diffusion of Ni[sup 2+] through the oxide layer. The Ni[sup 2+] is formed at the metal/oxide interface. The slowest process is the diffusion of bivalent nickel ions through the passive scale. The formation of trivalent nickel ions probably takes place at the oxide/melt interface. This reaction is accompanied by the incorporation of an oxygen ion and a nickel vacancy in the NiO lattice. The trivalent nickel ions and the nickel vacancy diffuse to the bulk of the oxide scale. The slowest step in this sequence is the dissociation of the carbonate ions and the incorporation of the oxygen ion in the NiO lattice. 9 figs., 2 tabs., 11 refs.

Nickel foam/polyaniline-based carbon/palladium composite electrodes for hydrogen storage

International Nuclear Information System (INIS)

Skowronski, Jan M.; Urbaniak, Jan

2008-01-01

The sandwich-like nickel/palladium/carbon electrodes exhibiting ability to absorb hydrogen in alkaline solution are presented. Electrodes were prepared by successive deposition of palladium and polyaniline layers on nickel foam substrate followed by heat treatment to give Ni/Pd/C electrode. It was shown that thermal conversion of polymer into carbon layer and subsequent thermal activation of carbon component bring about the modification of the mechanism of reversible hydrogen sorption. It was proven that carbon layer, interacting with Pd catalyst, plays a considerable role in the process of hydrogen storage. In the other series of experiments, Pd particles were dispersed electrochemically on carbon coating leading to Ni/C/Pd system. The adding of the next carbon layer resulted in Ni/C/Pd/C electrodes. Electrochemical properties of the electrodes depend on both the sequence of Pd and C layers and the preparation/activation of carbon coating. Electrochemical behavior of sandwich-like electrodes in the reaction of hydrogen sorption/desorption was characterized in 6 M KOH using the cyclic voltammetry method and the results obtained were compared to those for Ni/Pd electrode. The anodic desorption of hydrogen from electrodes free and containing carbon layer was considered after the potentiodynamic as well as potentiostatic sorption of hydrogen. The influence of the sorption potential and the time of rest of electrodes at a cut-off circuit on the kinetics of hydrogen recovery were examined. The results obtained for Ni/Pd/C electrodes indicate that the displacement of hydrogen between C and Pd phase takes place during the rest at a cut-off circuit. Electrodes containing carbon layer require longer time for hydrogen electrosorption. On the other hand, the presence of carbon layer in electrodes is advantageous because a considerable longer retention of hydrogen is possible, as compared to Pd/Ni electrode. Hydrogen stored in sandwich-like electrodes can instantly be

Plasma assisted fabrication of multi-layer graphene/nickel hybrid film as enhanced micro-supercapacitor electrodes

Science.gov (United States)

Ding, Q.; Li, W. L.; Zhao, W. L.; Wang, J. Y.; Xing, Y. P.; Li, X.; Xue, T.; Qi, W.; Zhang, K. L.; Yang, Z. C.; Zhao, J. S.

2017-03-01

A facile synthesis strategy has been developed for fabricating multi-layer graphene/nickel hybrid film as micro-supercapacitor electrodes by using plasma enhanced chemical vapor deposition. The as-presented method is advantageous for rapid graphene growth at relatively low temperature of 650 °C. In addition, after pre-treating for the as-deposited nickel film by using argon plasma bombardment, the surface-to-volume ratio of graphene film on the treated nickel substrate is effectively increased by the increasing of surface roughness. This is demonstrated by the characterization results from transmission electron microscopy, scanning electron microscope and atomic force microscopy. Moreover, the electrochemical performance of the resultant graphene/nickel hybrid film as micro-supercapacitor working electrode was investigated by cyclic voltammetry and galvanostatic charge/discharge measurements. It was found that the increase of the surface-to-volume ratio of graphene/nickel hybrid film improved the specific capacitance of 10 times as the working electrode of micro-supercapacitor. Finally, by using comb columnar shadow mask pattern, the micro-supercapacitor full cell device was fabricated. The electrochemical performance measurements of the micro-supercapacitor devices indicate that the method presented in this study provides an effective way to fabricate micro-supercapacitor device with enhanced energy storage property.

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.

Corrosion and Passivation of Nickel Rotating Disk Electrode in Borate Buffer Solution

Energy Technology Data Exchange (ETDEWEB)

Kim, Younkyoo [Hankuk Univ. of Foreign Studies, Yongin (Korea, Republic of)

2013-10-15

The electrochemical corrosion and passivation of Ni rotating disk electrod in borate buffer solution was studied with potentiodynamic and electrochemical impedance spectroscopy. The mechanisms of both the active dissolution and passivation of nickel and the hydrogen evolution in reduction reaction were hypothetically established while utilizing the Tafel slope, impedance data, the rotation speed of Ni-RDE and the pH dependence of corrosion potential and current. Based on the EIS data, an equivalent circuit was suggested. In addition, carefully measured were the electrochemical parameters for specific anodic dissolution regions. It can be concluded from the data collected that the Ni(OH){sub 2} oxide film, which is primarily formed by passivation, is converted to NiO by dehydration under the influence of an electrical field.

An Electrochemical Investigation of Methanol Oxidation on Nickel ...

African Journals Online (AJOL)

NICO

Cyclic voltammetry, electrooxidation, glassy carbon electrode, methanol, nickel hydroxide nanoparticles. 1. ... substrate at room temperature without templates. Recently, we ... placed in ethanol and sonicated to remove adsorbed particles.

The study of hydrogen electrosorption in layered nickel foam/palladium/carbon nanofibers composite electrodes

International Nuclear Information System (INIS)

Skowronski, J.M.; Czerwinski, A.; Rozmanowski, T.; Rogulski, Z.; Krawczyk, P.

2007-01-01

In the present work, the process of hydrogen electrosorption occurring in alkaline KOH solution on the nickel foam/palladium/carbon nanofibers (Ni/Pd/CNF) composite electrodes is examined. The layered Ni/Pd/CNF electrodes were prepared by a two-step method consisting of chemical deposition of a thin layer of palladium on the nickel foam support to form Ni/Pd electrode followed by coating the palladium layer with carbon nanofibers layer by means of the CVD method. The scanning electron microscope was used for studying the morphology of both the palladium and carbon layer. The process of hydrogen sorption/desorption into/from Ni/Pd as well as Ni/Pd/CNF electrode was examined using the cyclic voltammetry method. The amount of hydrogen stored in both types of composite electrodes was shown to increase on lowering the potential of hydrogen sorption. The mechanism of the anodic desorption of hydrogen changes depending on whether or not CNF layer is present on the Pd surface. The anodic peak corresponding to the removal of hydrogen from palladium is lower for Ni/Pd/CNF electrode as compared to that measured for Ni/Pd one due to a partial screening of the Pd surface area by CNF layer. The important feature of Ni/Pd/CNF electrode is anodic peak appearing on voltammetric curves at potential ca. 0.4 V more positive than the peak corresponding to hydrogen desorption from palladium. The obtained results showed that upon storing the hydrogen saturated Ni/Pd/CNF electrode at open circuit potential, diffusion of hydrogen from carbon to palladium phase occurs due to interaction between carbon fibers and Pd sites on the nickel foam support

Nickel-hydrogen battery and hydrogen storage alloy electrode; Nikkeru suiso denchi oyobi suiso kyuzo gokin denkyoku

Energy Technology Data Exchange (ETDEWEB)

Ono, T. [Furukawa Electric Co. Ltd., Tokyo (Japan); Furukawa, J. [The Furukawa Battery Co. Ltd., Yokohama (Japan)

1996-03-22

Hermetically sealed nickel-hydrogen battery has such problem that the inner pressure of the battery elevates when it is overcharged since the oxygen gas evolves from the positive electrode. This invention relates to the hermetically sealed nickel-hydrogen battery consisting of positive electrode composed mainly of nickel hydroxide and negative electrode composed mainly of hydrogen storage alloy. According to the invention, the negative electrode contains organic sulfur compound having carbon-sulfur bond. As a result, the elevation of battery inner pressure due to the hydrogen gas evolution, the decrease in discharge capacity due to the repetition of charge and discharge, and the lowering of voltage after charging can be suppressed. The adequate content of the organic sulfur compound is 0.05 - 1 part in weight to 100 part in weight of hydrogen storage alloy. As for the organic sulfur compound, n-butylthiol, ethylthioethane, phenyldithiobenzene, trimethylsulfonium bromide, thiobenzophenone, 2,4-dinitrobenzenesulfenyl chloride, and ethylene sulphidic acid are employed. 2 figs., 1 tab.

Oxidation characteristics of porous-nickel prepared by powder metallurgy and cast-nickel at 1273 K in air for total oxidation time of 100 h

Directory of Open Access Journals (Sweden)

Lamiaa Z. Mohamed

2017-11-01

Full Text Available The oxidation behavior of two types of inhomogeneous nickel was investigated in air at 1273 K for a total oxidation time of 100 h. The two types were porous sintered-nickel and microstructurally inhomogeneous cast-nickel. The porous-nickel samples were fabricated by compacting Ni powder followed by sintering in vacuum at 1473 K for 2 h. The oxidation kinetics of the samples was determined gravimetrically. The topography and the cross-section microstructure of each oxidized sample were observed using optical and scanning electron microscopy. X-ray diffractometry and X-ray energy dispersive analysis were used to determine the nature of the formed oxide phases. The kinetic results revealed that the porous-nickel samples had higher trend for irreproducibility. The average oxidation rate for porous- and cast-nickel samples was initially rapid, and then decreased gradually to become linear. Linear rate constants were 5.5 × 10−8 g/cm2 s and 3.4 × 10−8 g/cm2 s for the porous- and cast-nickel samples, respectively. Initially a single-porous non-adherent NiO layer was noticed on the porous- and cast-nickel samples. After a longer time of oxidation, a non-adherent duplex NiO scale was formed. The two layers of the duplex scales were different in color. NiO particles were observed in most of the pores of the porous-nickel samples. Finally, the linear oxidation kinetics and the formation of porous non-adherent duplex oxide scales on the inhomogeneous nickel substrates demonstrated that the addition of new layers of NiO occurred at the scale/metal interface due to the thermodynamically possible reaction between Ni and the molecular oxygen migrating inwardly.

Oxidation characteristics of porous-nickel prepared by powder metallurgy and cast-nickel at 1273 K in air for total oxidation time of 100 h.

Science.gov (United States)

Mohamed, Lamiaa Z; Ghanem, Wafaa A; El Kady, Omayma A; Lotfy, Mohamed M; Ahmed, Hafiz A; Elrefaie, Fawzi A

2017-11-01

The oxidation behavior of two types of inhomogeneous nickel was investigated in air at 1273 K for a total oxidation time of 100 h. The two types were porous sintered-nickel and microstructurally inhomogeneous cast-nickel. The porous-nickel samples were fabricated by compacting Ni powder followed by sintering in vacuum at 1473 K for 2 h. The oxidation kinetics of the samples was determined gravimetrically. The topography and the cross-section microstructure of each oxidized sample were observed using optical and scanning electron microscopy. X-ray diffractometry and X-ray energy dispersive analysis were used to determine the nature of the formed oxide phases. The kinetic results revealed that the porous-nickel samples had higher trend for irreproducibility. The average oxidation rate for porous- and cast-nickel samples was initially rapid, and then decreased gradually to become linear. Linear rate constants were 5.5 × 10 -8  g/cm 2  s and 3.4 × 10 -8  g/cm 2  s for the porous- and cast-nickel samples, respectively. Initially a single-porous non-adherent NiO layer was noticed on the porous- and cast-nickel samples. After a longer time of oxidation, a non-adherent duplex NiO scale was formed. The two layers of the duplex scales were different in color. NiO particles were observed in most of the pores of the porous-nickel samples. Finally, the linear oxidation kinetics and the formation of porous non-adherent duplex oxide scales on the inhomogeneous nickel substrates demonstrated that the addition of new layers of NiO occurred at the scale/metal interface due to the thermodynamically possible reaction between Ni and the molecular oxygen migrating inwardly.

Nickel Hexacyanoferrate Nanoparticle Electrodes For Aqueous Sodium and Potassium Ion Batteries

KAUST Repository

Wessells, Colin D.; Peddada, Sandeep V.; Huggins, Robert A.; Cui, Yi

2011-01-01

needed for grid-scale storage pose substantial challenges for conventional battery technology.(1, 2)Here, we demonstrate insertion/extraction of sodium and potassium ions in a low-strain nickel hexacyanoferrate electrode material for at least five

Controlled synthesis of size-tunable nickel and nickel oxide nanoparticles using water-in-oil microemulsions

International Nuclear Information System (INIS)

Kumar, Ajeet; Saxena, Amit; Shankar, Ravi; Mozumdar, Subho; De, Arnab

2013-01-01

Industrial demands have generated a growing need to synthesize pure metal and metal–oxide nanoparticles of a desired size. We report a novel and convenient method for the synthesis of spherical, size tunable, well dispersed, stable nickel and nickel oxide nanoparticles by reduction of nickel nitrate at room temperature in a TX-100/n-hexanol/cyclohexane/water system by a reverse microemulsion route. We determined that reduction with alkaline sodium borohydrate in nitrogen atmosphere leads to the formation of nickel nanoparticles, while the use of hydrazine hydrate in aerobic conditions leads to the formation of nickel oxide nanoparticles. The influence of several reaction parameters on the size of nickel and nickel oxide nanoparticles were evaluated in detail. It was found that the size can be easily controlled either by changing the molar ratio of water to surfactant or by simply altering the concentration of the reducing agent. The morphology and structure of the nanoparticles were characterized by quasi-elastic light scattering (QELS), transmission electron microscopy (TEM), x-ray diffraction (XRD), electron diffraction analysis (EDA) and energy dispersive x-ray (EDX) spectroscopy. The results show that synthesized nanoparticles are of high purity and have an average size distribution of 5–100 nm. The nanoparticles prepared by our simple methodology have been successfully used for catalyzing various chemical reactions. (paper)

Mathematical modeling of the nickel/metal hydride battery system

Energy Technology Data Exchange (ETDEWEB)

Paxton, Blaine Kermit [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

1995-09-01

A group of compounds referred to as metal hydrides, when used as electrode materials, is a less toxic alternative to the cadmium hydroxide electrode found in nickel/cadmium secondary battery systems. For this and other reasons, the nickel/metal hydride battery system is becoming a popular rechargeable battery for electric vehicle and consumer electronics applications. A model of this battery system is presented. Specifically the metal hydride material, LaNi{sub 5}H{sub 6}, is chosen for investigation due to the wealth of information available in the literature on this compound. The model results are compared to experiments found in the literature. Fundamental analyses as well as engineering optimizations are performed from the results of the battery model. In order to examine diffusion limitations in the nickel oxide electrode, a ``pseudo 2-D model`` is developed. This model allows for the theoretical examination of the effects of a diffusion coefficient that is a function of the state of charge of the active material. It is found using present data from the literature that diffusion in the solid phase is usually not an important limitation in the nickel oxide electrode. This finding is contrary to the conclusions reached by other authors. Although diffusion in the nickel oxide active material is treated rigorously with the pseudo 2-D model, a general methodology is presented for determining the best constant diffusion coefficient to use in a standard one-dimensional battery model. The diffusion coefficients determined by this method are shown to be able to partially capture the behavior that results from a diffusion coefficient that varies with the state of charge of the active material.

Surfactant-assisted ultrasonic spray pyrolysis of nickel oxide and lithium-doped nickel oxide thin films, toward electrochromic applications

Energy Technology Data Exchange (ETDEWEB)

Denayer, Jessica [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Bister, Geoffroy [Environmental and Material Research Association (CRIBC-INISMa), avenue gouverneur cornez 4, 7000 Mons (Belgium); Simonis, Priscilla [Laboratory LPS, University of Namur, rue de bruxelles 61, 5000 Namur (Belgium); Colson, Pierre; Maho, Anthony [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Aubry, Philippe [Environmental and Material Research Association (CRIBC-INISMa), avenue gouverneur cornez 4, 7000 Mons (Belgium); Vertruyen, Bénédicte [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Henrist, Catherine, E-mail: catherine.henrist@ulg.ac.be [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Lardot, Véronique; Cambier, Francis [Environmental and Material Research Association (CRIBC-INISMa), avenue gouverneur cornez 4, 7000 Mons (Belgium); Cloots, Rudi [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium)

2014-12-01

Highlights: • Surfactant-assisted USP: a novel and low cost process to obtain high quality nickel oxide films, with or without lithium dopant. • Increased uniformity and reduced light scattering thanks to the addition of a surfactant. • Improved electrochromic performance (coloration efficiency and contrast) for lithium-doped films by comparison with the undoped NiO film. - Abstract: Lithium-doped nickel oxide and undoped nickel oxide thin films have been deposited on FTO/glass substrates by a surfactant-assisted ultrasonic spray pyrolysis. The addition of polyethylene glycol in the sprayed solution has led to improved uniformity and reduced light scattering compared to films made without surfactant. Furthermore, the presence of lithium ions in NiO films has resulted in improved electrochromic performances (coloration contrast and efficiency), but with a slight decrease of the electrochromic switching kinetics.

Electrodes from carbon nanotubes/NiO nanocomposites synthesized in modified Watts bath for supercapacitors

Science.gov (United States)

Hakamada, Masataka; Abe, Tatsuhiko; Mabuchi, Mamoru

2016-09-01

A modified Watts bath coupled with pulsed current electroplating is used to uniformly deposit ultrafine nickel oxide particles (diameter < 4 nm) on multiwalled carbon nanotubes. The capacitance of the multiwalled carbon nanotubes/nickel oxide electrodes was as high as 2480 F g-1 (per mass of nickel oxide), which is close to the theoretical capacitance of NiO.

Graphene-modified nickel foam electrode for cathodic degradation of nitrofuranzone: Kinetics, transformation products and toxicity

Directory of Open Access Journals (Sweden)

Ya Ma

2017-12-01

Full Text Available Simple, efficient, and durable electrodes are highly demanded for practical electro­chemical process. In this study, a reduced graphene oxide modified nickel foam electrode (GR‑Ni foam was facilely prepared via one-step cyclic voltammetry electrodeposition of gra­phene oxide suspension onto the Ni foam. The electrochemical degradation of nitrofuran­zone (NFZ, a kind of typical antibiotics was studied on the GR-Ni foam cathode. The cyclic voltammetry and electrochemical impedance spectra analysis confirmed that presence of GR loading accelerated the electron transfer from the cathode surface to NFZ. With the applied cathode potential of −1.25 V (vs. Ag/AgCl, the removal efficiency of NFZ (C0 = 20 mg L−1 at the GR-Ni foam electrode reached up to 99 % within 30 min, showing a higher reaction rate constant (0.1297 min−1 than 0.0870 min−1 at the Pd-Ni foam and 0.0186 min−1 at the Ni foam electrode. It was also found that the pH, dissolved oxygen and NFZ initial concentration have slight effect on NFZ degradation at the GR-Ni foam electrode. The reactions first occurred at nitro groups (-NO2, unsaturated C=N bonds and N-N bonds to generate furan ring-containing products, and then these products were transformed into linear diamine products. The direct reduction by electrons was mainly responsible for NFZ reduction at the GR-Ni foam electrode. Even after 18 cycles, the removal efficiency of NFZ still reached up to 98 % within 1 h. In addition, the cathodic degradation process could eliminate the antibacterial activity of NFZ. The GR-Ni foam electrode would have a great potential in electrochemical process for treating wastewater containing furan antibiotics.

Electrochemical determination of serotonin in urine samples based on metal oxide nanoparticles/MWCNT on modified glassy carbon electrode

Directory of Open Access Journals (Sweden)

Omolola E. Fayemi

2017-04-01

Full Text Available The electrochemical response of serotonin on the modified electrode based on multiwalled-carbon-nanotube (MWCNT doped respectively with nickel, zinc and iron oxide nanoparticles coating on glassy carbon electrode (GCE at physiological pH 7 was determined using cyclic voltammetry (CV and square wave voltammetry (SWV. The modified GCE/MWCNT-metal oxide electrodes exhibited excellent electrocatalytic activity towards the detection of serotonin at large peak current and lower oxidation potentials compared to other electrodes investigated. The dynamic range for the serotonin determination was between 5.98 × 10−3 μM to 62.8 μM with detection limits 118, 129 and 166 nM for GCE/MWCNT-NiO, GCE/MWCNT-ZnO and GCE/MWCNT-Fe3O4 sensors respectively. GCE-MWCNT-NiO was the best electrode in terms of serotonin current response, electrode stability, resistance to fouling and limit of detection towards the analyte. The developed sensors were found to be electrochemically stable, reusable, economically effective due to their extremely low operational cost, and have demonstrated good limit of detection, sensitivity and selectivity towards serotonin determination in urine samples. Keywords: Metal oxides nanoparticles, Multiwalled carbon nanotubes, Glassy carbon electrode, Serotonin, Cyclic voltammetry, Square wave voltammetry

Potassium/calcium/nickel oxide catalysts for the oxidative coupling of methane

NARCIS (Netherlands)

Dooley, K.; Dooley, Kerry M.; Ross, J.R.H.; Ross, Julian R.H.

1992-01-01

A series of potassium/calcium/nickel oxides were tested for the oxidative coupling of methane (OCM) at 843–943 K and water addition to the feed at 0–66 mol-%. The K/Ni ratios varied from 0.0–0.6 and Ca/Ni from 0.0–11; catalysts with no nickel were also tested. At least 10% water in the feed and

Storage-battery electrodes. [preparation

Energy Technology Data Exchange (ETDEWEB)

1961-12-29

Two incompatible thermoplastic resins are mixed with a powdered electrochemical active substance. The substance may be, for example, an oxide of cadmium, iron, lead, or zinc or nickel hydroxide. After the mixture is shaped into elements which are inserted into conducting sheaths for an electrode, the one resin is washed out to form a porous electrode. (RWR)

Two-dimensional nickel hydroxide nanosheets as high performance pseudo-capacitor electrodes

Science.gov (United States)

Bhat, Karthik S.; Nagaraja, H. S.

2018-04-01

Electrochemical supercapacitor is a vital technology for the progress of consistent energy harvesting devices. Herein, we report the fabrication of supercapacitor electrodes based on nickel hydroxide nanosheets synthesized via one-pot hydrothermal method. Structure and shape of synthesized materials were analyzed with XRD and SEM measurements. Pseudo-capacitive performances of the fabricated electrodes were evaluated through cyclic voltammetry and galvanostatic charge-discharge measurements with three-electrode configurations. Results indicated the specific capacitance of l80 F g-1 at 5 mV s-1 scan rate and complimented with capacitance retention of 76% for l500 cycles.

Mesoporous Transition Metal Oxides for Supercapacitors.

Science.gov (United States)

Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

2015-10-14

Recently, transition metal oxides, such as ruthenium oxide (RuO₂), manganese dioxide (MnO₂), nickel oxides (NiO) and cobalt oxide (Co₃O₄), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO₂, MnO₂, NiO, Co₃O₄ and nickel cobaltite (NiCo₂O₄), and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

One-pot hydrothermal synthesis of reduced graphene oxide/Ni(OH)2 films on nickel foam for high performance supercapacitors

International Nuclear Information System (INIS)

Min, Shudi; Zhao, Chongjun; Chen, Guorong; Qian, Xiuzhen

2014-01-01

Reduced graphene oxide (RGO) on nickel hydroxide (Ni(OH) 2 ) film was synthesized via a green and facile hydrothermal approach. In this process, graphene oxide (GO) was reduced by nickel foam (NF) while the nickel metal was oxidized to Ni(OH) 2 film simultaneously, which resulted in RGO on Ni(OH) 2 structure. The RGO/Ni(OH) 2 composite film was characterized using by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscope (FESEM). The electrochemical performances of the supercapacitor with the as-synthesized RGO/Ni(OH) 2 composite films as electrodes were evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectrometry (EIS) in 1 M KOH aqueous solution. Results indicated that the RGO/Ni(OH) 2 /NF composite electrodes exhibited superior capacitive performance with high capability (2500 mF cm −2 at a current density of 5 mA cm −2 , or 1667 F g −1 at 3.3 A g −1 ), compared with pure Ni(OH) 2 /NF (450 mF cm −2 at 5 mA cm −2 , 409 F g −1 at 3.3 A g −1 ) prepared under the identical conditions. Our study highlights the importance of anchoring RGO films on Ni(OH) 2 surface for maximizing the optimized utilization of electrochemically active Ni(OH) 2 and graphene for energy storage application in supercapacitors

Spectrochemical analysis of impurities in nickel and in nickel oxide

International Nuclear Information System (INIS)

Goldbart, Z.; Lorber, A.; Harel, A.

1981-11-01

Various spectrochemical methods are described for the quantitative determination of 23 impurities in metallic nickel and in nickel oxide. The average limit of detection is from 1 to 5 ppm and the dynamic range lies over 2.5 orders of magnitude. The elements that were determined are: Al,B,Ba,Bi,Ca,Cd,Co,Cu,Fe,Ga,Ge,In,Mg,Mn,Mo,Nb,Si,Sn,Sr,Ti,Cr,V. (author)

The effect of the presence of fine YSZ particles on the performance of porous nickel electrodes

NARCIS (Netherlands)

de Boer, B.; de Boer, B.; Gonzalez, M.; Gonzalez Cuenca, M.M.; Bouwmeester, Henricus J.M.; Verweij, H.

2000-01-01

The electrochemical performance of a porous nickel electrode with its surface modified by deposition with fine yttria-stabilised zirconia (YSZ) powder is compared with that of the ‘bare’ electrode. Image analysis of the electrode microstructure yields values for the triple phase boundary (TPB)

Reactivating the Ni-YSZ electrode in solid oxide cells and stacks by infiltration

Science.gov (United States)

Skafte, Theis Løye; Hjelm, Johan; Blennow, Peter; Graves, Christopher

2018-02-01

The solid oxide cell (SOC) could play a vital role in energy storage when the share of intermittent electricity production is high. However, large-scale commercialization of the technology is still hindered by the limited lifetime. Here, we address this issue by examining the potential for repairing various failure and degradation mechanisms occurring in the fuel electrode, thereby extending the potential lifetime of a SOC system. We successfully infiltrated the nickel and yttria-stabilized zirconia cermet electrode in commercial cells with Gd-doped ceria after operation. By this method we fully reactivated the fuel electrode after simulated reactant starvation and after carbon formation. Furthermore, by infiltrating after 900 h of operation, the degradation of the fuel electrode was reduced by a factor of two over the course of 2300 h. Lastly, the scalability of the concept is demonstrated by reactivating an 8-cell stack based on a commercial design.

Nanoroses of nickel oxides: Synthesis, electron tomography study, and application in CO oxidation and energy storage

KAUST Repository

Fihri, Aziz

2012-04-11

Nickel oxide and mixed-metal oxide structures were fabricated by using microwave irradiation in pure water. The nickel oxide self-assembled into unique rose-shaped nanostructures. These nickel oxide roses were studied by performing electron tomography with virtual cross-sections through the particles to understand their morphology from their interior to their surface. These materials exhibited promising performance as nanocatalysts for CO oxidation and in energy storage devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nickel-cadmium batteries: effect of electrode phase composition on acid leaching process.

Science.gov (United States)

Nogueira, C A; Margarido, F

2012-01-01

At the end of their life, Ni-Cd batteries cause a number of environmental problems because of the heavy metals they contain. Because of this, recycling of Ni-Cd batteries has been carried out by dedicated companies using, normally, pyrometallurgical technologies. As an alternative, hydrometallurgical processes have been developed based on leaching operations using several types of leachants. The effect of factors like temperature, acid concentration, reaction time, stirring speed and grinding of material on the leaching yields of metals contained in anodic and cathodic materials (nickel, cadmium and cobalt) using sulphuric acid, is herein explained based on the structural composition of the electrode materials. The nickel, cobalt and cadmium hydroxide phases, even with a small reaction time (less than 15 minutes) and low temperature (50 degrees C) and acid concentration (1.1 M H2SO4), were efficiently leached. However, leaching of the nickel metallic phase was more difficult, requiring higher values of temperature, acid concentration and reaction time (e.g. 85 degrees C, 1.1 M H2SO4 and 5 h, respectively) in order to obtain a good leaching efficiency for anodic and cathodic materials (70% and 93% respectively). The stirring speed was not significant, whereas the grinding of electrode materials seems to promote the compaction of particles, which appears to be critical in the leaching of Ni degrees. These results allowed the identification and understanding of the relationship between the structural composition of electrode materials and the most important factors that affect the H2SO4 leaching of spent Ni-Cd battery electrodes, in order to obtain better metal-recovery efficiency.

Electrochemical reactor with rotating cylinder electrode for optimum electrochemical recovery of nickel from plating rinsing effluents

Energy Technology Data Exchange (ETDEWEB)

Hernández-Tapia, J.R.; Vazquez-Arenas, J., E-mail: jgva@xanum.uam.mx; González, I.

2013-11-15

Highlights: • Rotating cylinder cathode enhanced mass transport rates of Ni(II) species. • pH control around 4 is crucial to recover high purity nickel. • Increasing cathodic currents increased energy consumptions for nickel recovery. • Specific energy consumptions increase drastically at the end of electrolysis. -- Abstract: This study is devoted to analyze the metallic electrochemical recovery of nickel from synthetic solutions simulating plating rinsing discharges, in order to meet the water recycling policies implemented in these industries. These effluents present dilute Ni(II) concentrations (100 and 200 ppm) in chloride and sulfate media without supporting electrolyte (397–4202 μS cm{sup −1}), which stems poor current distribution, limited mass transfer, ohmic drops and enhancement of parasitic reactions. An electrochemical reactor with rotating cylinder electrode (RCE) and a pH controller were utilized to overcome these problems. The pH control around 4 was crucial to yield high purity nickel, and thus prevent the precipitation of hydroxides and oxides. Macroelectrolysis experiments were systematically conducted to analyze the impacts of the applied current density in the recovery efficiency and energy consumption, particularly for very diluted effluents (100 and 200 ppm Ni(II)), which present major recovery problems. Promising nickel recoveries in the order of 90% were found in the former baths using a current density of −3.08 mA cm{sup −2}, and with overall profits of 9.64 and 14.69 USD kg{sup −1}, respectively. These estimations were based on the international market price for nickel ($18 USD kg{sup −1})

Early stages of oxidation of ion-implanted nickel at high temperature

International Nuclear Information System (INIS)

Peide, Z.; Grant, W.A.; Procter, R.P.M.

1981-01-01

The early stages of oxidation of nickel implanted with nickel, chromium, or lithium ions in oxygen at 1100 0 C have been studied using various electron-optical techniques. The unimplanted metal develops initially a fine-grained, convoluted scale having a ridged, cellular structure. Subsequently, the oxide grains increase in size significantly and oxidation becomes predominantly controlled by diffusion of Ni /sup 2+/ ions across a compact, columnar scale. Implantation of the surface with nickel ions has no significant effect on the initial oxidation behavior. However, after implantation with chromium or lithium ions, the development of the NiO scale is, in the early stages of oxidation, suppressed by formation of NiCr 2 O 4 or LiO 2 nodules, respectively. Subsequently, the implanted species are incorporated into the steady-state NiO scale where they dope the oxide and thus influence the diffusion rate of Ni /sup 2+/ ions through it. As would be predicted, the steady-state oxidation rate of chromium-implanted nickel is increased while that of lithium- implanted nickel is decreased compared with that of the unimplanted metal

Design of Nickel-Based Cation-Disordered Rock-Salt Oxides: The Effect of Transition Metal (M = V, Ti, Zr) Substitution in LiNi0.5M0.5O2 Binary Systems.

Science.gov (United States)

Cambaz, Musa Ali; Vinayan, Bhaghavathi P; Euchner, Holger; Johnsen, Rune E; Guda, Alexander A; Mazilkin, Andrey; Rusalev, Yury V; Trigub, Alexander L; Gross, Axel; Fichtner, Maximilian

2018-06-20

Cation-disordered oxides have been ignored as positive electrode material for a long time due to structurally limited lithium insertion/extraction capabilities. In this work, a case study is carried out on nickel-based cation-disordered Fm3 ̅m LiNi 0.5 M 0.5 O 2 positive electrode materials. The present investigation targets tailoring the electrochemical properties for nickel-based cation-disordered rock-salt by electronic considerations. The compositional space for binary LiM +3 O 2 with metals active for +3/+4 redox couples is extended to ternary oxides with LiA 0.5 B 0.5 O 2 with A = Ni 2+ and B = Ti 4+ , Zr 4+ , and V +4 to assess the impact of the different transition metals in the isostructural oxides. The direct synthesis of various new unknown ternary nickel-based Fm3̅ m cation-disordered rock-salt positive electrode materials is presented with a particular focus on the LiNi 0.5 V 0.5 O 2 system. This positive electrode material for Li-ion batteries displays an average voltage of ∼2.55 V and a high discharge capacity of 264 mAhg -1 corresponding to 0.94 Li. For appropriate cutoff voltages, a long cycle life is achieved. The charge compensation mechanism is probed by XANES, confirming the reversible oxidation and reduction of V 4+ /V 5+ . The enhancement in the electrochemical performances within the presented compounds stresses the importance of mixed cation-disordered transition metal oxides with different electronic configuration.

Fabrication of nickel hydroxide electrodes with open-ended hexagonal nanotube arrays for high capacitance supercapacitors.

Science.gov (United States)

Wu, Mao-Sung; Huang, Kuo-Chih

2011-11-28

A nickel hydroxide electrode with open-ended hexagonal nanotube arrays, prepared by hydrolysis of nickel chloride in the presence of hexagonal ZnO nanorods, shows a very high capacitance of 1328 F g(-1) at a discharge current density of 1 A g(-1) due to the significantly improved ion transport.

Nickel oxide/hydroxide nanoplatelets synthesized by chemical precipitation for electrochemical capacitors

International Nuclear Information System (INIS)

Wu, M.-S.; Hsieh, H.-H.

2008-01-01

Nickel hydroxide powder prepared by directly chemical precipitation method at room temperature has a nanoplatelet-like morphology and could be converted into nickel oxide at annealing temperature higher than 300 deg. C, confirmed by the thermal gravimetric analysis and X-ray diffraction. Annealing temperature influences significantly both the electrical conductivity and the specific surface area of nickel oxide/hydroxide powder, and consequently determines the capacitor behavior. Electrochemical capacitive behavior of the synthesized nickel hydroxide/oxide film is investigated by cyclic voltammetry and electrochemical impedance spectroscope methods. After 300 deg. C annealing, the highest specific capacitance of 108 F g -1 is obtained at scan rate of 10 mV s -1 . When annealing temperature is lower than 300 deg. C, the electrical conductivity of nickel hydroxide dominates primarily the capacitive behavior. When annealing temperature is higher than 300 deg. C, both electrical conductivity and specific surface area of the nickel oxide dominate the capacitive behavior

Preliminary study on zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction

Science.gov (United States)

Wen, Yue-Hua; Cheng, Jie; Ning, Shang-Qi; Yang, Yu-Sheng

A zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H 2-overpotential metal, cadmium, was used as the negative substrate electrode, the dendritic formation and hydrogen evolution are suppressed effectively, and granular zinc deposits become larger but relatively dense with the increase of charge time. The performance of batteries is favorable even if the charge time is as long as 5 h at the current density of 20 mA cm -2. Better discharge performance is achieved using a 'cavity-opening' configuration for the discharge cell rather than a 'gas-introducing' configuration. The highest energy efficiency is up to 59.2%. That is, the energy consumed by organic electro-synthesis can be recovered by 59.2%. Cyclic voltammograms show that the sintered nickel electrode exhibits a good electro-catalysis activity for the propanol oxidation. The increase of propanol concentration conduces to an enhancement in the organic electro-synthesis efficiency. The organic electro-synthesis current efficiency of 82% can be obtained.

Mesoporous Transition Metal Oxides for Supercapacitors

Science.gov (United States)

Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

2015-01-01

Recently, transition metal oxides, such as ruthenium oxide (RuO2), manganese dioxide (MnO2), nickel oxides (NiO) and cobalt oxide (Co3O4), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4), and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors. PMID:28347088

Mesoporous Transition Metal Oxides for Supercapacitors

Directory of Open Access Journals (Sweden)

Yan Wang

2015-10-01

Full Text Available Recently, transition metal oxides, such as ruthenium oxide (RuO2, manganese dioxide (MnO2, nickel oxides (NiO and cobalt oxide (Co3O4, have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4, and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

Electrochemical Oxidation of Glycerol Using Gold Electrode

International Nuclear Information System (INIS)

Mohamed Rozali Othman; Amirah Ahmad

2015-01-01

Cyclic voltammetry, potential linear V and chronocuolometry methods were carried out to gain electrochemical behavior of glycerol at a gold electrode. Potassium hydroxide and sulfuric acid were chosen to be the electrolyte for the electro-oxidation of this organic compound. Besides gold plate electrode, gold composite electrode (Au-PVC) was also used as the working electrode. The Au-PVC composite electrode was characterized by Scanning Electron Microscopy (SEM) to determine its morphological aspects before and after used in electrochemical oxidation of glycerol. In alkaline solution, the adsorption of hydroxide species onto the surface of both gold plate and composite Au-PVC electrodes occurs at potential around 500 mV vs SCE. However, at gold plate electrode, there was a small, broad peak before the drastic escalation of current densities which indicates the charge transfer of the chemisorbed OH - anion. In acidic media, the gold oxide was formed after potential 1.0 V. From the cyclic voltammogram glycerol undergo oxidation twice in potassium hydroxide at gold plate and Au-PVC composite electrodes, while in sulfuric acid, oxidation reaction happened once for glycerol on the gold plate electrode. Overall, electrochemical oxidation of glycerol was more effective in alkaline media. Tafel graph which plotted from potential linear V method shows that Au-PVC composite electrode is better than gold plate electrode for the electro-oxidation of glycerol in alkaline solution. Electrochemical oxidation of glycerol products as analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) produced several carboxylic acids and phenolic compounds. (author)

Specification for corrosion-resisting chromium and chromium-nickel steel bare and composite metal cored and stranded arc welding electrodes and welding rods

International Nuclear Information System (INIS)

Anon.

1983-01-01

This specification prescribes requirements for corrosion or heat resisting chromium and chromium-nickel steel electrodes and welding rods. These electrodes and welding rods are normally used for arc welding and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

Zinc electrode shape change II. Process and mechanism

NARCIS (Netherlands)

Einerhand, R.E.F.; Visscher, W.; de Goeij, J.J.M.; Barendrecht, E.

1991-01-01

The process and mechanism of zinc electrode shape change is investigated with the radiotracer technique. It is shownthat during repeated cycling of the nickel oxide/zinc battery zinc material is transported over the zinc electrode via the battery electrolyte. During charge as well as during

Hydrogen storage alloy electrode and the nickel-hydrogen secondary battery using the electrode; Suiso kyuzo gokin denkyoku to sorewo mochiita nikkeru/suiso niji denchi

Energy Technology Data Exchange (ETDEWEB)

Ono, T. [Furukawa Electric Co. Ltd., Tokyo (Japan); Furukawa, J. [The Furukawa Battery Co. Ltd., Yokohama (Japan)

1997-02-14

With respect to the conventional nickel-hydrogen secondary battery, pulverization of the hydrogen storage alloy due to repetition of charging-discharging cycles can be prevented by using a fluorocarbon resin as a binder in manufacture of the hydrogen storage alloy electrode; however, the inner pressure increase of the battery in case of overcharging can not be fully controlled. The invention relates to control of the inner pressure increase of the nickel-hydrogen secondary battery in case of overcharging. As to the hydrogen storage alloy electrode, the compound comprising the hydrogen storage alloy powder as a main ingredient is supported by a current collector; further, the compound particularly comprises a fluororubber as a binder. The nickel-hydrogen secondary battery equipped with the hydrogen storage alloy electrode can control the inner pressure increase of the battery in case of overcharging, and lessen decrease of the battery capacity due to repetition of charging-discharging cycles over long time. The effects are dependent on the use of the fluororubber as a binder which has good flexibility, and strong binding capacity as well as water repellency. 1 tab.

Nickel-Tin Electrode Materials for Nonaqueous Li-Ion Cells

Science.gov (United States)

Ehrlich, Grant M.; Durand, Christopher

2005-01-01

Experimental materials made from mixtures of nickel and tin powders have shown promise for use as the negative electrodes of rechargeable lithium-ion electrochemical power cells. During charging (or discharging) of a lithium-ion cell, lithium ions are absorbed into (or desorbed from, respectively) the negative electrode, typically through an intercalation or alloying process. The negative electrodes (for this purpose, designated as anodes) in state-of-the-art Li-ion cells are made of graphite, in which intercalation occurs. Alternatively, the anodes can be made from metals, in which alloying can occur. For reasons having to do with the electrochemical potential of intercalated lithium, metallic anode materials (especially materials containing tin) are regarded as safer than graphite ones; in addition, such metallic anode materials have been investigated in the hope of obtaining reversible charge/discharge capacities greater than those of graphite anodes. However, until now, each of the tin-containing metallic anode formulations tested has been found to be inadequate in some respect.

Diffusion of Nickel into Ferritic Steel Interconnects of Solid Oxide Fuel/Electrolysis Stacks

DEFF Research Database (Denmark)

Molin, Sebastian; Chen, Ming; Bowen, Jacob R.

2013-01-01

diffusion of nickel from the Ni/YSZ electrode or the contact layer into the interconnect plate. Such diffusion can cause austenization of the ferritic structure and could possibly alter corrosion properties of the steel. Whereas this process has already been recognized by SOFC stack developers, only...... a limited number of studies have been devoted to the phenomenon. Here, diffusion of Ni into ferritic Crofer 22 APU steel is studied in a wet hydrogen atmosphere after 250 hours of exposure at 800 °C using Ni-plated (~ 10 micron thick coatings) sheet steel samples as a model system. Even after...... this relatively short time all the metallic nickel in the coating has reacted and formed solid solutions with iron and chromium. Diffusion of Ni into the steel causes formation of the austenite FCC phase. The microstructure and composition of the oxide scale formed on the sample surface after 250 hours is similar...

Mesoporous Nickel Oxide (NiO) Nanopetals for Ultrasensitive Glucose Sensing

Science.gov (United States)

Mishra, Suryakant; Yogi, Priyanka; Sagdeo, P. R.; Kumar, Rajesh

2018-01-01

Glucose sensing properties of mesoporous well-aligned, dense nickel oxide (NiO) nanostructures (NSs) in nanopetals (NPs) shape grown hydrothermally on the FTO-coated glass substrate has been demonstrated. The structural study based investigations of NiO-NPs has been carried out by X-ray diffraction (XRD), electron and atomic force microscopies, energy dispersive X-ray (EDX), and X-ray photospectroscopy (XPS). Brunauer-Emmett-Teller (BET) measurements, employed for surface analysis, suggest NiO's suitability for surface activity based glucose sensing applications. The glucose sensor, which immobilized glucose on NiO-NPs@FTO electrode, shows detection of wide range of glucose concentrations with good linearity and high sensitivity of 3.9 μA/μM/cm2 at 0.5 V operating potential. Detection limit of as low as 1 μΜ and a fast response time of less than 1 s was observed. The glucose sensor electrode possesses good anti-interference ability, stability, repeatability & reproducibility and shows inert behavior toward ascorbic acid (AA), uric acid (UA) and dopamine acid (DA) making it a perfect non-enzymatic glucose sensor.

Elaboration of modified poly(NiII-DHS films as electrodes by the electropolymerization of Ni(II-[5,5′-dihydroxysalen] onto indium tin oxide surface and study of their electrocatalytic behavior toward aliphatic alcohols

Directory of Open Access Journals (Sweden)

Ali Ourari

2017-11-01

Full Text Available Nickel(II-DHS complex was obtained from N,N′-bis(2,5-dihydroxybenzylidene-1,2-diaminoethane (H2DHS ligand and nickel acetate tetrahydrated in ethanolic solution with stirring under reflux. This complex, dissolved in an alkaline solution, was oxidized to form electroactive films strongly adhered on the ITO (indium tin oxide electrode surface. In this alkaline solution, the poly-[NiII-DHS]/ITO films showed the typical voltammetric response of (Ni2+/Ni3+ redox couple centers which are immobilized in the polymer-film. The modified electrodes (MEs obtained were also characterized by several techniques such as scanning electronic microscopy, atomic force microscopy and electrochemical methods. The electrocatalytic behavior of these MEs toward the oxidation reaction of some aliphatic alcohols such as methanol, ethanol, 2-Methyl-1-propanol and isopropanol was investigated. The voltammograms recorded with these alcohols showed good electrocatalytic efficiency. The electrocatalytic currents were at least 80 times higher than those obtained for the oxidation of methanol on electrodes modified with nickel hydroxide films in alkaline solutions. We noticed that these electrocatalytic currents are proportional to the concentration of methanol (0.050–0.30 μM. In contrast, those recorded for the oxidation of other aliphatic short chain alcohols such as ethanol, 2-methyl-1-propanol and isopropanol are rather moderately weaker. In all cases the electrocatalytic currents presented a linear dependence with the concentration of alcohol. These modified electrodes could be applied as alcohol sensors.

Borate electrolyte additives for high voltage lithium nickel manganese oxide electrode: A comparative study

International Nuclear Information System (INIS)

Chen, Zhiting; Wang, Cun; Xing, Lidan; Wang, Xianshu; Tu, Wenqiang; Zhu, Yunmin; Li, Weishan

2017-01-01

Highlights: •TMB and TEB effective improve the cyclic stability of LNMO at high voltage. •The performance of LNMO with TMB-containing electrolyte is superior to that of TEB. •LNMO shows catalytic effect on the oxidation reaction of TEB. •The film generated in TMB shows better ability on suppressing LNMO shedding than TEB. -- Abstract: Trimethyl borate (TMB) and triethyl borate (TEB) are used as film-forming electrolyte additives for high voltage Lithium nickel manganese oxide (LNMO) cathode. DFT calculation and initial charge curve of LNMO reveal that the oxidation activity of TEB is higher than that of TMB. Addition of 2% TMB and 2% TEB effectively improve the capacity retention of high voltage LNMO from 23.4% to 85.3% and 72.6% after 600 cycles, respectively. The film generated in TMB-containing electrolyte shows better ability on suppressing the LNMO shedding in comparison with that of TEB, resulting in higher capacity retention of LNMO in TMB-containing electrolyte at high voltage. The superior performance of LNMO with TMB-containing electrolyte should be ascribed to its less intense film-forming reaction which generates a denser protective surface film on LNMO surface. However, why LNMO shows catalyzation effect on TEB oxidation but not on TMB is unclear, which needs further intensive investigation.

Study of the oxidation kinetics of the nickel-molybdenum alloy

International Nuclear Information System (INIS)

Gouillon, Marie-Josephe

1974-01-01

This research thesis reports the study of the oxidation of a nickel-molybdenum alloy in the high-nickel-content part of this alloy. After a bibliographical study on the both metals, the author proposes a physical model based on observed phenomena and based on experimental results. Based on a thermodynamic study, the author compares the stability of the different oxides which may be formed, and reports a prediction of oxides obtained on the alloy during oxidation. Qualitative and quantitative studies have been performed by scanning electron microscopy coupled with electronic microprobe analysis to investigate morphological characteristics on oxidation films. A kinetic study by thermogravimetry shows a decrease of the alloy oxidation rate with respect to that of pure nickel at temperatures lower than 800 degrees C. This result is interpreted by the intervention of two opposed diffusion phenomena which act against each other [fr

76 FR 47996 - Cobalt Lithium Manganese Nickel Oxide; Significant New Use Rule

Science.gov (United States)

2011-08-08

... Safety and Health Administration (OSHA) Permissible Exposure Level (PEL) of 0.1 mg/m\\3\\ for nickel. The... 2070-AB27 Cobalt Lithium Manganese Nickel Oxide; Significant New Use Rule AGENCY: Environmental... lithium manganese nickel oxide (CAS No. 182442-95-1), which was the subject of premanufacture notice (PMN...

A paste type negative electrode using a MmNi{sub 5} based hydrogen storage alloy for a nickel-metal hydride (Ni-MH) battery

Energy Technology Data Exchange (ETDEWEB)

Uchida, H.; Matsumoto, T.; Watanabe, S.; Kobayashi, K.; Hoshino, H. [Tokai Univ., Kanagawa (Japan). School of Engineering

2001-07-01

Different conducting materials (nickel, copper, cobalt, graphite) were mixed with a MmNi{sub 5} type hydrogen storage alloy, and negative electrodes for a nickel-metal hydride(Ni-MH) rechargeable battery were prepared and examined with respect to the discharge capacity of the electrodes. The change in the discharge capacity of the electrodes with different conducting materials was measured as a function of the number of electrochemical charge and discharge cycles. From the measurements, the electrodes with cobalt and graphite were found to yield much higher discharge capacities than those with nickel or cobalt. From a comparative discharge measurements for an electrode composed of only cobalt powder without the alloy and an electrode with a mixture of cobalt and the alloy, an appreciable contribution of the cobalt surface to the enhancement of charge and discharge capacities was found. (author)

Electrochemical Characterization of Nanoporous Nickel Oxide Thin Films Spray-Deposited onto Indium-Doped Tin Oxide for Solar Conversion Scopes

Directory of Open Access Journals (Sweden)

Muhammad Awais

2015-01-01

Full Text Available Nonstoichiometric nickel oxide (NiOx has been deposited as thin film utilizing indium-doped tin oxide as transparent and electrically conductive substrate. Spray deposition of a suspension of NiOx nanoparticles in alcoholic medium allowed the preparation of uniform NiOx coatings. Sintering of the coatings was conducted at temperatures below 500°C for few minutes. This scalable procedure allowed the attainment of NiOx films with mesoporous morphology and reticulated structure. The electrochemical characterization showed that NiOx electrodes possess large surface area (about 1000 times larger than their geometrical area. Due to the openness of the NiOx morphology, the underlying conductive substrate can be contacted by the electrolyte and undergo redox processes within the potential range in which NiOx is electroactive. This requires careful control of the conditions of polarization in order to prevent the simultaneous occurrence of reduction/oxidation processes in both components of the multilayered electrode. The combination of the open structure with optical transparency and elevated electroactivity in organic electrolytes motivated us to analyze the potential of the spray-deposited NiOx films as semiconducting cathodes of dye-sensitized solar cells of p-type when erythrosine B was the sensitizer.

Applications of x ray absorption fine structure to the in situ study of the effect of cobalt in nickel hydrous oxide electrodes for fuel cells and rechargeable batteries

Science.gov (United States)

Kim, Sunghyun; Tryk, Donald A.; Scherson, Daniel A.; Antonio, Mark R.

1993-01-01

Electronic and structural aspects of composite nickel-cobalt hydrous oxides have been examined in alkaline solutions using in situ X-ray absorption fine structure (XAFS). The results obtained have indicated that cobalt in this material is present as cobaltic ions regardless of the oxidation state of nickel in the lattice. Furthermore, careful analysis of the Co K-edge Extended X-ray absorption fine structure data reveals that the co-electrodeposition procedure generates a single phase, mixed metal hydrous oxide, in which cobaltic ions occupy nickel sites in the NiO2 sheet-like layers and not two intermixed phases each consisting of a single metal hydrous oxide.

Rapid synthesis of monodispersed highly porous spinel nickel cobaltite (NiCo{sub 2}O{sub 4}) electrode material for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Naveen, A. Nirmalesh, E-mail: nirmalesh.naveen@gmail.com; Selladurai, S. [Ionics Laboratory, Department of Physics, Anna University, Chennai-600025 (India)

2015-06-24

Monodispersed highly porous spinel nickel cobaltite electrode material was successfully synthesized in a short time using combustion technique. Single phase cubic nature of the spinel nickel cobaltite with average crystallite size of 24 nm was determined from X-ray diffraction study. Functional groups present in the compound were determined from FTIR study and it further confirms the spinel formation. FESEM images reveal the porous nature of the prepared material and uniform size distribution of the particles. Electrochemical evaluation was performed using Cyclic Voltammetry (CV) technique, Chronopotentiometry (CP) and Electrochemical Impedance Spectroscopy (EIS). Results reveal the typical pseudocapacitive behaviour of the material. Maximum capacitance of 754 F/g was calculated at the scan rate of 5 mV/s, high capacitance was due to the unique porous morphology of the electrode. Nyquist plot depicts the low resistance and good electrical conductivity of nickel cobaltite. It has been found that nickel cobaltite prepared by this typical method will be a potential electrode material for supercapcitor application.

Optimization of synthesis of the nickel-cobalt oxide based anode electrocatalyst and of the related membrane-electrode assembly for alkaline water electrolysis

Science.gov (United States)

Chanda, Debabrata; Hnát, Jaromir; Bystron, Tomas; Paidar, Martin; Bouzek, Karel

2017-04-01

In this work, the Ni-Co spinel oxides are synthesized via different methods and using different calcination temperatures. Properties of the prepared materials are compared. The best route is selected and used to prepare a Ni1+xCo2-xO4 (-1 ≤ x ≤ 1) series of materials in order to investigate their catalytic activity towards the oxygen evolution reaction (OER). The results show that hydroxide preparation yields NiCo2O4 oxide with the highest activity. 325 °C is identified as the optimum calcination temperature. Subsequently, the catalysts are tested in an electrolysis cell. To prepare an anode catalyst layer based on NiCo2O4 catalyst on top of a nickel foam substrate for membrane electrode assembly (MEA) construction, following polymer binders are used: anion-selective quaternized polyphenylene oxide (qPPO), inert polytetrafluoroethylene (PTFE®), and cation-selective Nafion®. qPPO ionomer containing MEA exhibited highest OER activity. The current density obtained using a MEA containing qPPO binder attains a value of 135 mA cm-2 at a cell voltage of 1.85 V. After 7 h chronopotentiometric experiment at a constant current density of 225 mA cm-2, the MEA employing PTFE® binder shows higher stability than the other binders in alkaline water electrolysis at 50 °C. Under similar conditions, stability of the PTFE®-binding MEA is examined for 135 h.

Solvothermal synthesis of NiAl double hydroxide microspheres on a nickel foam-graphene as an electrode material for pseudo-capacitors

International Nuclear Information System (INIS)

Momodu, Damilola; Bello, Abdulhakeem; Dangbegnon, Julien; Barzeger, Farshad; Taghizadeh, Fatimeh; Fabiane, Mopeli; Manyala, Ncholu; Johnson, A. T. Charlie

2014-01-01

In this paper, we demonstrate excellent pseudo-capacitance behavior of nickel-aluminum double hydroxide microspheres (NiAl DHM) synthesized by a facile solvothermal technique using tertbutanol as a structure-directing agent on nickel foam-graphene (NF-G) current collector as compared to use of nickel foam current collector alone. The structure and surface morphology were studied by X-ray diffraction analysis, Raman spectroscopy and scanning and transmission electron microscopies respectively. NF-G current collector was fabricated by chemical vapor deposition followed by an ex situ coating method of NiAl DHM active material which forms a composite electrode. The pseudocapacitive performance of the composite electrode was investigated by cyclic voltammetry, constant charge–discharge and electrochemical impedance spectroscopy measurements. The composite electrode with the NF-G current collector exhibits an enhanced electrochemical performance due to the presence of the conductive graphene layer on the nickel foam and gives a specific capacitance of 1252 F g −1 at a current density of 1 A g −1 and a capacitive retention of about 97% after 1000 charge–discharge cycles. This shows that these composites are promising electrode materials for energy storage devices

Design of a neutral three-dimensional electro-Fenton system with foam nickel as particle electrodes for wastewater treatment

International Nuclear Information System (INIS)

Liu, Wei; Ai, Zhihui; Zhang, Lizhi

2012-01-01

Highlights: ► Remove RhB by a novel 3D-E-Fenton system using foam nickel as particle electrodes. ► The 3D-E-Fenton system exhibit much higher RhB removal efficiency than the counterpart 3D-E and E-Fenton system. ► Foam nickel as a particle electrode displays good oxygen reduction activity. ► The performance of RhB removal was optimized by some operating parameters and the optimization pH was the neutral. - Abstract: In this work, we demonstrate a novel three-dimensional electro-Fenton system (3D-E-Fenton) for wastewater treatment with foam nickel, activated carbon fiber and Ti/RuO 2 –IrO 2 as the particle electrodes, the cathode, and the anode respectively. This 3D-E-Fenton system could exhibit much higher rhodamine B removal efficiency (99%) than the counterpart three-dimensional electrochemical system (33%) and E-Fenton system (19%) at neutral pH in 30 min. The degradation efficiency enhancement was attributed to much more hydroxyl radicals generated in the 3D-E-Fenton system because foam nickel particle electrodes could activate molecular oxygen to produce ·O 2 − via a single-electron transfer pathway to subsequently generate more H 2 O 2 and hydroxyl radicals. This is the first observation of molecular oxygen activation over the particle electrodes in the three-dimensional electrochemical system. These interesting findings could provide some new insight on the development of high efficient E-Fenton system for wastewater treatment at neutral pH.

Flexible, silver nanowire network nickel hydroxide core-shell electrodes for supercapacitors

Science.gov (United States)

Yuksel, Recep; Coskun, Sahin; Kalay, Yunus Eren; Unalan, Husnu Emrah

2016-10-01

We present a novel one-dimensional coaxial architecture composed of silver nanowire (Ag NW) network core and nickel hydroxide (Ni(OH)2) shell for the realization of coaxial nanocomposite electrode materials for supercapacitors. Ag NWs are formed conductive networks via spray coating onto polyethylene terephthalate (PET) substrates and Ni(OH)2 is gradually electrodeposited onto the Ag NW network to fabricate core-shell electrodes for supercapacitors. Synergy of highly conductive Ag NWs and high capacitive Ni(OH)2 facilitate ion and electron transport, enhance electrochemical properties and result in a specific capacitance of 1165.2 F g-1 at a current density of 3 A g-1. After 3000 cycles, fabricated nanocomposite electrodes show 93% capacity retention. The rational design explored in this study points out the potential of nanowire based coaxial energy storage devices.

Nickel hydroxide positive electrode for alkaline rechargeable battery

Science.gov (United States)

Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

2018-02-20

Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

Nickel hydroxide positive electrode for alkaline rechargeable battery

Science.gov (United States)

Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

2018-04-03

Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

Zinc electrode - its behaviour in the nickel oxide-zinc accumulator

Energy Technology Data Exchange (ETDEWEB)

1984-01-01

Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling. 193 references.

Microwave-assisted hydrothermal synthesis of coralloid nanostructured nickel hydroxide hydrate and thermal conversion to nickel oxide

International Nuclear Information System (INIS)

Lai, Teh-Long; Lai, Yuan-Lung; Yu, Jen-Wei; Shu, Youn-Yuen; Wang, Chen-Bin

2009-01-01

Coralloid nanostructured nickel hydroxide hydrate has been successfully synthesized by a simple microwave-assisted hydrothermal process using nickel sulfate hexahydrate as precursor and urea as hydrolysis-controlling agent. A pure coralloid nanostructured nickel oxide can be obtained from the nickel hydroxide hydrate after calcination at 400 deg. C. The thermal property, structure and morphology of samples were characterized by thermogravimetry (TG), temperature-programmed reduction (TPR), X-ray (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Microwave-assisted hydrothermal synthesis of coralloid nanostructured nickel hydroxide hydrate and thermal conversion to nickel oxide

Energy Technology Data Exchange (ETDEWEB)

Lai, Teh-Long [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Lai, Yuan-Lung [Department of Mechanical and Automation Engineering, Da-Yeh University, Changhua 515, Taiwan (China); Yu, Jen-Wei [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Shu, Youn-Yuen, E-mail: shuyy@nknucc.nknu.edu.tw [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Wang, Chen-Bin, E-mail: chenbin@ccit.edu.tw [Department of Applied Chemistry and Materials Science, Chung Cheng Institute of Technology, National Defense University, Tahsi, Taoyuan 335, Taiwan (China)

2009-10-15

Coralloid nanostructured nickel hydroxide hydrate has been successfully synthesized by a simple microwave-assisted hydrothermal process using nickel sulfate hexahydrate as precursor and urea as hydrolysis-controlling agent. A pure coralloid nanostructured nickel oxide can be obtained from the nickel hydroxide hydrate after calcination at 400 deg. C. The thermal property, structure and morphology of samples were characterized by thermogravimetry (TG), temperature-programmed reduction (TPR), X-ray (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

New process to discharge negative cadmium electrodes for Ni/Cd batteries

International Nuclear Information System (INIS)

Stiker, B.; Vignaud, R.

1984-01-01

The new process relates to the chemical oxidation (whether partial or total) of cadmium metal negative electrodes, as used in alkaline nickel-cadmium or silver-cadmium batteries. This process concerns all cadmium electrodes but more particularly the electrodeposited cadmium electrode developed by the company LES PILES WONDER and described in this publication

Silver manganese oxide electrodes for lithium batteries

Science.gov (United States)

Thackeray, Michael M.; Vaughey, John T.; Dees, Dennis W.

2006-05-09

This invention relates to electrodes for non-aqueous lithium cells and batteries with silver manganese oxide positive electrodes, denoted AgxMnOy, in which x and y are such that the manganese ions in the charged or partially charged electrodes cells have an average oxidation state greater than 3.5. The silver manganese oxide electrodes optionally contain silver powder and/or silver foil to assist in current collection at the electrodes and to improve the power capability of the cells or batteries. The invention relates also to a method for preparing AgxMnOy electrodes by decomposition of a permanganate salt, such as AgMnO4, or by the decomposition of KMnO4 or LiMnO4 in the presence of a silver salt.

Synthesis, spectroscopic and electrochemical performance of pasted β-nickel hydroxide electrode in alkaline electrolyte

Science.gov (United States)

Shruthi, B.; Bheema Raju, V.; Madhu, B. J.

2015-01-01

β-Nickel hydroxide (β-Ni(OH)2) was successfully synthesized using precipitation method. The structure and property of the β-Ni(OH)2 were characterized by X-ray diffraction (XRD), Fourier Transform infra-red (FT-IR), Raman spectra and thermal gravimetric-differential thermal analysis (TG-DTA). The results of the FTIR spectroscopy and TG-DTA studies indicate that the β-Ni(OH)2 contains water molecules and anions. The microstructural and composition studies have been performed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. A pasted-type electrode is prepared using β-Ni(OH)2 powder as the active material on a nickel sheet as a current collector. Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) studies were performed to evaluate the electrochemical performance of the β-Ni(OH)2 electrode in 6 M KOH electrolyte. CV curves showed a pair of strong redox peaks as a result of the Faradaic redox reactions of β-Ni(OH)2. The proton diffusion coefficient (D) for the present β-Ni(OH)2 electrode material is found to be 1.44 × 10-12 cm2 s-1. Further, electrochemical impedance studies confirmed that the β-Ni(OH)2 electrode reaction processes are diffusion controlled.

Electrocatalytic Study of Paracetamol at a Single-Walled Carbon Nanotube/Nickel Nanocomposite Modified Glassy Carbon Electrode

Directory of Open Access Journals (Sweden)

Koh Sing Ngai

2015-01-01

Full Text Available A rapid, simple, and sensitive method for the electrochemical determination of paracetamol was developed. A single-walled carbon nanotube/nickel (SWCNT/Ni nanocomposite was prepared and immobilized on a glassy carbon electrode (GCE surface via mechanical attachment. This paper reports the voltammetry study on the effect of paracetamol concentration, scan rate, pH, and temperature at a SWCNT/Ni-modified electrode in the determination of paracetamol. The characterization of the SWCNT/Ni/GCE was performed by cyclic voltammetry. Variable pressure scanning electron microscopy (VPSEM and energy dispersive X-ray (EDX spectrometer were used to examine the surface morphology and elemental profile of the modified electrode, respectively. Cyclic voltammetry showed significant enhancement in peak current for the determination of paracetamol at the SWCNT/Ni-modified electrode. A linear calibration curve was obtained for the paracetamol concentration between 0.05 and 0.50 mM. The SWCNT/Ni/GCE displayed a sensitivity of 64 mA M−1 and a detection limit of 1.17 × 10−7 M in paracetamol detection. The proposed electrode can be applied for the determination of paracetamol in real pharmaceutical samples with satisfactory performance. Results indicate that electrodes modified with SWCNT and nickel nanoparticles exhibit better electrocatalytic activity towards paracetamol.

Platinized titanium dioxide electrodes for methanol oxidation and photo-oxidation

Directory of Open Access Journals (Sweden)

IOANNIS POULIOS

2012-11-01

Full Text Available Platinized deposits have been formed on TiO2 particulate films supported on Ti substrates, by means of galvanic replacement of pre-deposited metallic Cu and subsequent immersion of the Cu/TiO2 coatings into a chloroplatinic acid solution. The spontaneous replacement of Cu by Pt results in Pt(Cu/TiO2/Ti electrodes. Both the platinized and the precursor TiO2/Ti electrodes have been characterized by SEM micro­scopy/EDS spectroscopy, their surface electrochemistry has been assessed by cyclic voltammetry in the dark and their photoelectrochemical properties by photovolta­m­metry under UV illumination. It has been found that, although platinized rutile-rich electrodes exhibit typical Pt surface electrochemistry, the anatase-rich electrodes show only traces of oxide formation and stripping. The latter has been translated to a suppression of methanol oxidation at anatase-rich electrodes. On the contrary, methanol oxidation at platinized rutile-rich electrodes occurs at significant rates and can be further enhanced upon UV illumination, as a result of Pt and TiO2 synergism in the photoelectrochemical oxidation of methanol.

Polynitroaniline as brightener for zinc–nickel alloy plating from non ...

Indian Academy of Sciences (India)

Corrosion resistance test revealed good protection of base metal by zinc–nickel coating obtained from the ... Electroplated zinc coatings are considered as one of the many ways of corrosion ... oxidation of orthonitroaniline. Graphite electrodes ...

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.

Impedances of nickel electrodes cycled in various KOH concentrations

Science.gov (United States)

Reid, Margaret A.; Loyselle, Patricia L.

1991-01-01

Recent tests at Hughes have shown that Ni/H2 cells cycled in 26 percent KOH have much longer lives than those cycled in other concentrations. As part of an ongoing program to try to correlate the impedances of nickel electrodes with their life and performance, impedances were measured of a number of electrodes from these tests that had been cycled in concentrations from 21 to 36 percent KOH. These had ranged from about 1000 to 40,000 cycles. After cycling ten times to reduce possible changes due to storage, impedances were measured at five voltages corresponding to low states of charge. The results were analyzed using a standard circuit model including Warburg impedance term. Lower kinetic resistances and Warburg slopes were found for several electrodes which had been cycled in 26 percent KOH even though they had been cycled for a much longer time than the others. Interpretation of the data is complicated by the fact that the cycle lives, storage times, and failure mechanisms varied. Several other circuit models have also been examined, but the best correlations with life were found with parameters obtained from the simple model.

Electrochemical Behaviour of Ni and Ni-PVC Electrodes for the Electroxidation of Ethanol

International Nuclear Information System (INIS)

Mohd Syafiq Hamdan; Norazzizi Nordin; Siti Fathrita Mohd Amir; Riyanto; Mohamed Rozali Othman

2011-01-01

In this study, two nickel based electrodes were prepared; nickel foil and nickel-polyvinylchloride (Ni-PVC), in order to study their electrochemical behavior using cyclic voltammetry, CV and chronocoulometry, CC. Ni electrode was prepared from Ni metal foil while Ni-PVC electrode was prepared by mixing a weighed portion of Ni powder and PVC in THF solvent, swirled until the suspension was homogeneous and drying the suspension in an oven at 50 degree Celsius for 3 h. The dry sample was then placed in a 1 cm diameter stainless steel mould and pressed at 10 ton/ cm 2 . From CV data, Ni-PVC electrode showed a better electrochemical behavior compared to Ni metal foil electrode. The use of Ni-PVC electrode at higher concentration of supporting electrolyte (1.0 M KOH) was better than at lower concentration of the same supporting electrolyte in electroxidation of ethanol. In addition to acetic acid, the oxidation of ethanol also produced ethyl acetate and acetaldehyde. (author)

Monodispersed macroporous architecture of nickel-oxide film as an anode material for thin-film lithium-ion batteries

International Nuclear Information System (INIS)

Wu, Mao-Sung; Lin, Ya-Ping

2011-01-01

A nickel-oxide film with monodispersed open macropores was prepared on a stainless-steel substrate by electrophoretic deposition of a polystyrene-sphere monolayer followed by anodic electrodeposition of nickel oxy-hydroxide. The deposited films convert to cubic nickel oxide after annealing at 400 o C for 1 h. Galvanostatic charge and discharge results indicate that the nickel-oxide film with monodispersed open macropores is capable of delivering a higher capacity than the bare nickel-oxide film, especially in high-rate charge and discharge processes. The lithiation capacity of macroporous nickel oxide reaches 1620 mA h g -1 at 1 C current discharge and decreases to 990 mA h g -1 at 15 C current discharge. The presence of monodispersed open macropores in the nickel-oxide film might facilitate the electrolyte penetration, diffusion, and migration. Electrochemical reactions between nickel oxide and lithium ions are therefore markedly improved by this tailored film architecture.

Graphene hydrogels deposited in nickel foams for high-rate electrochemical capacitors.

Science.gov (United States)

Chen, Ji; Sheng, Kaixuan; Luo, Peihui; Li, Chun; Shi, Gaoquan

2012-08-28

Graphene hydrogel/nickel foam composite electrodes for high-rate electrochemical capacitors are produced by reduction of an aqueous dispersion of graphene oxide in a nickel foam (upper half of figure). The micropores of the hydrogel are exposed to the electrolyte so that ions can enter and form electrochemical double-layers. The nickel framework shortens the distances of charge transfer. Therefore, the electrochemical capacitor exhibits highrate performance (see plots). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of oxidation of self-baking electrodes (Soederberg electrodes) by means of three-dimensional model

Science.gov (United States)

Pashnin, S. V.

2017-10-01

The paper presents the methodology and results of the development of the temperature dependence of the oxidation speed of the self-baking electrode (Soederberg Electrodes) in the ore-thermal furnaces. For the study of oxidation, the working ends of the self-baking electrodes, which were taken out from the ore-thermal furnaces after their scabbings, were used. The temperature of the electrode surface by its height was calculated with the help of the mathematical model of heat work of self-baking electrode. The comparison of electrode surface temperatures with the speed of oxidation of the electrode allowed one to obtain the temperature dependency of the oxidation of the lateral electrode surface. Comparison of the experimental data, obtained in the laboratory by various authors, showed their qualitative coincidence with results of calculations of the oxidation rate presented in this article. With the help of the mathematical model of temperatures fields of electrode, the calculations of the sizes of the cracks, appearing after burnout ribs, were performed. Calculations showed that the sizes of the cracks after the ribs burnout, calculated by means of the obtained temperature dependence, coincide with the experimental data with sufficient accuracy.

Insights into the Surface Reactivity of Cermet and Perovskite Electrodes in Oxidizing, Reducing, and Humid Environments.

Science.gov (United States)

Paloukis, Fotios; Papazisi, Kalliopi M; Dintzer, Thierry; Papaefthimiou, Vasiliki; Saveleva, Viktoriia A; Balomenou, Stella P; Tsiplakides, Dimitrios; Bournel, Fabrice; Gallet, Jean-Jacques; Zafeiratos, Spyridon

2017-08-02

Understanding the surface chemistry of electrode materials under gas environments is important in order to control their performance during electrochemical and catalytic applications. This work compares the surface reactivity of Ni/YSZ and La 0.75 Sr 0.25 Cr 0.9 Fe 0.1 O 3 , which are commonly used types of electrodes in solid oxide electrochemical devices. In situ synchrotron-based near-ambient pressure photoemission and absorption spectroscopy experiments, assisted by theoretical spectral simulations and combined with microscopy and electrochemical measurements, are used to monitor the effect of the gas atmosphere on the chemical state, the morphology, and the electrical conductivity of the electrodes. It is shown that the surface of both electrode types readjusts fast to the reactive gas atmosphere and their surface composition is notably modified. In the case of Ni/YSZ, this is followed by evident changes in the oxidation state of nickel, while for La 0.75 Sr 0.25 Cr 0.9 Fe 0.1 O 3 , a fine adjustment of the Cr valence and strong Sr segregation is observed. An important difference between the two electrodes is their capacity to maintain adsorbed hydroxyl groups on their surface, which is expected to be critical for the electrocatalytic properties of the materials. The insight gained from the surface analysis may serve as a paradigm for understanding the effect of the gas environment on the electrochemical performance and the electrical conductivity of the electrodes.

Preparation and characterization of nickel oxide nanoparticles and their application in glucose and methanol sensing

Directory of Open Access Journals (Sweden)

Mahsa Hasanzadeh

2015-03-01

Full Text Available In this work, a low cost glucose and methanol nonenzymatic sensor was prepared using nickel oxide (NiO nanofilm electrodeposited on a bare Cu electrode. Electrochemical deposition was assisted with cetyl trimethylammonium bromide (CTAB as a template. Scanning electron microscopy (SEM was applied to observe the surface morphology of the modified electrode. Cyclic voltammetry (CV and amperometry techniques were used to study the electrocatalytic behavior of NiO porous film in glucose and methanol detection. For glucose sensing, the electrode showed a linear relationship in the concentration range of 0.01-2.14 mM with a low limit of detection (LOD 1.7 µM (signal/noise ratio (S/N=3. Moreover, high sensitivities of 4.02 mA mM−1 cm−2 and 0.38 mA mM−1 cm−2 respectively in glucose and methanol monitoring suggested the modified electrode as an excellent sensor. The NiO-Cu modified electrode was relatively insensitive to common biological interferers. This sensor possessed good poison resistance towards chloride ions, and long term stability and significant selectivity towards glucose and methanol. Finally the proposed sensor was successfully applied for determination of glucose in human blood serum samples.

Thermal Oxidation of a Carbon Condensate Formed in High-Frequency Carbon and Carbon-Nickel Plasma Flow

Science.gov (United States)

Churilov, G. N.; Nikolaev, N. S.; Cherepakhin, A. V.; Dudnik, A. I.; Tomashevich, E. V.; Trenikhin, M. V.; Bulina, N. G.

2018-02-01

We have reported on the comparative characteristics of thermal oxidation of a carbon condensate prepared by high-frequency arc evaporation of graphite rods and a rod with a hollow center filled with nickel powder. In the latter case, along with different forms of nanodisperse carbon, nickel particles with nickel core-carbon shell structures are formed. It has been found that the processes of the thermal oxidation of carbon condensates with and without nickel differ significantly. Nickel particles with the carbon shell exhibit catalytic properties with respect to the oxidation of nanosized carbon structures. A noticeable difference between the temperatures of the end of the oxidation process for various carbon nanoparticles and nickel particles with the carbon shell has been established. The study is aimed at investigations of the effect of nickel nanoparticles on the dynamics of carbon condensate oxidation upon heating in the argon-oxygen flow.

The Effect of Annealing Temperature on Nickel on Reduced Graphene Oxide Catalysts on Urea Electrooxidation

International Nuclear Information System (INIS)

Glass, Dean E.; Galvan, Vicente; Prakash, G.K. Surya

2017-01-01

Highlights: •Nickel was reduced on graphene oxide and annealed under argon from 300 to 700 °C. •Nickel was oxidized from the removal of oxygen groups on the graphene oxide. •Higher annealed catalysts displayed decreased urea electrooxidation currents. •Micro direct urea/hydrogen peroxide fuel cells were employed for the first time. •Ni/rGO catalysts displayed enhanced fuel cell performance than the bare nickel. -- Abstract: The annealing temperature effects on nickel on reduced graphene oxide (Ni/rGO) catalysts for urea electrooxidation were investigated. Nickel chloride was directly reduced in an aqueous solution of graphene oxide (GO) followed by annealing under argon at 300, 400, 500, 600, and 700 °C, respectively. X-ray Diffraction (XRD) patterns revealed an increase in the crystallite size of the nickel nanoparticles while the Raman spectra displayed an increase in the graphitic disorder of the reduced graphene oxide at higher annealing temperatures due to the removal of oxygen functional groups. The Ni/rGO catalysts annealed at higher temperatures displayed oxidized nickel surface characteristics from the Ni 2p X-ray Photoelectron Spectra (XPS) due to the oxidation of the nickel from the oxygen functional groups in the graphitic lattice. In the half-cell testing, the onset potential of urea electrooxidation decreased while the urea electrooxidation currents decreased as the annealing temperature was increased. The nickel catalyst annealed at 700 °C displayed a 31% decrease in peak power density while the catalyst annealed at 300 °C displayed a 13% increase compared with the unannealed Ni/rGO catalyst in the micro direct urea/hydrogen peroxide fuel cells tests.

Batch fabrication of mesoporous boron-doped nickel oxide nanoflowers for electrochemical capacitors

International Nuclear Information System (INIS)

Yang, Jing-He; Yu, Qingtao; Li, Yamin; Mao, Liqun; Ma, Ding

2014-01-01

Highlights: • A new facile liquid-phase method has been employed for synthesis boron-doped NiO nanoflowers. • The specific surface area of NiO is as high as 200 m 2 g −1 . • NiO nanoflowers exhibit a high specific capacitance of ∼1309 F g −1 at a charge and discharge current density of 3 A g −1 . • NiO nanoflowers have excellent cycling ability and even after 2500 cycles there is no significant reduction in specific capacitance. - Abstract: Boron-doped nickel oxide (B-NiO) nanoflowers are prepared by simple thermal decomposition of nickel hydroxide. B-NiO is porous sphere with a diameter of about 400 nm. B-NiO nanoflowers are composed of approximately 30 nm nanoplates and the thickness of the nanosheets is approximately 3 nm. The specific surface area of the material is as high as 200 m 2 g −1 and the pore size distribution curves of B-NiO has three typical peaks in the range of mesoporous (5 nm, 13 nm and 18 nm). As an electrode for supercapacitors, the crystalline B-NiO nanoflowers have favorable characteristics, for instance, a specific capacitance of 1309 F g −1 at a current density of 3 A g −1 and no significant reduction in Coulombic efficiency after 2500 cycles at 37.5 A g −1 . This remarkable electrochemical performance will make B-NiO nanoflowers a promising electrode material for high performance supercapacitors

Critical survey on electrode aging in molten carbonate fuel cells

Energy Technology Data Exchange (ETDEWEB)

Kinoshita, K.

1979-12-01

To evaluate potential electrodes for molten carbonate fuel cells, we reviewed the literature pertaining to these cells and interviewed investigators working in fuel cell technology. In this critical survey, the effect of three electrode aging processes - corrosion or oxidation, sintering, and poisoning - on these potential fuel-cell electrodes is presented. It is concluded that anodes of stabilized nickel and cathodes of lithium-doped NiO are the most promising electrode materials for molten carbonate fuel cells, but that further research and development of these electrodes are needed. In particular, the effect of contaminants such as H/sub 2/S and HCl on the nickel anode must be investigated, and methods to improve the physical strength and to increase the conductivity of NiO cathodes must be explored. Recommendations are given on areas of applied electrode research that should accelerate the commercialization of the molten carbonate fuel cell. 153 references.

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).

Size-dependent magnetic properties of branchlike nickel oxide nanocrystals

Directory of Open Access Journals (Sweden)

Dan Liu

2017-01-01

Full Text Available Branchlike nickel oxide nanocrystals with narrow size distribution are obtained by a solution growth method. The size-dependent of magnetic properties of the nickel oxides were investigated. The results of magnetic characterization indicate that the NiO nanocrystals with size below 12.8 nm show very weak ferromagnetic state at room temperature due to the uncompensated spins. Both of the average blocking temperature (Tb and the irreversible temperature (Tirr increase with the increase of nanoparticle sizes, while both the remnant magnetization and the coercivity at 300 K increase with the decrease of the particle sizes. Moreover, the disappearance of two-magnon (2M band and redshift of one-phonon longitudinal (1LO and two-phonon LO in vibrational properties due to size reduction are observed. Compared to the one with the spherical morphological, it is also found that nano-structured nickel oxides with the branchlike morphology have larger remnant magnetization and the coercivity at 5 K due to their larger surface-to-volume ratio and greater degree of broken symmetry at the surface or the higher proportion of broken bonds.

Kinetics of oxidation of nickel(II) aza macrocycles by ...

Indian Academy of Sciences (India)

The kinetics of the oxidation of nickel (II) hexaaza and nickel (II) pentaaza macrocycles by the peroxydisulphate anion, S2O8 2-, were studied in aqueous media. Effect of H on reaction rate was also studied. The rate increases with increase of S2OO8 2- concentration. Rates are almost independent of acid between H 4 ...

The development of hydrogen storage electrode alloys for nickel hydride batteries

Science.gov (United States)

Hong, Kuochih

The development of hydrogen storage electrode alloys in the 1980s resulted in the birth and growth of the rechargeable nickel hydride (Ni/MH) battery. In this paper we describe briefly a semi-empirical electrochemical/thermodynamic approach to develop/screen a hydrogen storage alloy for electrochemical application. More specifically we will discuss the AB x Ti/Zr-based alloys. Finally, the current state of the Ni/MH batteries including commercial manufacture processes, cell performance and applications is given.

Three-dimensional cotton-like nickel nanowire@Ni-Co hydroxide nanosheet arrays as binder-free electrode for high-performance asymmetric supercapacitor

Science.gov (United States)

Wan, Houzhao; Li, Lang; Xu, Yang; Tan, Qiuyang; Liu, Xiang; Zhang, Jun; Wang, Hanbin; Wang, Hao

2018-05-01

Three-dimensional (3D) cotton-like Ni-Co layered double hydroxide nanosheet arrays/nickel nanowires (3D Ni-Co LDH/NiNw) were successfully fabricated through a facile chemical bath deposition method. The 3D nickel nanowires are used as a conductive substrate with robust adhesion for high-pseudocapacitance Ni-Co LDH. The 3D Ni-Co LDH/NiNw electrode shows a high areal specific capacitance of 14 F cm-2 at 5 mA cm-2 and quality specific capacitance of 466.6 F g-1 at 0.125 A g-1 with respect to the whole quality of the electrode. The fabricated asymmetric supercapacitor exhibits a remarkable energy density of 0.387 mWh cm-2 using Ni-Co LDH/NiNw as the negative electrode. This high-performance composite electrode presents a new and affordable general approach for supercapacitors.

High Electrocatalytic Performance of CuCoNi@CNTs Modified Glassy Carbon Electrode towards Methanol Oxidation in Alkaline Medium

Directory of Open Access Journals (Sweden)

Amina A. Hamza

2017-01-01

Full Text Available A novel non-precious multiwalled carbon nanotubes (CNTs—supported metal oxide electrocatalyst was developed for methanol electrooxidation in alkaline medium. The catalyst was fabricated by simultaneous electrodeposition of copper-cobalt-nickel ternary nanostructures (CuCoNi on a glassy carbon electrode (GCE modified with CNTs. The proposed electrode was characterized using X-ray diffraction (XRD, energy dispersive X-ray (EDX, and scanning electron microscopy (SEM. The electrochemical behavior and the electrocatalytic performance of the suggested electrode towards the oxidation of methanol were evaluated by cyclic voltammetry (CV, linear sweep voltammetry (LSV, and chronoamperometry (CA in alkaline medium. Several parameters were investigated, e.g., deposition time, potential scan rate, etc. Compared to Cu, Co, or Ni mono electrocatalysts, the electrode based on ternary-metals exhibited superior electrocatalytic activity and stability towards methanol electrooxidation. For instance, CuCoNi@CNTs/GCE has shown at least 2.5 times electrocatalytic activity and stability compared to the mono eletrocatalysts. Moreover, the present study found that the optimized loading level is 1500 s of simultaneous electrodeposition. At this loading level, it was found that the relation between the Ip/ν1/2 function and scan rate gives the characteristic features of a catalytic process. The enhanced activity and stability of CuCoNi@CNTs/GCE was attributed to (i a synergism between three metal oxides coexisting in the same structure; (ii the presence of CNTs as a support for the metal oxides, that offers high surface area for the deposited tertiary alloy and suppresses the aggregation and sintering of the metals oxide with time; as well as (iii the increase of the conductivity of the deposited semiconducting metal oxides.

Two – step approach of fabrication of three – dimensional reduced graphene oxide – carbon nanotubes – nickel foams hybrid as a binder – free supercapacitor electrode

International Nuclear Information System (INIS)

Xiong, Chuanyin; Li, Tiehu; Zhao, Tingkai; Shang, Yudong; Dang, Alei; Ji, Xianglin; Li, Hao; Wang, Jungao

2016-01-01

Highlights: • 3D rGO-CNTs-NF electrode is fabricated by combination of EPD and FCCVD. • EPD with excellent uniformity is an economical processing technique. • FCCVD is beneficial to obtain more compact and uniform VACNTs. • The hybrid shows a high specific capacitance of 236.18 F g −1 and a high energy density of 19.24 Wh kg −1 . • This work provides various assumptions for designing hierarchical rGO-based architecture. - Abstract: A facile method is designed to prepare 3D reduced graphene oxide (rGO) - carbon nanotubes (CNTs) - nickel foams (NF). In this research, the 3D rGO-CNTs-NF electrode is fabricated by combination of electrophoretic deposition and floating catalyst chemical vapor deposition. The vertically-aligned CNTs forests not only effectively prevent stacking of rGO sheets but also facilitate the electron transfer during the charge/discharge process and contribute to the whole capacitance. Moreover, the 3D rGO-CNTs-NF hybrid can be used directly as electrodes of supercapacitor without binder. Additionally, the hybrid shows a specific capacitance of 236.18 F g −1 which is much higher than that of the rGO - NF electrode (100.23 F g −1 ). Importantly, the energy density and power density of 3D rGO-CNTs-NF are respectively as high as 19.24 Wh kg −1 and 5398 W kg −1 , indicating that our work provides a way to design hierarchical rGO-based architecture composed of rGO, CNTs and various electroactive materials for high-performance energy storage devices.

Electrochemical oxidation of nitrite on nanodiamond powder electrode

Energy Technology Data Exchange (ETDEWEB)

Chen, L.H.; Zang, J.B.; Wang, Y.H.; Bian, L.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

2008-03-10

Nanodiamond (ND) powder electrodes were fabricated and the electrochemical properties were investigated in the solution containing nitrite in this article. This electrode exhibits substantial catalytic ability toward the oxidation of nitrite anions. The electrochemical oxidation mechanism of nitrite on the ND powder electrode is discussed. The oxidation of NaNO{sub 2} is a two-electron transfer process. The electrode reaction rate constant k is estimated to be 2.013 x 10{sup -4} cm/s and (1 - {alpha})n{sub {alpha}} is 0.1643. The peak current increases linearly with the rising of the concentration of NaNO{sub 2}. (author)

Three-dimensional hierarchical porous flower-like nickel-cobalt oxide/multi-walled carbon nanotubes nanocomposite for high-capacity supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Liu, Peipei; Hu, Zhonghua, E-mail: huzh@tongji.edu.cn; Liu, Yafei; Yao, Mingming; Zhang, Qiang

2015-02-15

Highlights: • 3D hierarchical porous flower-like Ni-Co oxide/MWCNTs was synthesized. • The electrode shows a large specific surface area and desirable mesoporosity. • High specific capacitances and outstanding stability were obtained. • The content of MWCNTs affects the electrochemical properties of the electrode. - Abstract: Three-dimensional (3D) hierarchical porous flower-like nickel-cobalt oxide/multi-walled carbon nanotubes (Ni-Co oxide/MWCNTs) nanocomposites were fabricated by a facile and template-free hydrothermal method as electrodes for high-capacity supercapacitors. The samples were characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption and thermal gravimetric analysis (TGA). The electrochemical performance was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge, and cycle life. It was found that Ni-Co oxide/MWCNTs nanocomposites displayed a high specific capacitance (1703 F g{sup −1} at a discharge current density of 1 A g{sup −1}) and, additionally, an excellent cycling performance, retaining 97% of the maximum capacitance after 2000 cycles at 10 A g{sup −1}. Even at a high current density (20 A g{sup −1}), the specific capacitance was still up to 1309 F g{sup −1}. This outstanding capacitive performance may be attributed to the ideal composition of the material and to its unique 3D hierarchical porous flower-like architecture.

Three-dimensional hierarchical porous flower-like nickel-cobalt oxide/multi-walled carbon nanotubes nanocomposite for high-capacity supercapacitors

International Nuclear Information System (INIS)

Liu, Peipei; Hu, Zhonghua; Liu, Yafei; Yao, Mingming; Zhang, Qiang

2015-01-01

Highlights: • 3D hierarchical porous flower-like Ni-Co oxide/MWCNTs was synthesized. • The electrode shows a large specific surface area and desirable mesoporosity. • High specific capacitances and outstanding stability were obtained. • The content of MWCNTs affects the electrochemical properties of the electrode. - Abstract: Three-dimensional (3D) hierarchical porous flower-like nickel-cobalt oxide/multi-walled carbon nanotubes (Ni-Co oxide/MWCNTs) nanocomposites were fabricated by a facile and template-free hydrothermal method as electrodes for high-capacity supercapacitors. The samples were characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption and thermal gravimetric analysis (TGA). The electrochemical performance was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge, and cycle life. It was found that Ni-Co oxide/MWCNTs nanocomposites displayed a high specific capacitance (1703 F g −1 at a discharge current density of 1 A g −1 ) and, additionally, an excellent cycling performance, retaining 97% of the maximum capacitance after 2000 cycles at 10 A g −1 . Even at a high current density (20 A g −1 ), the specific capacitance was still up to 1309 F g −1 . This outstanding capacitive performance may be attributed to the ideal composition of the material and to its unique 3D hierarchical porous flower-like architecture

PREPARATION OF NICKEL - COBALT SPINEL OXIDES NixCO3 ...

African Journals Online (AJOL)

degree of crystallinity give rise to reversible nickel incorporation. Pellets ... are of interest in solid oxide fuel cell and this is one of the features which make them attractive ... oxide system can only be obtained in a limited composition extent.

Nickel doped cobalt sulfide as a high performance counter electrode for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Hee-Je; Kim, Chul-Woo; Punnoose, Dinah; Gopi, Chandu V.V.M.; Kim, Soo-Kyoung; Prabakar, K.; Rao, S. Srinivasa, E-mail: srinu.krs@gmail.com

2015-02-15

Graphical abstract: - Highlights: • First ever employment of Ni doped CoS{sub 2} counter electrode as a replacement of Pt counter electrode. • Efficiency of 5.50% was achieved using Ni doped CoS{sub 2} counter electrode in contrast to 5.21% efficiency obtained using Pt electrode. • Dependency of efficiency on Ni dopant reported for the first time. • Cost effective chemical bath deposition was used for the fabrication of the counter electrode. - Abstract: The use of cells based on cobalt sulfide (CoS{sub 2}) and nickel sulfide (NiS) has found a steep upsurge in solar cell applications and as a substitute for conventional Pt-based cells owing to their low cost, low-temperature processing ability, and promising electro-catalytic activity. In this study, CoS{sub 2}, NiS and Ni-doped CoS{sub 2} nanoparticles were incorporated on a fluorine-doped tin oxide (FTO) substrate by simple chemical bath deposition (CBD). The surface morphology of the obtained films was analyzed by scanning electron microscope. Tafel polarization, electrochemical impedance spectroscopy and cyclic voltammograms of the Ni-doped CoS{sub 2} (Ni 15%) films indicated enhanced electro-catalytic activity for I{sub 3}{sup −} reduction in dye sensitized solar cells (DSSCs) compared to a Pt CE. The Ni-doped CoS{sub 2} CE also showed an impressive photovoltaic conversion efficiency of 5.50% under full sunlight illumination (100 mW cm{sup −2}, AM 1.5 G), exceeding that of DSSCs using a Pt CE (5.21%). We show that the highest conversion efficiency mainly depends on the charge transfer resistance and adequate Ni ion doping with CoS{sub 2} nanoparticles.

First principles nickel-cadmium and nickel hydrogen spacecraft battery models

Energy Technology Data Exchange (ETDEWEB)

Timmerman, P.; Ratnakumar, B.V.; Distefano, S.

1996-02-01

The principles of Nickel-Cadmium and Nickel-Hydrogen spacecraft battery models are discussed. The Ni-Cd battery model includes two phase positive electrode and its predictions are very close to actual data. But the Ni-H2 battery model predictions (without the two phase positive electrode) are unacceptable even though the model is operational. Both models run on UNIX and Macintosh computers.

Effect of charge state and stoichiometry on the structure and reactivity of nickel oxide clusters with CO

Science.gov (United States)

Johnson, Grant E.; Reilly, Nelly M.; Castleman, A. W., Jr.

2009-02-01

The collision induced fragmentation and reactivity of cationic and anionic nickel oxide clusters with carbon monoxide were studied experimentally using guided-ion-beam mass spectrometry. Anionic clusters with a stoichiometry containing one more oxygen atom than nickel atom (NiO2-, Ni2O3-, Ni3O4- and Ni4O5-) were found to exhibit dominant products resulting from the transfer of a single oxygen atom to CO, suggesting the formation of CO2. Of these four species, Ni2O3- and Ni4O5- were observed to be the most reactive having oxygen transfer products accounting for approximately 5% and 10% of the total ion intensity at a maximum pressure of 15 mTorr of CO. Our findings, therefore, indicate that anionic nickel oxide clusters containing an even number of nickel atoms and an odd number of oxygen atoms are more reactive than those with an odd number of nickel atoms and an even number of oxygen atoms. The majority of cationic nickel oxides, in contrast to anionic species, reacted preferentially through the adsorption of CO onto the cluster accompanied by the loss of either molecular O2 or nickel oxide units. The adsorption of CO onto positively charged nickel oxides, therefore, is exothermic enough to break apart the gas-phase clusters. Collision induced dissociation experiments, employing inert xenon gas, were also conducted to gain insight into the structural properties of nickel oxide clusters. The fragmentation products were found to vary considerably with size and stoichiometry as well as ionic charge state. In general, cationic clusters favored the collisional loss of molecular O2 while anionic clusters fragmented through the loss of both atomic oxygen and nickel oxide units. Our results provide insight into the effect of ionic charge state on the structure of nickel oxide clusters. Furthermore, we establish how the size and stoichiometry of nickel oxide clusters influences their ability to oxidize CO, an important reaction for environmental pollution abatement.

Hydrogen oxidation mechanisms on Ni/yttria stabilized zirconia anodes: Separation of reaction pathways by geometry variation of pattern electrodes

Science.gov (United States)

Doppler, M. C.; Fleig, J.; Bram, M.; Opitz, A. K.

2018-03-01

Nickel/yttria stabilized zirconia (YSZ) electrodes are affecting the overall performance of solid oxide fuel cells (SOFCs) in general and strongly contribute to the cell resistance in case of novel metal supported SOFCs in particular. The electrochemical fuel conversion mechanisms in these electrodes are, however, still only partly understood. In this study, micro-structured Ni thin film electrodes on YSZ with 15 different geometries are utilized to investigate reaction pathways for the hydrogen electro-oxidation at Ni/YSZ anodes. From electrodes with constant area but varying triple phase boundary (TPB) length a contribution to the electro-catalytic activity is found that does not depend on the TPB length. This additional activity could clearly be attributed to a yet unknown reaction pathway scaling with the electrode area. It is shown that this area related pathway has significantly different electrochemical behavior compared to the TPB pathway regarding its thermal activation, sulfur poisoning behavior, and H2/H2O partial pressure dependence. Moreover, possible reaction mechanisms of this reaction pathway are discussed, identifying either a pathway based on hydrogen diffusion through Ni with water release at the TPB or a path with oxygen diffusion through Ni to be a very likely explanation for the experimental results.

Reactivating the Ni-YSZ electrode in solid oxide cells and stacks by infiltration

DEFF Research Database (Denmark)

Skafte, Theis Løye; Hjelm, Johan; Blennow Tullmar, Peter

2018-01-01

for repairing various failure and degradation mechanisms occurring in the fuel electrode, thereby extending the potential lifetime of a SOC system. We successfully infiltrated the nickel and yttria-stabilized zirconia cermet electrode in commercial cells with Gd-doped ceria after operation. By this method we...

Oxidation resistance of nickel alloys at high temperature

International Nuclear Information System (INIS)

Tyuvin, Yu.D.; Rogel'berg, I.L.; Ryabkina, M.M.; Plakushchaya, A.F.

1977-01-01

The heat resistance properties of nickel alloys Ni-Cr-Si, Ni-Si-Al, Ni-Si-Mn and Ni-Al-Mn have been studied by the weight method during oxidation in air at 1000 deg and 1200 deg C. It is demonstrated that manganese reduces the heat resistance properties of Ni-Si and Ni-Al alloys, whilst the addition of over 3% aluminium enhances the heat resistance properties of Ni-Si (over 1.5%) alloys. The maximum heat resistance properties are shown by Ni-Si-Al and Ni-Cr-Si alloys with over 2% Si. These alloys offer 3 to 4 times better oxidation resistance as compared with pure nickel at 1000 deg C and 10 times at 1200 deg C

Nickel tungstate (NiWO4) nanoparticles/graphene composites: preparation and photoelectrochemical applications

Science.gov (United States)

Hosseini, Seyyedamirhossein; Farsi, Hossein; Moghiminia, Shokufeh; Zubkov, Tykhon; Lightcap, Ian V.; Riley, Andrew; Peters, Dennis G.; Li, Zhihai

2018-05-01

Nickel tungstate/graphene composite was synthesized in various compositions with application of a hydrothermal method. Chemical composition and morphology of each sample was studied via application of x-ray diffraction and transmission electron microscopy techniques. In the continuous, a photosystem was obtained by deposition of composite sample on a fluorine-doped tin oxide electrode with application of electrophoretic method. Electrode morphology was studied by employment of atomic force microscopy and SEM techniques. Eventually, light conversion properties and involved mechanism of fabricated photosystem was studied with application of the Mott–Schottky method. Our results confirmed that the optimum ratio between graphene and nickel tungstate is in the regime of 1:1.

Electrochemical activity of iron in acid treated bentonite and influence of added nickel

Energy Technology Data Exchange (ETDEWEB)

Mudrinić, T., E-mail: tihana@nanosys.ihtm.bg.ac.rs [University of Belgrade-Institute of Chemistry, Technology and Metallurgy, Center for Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Mojović, Z.; Milutinović-Nikolić, A. [University of Belgrade-Institute of Chemistry, Technology and Metallurgy, Center for Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Mojović, M. [University of Belgrade, Faculty of Physical Chemistry, Studenski trg 12-16, 11000 Belgrade (Serbia); Žunić, M. [University of Belgrade-Institute of Chemistry, Technology and Metallurgy, Center for Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Vukelić, N. [University of Belgrade, Faculty of Physical Chemistry, Studenski trg 12-16, 11000 Belgrade (Serbia); Jovanović, D. [University of Belgrade-Institute of Chemistry, Technology and Metallurgy, Center for Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia)

2015-10-30

Highlights: • Mild acid treatment followed by incorporation of nickel was performed on bentonite. • Modified bentonites based electrodes were tested in H{sub 2}SO{sub 4} by cyclic voltammetry. • Acid treatment increased current response of electroactive iron within smectite. • Incorporation of Ni improved reversibility of Fe{sup 2+}/Fe{sup 3+} oxidation/reduction process. - Abstract: Bentonite originated from Mečji Do, Serbia, was submitted to acid treatment at 70 °C for 30 min, while only the concentration of applied HCl varied. The obtained acid treated samples were used to modify glassy carbon (GC) electrode. The effect of applied acid treatment on the electrochemical behavior of GC electrodes modified with these materials was investigated. Furthermore, the effect of the introduction of nickel into acid treated samples was studied. The incorporation of nickel into acid treated bentonite was achieved by either ion exchange or impregnation/decomposition method. The obtained samples were characterized using the following methods: inductively coupled plasma (ICP), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and electron spin resonance (ESR) spectroscopy. The electrochemical behavior of these samples was tested by cyclic voltammetry in 0.1 mol dm{sup −3} H{sub 2}SO{sub 4} solution. The ICP, FTIR and ESR results exhibited a slight decrease of iron content in the acid treated samples. XRD and FTIR results confirmed that the conditions applied for the acid treatment were mild enough for the smectite structure to be preserved. The electrocatalytic test showed that the current response of Fe{sup 2+}/Fe{sup 3+} oxidation/reduction process increased on the GC electrodes separately modified with each of the acid treated samples in comparison with current obtained on the GC electrode modified with untreated sample. These results indicated that applied acid treatment probably increased the accessibility of the electroactive iron within

Liquid membrane ion-selective electrodes for potentiometric dosage of coper and nickel

Directory of Open Access Journals (Sweden)

MARIA PLENICEANY

2005-02-01

Full Text Available This paper presents experimental and theoretical data regarding the preparation and characterization of three liquid-membrane electrodes, which have not been mentioned in the specialized literature so far. The active substances, the solutions of which in nitrobenzene formed the membranes on a graphite rod, are simple complex combinations of Cu(II and Ni(II ions with an organic ligand belonging to the Schiff base class: N-[2-thienylmethilidene]-2-aminoethanol (TNAHE. The Cu2+ -selective and Ni2+ -selective electrodes were used to determine the copper and nickel ions in aqueous solutions, both by direct potentiometry and by potentiometric titration with EDTA. They were also used for the determination of Cu2+ and Ni2+ ions in industrial waters by direct potentiometry.

Characterization of composite metal-ceramic of nickel-oxide cerium doped gadolinium

International Nuclear Information System (INIS)

Silva, M.L.A. da; Varela, M.C.R.S.

2016-01-01

Composite nickel doped cerium oxide are used in SOFC anode materials. In this study we evaluated the effect of the presence of gadolinium on the properties of composite nickel and ceria and. The supports were synthesized by sol-gel method. The impregnation with nickel nitrate was taken sequentially, followed by calcination. The materials were characterized by X-ray diffraction, measurement of specific surface area, temperature programmed reduction, Raman spectroscopy. The presence of gadolinium retained the fluorite structure of ceria by forming a solid solution, also not influencing significantly on the specific surface area of the support. On the other hand, there was a decrease in the area catalysts, which can be attributed to sintering of nickel. Furthermore, addition of gadolinium favored the formation of intrinsic and extrinsic vacancies in cerium oxide, which leads to an increase in the ionic conductivity of the solid, desirable property for an SOFC anode catalyst. (author)

Nickel Hexacyanoferrate Nanoparticle Electrodes For Aqueous Sodium and Potassium Ion Batteries

KAUST Repository

Wessells, Colin D.

2011-12-14

The electrical power grid faces a growing need for large-scale energy storage over a wide range of time scales due to costly short-term transients, frequency regulation, and load balancing. The durability, high power, energy efficiency, and low cost needed for grid-scale storage pose substantial challenges for conventional battery technology.(1, 2)Here, we demonstrate insertion/extraction of sodium and potassium ions in a low-strain nickel hexacyanoferrate electrode material for at least five thousand deep cycles at high current densities in inexpensive aqueous electrolytes. Its open-framework structure allows retention of 66% of the initial capacity even at a very high (41.7C) rate. At low current densities, its round trip energy efficiency reaches 99%. This low-cost material is readily synthesized in bulk quantities. The long cycle life, high power, good energy efficiency, safety, and inexpensive production method make nickel hexacyanoferrate an attractive candidate for use in large-scale batteries to support the electrical grid. © 2011 American Chemical Society.

Research and development of tungsten electrodes added with rare earth oxides

International Nuclear Information System (INIS)

Zuoren Nie; Ying Chen; Meiling Zhou; Tieyong Zuo

2001-01-01

The recent research and development of tungsten electrodes used in TIG and Plasma technologies are introduced, and the tungsten materials as well as the effects of rare earth oxides are specially discussed. in W-La 2 O 3 , W-CeO 2 , W-Y 2 O 3 and W-ThO 2 electrode materials, the W-2.2mass%La 2 O 3 electrode exhibited the best properties when the current is of little or middle volume, and when the electrodes are used in large current, the W-Y 2 O 3 electrode is the best. By a comparative study between the tungsten electrodes activated with single metal oxides, as above-mentioned, and those containing two or three rare earth oxides, namely La 2 O 3 , CeO 2 and Y 2 O 3 , it was indicated that the welding arc properties of the tungsten electrodes activated with combined rare earth oxides additions is superior than that of the electrodes containing single oxides as above mentioned. It was also shown that the operating properties of tungsten electrodes depend intensively on the rare earth oxides contained in the electrodes, and the actions of rare earth oxides during arcing are the most important factors to the electrodes' operating properties, temperature, work function as well as the arc stability. (author)

Investigation of supercapacitors with carbon electrodes obtained from argon-acetylene arc plasma

OpenAIRE

Kavaliauskas, Žydrūnas

2010-01-01

The dissertation examines topics related to the formation of supercapacitors using plasma technology and their analysis. Plasma spray technology was used to form supercapacitors electrodes. Carbon was deposited on stainless steel surface using the atmospheric pressure argon-acetylene plasma. The deposition of nickel oxide on the surface of carbon electrodes was made using magnetron sputtering method. The influence of acetylene amount to the supercapacitors electrodes and the electrical charac...

Reverse microemulsion synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide nanocomposites for high-performance supercapacitors and sodium ion batteries

Science.gov (United States)

Qiu, Xiaoming; Liu, Yongchang; Wang, Luning; Fan, Li-Zhen

2018-03-01

Prussian blue analogues with tunable open channels are of fundamental and technological importance for energy storage systems. Herein, a novel facile synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide (denoted as Ni-CoHCF/rGO) nanocomposite is realized by a reverse microemulsion method. The very fine Ni-CoHCF nanoparticles (10-20 nm) are homogeneously anchored on the surface of reduced graphene oxide by electrostatic adsorption and reduced graphene oxide is well-separated by Ni-CoHCF particles. Benefiting from the combined advantages of this structure, the Ni-. It CoHCF/rGO nanocomposite can be used as electrodes for both supercapacitors and sodium ion batteries exhibits excellent pseudocapacitve performance in terms of high specific capacitance of 466 F g-1 at 0.2 A g-1 and 350 F g-1 at 10 A g-1, along with high cycling stabilities. As a cathode material for sodium ion batteries, it also demonstrates a high reversible capacity of 118 mAh g-1 at 0.1 A g-1, good rate capability, and superior cycling stability. These results suggest its potential as an efficient electrode for high-performance energy storage and renewable delivery devices.

Fabrication technology of CNT-Nickel Oxide based planar pseudocapacitor for MEMS and NEMS

Science.gov (United States)

Lebedev, E. A.; Kitsyuk, E. P.; Gavrilin, I. M.; Gromov, D. G.; Gruzdev, N. E.; Gavrilov, S. A.; Dronov, A. A.; Pavlov, A. A.

2015-11-01

Fabrication technology of planar pseudocapacitor (PsC) based on carbon nanotube (CNT) forest, synthesized using plasma enhanced chemical vapor deposition (PECVD) method, covered with thin nickel oxide layer deposited by successive ionic layer adsorption and reaction (SILAR) method, is demonstrated. Dependences of deposited oxide layers thickness on device specific capacities is studied. It is shown that pseudocapacity of nickel oxide thin layer increases specific capacity of the CNT's based device up to 2.5 times.

Synthesis and characterization of nickel oxide particulate annealed at different temperatures

Science.gov (United States)

Sharma, Khem Raj; Thakur, Shilpa; Negi, N. S.

2018-04-01

Nickel oxide has been synthesized by solution combustion technique. The nickel oxide ceramic was annealed at 600°C and 1000°C for 2 hours. Structural, electrical, dielectric and magnetic properties were analyzed which are strongly dependent upon the synthesis method. Structural properties were examined by X-ray diffractometer (XRD), which confirmed the purity and cubic phase of nickel oxide. XRD data reveals the increase in crystallite size and decrease in full width half maximum (FWHM) as the annealing temperature increases. Electrical conductivity is found to increase from 10-6 to 10-5 (Ω-1cm-1) after annealing. Dielectric constant is observed to increase from 26 to 175 when the annealing temperature is increased from 600°C to 1000°C. Low value of coercive field is found which shows weak ferromagnetic behavior of NiO. It is observed that all the properties of NiO particulate improve with increasing annealing temperature.

Electrochemical removal of nickel ions from industrial wastewater

NARCIS (Netherlands)

Njau, K.N.; Woude, van der M.E.; Visser, G.J.; Janssen, L.J.J.

2000-01-01

The electrochemical reduction of nickel ions in dilute industrial wastewater from a galvanic nickel plating plant was carried out on a three-dimensional electrode in a gas diffusion electrode packed bed electrode cell (GBC) and also on a rotating disc electrode. To explain the experimental results,

Study of NiO cathode modified by rare earth oxide additive for MCFC by electrochemical impedance spectroscopy

International Nuclear Information System (INIS)

Huang Bo; Chen Gang; Li Fei; Yu Qingchun; Hu Keao

2004-01-01

The preparation and subsequent oxidation of nickel cathodes modified by impregnation with rare earth oxide were evaluated by surface and bulk analysis. The electrochemical behaviors of rare earth oxide impregnated nickel oxide cathodes were also evaluated in a molten 62 mol% Li 2 CO 3 +38 mol% K 2 CO 3 eutectic at 650 deg. C by electrochemical impedance spectroscopy (EIS) as a function of rare earth oxide content and immersion time. The rare earth oxide-impregnated nickel cathodes show almost the similar porosity, pore size, and morphology to the reference nickel cathode. The stability tests of rare earth oxide-impregnated nickel oxide cathodes show that the rare earth oxide additive can dramatically reduce the solubility of nickel oxide in a eutectic carbonate mixture under the standard cathode gas condition. The impedance response of all cathode materials at different immersion time is characterized by the presence of depressed semicircles in the high frequency range changing over into the lines with the angles of which observed with the real axis differing 45 deg. or 90 deg. in the low frequency range. The experimental Nyquist plots can be well analyzed theoretically with a modified model based on the well-known Randles-Ershler equivalent circuit model. In the new model, the double layer capacity (C d ) is replaced by the parallel combination of C d and b/ω; therefore, this circuit is modified to be the parallel combination of (C d ), b/ω, and the charge transfer resistance (R ct ) based on the Randles-Ershler equivalent circuit, to take into consideration both the non-uniformity of electric field at the electrode/electrolyte interface owing to the roughness of electrode surface, and the variety of relaxation times with adsorbed species on the electrode surface. The impedance spectra for all cathode materials show important variations during the 200 h of immersion. The incorporation of lithium in its structure and the low dissolution of nickel oxide and rare

Inkjet-printed p-type nickel oxide thin-film transistor

Science.gov (United States)

Hu, Hailong; Zhu, Jingguang; Chen, Maosheng; Guo, Tailiang; Li, Fushan

2018-05-01

High-performance inkjet-printed nickel oxide thin-film transistors (TFTs) with Al2O3 high-k dielectric have been fabricated using a sol-gel precursor ink. The "coffee ring" effect during the printing process was facilely restrained by modifying the viscosity of the ink to control the outward capillary flow. The impacts on the device performance was studied in detail in consideration of annealing temperature of the nickel oxide film and the properties of dielectric layer. The optimized switching ability of the device were achieved at an annealing temperature of 280 °C on a 50-nm-thick Al2O3 dielectric layer, with a hole mobility of 0.78 cm2/V·s, threshold voltage of -0.6 V and on/off current ratio of 5.3 × 104. The as-printed p-type oxide TFTs show potential application in low-cost, large-area complementary electronic devices.

Electrochemical characteristics of silver- and nickel-coated synthetic graphite prepared by a gas suspension spray coating method for the anode of lithium secondary batteries

International Nuclear Information System (INIS)

Choi, Won Chang; Byun, Dongjin; Lee, Joong Kee; Cho, Byung won

2004-01-01

Four kinds of synthetic graphite coated with silver and nickel for the anodes of lithium secondary batteries were prepared by a gas suspension spray coating method. The electrode coated with silver showed higher charge-discharge capacities due to a Ag-Li alloy, but rate capability decreased at higher charge-discharge rate. This result can be explained by the formation of an artificial Ag oxidation film with higher impedance, this lowered the rate capability at high charge-discharge rate due to its low electrical conductivity. Rate capability is improved, however, by coating nickel and silver together on the surface of synthetic graphite. The nickel which is inactive with oxidation reaction plays an important role as a conducting agent which enhanced the conductivity of the electrode

Nickel exposure induces oxidative damage to mitochondrial DNA in Neuro2a cells: the neuroprotective roles of melatonin.

Science.gov (United States)

Xu, Shang-Cheng; He, Min-Di; Lu, Yong-Hui; Li, Li; Zhong, Min; Zhang, Yan-Wen; Wang, Yuan; Yu, Zheng-Ping; Zhou, Zhou

2011-11-01

Recent studies suggest that oxidative stress and mitochondrial dysfunction play important roles in the neurotoxicity of nickel. Because mitochondrial DNA (mtDNA) is highly vulnerable to oxidative stress and melatonin can efficiently protect mtDNA against oxidative damage in various pathological conditions, the aims of this study were to determine whether mtDNA oxidative damage was involved in the neurotoxicity of nickel and to assay the neuroprotective effects of melatonin in mtDNA. In this study, we exposed mouse neuroblastoma cell lines (Neuro2a) to different concentrations of nickel chloride (NiCl(2), 0.125, 0.25, and 0.5 mm) for 24 hr. We found that nickel significantly increased reactive oxygen species (ROS) production and mitochondrial superoxide levels. In addition, nickel exposure increased mitochondrial 8-hydroxyguanine (8-OHdG) content and reduced mtDNA content and mtDNA transcript levels. Consistent with this finding, nickel was found to destroy mtDNA nucleoid structure and decrease protein levels of Tfam, a key protein component for nucleoid organization. However, all the oxidative damage to mtDNA induced by nickel was efficiently attenuated by melatonin pretreatment. Our results suggest that oxidative damage to mtDNA may account for the neurotoxicity of nickel. Melatonin has great pharmacological potential in protecting mtDNA against the adverse effects of nickel in the nervous system. © 2011 John Wiley & Sons A/S.

Electrolytic trichloroethene degradation using mixed metal oxide coated titanium mesh electrodes.

Science.gov (United States)

Petersen, Matthew A; Sale, Thomas C; Reardon, Kenneth F

2007-04-01

Electrochemical systems provide a low cost, versatile, and controllable platform to potentially treat contaminants in water, including chlorinated solvents. Relative to bare metal or noble metal amended materials, dimensionally stable electrode materials such as mixed metal oxide coated titanium (Ti/MMO) have advantages in terms of stability and cost, important factors for sustainable remediation solutions. Here, we report the use of Ti/MMO as an effective cathode substrate for treatment of trichloroethene (TCE). TCE degradation in a batch reactor was measured as the decrease of TCE concentration over time and the corresponding evolution of chloride; notably, this occurred without the formation of commonly encountered chlorinated intermediates. The reaction was initiated when Ti/MMO cathode potentials were less than -0.8 V vs. the standard hydrogen electrode, and the rate of TCE degradation increased linearly with progressively more negative potentials. The maximum pseudo-first-order heterogeneous rate constant was approximately 0.05 cm min(-1), which is comparable to more commonly used cathode materials such as nickel. In laboratory-scale flow-though column reactors designed to simulate permeable reactive barriers (PRBs), TCE concentrations were reduced by 80-90%. The extent of TCE flux reduction increased with the applied potential difference across the electrodes and was largely insensitive to the spacing distance between the electrodes. This is the first report of the electrochemical reduction of a chlorinated organic contaminant at a Ti/MMO cathode, and these results support the use of this material in PRBs as a possible approach to manage TCE plume migration.

Clad modified optical fiber gas sensors based on nanocrystalline nickel oxide embedded coatings

Science.gov (United States)

Yamini, K.; Renganathan, B.; Ganesan, A. R.; Prakash, T.

2017-07-01

A clad modified optical fiber gas sensor for sensing volatile organic compound vapours (VOCs) such as formaldehyde (HCHO), ammonia (NH3), ethanol (C2H5OH) and methanol (CH3OH) up to 500 ppm was studied using nanocrystalline nickel oxide embedded coatings. Prior to the measurements, nickel oxide in two different crystallite sizes such as 24 nm and 76 nm was synthesized by calcination of reverse precipitated nickel hydroxide subsequently at 450 °C and 900 °C for 30 min. Then, samples physical properties were characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). Our gas sensing measurement concludes that the lower crystallite size (24 nm) nickel oxide nanocrystals exhibits superior performance to formaldehyde and ethanol vapours as compared with other two VOCs, the observed experimental results were discussed in detail.

Transparent nickel selenide used as counter electrode in high efficient dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Jia, Jinbiao; Wu, Jihuai, E-mail: jhwu@hqu.edu.cn; Tu, Yongguang; Huo, Jinghao; Zheng, Min; Lin, Jianming

2015-08-15

Highlights: • A transparent Ni{sub 0.85}Se is prepared by a facile solvothermal reaction. • Ni{sub 0.85}Se electrode has better electrocatalytic activity than Pt electrode. • DSSC with Ni{sub 0.85}Se electrode obtains efficiency of 8.88%, higher than DSSC with Pt. • DSSC with Ni{sub 0.85}Se/mirror electrode achieves an efficiency of 10.19%. - Abstract: A transparent nickel selenide (Ni{sub 0.85}Se) is prepared by a facile solvothermal reaction and used as an efficient Pt-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). Field emission scanning electron microscopy observes that the as-prepared Ni{sub 0.85}Se possesses porous structure. Cyclic voltammogram measurement indicates that Ni{sub 0.85}Se electrode has larger current density than Pt electrode. Electrochemical impedance spectroscopy shows that the Ni{sub 0.85}Se electrode has lower charge-transfer resistance than Pt electrode. Under simulated solar light irradiation with intensity of 100 mW cm{sup −2} (AM 1.5), the DSSC based on the Ni{sub 0.85}Se CE achieves a power conversion efficiency (PCE) of 8.88%, which is higher than the solar cell based on Pt CE (8.13%). Based on the transparency of Ni{sub 0.85}Se, the DSSC with Ni{sub 0.85}Se/mirror achieves a PCE of 10.19%.

Initial stages of high temperature metal oxidation

International Nuclear Information System (INIS)

Yang, C.Y.; O'Grady, W.E.

1981-01-01

The application of XPS and UPS to the study of the initial stages of high temperature (> 350 0 C) electrochemical oxidation of iron and nickel is discussed. In the high temperature experiments, iron and nickel electrodes were electrochemically oxidized in contact with a solid oxide electrolyte in the uhv system. The great advantages of this technique are that the oxygen activity at the interface may be precisely controlled and the ability to run the reactions in uhv allows the simultaneous observation of the reactions by XPS

Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films

KAUST Repository

Sun, Ke; Saadi, Fadl H.; Lichterman, Michael F.; Hale, William G.; Wang, Hsinping; Zhou, Xinghao; Plymale, Noah T.; Omelchenko, Stefan T.; He, Jr-Hau; Papadantonakis, Kimberly M.; Brunschwig, Bruce S.; Lewis, Nathan S.

2015-01-01

Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide

Engineered nickel oxide nanoparticle causes substantial physicochemical perturbation in plants

Science.gov (United States)

Manna, Indrani; Bandyopadhyay, Maumita

2017-11-01

Concentration of engineered NiO-NP in nature is on the rise, owing to large scale industrial uses and human interventions, which have accreted the scope of exposure especially at the primary trophic levels of the ecosystem. Nickel content in air, drinking water and soil is already above permissible limits in most parts of the developed world. Though nickel oxide is an essential micronutrient in the animal system, it has already been graded as a human carcinogen by WHO, and numerous studies have established the toxic nature of nickel in higher dosage in the animal system. Though studies depicting toxicity and bioaccumulation of nickel in plants is documented, the interaction of nickel oxide nanoparticle with plants is not fully a well-studied, well elucidated topic. What is known is that, exposure to nickel oxide nanoparticle, arouses stress response and leads to cytotoxicity and growth retardation in a handful of plants, a defined work on the intricate physicochemical cellular responses and genotoxic challenges has been so far absent. We have tried to fill in such gaps with this study. We planned the work around pertinent hypotheses like: whether NiO-NP cause cytotoxicity in a model plant system (Allium cepa L.)?If so, does internalization of nickel ion (the potent toxic) take place in the tissue? Does internalized NiO-NP create furore in the antioxidant enzyme system of the plant leading to cytotoxicity? In that case, whether the ENP causes genotoxicity and leads to pycknosis of the cell. The study has been designed to assess the change in biochemical profile and genotoxicity potential of NiO-NP at a wide range of concentrations using root tips of Allium cepa L., the model system for study of cytotoxicity and genotoxicity, and four of its closest relatives, Allium sativum L., Allium schoenoprasum L., Allium porrum L., Allium fistulosum L., chosen for their immense economic importance. Growing root tips were treated with seven different concentrations of Ni

On the Ageing of High Energy Lithium-Ion Batteries—Comprehensive Electrochemical Diffusivity Studies of Harvested Nickel Manganese Cobalt Electrodes

Directory of Open Access Journals (Sweden)

Odile Capron

2018-01-01

Full Text Available This paper examines the impact of the characterisation technique considered for the determination of the L i + solid state diffusion coefficient in uncycled as in cycled Nickel Manganese Cobalt oxide (NMC electrodes. As major characterisation techniques, Cyclic Voltammetry (CV, Galvanostatic Intermittent Titration Technique (GITT and Electrochemical Impedance Spectroscopy (EIS were systematically investigated. L i + diffusion coefficients during the lithiation process of the uncycled and cycled electrodes determined by CV at 3.71 V are shown to be equal to 3 . 48 × 10 - 10 cm 2 ·s - 1 and 1 . 56 × 10 - 10 cm 2 ·s - 1 , respectively. The dependency of the L i + diffusion with the lithium content in the electrodes is further studied in this paper with GITT and EIS. Diffusion coefficients calculated by GITT and EIS characterisations are shown to be in the range between 1 . 76 × 10 - 15 cm 2 ·s - 1 and 4 . 06 × 10 - 12 cm 2 ·s - 1 , while demonstrating the same decreasing trend with the lithiation process of the electrodes. For both electrode types, diffusion coefficients calculated by CV show greater values compared to those determined by GITT and EIS. With ageing, CV and EIS techniques lead to diffusion coefficients in the electrodes at 3.71 V that are decreasing, in contrast to GITT for which results indicate increasing diffusion coefficient. After long-term cycling, ratios of the diffusion coefficients determined by GITT compared to CV become more significant with an increase about 1 order of magnitude, while no significant variation is seen between the diffusion coefficients calculated from EIS in comparison to CV.

Evolution of grain structure in nickel oxide scales

International Nuclear Information System (INIS)

Atkinson, H.V.

1987-01-01

In systems such as the oxidation of nickel, in which grain-boundary diffusion in the oxide can control the rate of oxidation, understanding of the factors governing the grain structure is of importance. High-purity mechanically polished polycrystalline nickel was oxidized at 700 0 C, 800 0 C, and 1000 0 C for times up to 20 hr in 1 atm O 2 . The scale microstructures were examined by parallel and transverse cross section transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Texture coefficients were found by x-ray diffraction (XRD). Each grain in the transverse section grain boundary networks was systematically analyzed for width parallel to the Ni-NiO interface and perpendicular length, for boundary radius of curvature and for number of sides. The variation of these parameters with depth in the scale was examined. In particular, grains were increasingly columnar (i.e., with ratio of grain length to width > 1) at higher temperatures and longer times. Columnar grain boundaries tended to be fairly static; the columnar grain width was less than the rate controlling grain size predicted from the oxidation rate. The mean boundary curvature per grain provided a guide to the tendency for grain growth, except in the region of the Ni-NiO interface, where the boundaries were thought to be pinned

Nb effect in the nickel oxide-catalyzed low-temperature oxidative dehydrogenation of ethane

KAUST Repository

Zhu, Haibo

2012-01-01

A method for the preparation of NiO and Nb-NiO nanocomposites is developed, based on the slow oxidation of a nickel-rich Nb-Ni gel obtained in citric acid. The resulting materials have higher surface areas than those obtained by the classical evaporation method from nickel nitrate and ammonium niobium oxalate. These consist in NiO nanocrystallites (7-13 nm) associated, at Nb contents >3 at.%., with an amorphous thin layer (1-2 nm) of a niobium-rich mixed oxide with a structure similar to that of NiNb 2O 6. Unlike bulk nickel oxides, the activity of these nanooxides for low-temperature ethane oxidative dehydrogenation (ODH) has been related to their redox properties. In addition to limiting the size of NiO crystallites, the presence of the Nb-rich phase also inhibits NiO reducibility. At Nb content >5 at.%, Nb-NiO composites are thus less active for ethane ODH but more selective, indicating that the Nb-rich phase probably covers part of the unselective, non-stoichiometric, active oxygen species of NiO. This geometric effect is supported by high-resolution transmission electron microscopy observations. The close interaction between NiO and the thin Nb-rich mixed oxide layer, combined with possible restructuration of the nanocomposite under ODH conditions, leads to significant catalyst deactivation at high Nb loadings. Hence, the most efficient ODH catalysts obtained by this method are those containing 3-4 at.% Nb, which combine high activity, selectivity, and stability. The impact of the preparation method on the structural and catalytic properties of Nb-NiO nanocomposites suggests that further improvement in NiO-catalyzed ethane ODH can be expected upon optimization of the catalyst. © 2011 Elsevier Inc. All rights reserved.

Nickel cobaltite nanograss grown around porous carbon nanotube-wrapped stainless steel wire mesh as a flexible electrode for high-performance supercapacitor application

International Nuclear Information System (INIS)

Wu, Mao-Sung; Zheng, Zhi-Bin; Lai, Yu-Sheng; Jow, Jiin-Jiang

2015-01-01

Graphical abstract: Nickel cobaltite nanograss with bimodal pore size distribution is grown around the carbon nanotube-wrapped stainless steel wire mesh as a high capacitance and stable electrode for high-performance and flexible supercapacitors. - Highlights: • NiCo 2 O 4 nanograss with bimodal pore size distribution is hydrothermally prepared. • Carbon nanotubes (CNTs) wrap around stainless steel (SS) wire mesh as a scaffold. • NiCo 2 O 4 grown on CNT-wrapped SS mesh shows excellent capacitive performance. • Porous CNT layer allows for rapid transport of electron and electrolyte. - Abstract: Nickel cobaltite nanograss with bimodal pore size distribution (small and large mesopores) is grown on various electrode substrates by one-pot hydrothermal synthesis. The small pores (<5 nm) in the nanograss of individual nanorods contribute to large surface area, while the large pore channels (>20 nm) between nanorods offer fast transport paths for electrolyte. Carbon nanotubes (CNTs) with high electrical conductivity wrap around stainless steel (SS) wire mesh by electrophoresis as an electrode scaffold for supporting the nickel cobaltite nanograss. This unique electrode configuration turns out to have great benefits for the development of supercapacitors. The specific capacitance of nickel cobaltite grown around CNT-wrapped SS wire mesh reaches 1223 and 1070 F g −1 at current densities of 1 and 50 A g −1 , respectively. CNT-wrapped SS wire mesh affords porous and conductive networks underneath the nanograss for rapid transport of electron and electrolyte. Flexible CNTs connect the nanorods to mitigate the contact resistance and the volume expansion during cycling test. Thus, this tailored electrode can significantly reduce the ohmic resistance, charge-transfer resistance, and diffusive impedance, leading to high specific capacitance, prominent rate performance, and good cycle-life stability.

Development of high-capacity nickel-metal hydride batteries using superlattice hydrogen-absorbing alloys

International Nuclear Information System (INIS)

Yasuoka, Shigekazu; Magari, Yoshifumi; Murata, Tetsuyuki; Tanaka, Tadayoshi; Ishida, Jun; Nakamura, Hiroshi; Nohma, Toshiyuki; Kihara, Masaru; Baba, Yoshitaka; Teraoka, Hirohito

2006-01-01

New R-Mg-Ni (R: rare earths) superlattice alloys with higher-capacity and higher-durability than the conventional Mm-Ni alloys with CaCu 5 structure have been developed. The oxidation resistibility of the superlattice alloys has been improved by optimizing the alloy composition by such as substituting aluminum for nickel and optimizing the magnesium content in order to prolong the battery life. High-capacity nickel-metal hydride batteries for the retail market, the Ni-MH2500/900 series (AA size type 2500mAh, AAA size type 900mAh), have been developed and commercialized by using an improved superlattice alloy for negative electrode material. alized by using an improved superlattice alloy for negative electrode material. (author)

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.

Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization.

Science.gov (United States)

Hatzell, Kelsey B; Hatzell, Marta C; Cook, Kevin M; Boota, Muhammad; Housel, Gabrielle M; McBride, Alexander; Kumbur, E Caglan; Gogotsi, Yury

2015-03-03

Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. Chemical oxidation of granular activated carbon (AC) was examined here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (∼21 Pa s) to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g(-1)) without sacrificing flowability (viscosity). The electrical energy required to remove ∼18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (∼60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. It is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.

Synthesis and characterization of nickel oxide doped barium strontium titanate ceramics

Energy Technology Data Exchange (ETDEWEB)

Banerjee, M. [Dept. of Electrical Engineering, Bengal Institute of Technology Kolkata (India); Mukherjee, S. [Dept. of Metallurgical Engineering, Jadavpur University, Kolkata (India); Maitra, S. [Govt. College of Engg. and Ceramic Technology, Kolkata (India)

2012-01-15

Barium strontium titanate (BST) ceramics (Ba{sub 0.6}Sr{sub 0.4})TiO{sub 3} were synthesized by solid state sintering using barium carbonate, strontium carbonate and rutile as the precursor materials. The samples were doped with nickel oxide in different proportions. Different phases present in the sintered samples were determined from X-ray diffraction investigation and the distribution of different phases in the microstructure was assessed from scanning electron microscopy study. It was observed that the dielectric properties of BST were modified significantly with nickel oxide doping. These ceramics held promise for applications in tuned circuits. (author)

Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks

Science.gov (United States)

Jones, J. Graham; Warner, C. G.

1972-01-01

Graham Jones, J., and Warner, C. G. (1972).Brit. J. industr. Med.,29, 169-177. Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks. Occupational and medical histories, smoking habits, respiratory symptoms, chest radiographs, and ventilatory capacities were studied in 14 steelworkers employed as deseamers of steel ingots for periods of up to 16 years. The men were exposed for approximately five hours of each working shift to fume concentrations ranging from 1·3 to 294·1 mg/m3 made up mainly of iron oxide with varying proportions of chromium oxide and nickel oxide. Four of the men, with 14 to 16 years' exposure, showed radiological evidence of pneumoconiosis classified as ILO categories 2 or 3. Of these, two had pulmonary function within the normal range and two had measurable loss of function, moderate in one case and mild in the other. Many observers would diagnose these cases as siderosis but the authors consider that this term should be reserved for cases exposed to pure iron compounds. The correct diagnosis is mixed-dust pneumoconiosis and the loss of pulmonary function is caused by the effects of the mixture of metallic oxides. It is probable that inhalation of pure iron oxide does not cause fibrotic pulmonary changes, whereas the inhalation of iron oxide plus certain other substances obviously does. Images PMID:5021996

Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

Science.gov (United States)

Li, M. M.; Yang, C. C.; Wang, C. C.; Wen, Z.; Zhu, Y. F.; Zhao, M.; Li, J. C.; Zheng, W. T.; Lian, J. S.; Jiang, Q.

2016-06-01

Nickel metal hydride (Ni-MH) batteries have demonstrated key technology advantages for applications in new-energy vehicles, which play an important role in reducing greenhouse gas emissions and the world’s dependence on fossil fuels. However, the poor high-rate dischargeability of the negative electrode materials—hydrogen storage alloys (HSAs) limits applications of Ni-MH batteries in high-power fields due to large polarization. Here we design a hybrid electrode by integrating HSAs with a current collector of three-dimensional bicontinuous nanoporous Ni. The electrode shows enhanced high-rate dischargeability with the capacity retention rate reaching 44.6% at a discharge current density of 3000 mA g-1, which is 2.4 times that of bare HSAs (18.8%). Such a unique hybrid architecture not only enhances charge transfer between nanoporous Ni and HSAs, but also facilitates rapid diffusion of hydrogen atoms in HSAs. The developed HSAs/nanoporous metals hybrid structures exhibit great potential to be candidates as electrodes in high-performance Ni-MH batteries towards applications in new-energy vehicles.

Universal electrode interface for electrocatalytic oxidation of liquid fuels.

Science.gov (United States)

Liao, Hualing; Qiu, Zhipeng; Wan, Qijin; Wang, Zhijie; Liu, Yi; Yang, Nianjun

2014-10-22

Electrocatalytic oxidations of liquid fuels from alcohols, carboxylic acids, and aldehydes were realized on a universal electrode interface. Such an interface was fabricated using carbon nanotubes (CNTs) as the catalyst support and palladium nanoparticles (Pd NPs) as the electrocatalysts. The Pd NPs/CNTs nanocomposite was synthesized using the ethylene glycol reduction method. It was characterized using transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, voltammetry, and impedance. On the Pd NPs/CNTs nanocomposite coated electrode, the oxidations of those liquid fuels occur similarly in two steps: the oxidations of freshly chemisorbed species in the forward (positive-potential) scan and then, in the reverse scan (negative-potential), the oxidations of the incompletely oxidized carbonaceous species formed during the forward scan. The oxidation charges were adopted to study their oxidation mechanisms and oxidation efficiencies. The oxidation efficiency follows the order of aldehyde (formaldehyde) > carboxylic acid (formic acid) > alcohols (ethanol > methanol > glycol > propanol). Such a Pd NPs/CNTs nanocomposite coated electrode is thus promising to be applied as the anode for the facilitation of direct fuel cells.

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.

Efficient CH3NH3PbI3 perovskite/fullerene planar heterojunction hybrid solar cells with oxidized Ni/Au/Cu transparent electrode

Science.gov (United States)

Lai, Wei-Chih; Lin, Kun-Wei; Guo, Tzung-Fang; Chen, Peter; Liao, Yuan-Yu

2018-02-01

We demonstrated the performance of inverted CH3NH3PbI3 perovskite-based solar cells (SCs) with a thermally oxidized nickel/gold/copper (Ni/Au/Cu) trilayer transparent electrode. Oxidized Ni/Au/Cu is a high transparent layer and has less resistance than the oxidized Ni/Au layer. Like the oxidized Ni/Au layer, oxidized Ni and Cu in oxidized Ni/Au/Cu could perform as a hole transport layer of the perovskite-based SCs. It leads to improved perovskite SC performance on an open circuit voltage of 1.01 V, a short circuit current density of 14.36 mA/cm2, a fill factor of 76.7%, and a power conversion efficiency (η%) of 11.1%. The η% of perovskite SCs with oxidized Ni (10 nm)/Au (6 nm)/Cu (1 nm) improved by approximately 10% compared with that of perovskite SCs with oxidized Ni/Au.

Nb effect in the nickel oxide-catalyzed low-temperature oxidative dehydrogenation of ethane

KAUST Repository

Zhu, Haibo; Ould-Chikh, Samy; Anjum, Dalaver Hussain; Sun, Miao; Biausque, Gregory; Basset, Jean-Marie; Caps, Valerie

2012-01-01

evaporation method from nickel nitrate and ammonium niobium oxalate. These consist in NiO nanocrystallites (7-13 nm) associated, at Nb contents >3 at.%., with an amorphous thin layer (1-2 nm) of a niobium-rich mixed oxide with a structure similar

Protecting nickel with graphene spin-filtering membranes: A single layer is enough

Energy Technology Data Exchange (ETDEWEB)

Martin, M.-B.; Dlubak, B.; Piquemal-Banci, M.; Collin, S.; Petroff, F.; Anane, A.; Fert, A.; Seneor, P. [Unité Mixte de Physique CNRS/Thales, 1 Avenue Augustin Fresnel, 91767 Palaiseau, France and Université Paris Sud, 91405 Orsay (France); Weatherup, R. S.; Hofmann, S.; Robertson, J. [Department of Engineering, University of Cambridge, Cambridge CB21PZ (United Kingdom); Yang, H. [IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Blume, R. [Helmholtz-Zentrum Berlin fur Materialien und Energie, 12489 Berlin (Germany); Schloegl, R. [Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany)

2015-07-06

We report on the demonstration of ferromagnetic spin injectors for spintronics which are protected against oxidation through passivation by a single layer of graphene. The graphene monolayer is directly grown by catalytic chemical vapor deposition on pre-patterned nickel electrodes. X-ray photoelectron spectroscopy reveals that even with its monoatomic thickness, monolayer graphene still efficiently protects spin sources against oxidation in ambient air. The resulting single layer passivated electrodes are integrated into spin valves and demonstrated to act as spin polarizers. Strikingly, the atom-thick graphene layer is shown to be sufficient to induce a characteristic spin filtering effect evidenced through the sign reversal of the measured magnetoresistance.

Template-free approach to synthesize hierarchical porous nickel cobalt oxides for supercapacitors

Science.gov (United States)

Chang, Jie; Sun, Jing; Xu, Chaohe; Xu, Huan; Gao, Lian

2012-10-01

Nickel cobalt oxides with various Ni/Co ratios were synthesized using a facile template-free approach for electrochemical supercapacitors. The texture and morphology of the nanocomposites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller analysis (BET). The results show that a hierarchical porous structure assembled from nanoflakes with a thickness of ~10 nm was obtained, and the ratio of nickel to cobalt in the nanocomposites was very close to the precursors. Cyclic voltammetry (CV) and galvanostatic charge and discharge tests were carried out to study the electrochemical performance. Both nickel cobalt oxides (Ni-Co-O-1 with Ni : Co = 1, Ni-Co-O-2 with Ni : Co = 2) outperform pure NiO and Co3O4. The Ni-Co-O-1 and Ni-Co-O-2 possess high specific capacities of 778.2 and 867.3 F g-1 at 1 A g-1 and capacitance retentions of 84.1% and 92.3% at 10 A g-1, respectively. After full activation, the Ni-Co-O-1 and Ni-Co-O-2 could achieve a maximum value of 971 and 1550 F g-1 and remain at ~907 and ~1450 F g-1 at 4 A g-1, respectively. Also, the nickel cobalt oxides show high capacity retention when fast charging.Nickel cobalt oxides with various Ni/Co ratios were synthesized using a facile template-free approach for electrochemical supercapacitors. The texture and morphology of the nanocomposites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller analysis (BET). The results show that a hierarchical porous structure assembled from nanoflakes with a thickness of ~10 nm was obtained, and the ratio of nickel to cobalt in the nanocomposites was very close to the precursors. Cyclic voltammetry (CV) and galvanostatic charge and discharge tests were carried out to study the electrochemical performance. Both nickel cobalt oxides (Ni-Co-O-1 with Ni : Co = 1, Ni-Co-O-2 with Ni

Microstructural characteristics of high-temperature oxidation in nickel-base superalloy

International Nuclear Information System (INIS)

Khalid, F.A.

1997-01-01

Superalloys are used for aerospace and nuclear applications where they can withstand high-temperature and severe oxidizing conditions. High-temperature oxidation behavior of a nickel-base superalloy is examined using optical and scanning electron microscopical techniques. The morphology of the oxide layers developed is examined, and EDX microanalysis reveals diffusion of the elements across the oxide-metal interface. Evidence of internal oxidation is presented, and the role of structural defects is considered. The morphology of the oxide-metal interface formed in the specimens exposed in steam and air is examined to elucidate the mechanism of high-temperature oxidation

Preliminary results on the chemical characterisation of the cathode nickel--emissive layer interface in oxide cathodes

International Nuclear Information System (INIS)

Jenkins, S.N.; Barber, D.K.; Whiting, M.J.; Baker, M.A.

2003-01-01

In cathode ray tube (CRT) thermionic oxide cathodes, the nickel-oxide interface properties are key to understanding the mechanisms of operation. At the elevated operational temperatures, free barium is formed at the interface by the reaction of reducing activators, from the nickel alloy, with barium oxide. The free barium diffuses to the outer surface of the oxide providing a low work function electron-emitting surface. However, during cathode life an interface layer grows between the nickel alloy and oxide, comprised of reaction products. The interfacial layer sets limits on the cathode performance and useful operational lifetime by inhibiting the barium reducing reaction. This paper discusses sample preparation procedures for exposure of the interface and the use of several surface and bulk analytical techniques to study interface layer formation. SEM, AES and SIMS data are presented, which provide preliminary insight into the mechanisms operating during the cathode's lifetime. There is evidence that the activator elements in the nickel alloy base, Al and Mg, are able to diffuse to the surface of the oxide during activation and ageing and that these elements are enriched at the interface after accelerated life

SOFC anode. Hydrogen oxidation at porous nickel and nickel/zirconia electrodes

NARCIS (Netherlands)

de Boer, B.

1998-01-01

In the ongoing search for alternative and environmental friendly power generation facilities, the fuel cell is a good candidate. There are several types of fuel cells with large differences in application, size, cost and operating range. The Solid Oxide Fuel Cell (SOFC) is a high temperature fuel

Effect of nickel oxide substitution on bioactivity and mechanical ...

Indian Academy of Sciences (India)

In the present work, the effect of addition of nickel oxide that annualizes the .... for required dimension using grinding machine, then sam- ples were subjected to ... the hardness testing machine, the size of the sample was. 10 × 10 × 10 mm ...

Study of the high temperature oxidation of nickel; Contribution a l'etude de l'oxydation du nickel aux temperatures elevees

Energy Technology Data Exchange (ETDEWEB)

Berry, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-11-01

The parabolic oxidation of nickel by oxygen and by air at atmospheric pressure has been studied in the temperature range 600 to 1400 C, in particular by thermogravimetric and micrographic techniques. The mechanism of the reaction has been determined; it has been shown in particular that the break in the Arrhenius plot of the kinetics, occurring at about 950 C, is the result of a stimulation of the diffusion across the nickel prot-oxide film above this temperature; this is the result of the presence of excess nickel vacancies in the film. A systematic study has also been made of the influence of the oxygen pressure P{sub O{sub 2}} (10{sup -2} torr {<=} P{sub O{sub 2}} {<=} 760 torr) on the parabolic oxidation of nickel between 800 and 1400 C. In the range 1000 to 1400 C, the activation energy of the process decreases monotonously from 57 to 34 kcal/mole as P{sub O{sub 2}} decreases from 760 to 1 torr. Furthermore, it has been shown that the parabolic oxidation constant is proportional to P{sub O{sub 2}}{sup 1/n} the value of n is not invariant however in the temperature range examined, but decreases from 6 to about 3 when the temperature increases from 900 to 1400 C. Finally, a study has been made of the oxidation of nickel in carbon dioxide at atmospheric pressure between 750 and 1400 C. The main reaction is Ni + CO{sub 2} {yields} NiO + CO, and corresponds, with a good approximation, to the reaction of the metal with the oxygen produced by the thermal dissociation of the CO{sub 2}. (author) [French] L'oxydation parabolique du nickel avec l'oxygene et l'air a la pression atmospherique a ete etudiee dans l'intervalle de temperatures 600-1400 C, surtout par voies thermogravimetrique et micrographique. Le mecanisme de la reaction a ete precise; en particulier, il a ete montre que la brisure de la courbe d'Arrhenius traduisant sa cinetique, qui se produit a 950 C environ, resulte d'une stimulation de la diffusion dans la pellicule de protoxyde de nickel au dessous de

Structural, optical and dielectric properties of pure and chromium (Cr) doped nickel oxide nanoparticles

Science.gov (United States)

Gupta, Jhalak; Ahmed, Arham S.

2018-05-01

The pure and Cr doped nickel oxide (NiO) nanoparticles have been synthesized by cost effective co-precipitation method having nickel nitrate as initial precursor. The synthesized samples were characterized by X-Ray diffraction (XRD), UV-Visible Spectroscopy(UV-Vis) and LCR meter for structural, optical and dielectric properties respectively. The crystallite size of pure nickel oxide nanoparticles characterized by XRD using Debye Scherer's formula was found to be 21.7nm and the same decreases on increasing Cr concentration whereas optical and dielectric properties were analyzed by UV-Vis and LCR meter respectively. The energy band gaps were determined by UV-Vis using Tauc relation.

Electrochemical Oxidation of Cyanide Using Platinized Ti Electrodes

Directory of Open Access Journals (Sweden)

Aušra VALIŪNIENĖ

2013-12-01

Full Text Available The cyanide-containing effluents are dangerous ecological hazards and must be treated before discharging into the environment. Anodic oxidation is one of the best ways to degrade cyanides. Pt anodes as the most efficient material for the cyanide electrochemical degradation are widely used. However, these electrodes are too expensive for industrial purposes. In this work Ti electrodes covered with nano-sized Pt particle layer were prepared and used for the anodic oxidation of cyanide ions. Surface images of Ti electrodes and Ti electrodes covered with different thickness layer of Pt were compared and characterized by the atomic force microscopy (AFM. The products formed in the solution during the CN- ions electrooxidation were examined by the Raman spectroscopy. An electrochemical Fast Fourier transformation (FFT impedance spectroscopy was used to estimate the parameters that reflect real surface roughness of Pt-modified Ti electrodes.DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2514

Electrochemical behavior of heavily cycled nickel electrodes in Ni/H2 cells containing electrolytes of various KOH concentrations

Science.gov (United States)

Lim, H. S.; Verzwyvelt, S. A.

1989-01-01

A study has been made of charge and discharge voltage changes with cycling of Ni/H2 cells containing electrolytes of various KOH concentrations. A study has also been made of electrochemical behavior of the nickel electrodes from the cycled Ni/H2 cells as a function of overcharge amounts. Discharge voltages depressed gradually with cycling for cells having high KOH concentrations (31 to 36 percent), but the voltages increased for those having low KOH concentrations (21 to 26 percent). To determine if there was a crystallographic change of the active material due to cycling, electrochemical behavior of nickel electrodes was studied in an electrolyte flooded cell containing either 31 or 26 percent KOH electrolyte as a function of the amount of overcharge. The changes in discharge voltage appear to indicate crystal structure changes of active material from gamma-phase to beta-phase in low KOH concentrations, and vice versa in high KOH concentration.

2D nickel oxide nanosheets with highly porous structure for high performance capacitive energy storage

Science.gov (United States)

Li, Zijiong; Zhang, Weiyang; Liu, Yanyue; Guo, Jinjin; Yang, Baocheng

2018-01-01

Developing advanced electrochemical electrode materials with excellent performance is critical to their future energy storage devices. Herein, we design and synthesize two-dimensional (2D) porous structure nickel oxide (NiO) nanosheets via a facile and scalable hydrothermal approach, and further heating. The effects of heating time on the electrochemical performances are investigated. The results indicate that the maximum specific capacitance is achieved for NiO nanosheets when heating temperature and time are 300 °C and 3 h, respectively (namely NiO-3). The as-prepared NiO-3 nanosheet are grown uniform on the skeleton of reduced graphene oxide (rGO). The optimum NiO/rGO displays a reversible discharge capacity of 781.7 F g-1 at 1 A g-1, and shows an ultra-long life-span with over 94% capacitance retention after 4000 cycles. The enhanced electrochemical properties for NiO/rGO can be ascribed to a collaborative effect between NiO and rGO, which possess high capacitance storage ability and excellent conductivity, respectively.

Nonlinear oxidation kinetics of nickel cermets

International Nuclear Information System (INIS)

Galinski, Henning; Bieberle-Huetter, Anja; Rupp, Jennifer L.M.; Gauckler, Ludwig J.

2011-01-01

The oxidation of a cermet of screen-printed nickel (Ni) and gadolinia-doped ceria (CGO) with an approximate median porosity of 50 vol.% has been studied via in situ X-ray diffraction and focused ion beam nanotomography in the temperature range 773-848 K. The oxidation kinetics of Ni to NiO is found to be highly nonlinear with an apparent activation energy of 2.8(2) eV in this temperature range. The nonlinear oxidation kinetics found is in good agreement with theoretical works on oxide growth driven by nonlinear inbuilt fields. Stress-induced Kirkendall void formation has been identified as the physical process that enhances the oxidation of Ni/CGO cermets. Compressive stresses within the Ni matrix result from the thermal expansion mismatch of Ni and CGO and cause plastic deformation as they exceed the yield stress of the Ni matrix. The pore size distribution of Kirkendall voids formed has been measured by FIB nanotomography and shows a significant temperature dependence. It is shown that even one cycle of reoxidation changes irreversibly the microstructure of the cermet which can be interpreted as the onset and main contribution to the mechanical degradation of the cermet.

Benzene oxidation at diamond electrodes: comparison of microcrystalline and nanocrystalline diamonds.

Science.gov (United States)

Pleskov, Yu V; Krotova, M D; Elkin, V V; Varnin, V P; Teremetskaya, I G; Saveliev, A V; Ralchenko, V G

2012-08-27

A comparative study of benzene oxidation at boron-doped diamond (BDD) and nitrogenated nanocrystalline diamond (NCD) anodes in 0.5 M K(2)SO(4) aqueous solution is conducted by using cyclic voltammetry and electrochemical impedance spectroscopy. It is shown by measurements of differential capacitance and anodic current that during the benzene oxidation at the BDD electrode, adsorption of a reaction intermediate occurs, which partially blocks the electrode surface and lowers the anodic current. At the NCD electrode, benzene is oxidized concurrently with oxygen evolution, a (quinoid) intermediate being adsorbed at the electrode. The adsorption and the electrode surface blocking are reflected in the impedance-frequency and impedance-potential complex-plane plots. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extra and intracellular synthesis of nickel oxide nanoparticles mediated by dead fungal biomass.

Directory of Open Access Journals (Sweden)

Marcia Regina Salvadori

Full Text Available The use of dead biomass of the fungus Hypocrea lixii as a biological system is a new, effective and environmentally friendly bioprocess for the production and uptake of nickel oxide nanoparticles (NPs, which has become a promising field in nanobiotechnology. Dead biomass of the fungus was successfully used to convert nickel ions into nickel oxide NPs in aqueous solution. These NPs accumulated intracellularly and extracellularly on the cell wall surface through biosorption. The average size, morphology and location of the NPs were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The NPs were mainly spherical and extra and intracellular NPs had an average size of 3.8 nm and 1.25 nm, respectively. X-ray photoelectron spectroscopy analysis confirmed the formation of nickel oxide NPs. Infrared spectroscopy detected the presence of functional amide groups, which are probable involved in particle binding to the biomass. The production of the NPs by dead biomass was analyzed by determining physicochemical parameters and equilibrium concentrations. The present study opens new perspectives for the biosynthesis of nanomaterials, which could become a potential biosorbent for the removal of toxic metals from polluted sites.

Mesoporous Transition Metal Oxides for Supercapacitors

OpenAIRE

Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

2015-01-01

Recently, transition metal oxides, such as ruthenium oxide (RuO2), manganese dioxide (MnO2), nickel oxides (NiO) and cobalt oxide (Co3O4), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are result...

Green synthesis of cobalt (II, III) oxide nanoparticles using Moringa Oleifera natural extract as high electrochemical electrode for supercapacitors

Science.gov (United States)

Matinise, N.; Mayedwa, N.; Fuku, X. G.; Mongwaketsi, N.; Maaza, M.

2018-05-01

The research work involved the development of a better, inexpensive, reliable, easily and accurate way for the fabrication of Cobalt (II, III) oxide (Co3O4) nanoparticles through a green synthetic method using Moringa Oleifera extract. The electrochemical activity, crystalline structure, morphology, isothermal behaviour and optical properties of Co3O4 nanoparticles were studied using various characterization techniques. The X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS) analysis confirmed the formation of Co3O4 nanoparticles. The pseudo-capacitor behaviour of spinel Co3O4 nanoparticles on Nickel foam electrode was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) in 3M KOH solution. The CV curve revealed a pairs of redox peaks, indicating the pseudo-capacitive characteristics of the Ni/Co3O4 electrode. EIS results showed a small semicircle and Warburg impedance, indicating that the electrochemical process on the surface electrode is kinetically and diffusion controlled. The charge-discharge results indicating that the specific capacitance Ni/Co3O4 electrode is approximately 1060 F/g at a discharge current density of at 2 A/g.

Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

Science.gov (United States)

Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

2016-07-01

Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

Energy Technology Data Exchange (ETDEWEB)

Ge, Jisheng [Iowa State Univ., Ames, IA (United States)

1996-01-08

This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

The study of chlorination of nickel oxide by chlorine and calcium chloride in the presence of active additives

OpenAIRE

Ilic, Ilija; Krstev, Boris; Stopic, Srecko; Cerovic, K

1997-01-01

Chlorination of nickel oxide by chlorine and calcium chloride in the presence of C, BaS and S were studied, both experimentally and theoretically. Chlorination of nickel oxide by chlorine was carried out in the temperature range 573-873 K and by calcium chloride in the temperature range 1023-1223 K. The results obtained of the chlorination of nickel oxide by chlorine showed that C has the strongest and S the weakest effect on the process. Addition of BaS has a favorable effect on the chlorina...

Electrochemical studies on nanometal oxide-activated carbon composite electrodes for aqueous supercapacitors

Science.gov (United States)

Ho, Mui Yen; Khiew, Poi Sim; Isa, Dino; Chiu, Wee Siong

2014-11-01

In present study, the electrochemical performance of eco-friendly and cost-effective titanium oxide (TiO2)-based and zinc oxide-based nanocomposite electrodes were studied in neutral aqueous Na2SO3 electrolyte, respectively. The electrochemical properties of these composite electrodes were studied using cyclic voltammetry (CV), galvanostatic charge-discharge (CD) and electrochemical impedance spectroscopy (EIS). The experimental results reveal that these two nanocomposite electrodes achieve the highest specific capacitance at fairly low oxide loading onto activated carbon (AC) electrodes, respectively. Considerable enhancement of the electrochemical properties of TiO2/AC and ZnO/AC nanocomposite electrodes is achieved via synergistic effects contributed from the nanostructured metal oxides and the high surface area mesoporous AC. Cations and anions from metal oxides and aqueous electrolyte such as Ti4+, Zn2+, Na+ and SO32- can occupy some pores within the high-surface-area AC electrodes, forming the electric double layer at the electrode-electrolyte interface. Additionally, both TiO2 and ZnO nanoparticles can provide favourable surface adsorption sites for SO32- anions which subsequently facilitate the faradaic processes for pseudocapacitive effect. These two systems provide the low cost material electrodes and the low environmental impact electrolyte which offer the increased charge storage without compromising charge storage kinetics.

Electrochemical characterisation of solid oxide cell electrodes for hydrogen production

DEFF Research Database (Denmark)

Bernuy-Lopez, Carlos; Knibbe, Ruth; He, Zeming

2011-01-01

Oxygen electrodes and steam electrodes are designed and tested to develop improved solid oxide electrolysis cells for H2 production with the cell support on the oxygen electrode. The electrode performance is evaluated by impedance spectroscopy testing of symmetric cells at open circuit voltage (OCV...

Hierarchical chestnut-like MnCo2O4 nanoneedles grown on nickel foam as binder-free electrode for high energy density asymmetric supercapacitors

Science.gov (United States)

Hui, Kwun Nam; Hui, Kwan San; Tang, Zikang; Jadhav, V. V.; Xia, Qi Xun

2016-10-01

Hierarchical chestnut-like manganese cobalt oxide (MnCo2O4) nanoneedles (NNs) are successfully grown on nickel foam using a facile and cost-effective hydrothermal method. High resolution TEM image further verifies that the chestnut-like MnCo2O4 structure is assembled by numerous 1D MnCo2O4 nanoneedles, which are formed by numerous interconnected MnCo2O4 nanoparticles with grain diameter of ∼10 nm. The MnCo2O4 electrode exhibits high specific capacitance of 1535 F g-1 at 1 A g-1 and good rate capability (950 F g-1 at 10 A g-1) in a 6 M KOH electrolyte. An asymmetric supercapacitor is fabricated using MnCo2O4 NNs on Ni foam (MnCo2O4 NNs/NF) as the positive electrode and graphene/NF as the negative electrode. The device shows an operation voltage of 1.5 V and delivers a high energy density of ∼60.4 Wh kg-1 at a power density of ∼375 W kg-1. Moreover, the device exhibits an excellent cycling stability of 94.3% capacitance retention after 12000 cycles at 30 A g-1. This work demonstrates that hierarchical chestnut-like MnCo2O4 NNs could be a promising electrode for the high performance energy storage devices.

Boron-doped diamond electrodes for the electrochemical oxidation and cleavage of peptides.

Science.gov (United States)

Roeser, Julien; Alting, Niels F A; Permentier, Hjalmar P; Bruins, Andries P; Bischoff, Rainer

2013-07-16

Electrochemical oxidation of peptides and proteins is traditionally performed on carbon-based electrodes. Adsorption caused by the affinity of hydrophobic and aromatic amino acids toward these surfaces leads to electrode fouling. We compared the performance of boron-doped diamond (BDD) and glassy carbon (GC) electrodes for the electrochemical oxidation and cleavage of peptides. An optimal working potential of 2000 mV was chosen to ensure oxidation of peptides on BDD by electron transfer processes only. Oxidation by electrogenerated OH radicals took place above 2500 mV on BDD, which is undesirable if cleavage of a peptide is to be achieved. BDD showed improved cleavage yield and reduced adsorption for a set of small peptides, some of which had been previously shown to undergo electrochemical cleavage C-terminal to tyrosine (Tyr) and tryptophan (Trp) on porous carbon electrodes. Repeated oxidation with BDD electrodes resulted in progressively lower conversion yields due to a change in surface termination. Cathodic pretreatment of BDD at a negative potential in an acidic environment successfully regenerated the electrode surface and allowed for repeatable reactions over extended periods of time. BDD electrodes are a promising alternative to GC electrodes in terms of reduced adsorption and fouling and the possibility to regenerate them for consistent high-yield electrochemical cleavage of peptides. The fact that OH-radicals can be produced by anodic oxidation of water at elevated positive potentials is an additional advantage as they allow another set of oxidative reactions in analogy to the Fenton reaction, thus widening the scope of electrochemistry in protein and peptide chemistry and analytics.

Absolute determination by X-ray diffraction of a binary or ternary mixture: nickel oxide and fluoride in a nickel powder (1960)

International Nuclear Information System (INIS)

Charpin, P.; Hauptman, A.

1960-01-01

The method employed is based upon the comparison between computed and measured intensities for conveniently selected X-Ray diffraction lines of each component of the powder. Care must be taken to allow for absorption, both inside each grain and in overall sample. This method has been applied to the determination of nickel oxide and fluoride in a nickel powder. (author) [fr

Process for electroforming nickel containing dispersed thorium oxide particles therein

International Nuclear Information System (INIS)

Malone, G.A.

1975-01-01

Nickel electroforming is effected by passing a direct current through a bath containing a dissolved nickel salt or a mixture of such salts, such as those present in sulfamate or Watts baths, and finely divided sol-derived thorium oxide particles of 75 to 300 angstroms, preferably 100 to 200 angstroms diameters therein, at a pH in the range of 0.4 to 1.9, preferably 0.8 to 1.3. The nickel so deposited, as on a pre-shaped stainless steel cathode, may be produced in desired shape and may be removed from the cathode and upon removal, without additional working, possesses desirable engineering properties at elevated temperatures, e.g., 1,500 to 2,200 0 F. Although the material produced is of improved high temperature stability, hardness, and ductility, compared with nickel alone, it is still ductile at room temperature and has properties equivalent or superior to nickel at room temperatures up to 1,500 0 F. Further improvements in mechanical properties of the material may be obtained by working. Also disclosed are electrodeposition baths, methods for their manufacture, and products resulting from the electrodeposition process. (U.S.)

Cyclic Oxidation and Hot Corrosion Behavior of Nickel-Iron-Based Superalloy

Science.gov (United States)

Chellaganesh, D.; Adam Khan, M.; Winowlin Jappes, J. T.; Sathiyanarayanan, S.

2018-01-01

The high temperature oxidation and hot corrosion behavior of nickel-iron-based superalloy are studied at 900 ° and 1000 °C. The significant role of alloying elements with respect to the exposed medium is studied in detail. The mass change per unit area was catastrophic for the samples exposed at 1000 °C and gradual increase in mass change was observed at 900 °C for both the environments. The exposed samples were further investigated with SEM, EDS and XRD analysis to study the metallurgical characteristics. The surface morphology has expressed the in situ nature of the alloy and its affinity toward the environment. The EDS and XRD analysis has evidently proved the presence of protective oxides formation on prolonged exposure at elevated temperature. The predominant oxide formed during the exposure at high temperature has a major contribution toward the protection of the samples. The nickel-iron-based superalloy is less prone to oxidation and hot corrosion when compared to the existing alloy in gas turbine engine simulating marine environment.

A uric acid sensor based on electrodeposition of nickel hexacyanoferrate nanoparticles on an electrode modified with multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Fang, B.; Feng, Y.; Wang, G.; Zhang, C.; Gu, A.; Liu, M.

2011-01-01

An electrode sensitive to uric acid was prepared by electrodeposition of nickel(II) hexacyanoferrate(III) on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes. The morphology of the material was characterized by scanning electron microscopy and Fourier transform infrared spectrometry. The modified electrode were characterized via cyclic voltammetry and amperometry (i - t). It exhibited efficient electron transfer ability and a strong and fast (< 3 s) response towards uric acid which is linear in the range from 0.1 μM to 18 μM, with a lower detection limit of 50 nM (at an S/N ratio of 3). In addition, the electrode exhibited good reproducibility and long-term stability. (author)

Structural characterization of nickel oxide/hydroxide nanosheets produced by CBD technique

Energy Technology Data Exchange (ETDEWEB)

Taşköprü, T., E-mail: ttaskopru@anadolu.edu.tr [Department of Physics, Anadolu University, Eskişehir 26470 (Turkey); Department of Physics, Çankırı Karatekin University, Çankırı 18100 (Turkey); Zor, M.; Turan, E. [Department of Physics, Anadolu University, Eskişehir 26470 (Turkey)

2015-10-15

Graphical abstract: SEM images of (a) as deposited β-Ni(OH)2 and (b) NiO samples deposited with pH 10 solution. The inset figures shows the absorbance spectra of (a) β-Ni(OH)2 and (b) NiO samples. - Highlights: • The formation of β-Ni(OH){sub 2} and NiO were confirmed with XRD, SEM, FT-IR and Raman. • Porous nickel oxide was synthesized after heat treatment of nickel hydroxide. • The increase in pH value changes the nanoflake structure to hexagonal nanosheet. • On increasing the pH from 8 to 11, the band gap decreases from 3.52 to 3.37 eV. - Abstract: Nickel hydroxide samples were deposited onto glass substrates using Ni(NO{sub 3}){sub 2}·6H{sub 2}O and aqueous ammonia by chemical bath deposition technique. The influence of pH of solution was investigated by means of X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, optical absorption and BET analysis. The as-deposited samples were identified as β-Ni(OH){sub 2}, were transformed into NiO after heat treatment in air at 500 °C for 2 h. Porous nickel oxide nanosheets are obtained by heating nickel hydroxide nanosheets. The optical transitions observed in the absorbance spectra below optical band gap is due to defects or Ni{sup 2+} vacancies in NiO samples. The band gap energy of NiO samples changes between 3.37 and 3.52 eV depending on the pH values.

In situ Reduction and Oxidation of Nickel from Solid Oxide Fuel Cells in a Transmission Electron Microscope

DEFF Research Database (Denmark)

Faes, Antonin; Jeangros, Quentin; Wagner, Jakob Birkedal

2009-01-01

Environmental transmission electron microscopy was used to characterize in situ the reduction and oxidation of nickel from a Ni/YSZ solid oxide fuel cell anode support between 300-500{degree sign}C. The reduction is done under low hydrogen pressure. The reduction initiates at the NiO/YSZ interface...

Solubility of nickel ferrite (NiFe2O4) from 100 to 200 deg. C

International Nuclear Information System (INIS)

Bellefleur, Alexandre; Bachet, Martin; Benezeth, Pascale; Schott, Jacques

2012-09-01

The solubility of nickel ferrite was measured in a Hydrogen-Electrode Concentration Cell (HECC) at temperatures of 100 deg. C, 150 deg. C and 200 deg. C and pH between 4 and 5.25. The experimental solution was composed of HCl and NaCl (0.1 mol.L -1 ). Based on other studies ([1,2]), pure nickel ferrite was experimentally synthesized by calcination of a mixture of hematite Fe 2 O 3 and bunsenite NiO in molten salts at 1000 deg. C for 15 hours in air. The so obtained powder was fully characterized. The Hydrogen-Electrode Concentration cell has been described in [3]. It allowed us to run solubility experiments up to 250 deg. C with an in-situ pH measurement. To avoid reduction of the solid phase to metallic nickel, a hydrogen/argon mixture was used instead of pure hydrogen. Consequently, the equilibration time for the electrodes was longer than with pure hydrogen. Eight samples were taken on a 70 days period. After the experiments, the powder showed no significant XRD evidence of Ni (II) reduction. Nickel concentration was measured by atomic absorption spectroscopy and iron concentration was measured by UV spectroscopy. The protocol has been designed to be able to measure both dissolved Fe (II) and total iron. The nickel solubility of nickel ferrite was slightly lower than the solubility of nickel oxide in close experimental conditions [3]. Dissolved iron was mainly ferrous and the solution was under-saturated relative to both hematite and magnetite. The nickel/iron ratio indicated a non-stoichiometric dissolution. The solubility measurements were compared with equilibrium calculations using the MULTEQ database. [1] Hayashi et al (1980) J. Materials Sci. 15, 1491-1497. [2] Ziemniak et al (2007) J. Physics and Chem. of Solids. 68,10-21. [3] EPRI Report 1003155 (2002). (authors)

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

Mesoporous NiCo2O4 nanoneedles grown on 3D graphene-nickel foam for supercapacitor and methanol electro-oxidation

International Nuclear Information System (INIS)

Yu, Mei; Chen, Jianpeng; Liu, Jianhua; Li, Songmei; Ma, Yuxiao; Zhang, Jingdan; An, Junwei

2015-01-01

Mesoporous NiCo 2 O 4 nanoneedles were directly grown on three dimensional (3D) graphene-nickel foam which was prepared by chemical vapor deposition, labeled as NCO/GNF. The structure and morphology of NCO/GNF were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, element mapping and Raman spectroscopy. The NCO/GNF was employed as electrodes for supercapacitor and methanol electro-oxidation. When used for supercapacitor, the NiCo 2 O 4 nanoneedles exhibit hi exhibit high specific capacitance (1588 F g −1 at 1 A g −1 ), high power density and energy density (33.88 Wh kg −1 at 5 kW kg −1 ) as well as long cycling stability. In methanol electro-oxidation, the NiCo 2 O 4 nanoneedles deliver high electro-oxidation activity (93.3 A g −1 at 0.65 V) and electro-oxidation stability. The good electrochemical performance of NiCo 2 O 4 nanoneedles is attributed to the 3D structure with large specific area, high conductivity and fast ions/electrons transport

Nanostructured manganese oxide thin films as electrode material for supercapacitors

Science.gov (United States)

Xia, Hui; Lai, Man On; Lu, Li

2011-01-01

Electrochemical capacitors, also called supercapacitors, are alternative energy storage devices, particularly for applications requiring high power densities. Recently, manganese oxides have been extensively evaluated as electrode materials for supercapacitors due to their low cost, environmental benignity, and promising supercapacitive performance. In order to maximize the utilization of manganese oxides as the electrode material for the supercapacitors and improve their supercapacitive performance, the nanostructured manganese oxides have therefore been developed. This paper reviews the synthesis of the nanostructured manganese oxide thin films by different methods and the supercapacitive performance of different nanostructures.

Electrochemical oxidation of p-nitrophenol using graphene-modified electrodes, and a comparison to the performance of MWNT-based electrodes

International Nuclear Information System (INIS)

Arvinte, A.; Pinteala, M.; Mahosenaho, M.; Sesay, A.M.; Virtanen, V.

2011-01-01

The electrochemical oxidation of p-nitrophenol (p-NP) has been studied comparatively on a graphene modified electrode and a multiwall carbon nanotube (MWNT) electrode by using cyclic and differential pulse voltammetry. The sensors were fabricated by modifying screen-printed electrodes with graphene and MWNT nanomaterials, respectively, both dispersed in Nafion polymer. p-NP is irreversibly oxidized at +0. 9 V (vs. the Ag/AgCl) in solutions of pH 7. The height and potential of the peaks depend on pH in the range from 5 to 11. In acidic media, p-NP yields a well-defined oxidation peak at +0. 96 V which gradually increases in height with the concentration of the analyte. In case of differential pulse voltammetry in sulfuric acid solution, the sensitivity is practically the same for both electrodes. The modified electrodes display an unusually wide linear response (from 10 μM to 0. 62 mM of p-NP), with a detection limit of 0. 6 μM in case of the graphene electrode, and of 1. 3 μM in case of the MWNT electrode. (author)

Sulfur tolerant composite cermet electrodes for solid oxide electrochemical cells

Science.gov (United States)

Isenberg, Arnold O.

1987-01-01

An electrochemical apparatus is made containing an exterior electrode bonded to the exterior of a tubular, solid, oxygen ion conducting electrolyte where the electrolyte is also in contact with an interior electrode, said exterior electrode comprising particles of an electronic conductor contacting the electrolyte, where a ceramic metal oxide coating partially surrounds the particles and is bonded to the electrolyte, and where a coating of an ionic-electronic conductive material is attached to the ceramic metal oxide coating and to the exposed portions of the particles.

Nickel-functionalized reduced graphene oxide with polyaniline for non-enzymatic glucose sensing

International Nuclear Information System (INIS)

Zhang, Bing; He, Yu; Liu, Bingqian; Tang, Dianping

2015-01-01

We have developed a new class of organic–inorganic hybrid nanostructures based on the use of reduced graphene oxide (rGO), polyaniline, and a nickel metal nanostructure. It was applied to efficient non-enzymatic sensing of glucose based on its electrocatalytic oxidation. Scanning electron microscopy and energy-dispersive X-Ray were employed to characterize the material. It is shown that the doped polyaniline plays an important role in the formation of the hybrid nanostructures. Improved analytical performance is found when the hybrid nanostructures were placed on a glassy carbon electrode and used for non-enzymatic sensing of glucose at a typical working potential of +450 mV and a pH value of 13. Features include a fast response (∼2 s), high sensitivity (6,050 μA mM −1 cm −2 ), a linear range from 0.1 μM to 1.0 mM, and a low detection limit (0.08 μM). The response to glucose follows a Michaelis-Menten kinetic behavior, and the K M value was determined to be 0.241 μM. Reproducibility and specificity are acceptable. Fructose and maltose do not interfere significantly. Importantly, the methodology was validated and evaluated for the analysis of 15 spiked human serum specimens, receiving in a good accordance with the results obtained by the non-enzymatic glucose sensing and the commercialized personal glucose meter. (author)

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

Nitric oxide and bcl-2 mediated the apoptosis induced by nickel(II) in human T hybridoma cells

International Nuclear Information System (INIS)

Guan Fuqin; Zhang Dongmei; Wang Xinchang; Chen Junhui

2007-01-01

Although effects of nickel(II) on the immune system have long been recognized, little is known about the effects of nickel(II) on the induction of apoptosis and related signaling events in T cells. In the present study, we investigated the roles and signaling pathways of nickel(II) in the induction of apoptosis in a human T cell line jurkat. The results showed that the cytotoxic effects of Ni involved significant morphological changes and chromosomal condensation (Hoechst 33258 staining). Analyses of hypodiploid cells and FITC-Annexin V and PI double staining showed significant increase of apoptosis in jurkat cells 6, 12 and 24 h after nickel(II) treatment. Flow cytometry analysis also revealed that the loss of mitochondrial membrane potential (MMP) occurred concomitantly with the onset of NiCl 2 -induced apoptosis. Induction of apoptotic cell death by nickel was mediated by reduction of bcl-2 expression. Furthermore, nickel stimulated the generation of nitric oxide (NO). These results suggest that nickel(II) chloride induces jurkat cells apoptosis via nitric oxide generation, mitochondrial depolarization and bcl-2 suppression

Electrocatalytic oxidation of cellulose at a gold electrode.

Science.gov (United States)

Sugano, Yasuhito; Latonen, Rose-Marie; Akieh-Pirkanniemi, Marceline; Bobacka, Johan; Ivaska, Ari

2014-08-01

The electrochemical properties of cellulose dissolved in NaOH solution at a Au surface were investigated by cyclic voltammetry, FTIR spectroscopy, the electrochemical quartz crystal microbalance technique, and electrochemical impedance spectroscopy. The reaction products were characterized by SEM, TEM, and FTIR and NMR spectroscopy. The results imply that cellulose is irreversibly oxidized. Adsorption and desorption of hydroxide ions at the Au surface during potential cycling have an important catalytic role in the reaction (e.g., approach of cellulose to the electrode surface, electron transfer, adsorption/desorption of the reaction species at the electrode surface). Moreover, two types of cellulose derivatives were obtained as products. One is a water-soluble cellulose derivative in which some hydroxyl groups are oxidized to carboxylic groups. The other derivative is a water-insoluble hybrid material composed of cellulose and Au nanoparticles (≈4 nm). Furthermore, a reaction scheme of the electrocatalytic oxidation of cellulose at a gold electrode in a basic medium is proposed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anodic oxidation with doped diamond electrodes: a new advanced oxidation process

International Nuclear Information System (INIS)

Kraft, Alexander; Stadelmann, Manuela; Blaschke, Manfred

2003-01-01

Boron-doped diamond anodes allow to directly produce OH· radicals from water electrolysis with very high current efficiencies. This has been explained by the very high overvoltage for oxygen production and many other anodic electrode processes on diamond anodes. Additionally, the boron-doped diamond electrodes exhibit a high mechanical and chemical stability. Anodic oxidation with diamond anodes is a new advanced oxidation process (AOP) with many advantages compared to other known chemical and photochemical AOPs. The present work reports on the use of diamond anodes for the chemical oxygen demand (COD) removal from several industrial wastewaters and from two synthetic wastewaters with malic acid and ethylenediaminetetraacetic (EDTA) acid. Current efficiencies for the COD removal between 85 and 100% have been found. The formation and subsequent removal of by-products of the COD oxidation has been investigated for the first time. Economical considerations of this new AOP are included

High-performance hybrid (electrostatic double-layer and faradaic capacitor-based) polymer actuators incorporating nickel oxide and vapor-grown carbon nanofibers.

Science.gov (United States)

Terasawa, Naohiro; Asaka, Kinji

2014-12-02

The electrochemical and electromechanical properties of polymeric actuators prepared using nickel peroxide hydrate (NiO2·xH2O) or nickel peroxide anhydride (NiO2)/vapor-grown carbon nanofibers (VGCF)/ionic liquid (IL) electrodes were compared with actuators prepared using solely VGCFs or single-walled carbon nanotubes (SWCNTs) and an IL. The electrode in these actuator systems is equivalent to an electrochemical capacitor (EC) exhibiting both electrostatic double-layer capacitor (EDLC)- and faradaic capacitor (FC)-like behaviors. The capacitance of the metal oxide (NiO2·xH2O or NiO2)/VGCF/IL electrode is primarily attributable to the EDLC mechanism such that, at low frequencies, the strains exhibited by the NiO2·xH2O/VGCF/IL and NiO2/VGCF/IL actuators primarily result from the FC mechanism. The VGCFs in the NiO2·xH2O/VGCF/IL and NiO2/VGCF/IL actuators strengthen the EDLC mechanism and increase the electroconductivity of the devices. The mechanism underlying the functioning of the NiO2·xH2O/VGCF/IL actuator in which NiO2·xH2O/VGCF = 1.0 was found to be different from that of the devices produced using solely VGCFs or SWCNTs, which exhibited only the EDLC mechanism. In addition, it was found that both NiO2 and VGCFs are essential with regard to producing actuators that are capable of exhibiting strain levels greater than those of SWCNT-based polymer actuators and are thus suitable for practical applications. Furthermore, the frequency dependence of the displacement responses of the NiO2·xH2O/VGCF and NiO2/VGCF polymer actuators were successfully simulated using a double-layer charging kinetic model. This model, which accounted for the oxidization and reduction reactions of the metal oxide, can also be applied to SWCNT-based actuators. The results of electromechanical response simulations for the NiO2·xH2O/VGCF and NiO2/VGCF actuators predicted the strains at low frequencies as well as the time constants of the devices, confirming that the model is applicable

Electrochemical reduction of nitroaromatic compounds by single sheet iron oxide coated electrodes

Energy Technology Data Exchange (ETDEWEB)

Huang, Li-Zhi, E-mail: lizhi@plen.ku.dk [Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK–1871 Frederiksberg C (Denmark); Hansen, Hans Christian B. [Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK–1871 Frederiksberg C (Denmark); Bjerrum, Morten Jannik [Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK–2100 København Ø (Denmark)

2016-04-05

Highlights: • Composite layers of single sheet iron oxides were coated on indium tin oxide electrodes. • Single sheet iron oxide is an electro-catalyst for reduction of nitroaromatic compounds in aqueous solution. • The reduction is well explained by a diffusion layer model. • The charge properties of the nitrophenols have an important influence on reduction. • Low-cost iron oxide based materials are promising electro-catalyst for water treatment. - Abstract: Nitroaromatic compounds are substantial hazard to the environment and to the supply of clean drinking water. We report here the successful reduction of nitroaromatic compounds by use of iron oxide coated electrodes, and demonstrate that single sheet iron oxides formed from layered iron(II)-iron(III) hydroxides have unusual electrocatalytic reactivity. Electrodes were produced by coating of single sheet iron oxides on indium tin oxide electrodes. A reduction current density of 10 to 30 μA cm{sup −2} was observed in stirred aqueous solution at pH 7 with concentrations of 25 to 400 μM of the nitroaromatic compound at a potential of −0.7 V vs. SHE. Fast mass transfer favors the initial reduction of the nitroaromatic compound which is well explained by a diffusion layer model. Reduction was found to comprise two consecutive reactions: a fast four-electron first-order reduction of the nitro-group to the hydroxylamine-intermediate (rate constant = 0.28 h{sup −1}) followed by a slower two-electron zero-order reduction resulting in the final amino product (rate constant = 6.9 μM h{sup −1}). The zero-order of the latter reduction was attributed to saturation of the electrode surface with hydroxylamine-intermediates which have a more negative half-wave potential than the parent compound. For reduction of nitroaromatic compounds, the SSI electrode is found superior to metal electrodes due to low cost and high stability, and superior to carbon-based electrodes in terms of high coulombic efficiency and

Coexistence of positive and negative photoconductivity in nickel oxide decorated multiwall carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Jiménez-Marín, E. [Departamento de Ingeniería en Metalurgia y Materiales, Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, Ciudad de México 07300 (Mexico); Villalpando, I. [Centro de Investigación para los Recursos Naturales, Salaices, Chihuahua 33941 (Mexico); Trejo-Valdez, M. [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, México, Ciudad de México 07738 (Mexico); Cervantes-Sodi, F. [Departamento de Física y Matemáticas, Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Ciudad de México 01219 (Mexico); Vargas-García, J.R. [Centro de Nanociencias y Micro y Nanotecnologías del Instituto Politécnico Nacional, Ciudad de México 07738 (Mexico); Torres-Torres, C., E-mail: ctorrest@ipn.mx [Sección de Estudios de Posgrado e Investigación, Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Zacatenco, Instituto Politécnico Nacional, Ciudad de México 07738 (Mexico)

2017-06-15

Highlights: • Nickel oxide decorated carbon nanotubes were prepared by chemical vapor deposition. • Contrast in photoconductivity phenomena in the nanohybrid was analyzed. • Electrical and nonlinear optical properties were evaluated. • A Wheatstone bridge sensor based metal/carbon nanostructures was proposed. - Abstract: Within this work was explored the influence of nickel oxide decoration on the photoconductive effects exhibited by multiwall carbon nanotubes. Samples in thin film form were prepared by a chemical vapor deposition method. Experiments for evaluating the photo-response of the nanomaterials at 532 nanometers wavelength were undertaken. A contrasting behavior in the photoelectrical characteristics of the decorated nanostructures was analyzed. The decoration technique allowed us to control a decrease in photoconduction of the sample from approximately 100 μmhos/cm to −600 μmhos/cm. Two-wave mixing experiments confirmed an enhancement in nanosecond nonlinearities derived by nickel oxide contributions. It was considered that metallic nanoparticles present a strong responsibility for the evolution of the optoelectronic phenomena in metal/carbon nanohybrids. Impedance spectroscopy explorations indicated that a capacitive behavior correspond to the samples. A potential development of high-sensitive Wheatstone bridge sensors based on the optoelectrical performance of the studied samples was proposed.

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.

Electrochemical oxidation of organic carbonate based electrolyte solutions at lithium metal oxide electrodes

Energy Technology Data Exchange (ETDEWEB)

Imhof, R; Novak, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

The oxidative decomposition of carbonate based electrolyte solutions at practical lithium metal oxide composite electrodes was studied by differential electrochemical mass spectrometry. For propylene carbonate (PC), CO{sub 2} evolution was detected at LiNiO{sub 2}, LiCoO{sub 2}, and LiMn{sub 2}O{sub 4} composite electrodes. The starting point of gas evolution was 4.2 V vs. Li/Li{sup +} at LiNiO{sub 2}, whereas at LiCoO{sub 2} and LiMn{sub 2}O{sub 4}, CO{sub 2} evolution was only observed above 4.8 V vs. Li/Li{sup +}. In addition, various other volatile electrolyte decomposition products of PC were detected when using LiCoO{sub 2}, LiMn{sub 2}O4, and carbon black electrodes. In ethylene carbonate / dimethyl carbonate, CO{sub 2} evolution was only detected at LiNiO{sub 2} electrodes, again starting at about 4.2 V vs. Li/Li{sup +}. (author) 3 figs., 2 refs.

The GENIALL process for generation of nickel-iron alloys from nickel ores or mattes

International Nuclear Information System (INIS)

Diaz, G.; Frias, C.; Palma, J.

2001-01-01

A new process, called GENIALL (acronym of Generation of Nickel Alloys), for nickel recovery as ferronickel alloys from ores or mattes without previous smelting is presented in this paper. Its core technology is a new electrolytic concept, the ROSEL cell, for electrowinning of nickel-iron alloys from concentrated chloride solutions. In the GENIALL Process the substitution of iron-based solid wastes as jarosite, goethite or hematite, by saleable ferronickel plates provides both economic and environmental attractiveness. Another advantage is that no associated sulfuric acid plant is required. The process starts with leaching of the raw material (ores or mattes) with a solution of ferric chloride. The leachate liquor is purified by conventional methods like cementation or solvent extraction, to remove impurities or separate by-products like copper and cobalt. The purified solution, that contains a mixture of ferrous and nickel chlorides is fed to the cathodic compartment of the electrowinning cell, where nickel and ferrous ions are reduced together to form an alloy. Simultaneously, ferrous chloride is oxidized to ferric chloride in the anodic compartment, from where it is recycled to the leaching stage. The new electrolytic equipment has been developed and scaled up from laboratory to pilot prototypes with commercial size electrodes of 1 m 2 . Process operating conditions have been established in continuous runs at bench and pilot plant scale. The technology has shown a remarkable capacity to produce nickel-iron alloys of a wide range of compositions, from 10% to 80% nickel, just by adjusting the operating parameters. This emerging technology could be implemented in many processes in which iron and other non-ferrous metals are harmful impurities to be removed, or valuable metals to be recovered as a marketable iron alloy. Other potential applications of this technology are regeneration of spent etching liquors, and iron removal from aqueous effluents. (author)

Initial study of Nickel Electrolyte for EnFACE Process

Directory of Open Access Journals (Sweden)

Tri Widayatno

2015-03-01

Full Text Available Nickel electrolyte for a micro-pattern transfer process without photolithography, EnFACE, has been developed. Previous work on copper deposition indicated that a conductivity of ~2.7 Sm-1 is required. Electrochemical parameters of electrolyte i.e. current density and overpotential are also crucial to govern a successful pattern replication. Therefore, the investigation focused on the measurement of physicochemical properties and electrochemical behaviour of the electrolyte at different nickel concentrations and complexing agents of chloride and sulfamate. Nickel electrolytes containing sulfamate, chloride and combined sulfamate-chloride with concentrations between 0.14 M and 0.3 M were investigated. Physicochemical properties i.e. pH and conductivity were measured to ensure if they were in the desired value. The electrochemical behaviour of the electrolytes was measured by polarisation experiments in a standard three-electrode cell. The working electrode was a copper disc (surface area of 0.196 cm2 and the counter electrode was platinum mesh. The potential was measured againts a saturated calomel reference electrode (SCE. The experiments were carried out at various scan rate and Rotating Disc Electrode (RDE rotation speed to see the effect of scan rate and agitation. Based on the measured physicochemical properties, the electrolyte of 0.19 M nickel sulfamate was chosen for experimentation. Polarisation curve of agitated solution suggested that overall nickel electrodeposition reaction is controlled by a combination of kinetics and mass transfer.  Reduction potential of nickel was in the range of -0.7 to -1.0 V. The corresponding current densities for nickel deposition were in the range of -0.1 to -1.5 mA cm-2.

Construction of Core-Shell NiMoO4@Ni-Co-S Nanorods as Advanced Electrodes for High-Performance Asymmetric Supercapacitors.

Science.gov (United States)

Chen, Chao; Yan, Dan; Luo, Xin; Gao, Wenjia; Huang, Guanjie; Han, Ziwu; Zeng, Yan; Zhu, Zhihong

2018-02-07

In this work, hierarchical core-shell NiMoO 4 @Ni-Co-S nanorods were first successfully grown on nickel foam by a facile two-step method to fabricate a bind-free electrode. The well-aligned electrode wrapped by Ni-Co-S nanosheets displays excellent nanostructural properties and outstanding electrochemical performance, owing to the synergistic effects of both nickel molybdenum oxides and nickel cobalt sulfides. The prepared core-shell nanorods in a three-electrode cell yielded a high specific capacitance of 2.27 F cm -2 (1892 F g -1 ) at a current density of 5 mA cm -2 and retained 91.7% of the specific capacitance even after 6000 cycles. Their electrochemical performance was further investigated for their use as positive electrode for asymmetric supercapacitors. Notably, the energy density of the asymmetric supercapacitor device reached 2.45 mWh cm -3 at a power density of 0.131 W cm -3 , and still retained a remarkable 80.3% of the specific capacitance after 3500 cycles. There is great potential for the electrode composed of the core-shell NiMoO 4 @Ni-Co-S nanorods for use in an all-solid-state asymmetric supercapacitor device.

Nanostructured Solid Oxide Fuel Cell Electrodes

Energy Technology Data Exchange (ETDEWEB)

Sholklapper, Tal Zvi [Univ. of California, Berkeley, CA (United States)

2007-01-01

The ability of Solid Oxide Fuel Cells (SOFC) to directly and efficiently convert the chemical energy in hydrocarbon fuels to electricity places the technology in a unique and exciting position to play a significant role in the clean energy revolution. In order to make SOFC technology cost competitive with existing technologies, the operating temperatures have been decreased to the range where costly ceramic components may be substituted with inexpensive metal components within the cell and stack design. However, a number of issues have arisen due to this decrease in temperature: decreased electrolyte ionic conductivity, cathode reaction rate limitations, and a decrease in anode contaminant tolerance. While the decrease in electrolyte ionic conductivities has been countered by decreasing the electrolyte thickness, the electrode limitations have remained a more difficult problem. Nanostructuring SOFC electrodes addresses the major electrode issues. The infiltration method used in this dissertation to produce nanostructure SOFC electrodes creates a connected network of nanoparticles; since the method allows for the incorporation of the nanoparticles after electrode backbone formation, previously incompatible advanced electrocatalysts can be infiltrated providing electronic conductivity and electrocatalysis within well-formed electrolyte backbones. Furthermore, the method is used to significantly enhance the conventional electrode design by adding secondary electrocatalysts. Performance enhancement and improved anode contamination tolerance are demonstrated in each of the electrodes. Additionally, cell processing and the infiltration method developed in conjunction with this dissertation are reviewed.

Properties of Copper Doped Neodymium Nickelate Oxide as Cathode Material for Solid Oxide Fuel Cells

Directory of Open Access Journals (Sweden)

Lee Kyoung-Jin

2016-06-01

Full Text Available Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1 powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2 resulted in the increased electrical conductivity and decreased polarization resistance. It appears that this phenomenon was associated with the high mean valence of nickel and copper and the resulting excess oxygen (δ. It was found that power densities of the cell with the Nd2Ni1-xCuxO4+δ (x=0.1 and 0.2 cathode were higher than that of the cell with the Nd2NiO4+δ cathode.

C-IOP/NiO/Ni7S6 composite with the inverse opal lattice as an electrode for supercapacitors

Science.gov (United States)

Sukhinina, Nadezhda S.; Masalov, Vladimir M.; Zhokhov, Andrey A.; Zverkova, Irina I.; Emelchenko, Gennadi A.

2015-06-01

In this work, we demonstrate the results of studies on the synthesis, the structure and properties of carbon inverted opal (C-IOP) nanostructures, the surface of which is modified by oxide and sulfide of nickel. It is shown that the modification of the matrix C-IOP by nickel compounds led to a decreasing the specific surface area more than three times and was 250 m2/g. The specific capacitance of the capacitor with the C-IOP/NiO/Ni7S6 composite as electrode has increased more than 4 times, from 130 F/g to 600 F/g, as compared with the sample C-IOP without the modification by nickel compounds. The significant contribution of the faradaic reactions in specific capacitance of the capacitor electrodes of the composites is marked.

Decomposition of hydrogen peroxide on nickel oxide - vanadium pentoxide catalysts and the effect of ionizing radiation on them

International Nuclear Information System (INIS)

Mucka, V.

1984-01-01

Some physico-chemical and catalytic properties of nickel oxide-vanadium pentoxide two-component catalysts were studied over the entire concentration range of the components, using the decomposition of hydrogen peroxide in an aqueous solution as the test reaction. The two oxides were found to affect each other; this was shown by the dependences of the specific surface area, the V 4+ ion concentration, and the catalyst activity on the system composition. At low vanadium pentoxide concentrations (up to 15 mol%) the reaction took place on nickel oxide modified with vanadium pentoxide, whereas in the region of higher vanadium pentoxide concentrations the decomposition of the peroxide was catalyzed primarily in the homogeneous phase by vanadium(V) peroxide ions; in a sample with 30 mol% V 2 O 5 , trivalent vanadium also played a part. With catalysts obtained by mere mechanical mixing of the two oxides, a modified activity was observed in the region of high excess of nickel oxide. The activity of catalyst, particularly pure nickel oxide, was increased by its partial reduction and decreased by its exposure to gamma radiation if the dose was higher than 10 5 Gy. The effects observed are interpreted in terms of the concept of bivalent catalytic centres. (author)

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.

Kinetic investigation of vanadium (V)/(IV) redox couple on electrochemically oxidized graphite electrodes

International Nuclear Information System (INIS)

Wang, Wenjun; Wei, Zengfu; Su, Wei; Fan, Xinzhuang; Liu, Jianguo; Yan, Chuanwei; Zeng, Chaoliu

2016-01-01

Highlights: • The VO_2"+/VO"2"+ redox reaction of the electrode could be facilitated to some extent with the increasing anodic corrosion. • A real reaction kinetic equation for the oxidation of VO"2"+ on the electrochemically oxidized electrode has been firstly obtained. • The establishment of the kinetic equation is conducive to predict polarization behaviors of the electrodes in engineering application. - Abstract: The morphology, surface composition, wettability and the kinetic parameters of the electrochemically oxidized graphite electrodes obtained under different anodic polarization conditions have been examined by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurements, steady-state polarization and cyclic voltammetry (CV) tests, with an attempt to investigate the inherent correlation between the physicochemical properties and the kinetic characteristics for carbon electrodes used in an all-vanadium redox flow battery (VRFB). When the anodic polarization potential raises up to 1.8 V vs. SCE, the anodic corrosion of the graphite might happen and a large number of oxygen-containing functional groups generate. The VO_2"+/VO"2"+ redox reaction can be facilitated and the reaction reversibility tends to become better with the increasing anodic potential, possibly owing to the increased surface oxides and the resulting improved wettability of the electrode. Based on this, a real reaction kinetic equation for the oxidation of VO"2"+ has been obtained on the electrode polarized at 1.8 V vs. SCE and it can be also well used to predict the polarization behavior of the oxidized electrode in vanadium (IV) acidic solutions.

Polyaniline silver nanoparticle coffee waste extracted porous graphene oxide nanocomposite structures as novel electrode material for rechargeable batteries

Science.gov (United States)

Sundriyal, Poonam; Bhattacharya, Shantanu

2017-03-01

The exploration of new and advanced electrode materials are required in electronic and electrical devices for power storage applications. Also, there has been a continuous endeavour to formulate strategies for extraction of high performance electrode materials from naturally obtained waste products. In this work, we have developed an in situ hybrid nanocomposite from coffee waste extracted porous graphene oxide (CEPG), polyaniline (PANI) and silver nanoparticles (Ag) and have found this novel composite to serve as an efficient electrode material for batteries. The successful interaction among the three phases of the nano-composite i.e. CEPG-PANI-Ag have been thoroughly understood through RAMAN, Fourier transform infrared and x-ray diffraction spectroscopy, morphological studies through field emission scanning electron microscope and transmission electron microscope. Thermo-gravimetric analysis of the nano-composite demonstrates higher thermal stability up-to a temperature of 495 °C. Further BET studies through nitrogen adsorption-desorption isotherms confirm the presence of micro/meso and macro-pores in the nanocomposite sample. The cyclic-voltammetry (CV) analysis performed on CEPG-PANI-Ag nanocomposite exhibits a purely faradic behaviour using nickel foam as a current collector thus suggests the prepared nanocomposite as a battery electrode material. The nanocomposite reports a maximum specific capacity of 1428 C g-1 and excellent cyclic stability up-to 5000 cycles.

Corrosion-electrochemical behavior of nickel in an alkali metal carbonate melt under a chlorine-containing atmosphere

Science.gov (United States)

Nikitina, E. V.; Kudyakov, V. Ya.; Malkov, V. B.; Plaksin, S. V.

2013-08-01

The corrosion-electrochemical behavior of a nickel electrode is studied in the melt of lithium, sodium, and potassium (40: 30: 30 mol %) carbonates in the temperature range 500-600°C under an oxidizing atmosphere CO2 + 0.5O2 (2: 1), which is partly replaced by gaseous chlorine (30, 50, 70%) in some experiments. In other experiments, up to 5 wt % chloride of sodium peroxide is introduced in a salt melt. A change in the gas-phase composition is shown to affect the mechanism of nickel corrosion.

Graphene Oxide/ Ruthenium Oxide Composites for Supercapacitors Electrodes

Science.gov (United States)

Amir, Fatima

Supercapacitors are electrical energy storage devices with high power density, high rate capability, low maintenance cost, and long life cycle. They complement or replace batteries in harvesting applications when high power delivery is needed. An important improvement in performance of supercapacitors has been achieved through recent advances in the development of new nanostructured materials. Here we will discuss the fabrication of graphene oxide/ ruthenium oxide supercacitors electrodes including electrophoretic deposition. The morphology and structure of the fabricated electrodes were investigated and will be discussed. The electrochemical properties were determined using cyclic voltammetry and galvanostatic charge/discharge techniques and the experiments that demonstrate the excellent capacitive properties of the obtained supercapacitors will also be discussed. The fabrication and characterization of the samples were performed at the Center of Functional Nanomaterials at Brookhaven National Lab. The developed approaches in our study represent an exciting direction for designing the next generation of energy storage devices. This work was supported in part by the U.S. Department of Energy through the Visiting Faculty Program and the research used resources of the Center for Functional Nanomaterials at Brookhaven National Laboratory.

3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

Science.gov (United States)

Huang, Wei; Cao, Yang; Chen, Yong; Zhou, Yang; Huang, Qingyou

2015-12-01

3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM-1 cm-2, and a possible mechanism was also given in the paper.

O2-enhanced methanol oxidation reaction at novel Pt-Ru-C co-sputtered electrodes

International Nuclear Information System (INIS)

Umeda, Minoru; Matsumoto, Yosuke; Inoue, Mitsuhiro; Shironita, Sayoko

2013-01-01

Highlights: ► Novel Pt-Ru-C electrodes were prepared by a co-sputtering technique. ► Co-sputtered electrodes with C result in highly efficient O 2 -enhanced methanol oxidation. ► Pt–Ru-alloy-based co-sputtered electrode induces a negative onset potential of methanol oxidation. ► The Pt-Ru-C electrodes allow a negative onset potential of O 2 -enhanced methanol oxidation. ► The optimum atomic ratios of Pt-Ru-C are Pt: 0.24–0.80, Ru: 0.14–0.61, C: 0.06–0.37. -- Abstract: A Pt-Ru-C electrode has been developed using a co-sputtering technique for use as the anode catalyst of a mixed-reactant fuel cell. The physical and electrochemical characteristics of the electrodes demonstrate that co-sputtered Pt and Ru form a Pt–Ru alloy. The crystallite sizes of the catalysts investigated in this study are reduced by the addition of C to the Pt–Ru alloy. Cu stripping voltammograms suggest that the sputtering of C and the formation of the Pt–Ru alloy synergically increase the electrochemical surface area of the electrodes. The methanol oxidation performances of the prepared electrodes were evaluated in N 2 and O 2 atmospheres; the Pt-Ru-C electrodes achieve an O 2 -induced negative shift in the onset potential of the methanol oxidation (E onset ) and enhance the methanol oxidation current density in the O 2 atmosphere. The mechanism of O 2 -enhanced methanol oxidation with a negative E onset at the Pt-Ru-C electrodes is attributed to a change in the electronic structure of Pt due to the formation of Pt–Ru alloy and the generation of O-based adsorption species by the reduction of O 2 . Finally, the composition of the Pt-Ru-C electrode for the O 2 -enhanced methanol oxidation with a negative E onset was found to be optimal at an atomic ratio of Pt: 0.24–0.80, Ru: 0.14–0.61, and C: 0.06–0.37

Reduced graphite oxide in supercapacitor electrodes.

Science.gov (United States)

Lobato, Belén; Vretenár, Viliam; Kotrusz, Peter; Hulman, Martin; Centeno, Teresa A

2015-05-15

The current energy needs have put the focus on highly efficient energy storage systems such as supercapacitors. At present, much attention focuses on graphene-like materials as promising supercapacitor electrodes. Here we show that reduced graphite oxide offers a very interesting potential. Materials obtained by oxidation of natural graphite and subsequent sonication and reduction by hydrazine achieve specific capacitances as high as 170 F/g in H2SO4 and 84F/g in (C2H5)4NBF4/acetonitrile. Although the particle size of the raw graphite has no significant effect on the physico-chemical characteristics of the reduced materials, that exfoliated from smaller particles (materials may suffer from a drop in their specific surface area upon fabrication of electrodes with features of the existing commercial devices. This should be taken into account for a reliable interpretation of their performance in supercapacitors. Copyright © 2015 Elsevier Inc. All rights reserved.

Catalytic Water Oxidation by a Bio-inspired Nickel Complex with Redox Active Ligand

Science.gov (United States)

Wang, Dong; Bruner, Charlie O.

2017-01-01

The oxidation of water to dioxygen is important in natural photosynthesis. One of nature’s strategies for managing such multi-electron transfer reactions is to employ redox active metal-organic cofactor arrays. One prototype example is the copper-tyrosinate active site found in galactose oxidase. In this work, we have implemented such a strategy to develop a bio-inspired nickel-phenolate complex capable of catalyzing the oxidation of water to O2 electrochemically at neutral pH with a modest overpotential. The employment of the redox-active ligand turned out to be a useful strategy to avoid the formation of high-valent nickel intermediates while a reasonable turnover rate (0.15 s−1) is retained. PMID:29099176

Optical modeling of nickel-base alloys oxidized in pressurized water reactor

Energy Technology Data Exchange (ETDEWEB)

Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)

2012-10-01

The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.

Nanoparticles of nickel oxide: growth and organization on zinc-substituted anionic clay matrix by one-pot route at room temperature

International Nuclear Information System (INIS)

Carja, Gabriela; Nakajima, Akira; Dranca, Cristian; Okada, Kiyoshi

2010-01-01

A room temperature nanocarving strategy is developed for the fabrication of nanoparticles of nickel oxide on zinc-substituted anionic clay matrix (Ni/ZnLDH). It is based on the growth and organization of nanoparticles of nickel oxide which occur during the structural reconstruction of the layered structure of the anionic clay in NiSO 4 aqueous solution. No organic compounds are used during the fabrication. The described material was characterized by X-ray diffraction (XRD), IR spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Results show that the nickel-clay nanoarchitecture consists of small nanoparticles of nickel oxide (average size 7 nm) deposited on the larger nanoparticles (average size 90 nm) of zinc-substituted clay. The optical properties of the new nickel-zinc formulation are studied by UV-Vis.

Nanoparticles of nickel oxide: growth and organization on zinc-substituted anionic clay matrix by one-pot route at room temperature

Science.gov (United States)

Carja, Gabriela; Nakajima, Akira; Dranca, Cristian; Okada, Kiyoshi

2010-10-01

A room temperature nanocarving strategy is developed for the fabrication of nanoparticles of nickel oxide on zinc-substituted anionic clay matrix (Ni/ZnLDH). It is based on the growth and organization of nanoparticles of nickel oxide which occur during the structural reconstruction of the layered structure of the anionic clay in NiSO4 aqueous solution. No organic compounds are used during the fabrication. The described material was characterized by X-ray diffraction (XRD), IR spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Results show that the nickel-clay nanoarchitecture consists of small nanoparticles of nickel oxide (average size 7 nm) deposited on the larger nanoparticles (average size 90 nm) of zinc-substituted clay. The optical properties of the new nickel-zinc formulation are studied by UV-Vis.

Computer Simulations of Composite Electrodes in Solid-Oxide Fuel-Cells

Energy Technology Data Exchange (ETDEWEB)

Sunde, Svein

1999-07-01

Fuel cells are devices for converting the combined chemical (free) energy of fuels and oxygen (air) directly to electrical energy without relying on the dynamic action of steam heated by reacting fuel-oxygen mixtures, like in steam turbines, or of the reacting gas mixtures themselves, like in gas turbines. The basic rationale for fuel cells is their high efficiencies as compared to indirect-conversion methods. Fuel cells are currently being considered for a number of applications, among them de-centralised power supply. Fuel cells come in five basic types and are usually classified according to the type of electrolyte used, which in turn to a significant degree limits the options for anode and cathode materials. The solid-oxide fuel-cell (SOFC) , with which this thesis is concerned, is thus named after its oxide electrolyte, typically the oxide-ion conducting material yttria-stabilised zirconia (YSZ). While the cathode of an SOFC is often uniform in chemical composition (or at least intended to be), various problems of delamination, cracking etc. associated with the use of metallic anode electrocatalysts led to the development of composite SOFC anodes. Porous anodes consisting of Ni and YSZ particles in roughly 50/50 wt-% mixtures are now almost standard with any SOFC-development programme. The designer of composite SOFC electrodes is faced with at least three, interrelated questions: (1) What will be the optimum microstructure and composition of the composite electrode? (2) If the structure changes during operation, as is often observed, what will be the consequences for the internal losses in the cell? (3) How do we interpret electrochemical and conductivity measurements with regard to structure and composition? It is the primary purpose of this thesis to provide a framework for modelling the electrochemical and transport properties of composite electrodes for SOFC, and to arrive at some new insights that cannot be offered by experiment alone. Emphasis is put on

Characterization of surfactant/hydrotalcite-like clay/glassy carbon modified electrodes: Oxidation of phenol

International Nuclear Information System (INIS)

Hernandez, Maria; Fernandez, Lenys; Borras, Carlos; Mostany, Jorge; Carrero, Hermes

2007-01-01

The characteristics of hydrotalcite (HT)-like clay films containing ionic and nonionic surfactants and their ability to oxidize phenol have been examined. The HT clay (Co/Al-NO 3 ) was synthesized by coprecipitation techniques and then modified with surfactants such as sodium dodecylbenzenesulfonate (SDBS), octylphenoxypolyethoxyethanol (TX100) or cetylpyridinium bromide (CPB). X-ray diffraction analysis revealed that the interlayer basal spacing varied depending on the type of surfactant retained by the HT. The presence of SDBS and CPB expanded the HT interlayer, which in the presence of TX100 did not show an appreciable change. Phenol oxidation is favored at surfactant-HT-GC modified electrodes, after a preconcentration time, compared to phenol oxidation at HT-GC or GC electrodes. Surfactant-HT-GC modified electrodes display good stability in continuous electrochemical phenol oxidation. At pH values between 6 and 10.8, both SDBS-HT-GC and TX100-HT-GC modified electrodes seem to be promising electrodes for the detection of phenol in water; while the CPB-HT-GC modified electrode should be affected by the inorganic anions

Electrolytic photodissociation of chemical compounds by iron oxide electrodes

Science.gov (United States)

Somorjai, Gabor A.; Leygraf, Christofer H.

1984-01-01

Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor diode having visible light as its sole source of energy. The diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.

Nitrogen-doped reduced graphene oxide electrodes for electrochemical supercapacitors.

Science.gov (United States)

Nolan, Hugo; Mendoza-Sanchez, Beatriz; Ashok Kumar, Nanjundan; McEvoy, Niall; O'Brien, Sean; Nicolosi, Valeria; Duesberg, Georg S

2014-02-14

Herein we use Nitrogen-doped reduced Graphene Oxide (N-rGO) as the active material in supercapacitor electrodes. Building on a previous work detailing the synthesis of this material, electrodes were fabricated via spray-deposition of aqueous dispersions and the electrochemical charge storage mechanism was investigated. Results indicate that the functionalised graphene displays improved performance compared to non-functionalised graphene. The simplicity of fabrication suggests ease of up-scaling of such electrodes for commercial applications.

Peptide methionine sulfoxide reductase A (MsrA): direct electrochemical oxidation on carbon electrodes.

Science.gov (United States)

Enache, T A; Oliveira-Brett, A M

2013-02-01

The direct electrochemical behaviour of peptide methionine sulfoxide reductase A (MsrA) adsorbed on glassy carbon and boron doped diamond electrodes surface, was studied over a wide pH range by cyclic and differential pulse voltammetry. MsrA oxidation mechanism occurs in three consecutive, pH dependent steps, corresponding to the oxidation of tyrosine, tryptophan and histidine amino acid residues. At the glassy carbon electrode, the first step corresponds to the oxidation of tyrosine and tryptophan residues and occurs for the same potential. The advantage of boron doped diamond electrode was to enable the separation of tyrosine and tryptophan oxidation peaks. On the second step occurs the histidine oxidation, and on the third, at higher potentials, the second tryptophan oxidation. MsrA adsorbs on the hydrophobic carbon electrode surface preferentially through the three hydrophobic domains, C1, C2 and C3, which contain the tyrosine, tryptophan and histidine residues, and tryptophan exists only in these regions, and undergo electrochemical oxidation. Copyright © 2012 Elsevier B.V. All rights reserved.

Mechanism of formation of corrosion layers on nickel and nickel-based alloys in melts containing oxyanions--a review

International Nuclear Information System (INIS)

Tzvetkoff, Tzvety; Gencheva, Petia

2003-01-01

A review of the corrosion of Ni and Ni-based alloys in melts containing oxyanions (nitrate, sulphate, hydroxide and carbonate) is presented, emphasising the mechanism of growth, the composition and structure of the passivating oxide films formed on the material in such conditions. First, the thermodynamical background involving solubility and point defect chemistry calculations for oxides formed on Ni, Cr and Ni-Cr alloys in molten salt media is briefly commented. The main passivation product on the Ni surface has been reported to be cubic NiO. In the transition stage, further oxidation of the compact NiO layer has been shown to take place in which Ni(III) ions and nickel cation vacancies are formed. Transport of nickel cation vacancies has been proposed to neutralise the charges of the excess oxide ions formed in the further oxidation reaction. Ex situ analysis studies reported in the literature indicated the possible formation of Ni 2 O 3 phase in the anodic layer. During the third stage of oxidation, a survey of the published data indicated that oxygen evolution from oxyanion melts is the predominant reaction taking place on the Ni/NiO electrode. This has been supposed to lead to a further accumulation of oxygen ions in the oxide lattice presumably as oxygen interstitials, and a NiO 2 phase formation has been also suggested. Literature data on the composition of the oxide film on industrial Ni-based alloys and superalloys in melts containing oxyanions are also presented and discussed. Special attention is paid to the effect of the composition of the alloy, the molten salt mixture and the gas atmosphere on the stability and protective ability of corrosion layers

Graphite-graphite oxide composite electrode for vanadium redox flow battery

International Nuclear Information System (INIS)

Li Wenyue; Liu Jianguo; Yan Chuanwei

2011-01-01

Highlights: → A new composite electrode is designed for vanadium redox flow battery (VRB). → The graphite oxide (GO) is used as electrode reactions catalyst. → The excellent electrode activity is attributed to the oxygen-containing groups attached on the GO surface. → A catalytic mechanism of the GO towards the redox reactions is presumed. - Abstract: A graphite/graphite oxide (GO) composite electrode for vanadium redox battery (VRB) was prepared successfully in this paper. The materials were characterized with X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The specific surface area was measured by the Brunauer-Emmett-Teller method. The redox reactions of [VO 2 ] + /[VO] 2+ and V 3+ /V 2+ were studied with cyclic voltammetry and electrochemical impedance spectroscopy. The results indicated that the electrochemical performances of the electrode were improved greatly when 3 wt% GO was added into graphite electrode. The redox peak currents of [VO 2 ] + /[VO] 2+ and V 3+ /V 2+ couples on the composite electrode were increased nearly twice as large as that on the graphite electrode, and the charge transfer resistances of the redox pairs on the composite electrode are also reduced. The enhanced electrochemical activity could be ascribed to the presence of plentiful oxygen functional groups on the basal planes and sheet edges of the GO and large specific surface areas introduced by the GO.

Characterization of Transition-Metal Oxide Deposition on Carbon Electrodes of a Supercapacitor

Directory of Open Access Journals (Sweden)

Ying-Chung Chen

2016-12-01

Full Text Available In order to fabricate the composite electrodes of a supercapacitor, transition-metal oxide materials NiO and WO3 were deposited on carbon electrodes by electron beam evaporation. The influences of various transition-metal oxides, scan rates of cyclic voltammograms (CVs, and galvanostatic charge/discharge tests on the characteristics of supercapacitor were studied. The charge/discharge efficiency and the lifetime of the composite electrodes were also investigated. It was found that the composite electrodes exhibited more favorable capacitance properties than those of the carbon electrodes at high scan rates. The results revealed the promotion of the capacitance property of the supercapacitor with composite electrode and the improving of the decay property in capacitance at high scan rate. In addition, the charge/discharge efficiency is close to 100% after 5000 cycles, and the composite electrode retains strong adhesion between the electrode material and the substrate.

Development of high-capacity nickel-metal hydride batteries using superlattice hydrogen-absorbing alloys

Science.gov (United States)

Yasuoka, Shigekazu; Magari, Yoshifumi; Murata, Tetsuyuki; Tanaka, Tadayoshi; Ishida, Jun; Nakamura, Hiroshi; Nohma, Toshiyuki; Kihara, Masaru; Baba, Yoshitaka; Teraoka, Hirohito

New R-Mg-Ni (R: rare earths) superlattice alloys with higher-capacity and higher-durability than the conventional Mm-Ni alloys with CaCu 5 structure have been developed. The oxidation resistibility of the superlattice alloys has been improved by optimizing the alloy composition by such as substituting aluminum for nickel and optimizing the magnesium content in order to prolong the battery life. High-capacity nickel-metal hydride batteries for the retail market, the Ni-MH2500/900 series (AA size type 2500 mAh, AAA size type 900 mAh), have been developed and commercialized by using an improved superlattice alloy for negative electrode material.

Anodic oxidation of anthraquinone dye Alizarin Red S at Ti/BDD electrodes

Energy Technology Data Exchange (ETDEWEB)

Sun Jianrui; Lu Haiyan [College of Chemistry, Jilin University, Changchun 130012 (China); Du Lili [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Lin Haibo, E-mail: lhb910@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China); State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130012 (China); Li Hongdong, E-mail: hdli@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China)

2011-05-15

The boron-doped diamond (BDD) thin-film electrode with high quality using industrially titanium plate (Ti/BDD) as substrate has been prepared and firstly used in the oxidation of anthraquinone dye Alizarin Red S (ARS) in wastewaters. The Ti/BDD electrodes are shown to have high concentration of sp{sup 3}-bonded carbon and wide electrochemical window. The results of the cyclic voltammetries show that BDD has unique properties such as high anodic stability and the production of active intermediates at the high potential. The oxidation regions of ARS and water are significantly separated at the Ti/BDD electrode, and the peak current increases linearly with increasing ARS concentration. The bulk electrolysis shows that removal of chemical oxygen demand (COD) and color can be completely reached and the electrooxidation of ARS behaves as a mass-transfer-controlled process at the Ti/BDD electrode. It is demonstrated that the performances of the Ti/BDD electrode for anodic oxidation ARS have been significantly improved with respect to the traditional electrodes.

Indirect Electrochemical Oxidation with Multi Carbon Electrodes for Restaurant Wastewater Treatment

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I Dewa Ketut Sastrawidana

2018-01-01

Full Text Available The removal of organic matter from the restaurant wastewater was investigated using the electrochemical oxida-tion method with multi carbon electrodes in a parallel construction. The degradation process was monitored by the measurement of COD concentration as a function of electrolysis time. The effectof operating parameter conditions on COD removal were investigated including initial pH, distance between electrodes, and the applied voltage difference.The results showed that the treatment of restaurant wastewater containing 2 g/L chloride ion using the electrochemical oxidation technique at the operation conditions characterized by: pH 5, distance between electrode of 10 cm and applied voltage of 12 V, enabled to obtained COD removal of 92.84% within 90 min electrolysis time. It is can be concluded that the indirect electrochemical oxidation method with multi carbon electrodes can be used effectivelyas an alternative technology for reducing COD and may be potentially applied for removal organic pollutants from wastewater at the industrial scale.

Nickel hydroxide–carbon nanotube nanocomposites as supercapacitor electrodes: crystallinity dependent performances

International Nuclear Information System (INIS)

Jiang, Wenchao; Zhai, Shengli; Wei, Li; Yuan, Yang; Yu, Dingshan; Chen, Yuan; Wang, Liang; Wei, Jun

2015-01-01

Nickel hydroxide (Ni(OH)_2) is a promising pseudocapacitive material to increase the energy storage capacity of supercapacitors. Ni(OH)_2 has three common crystalline structures: amorphous (amor-), α-, and β-Ni(OH)_2. There is a lack of good understanding on their pros and cons as supercapacitor electrodes. In this work, we synthesized three nanocomposites with thin layers (10–15 nm) of amor-, α-, and β-Ni(OH)_2 deposited on conductive multi-walled carbon nanotubes (MWCNTs). The mass loading of Ni(OH)_2 is analogous in these nanocomposites, ranging from 49.1–52.2 wt% with a comparable narrow-pore size distribution centered around 4–5 nm. They were fabricated into supercapacitor electrodes at a mass loading of 6 mg cm"−"2 with a thickness of ∼250 μm, similar to the electrodes used in commercial supercapacitors. Our results show that MWCNT/amor-Ni(OH)_2 has the highest specific capacitance (1495 or 2984 F g"−"1, based on the mass of total active materials or Ni(OH)_2 only at the scan rate of 5 mV s"−"1 in 1 M KOH electrolyte). It also has the best rate capability among the three nanocomposites. Better performances can be attributed to its disordered structure, which increases its effective surface area and reduces diffusion resistance for redox reactions. However, superior performances gradually deteriorate to the same level as that of MWCNT/β-Ni(OH)_2 over 3000 charge/discharge cycles, because amor- and α-Ni(OH)_2 transform slowly to more ordered β-Ni(OH)_2. Our results highlight that the electrochemical performances of MWCNT/Ni(OH)_2 nanocomposites depend on the crystallinity of Ni(OH)_2, and the performances of electrodes change upon the crystalline structure transformation of Ni(OH)_2 under repeated redox reactions. Future research should focus on improving the structure stability of amor-Ni(OH)_2. (paper)

Cytotoxicity and apoptotic effects of nickel oxide nanoparticles in cultured HeLa cells

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Kezban Ada

2010-04-01

Full Text Available The aim of this study was to observe the cytotoxicity and apoptotic effects of nickel oxide nanoparticles on humancervix epithelioid carcinoma cell line (HeLa. Nickel oxide precursors were synthesized by an nickel sulphate-excess ureareaction in boiling aqueous solution. The synthesized NiO nanoparticles (<200 nm were investigated by X-ray diffractionanalysis and transmission electron microscopy techniques. For cytotoxicity experiments, HeLa cells were incubated in50-500 μg/mL NiO for 2, 6, 12 and 16 hours. The viable cells were counted with a haemacytometer using light microscopy.The cytotoxicity was observed low in 50-200 μg/mL concentration for 16 h, but high in 400-500 μg/mL concentration for2-6 h. HeLa cells' cytoplasm membrane was lysed and detached from the well surface in 400 μg/mL concentration NiOnanoparticles. Double staining and M30 immunostaining were performed to quantify the number of apoptotic cells in cultureon the basis of apoptotic cell nuclei scores. The apoptotic effect was observed 20% for 16 h incubation.

In situ coating nickel organic complexes on free-standing nickel wire films for volumetric-energy-dense supercapacitors.

Science.gov (United States)

Hong, Min; Xu, Shusheng; Yao, Lu; Zhou, Chao; Hu, Nantao; Yang, Zhi; Hu, Jing; Zhang, Liying; Zhou, Zhihua; Wei, Hao; Zhang, Yafei

2018-07-06

A self-free-standing core-sheath structured hybrid membrane electrodes based on nickel and nickel based metal-organic complexes (Ni@Ni-OC) was designed and constructed for high volumetric supercapacitors. The self-standing Ni@Ni-OC film electrode had a high volumetric specific capacity of 1225.5 C cm -3 at 0.3 A cm -3 and an excellent rate capability. Moreover, when countered with graphene-carbon nanotube (G-CNT) film electrode, the as-assembled Ni@Ni-OC//G-CNT hybrid supercapacitor device delivered an extraordinary volumetric capacitance of 85 F cm -3 at 0.5 A cm -3 and an outstanding energy density of 33.8 at 483 mW cm -3 . Furthermore, the hybrid supercapacitor showed no capacitance loss after 10 000 cycles at 2 A cm -3 , indicating its excellent cycle stability. These fascinating performances can be ascribed to its unique core-sheath structure that high capacity nano-porous nickel based metal-organic complexes (Ni-OC) in situ coated on highly conductive Ni wires. The impressive results presented here may pave the way to construct s self-standing membrane electrode for applications in high volumetric-performance energy storage.

NASA Lewis advanced IPV nickel-hydrogen technology

Science.gov (United States)

Smithrick, John J.; Britton, Doris L.

1993-01-01

Individual pressure vessel (IPV) nickel-hydrogen technology was advanced at NASA Lewis and under Lewis contracts. Some of the advancements are as follows: to use 26 percent potassium hydroxide electrolyte to improve cycle life and performance, to modify the state of the art cell design to eliminate identified failure modes and further improve cycle life, and to develop a lightweight nickel electrode to reduce battery mass, hence reduce launch and/or increase satellite payload. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen battery cells was reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 accelerated LEO cycles at 80 percent DOD compared to 3,500 cycles for cells containing 31 percent KOH. Results of the boiler plate cell tests have been validated at NWSC, Crane, Indiana. Forty-eight ampere-hour flight cells containing 26 and 31 percent KOH have undergone real time LEO cycle life testing at an 80 percent DOD, 10 C. The three cells containing 26 percent KOH failed on the average at cycle 19,500. The three cells containing 31 percent KOH failed on the average at cycle 6,400. Validation testing of NASA Lewis 125 Ah advanced design IPV nickel-hydrogen flight cells is also being conducted at NWSC, Crane, Indiana under a NASA Lewis contract. This consists of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, on open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells have been cycled for over 22,694 cycles with no cell failures in the continuing test. All three of the non-catalyzed wall wick cells failed (cycles 9,588; 13,900; and 20,575). Cycle life test results of the Fibrex nickel electrode has demonstrated the feasibility of an improved nickel electrode giving a higher specific energy nickel-hydrogen cell. A nickel-hydrogen boiler plate cell using an 80

Electrochemical Glucose Oxidation Using Glassy Carbon Electrodes Modified with Au-Ag Nanoparticles: Influence of Ag Content

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Nancy Gabriela García-Morales

2015-01-01

Full Text Available This paper describes the application of glassy carbon modified electrodes bearing Aux-Agy nanoparticles to catalyze the electrochemical oxidation of glucose. In particular, the paper shows the influence of the Ag content on this oxidation process. A simple method was applied to prepare the nanoparticles, which were characterized by transmission electron microscopy, Ultraviolet-Visible spectroscopy, X-ray diffraction spectroscopy, and cyclic voltammetry. These nanoparticles were used to modify glassy carbon electrodes. The effectiveness of these electrodes for electrochemical glucose oxidation was evaluated. The modified glassy carbon electrodes are highly sensitive to glucose oxidation in alkaline media, which could be attributed to the presence of Aux-Agy nanoparticles on the electrode surface. The voltammetric results suggest that the glucose oxidation speed is controlled by the glucose diffusion to the electrode surface. These results also show that the catalytic activity of the electrodes depends on the Ag content of the nanoparticles. Best results were obtained for the Au80-Ag20 nanoparticles modified electrode. This electrode could be used for Gluconic acid (GA production.

Graphene electrode modified with electrochemically reduced graphene oxide for label-free DNA detection.

Science.gov (United States)

Li, Bing; Pan, Genhua; Avent, Neil D; Lowry, Roy B; Madgett, Tracey E; Waines, Paul L

2015-10-15

A novel printed graphene electrode modified with electrochemically reduced graphene oxide was developed for the detection of a specific oligonucleotide sequence. The graphene oxide was immobilized onto the surface of a graphene electrode via π-π bonds and electrochemical reduction of graphene oxide was achieved by cyclic voltammetry. A much higher redox current was observed from the reduced graphene oxide-graphene double-layer electrode, a 42% and 36.7% increase, respectively, in comparison with that of a bare printed graphene or reduced graphene oxide electrode. The good electron transfer activity is attributed to a combination of the large number of electroactive sites in reduced graphene oxide and the high conductivity nature of graphene. The probe ssDNA was further immobilized onto the surface of the reduced graphene oxide-graphene double-layer electrode via π-π bonds and then hybridized with its target cDNA. The change of peak current due to the hybridized dsDNA could be used for quantitative sensing of DNA concentration. It has been demonstrated that a linear range from 10(-7)M to 10(-12)M is achievable for the detection of human immunodeficiency virus 1 gene with a detection limit of 1.58 × 10(-13)M as determined by three times standard deviation of zero DNA concentration. Copyright © 2015 Elsevier B.V. All rights reserved.

High Performance Nano-Ceria Electrodes for Solid Oxide Cells

DEFF Research Database (Denmark)

Graves, Christopher R.; Martinez Aguilera, Lev; Sudireddy, Bhaskar Reddy

2016-01-01

forming the active surfaces on a porous backbone with embedded electronic current collector material, yielding one of the highest performances reported for an electrode that operates either on fuel or oxidant. The second is a nano-Ce0.9Gd0.1O2-δ thin film prepared by spin-coating, which provides......In solid oxide electrochemical cells, the conventional Ni-based fuel-electrodes provide high electrocatalytic activity but they are often a major source of long-term performance degradation due to carbon deposition, poisoning of reaction sites, Ni mobility, etc. Doped-ceria is a promising mixed...

Recovery Of Nickel From Spent Nickel-Cadmium Batteries Using A Direct Reduction Process

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Shin D.J.

2015-06-01

Full Text Available Most nickel is produced as Ferro-Nickel through a smelting process from Ni-bearing ore. However, these days, there have been some problems in nickel production due to exhaustion and the low-grade of Ni-bearing ore. Moreover, the smelting process results in a large amount of wastewater, slag and environmental risk. Therefore, in this research, spent Ni-Cd batteries were used as a base material instead of Ni-bearing ore for the recovery of Fe-Ni alloy through a direct reduction process. Spent Ni-Cd batteries contain 24wt% Ni, 18.5wt% Cd, 12.1% C and 27.5wt% polymers such as KOH. For pre-treatment, Cd was vaporized at 1024K. In order to evaluate the reduction conditions of nickel oxide and iron oxide, pre-treated spent Ni-Cd batteries were experimented on under various temperatures, gas-atmospheres and crucible materials. By a series of process, alloys containing 75 wt% Ni and 20 wt% Fe were produced. From the results, the reduction mechanism of nickel oxide and iron oxide were investigated.

Methods for making lithium vanadium oxide electrode materials

Science.gov (United States)

Schutts, Scott M.; Kinney, Robert J.

2000-01-01

A method of making vanadium oxide formulations is presented. In one method of preparing lithium vanadium oxide for use as an electrode material, the method involves: admixing a particulate form of a lithium compound and a particulate form of a vanadium compound; jet milling the particulate admixture of the lithium and vanadium compounds; and heating the jet milled particulate admixture at a temperature below the melting temperature of the admixture to form lithium vanadium oxide.

Morphology-Tuned Synthesis of Nickel Cobalt Selenides as Highly Efficient Pt-Free Counter Electrode Catalysts for Dye-Sensitized Solar Cells.

Science.gov (United States)

Qian, Xing; Li, Hongmei; Shao, Li; Jiang, Xiancai; Hou, Linxi

2016-11-02

In this work, morphology-tuned ternary nickel cobalt selenides based on different Ni/Co molar ratios have been synthesized via a simple precursor conversion method and used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). The experimental facts and mechanism analysis clarified the possible growth process of product. It can be found that the electrochemical performance and structures of ternary nickel cobalt selenides can be optimized by tuning the Ni/Co molar ratio. Benefiting from the unique morphology and tunable composition, among the as-prepared metal selenides, the electrochemical measurements showed that the ternary nickel cobalt selenides exhibited a more superior electrocatalytic activity in comparison with binary Ni and Co selenides. In particular, the three-dimensional dandelion-like Ni 0.33 Co 0.67 Se microspheres delivered much higher power conversion efficiency (9.01%) than that of Pt catalyst (8.30%) under AM 1.5G irradiation.

Nanostructured carbon-metal oxide composite electrodes for supercapacitors: a review

Science.gov (United States)

Zhi, Mingjia; Xiang, Chengcheng; Li, Jiangtian; Li, Ming; Wu, Nianqiang

2012-12-01

This paper presents a review of the research progress in the carbon-metal oxide composites for supercapacitor electrodes. In the past decade, various carbon-metal oxide composite electrodes have been developed by integrating metal oxides into different carbon nanostructures including zero-dimensional carbon nanoparticles, one-dimensional nanostructures (carbon nanotubes and carbon nanofibers), two-dimensional nanosheets (graphene and reduced graphene oxides) as well as three-dimensional porous carbon nano-architectures. This paper has described the constituent, the structure and the properties of the carbon-metal oxide composites. An emphasis is placed on the synergistic effects of the composite on the performance of supercapacitors in terms of specific capacitance, energy density, power density, rate capability and cyclic stability. This paper has also discussed the physico-chemical processes such as charge transport, ion diffusion and redox reactions involved in supercapacitors.

Nanostructured carbon-metal oxide composite electrodes for supercapacitors: a review.

Science.gov (United States)

Zhi, Mingjia; Xiang, Chengcheng; Li, Jiangtian; Li, Ming; Wu, Nianqiang

2013-01-07

This paper presents a review of the research progress in the carbon-metal oxide composites for supercapacitor electrodes. In the past decade, various carbon-metal oxide composite electrodes have been developed by integrating metal oxides into different carbon nanostructures including zero-dimensional carbon nanoparticles, one-dimensional nanostructures (carbon nanotubes and carbon nanofibers), two-dimensional nanosheets (graphene and reduced graphene oxides) as well as three-dimensional porous carbon nano-architectures. This paper has described the constituent, the structure and the properties of the carbon-metal oxide composites. An emphasis is placed on the synergistic effects of the composite on the performance of supercapacitors in terms of specific capacitance, energy density, power density, rate capability and cyclic stability. This paper has also discussed the physico-chemical processes such as charge transport, ion diffusion and redox reactions involved in supercapacitors.

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.

A microfabricated nickel-hydrogen battery using thick film printing techniques

Science.gov (United States)

Tam, Waiping G.; Wainright, Jesse S.

To utilize the distinctive cycle life and safety characteristics of the nickel-hydrogen chemistry while eliminating the high pressure limitations of conventional nickel-hydrogen cells, a microfabricated nickel-hydrogen battery using a low-pressure metal hydride for hydrogen storage is being developed for powering micro-electromechanical systems (MEMS) devices and for biomedical applications where the battery would be implanted within the body. Thick film printing techniques which are simple and low cost were used to fabricate this battery. Inks were developed for each of the different battery components, including the electrodes, current collectors and separator. SEM images on these printed components showed the desired characteristics for each. Positive electrode cycling tests were performed on the printed positive electrodes while cyclic voltammetry was used to characterize the printed negative electrodes. Consistent charge and discharge performance was observed during positive electrode cycling. Full cells with printed positive and negative assemblies were assembled and tested.

A microfabricated nickel-hydrogen battery using thick film printing techniques

Energy Technology Data Exchange (ETDEWEB)

Tam, Waiping G.; Wainright, Jesse S. [Department of Chemical Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States)

2007-02-25

To utilize the distinctive cycle life and safety characteristics of the nickel-hydrogen chemistry while eliminating the high pressure limitations of conventional nickel-hydrogen cells, a microfabricated nickel-hydrogen battery using a low-pressure metal hydride for hydrogen storage is being developed for powering micro-electromechanical systems (MEMS) devices and for biomedical applications where the battery would be implanted within the body. Thick film printing techniques which are simple and low cost were used to fabricate this battery. Inks were developed for each of the different battery components, including the electrodes, current collectors and separator. SEM images on these printed components showed the desired characteristics for each. Positive electrode cycling tests were performed on the printed positive electrodes while cyclic voltammetry was used to characterize the printed negative electrodes. Consistent charge and discharge performance was observed during positive electrode cycling. Full cells with printed positive and negative assemblies were assembled and tested. (author)

LONG-TERM PERFORMANCE OF SOLID OXIDE STACKS WITH ELECTRODE-SUPPORTED CELLS OPERATING IN THE STEAM ELECTROLYSIS MODE

Energy Technology Data Exchange (ETDEWEB)

J. E. O' Brien; R. C. O' Brien; X. Zhang; G. Tao; B. J. Butler

2011-11-01

Performance characterization and durability testing have been completed on two five-cell high-temperature electrolysis stacks constructed with advanced cell and stack technologies. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. The per-cell active area is 100 cm2. The stack is internally manifolded with compliant mica-glass seals. Treated metallic interconnects with integral flow channels separate the cells. Stack compression is accomplished by means of a custom spring-loaded test fixture. Initial stack performance characterization was determined through a series of DC potential sweeps in both fuel cell and electrolysis modes of operation. Results of these sweeps indicated very good initial performance, with area-specific resistance values less than 0.5 ?.cm2. Long-term durability testing was performed with A test duration of 1000 hours. Overall performance degradation was less than 10% over the 1000-hour period. Final stack performance characterization was again determined by a series of DC potential sweeps at the same flow conditions as the initial sweeps in both electrolysis and fuel cell modes of operation. A final sweep in the fuel cell mode indicated a power density of 0.356 W/cm2, with average per-cell voltage of 0.71 V at a current of 50 A.

Ammonium ions determination with polypyrrole modified electrode

Directory of Open Access Journals (Sweden)

Luiz Henrique Dall´Antonia

2007-03-01

Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.

Passivation behavior of AB{sub 5}-type hydrogen storage alloys for battery electrode application

Energy Technology Data Exchange (ETDEWEB)

Meli, F. [Fribourg Univ. (Switzerland). Inst. de Physique; Sakai, T. [Fribourg Univ. (Switzerland). Inst. de Physique; Zuettel, A. [Fribourg Univ. (Switzerland). Inst. de Physique; Schlapbach, L. [Fribourg Univ. (Switzerland). Inst. de Physique

1995-04-15

In many applications, AB{sub 5} type hydrogen storage alloys show passivation behavior, i.e. when fully discharged, metal hydride electrodes show (especially at higher temperatures) a decrease in activity and therefore a decrease in capacity at normal discharge currents for ensuing cycles. Passivation may continue to the point where activity becomes so low that the capacity is no longer accessible. Electrochemical measurements were taken of two different AB{sub 5}-type alloys, one with manganese and one without manganese (LaNi{sub 3.4}Co{sub 1.2}Al{sub 0.4} and LaNi{sub 3.4}Co{sub 1.2}Al{sub 0.3}Mn{sub 0.1}). Both alloys showed passivation behavior after remaining in the discharged state. The alloy with manganese showed a stronger tendency to passivation which is in contradiction with earlier observations. Photoelectron spectroscopic analysis together with sputter depth profiling was used to investigate the surface composition of samples which had undergone different surface pretreatments. Surface analysis of electrodes in the passivated state shows a lower content of metallic nickel and a thicker nickel surface oxide film. We attribute the low electrochemical kinetics of the alloys after passivation to the loss of metallic nickel and/or cobalt at the electrode-electrolyte interface. ((orig.))

3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

International Nuclear Information System (INIS)

Huang, Wei; Cao, Yang; Chen, Yong; Zhou, Yang; Huang, Qingyou

2015-01-01

Graphical abstract: The enzyme-less amperometric sensor based on 3-D periodic mesoporous NiO nanomaterials used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM"−"1 cm"−"2. - Highlights: • Microwave-assisted method was used to fabricate the 3-D periodic mesoporous NiO particles. • The mesoporous nickel oxide was applied to nonenzymatic uric acid biosensor. • The detection limit is 0.005 μM over wide linear detection ranges up to 0.374 mM. • The sensitivity is 756.26 μA mM"−"1 cm"−"2. - Abstract: 3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N_2 adsorption–desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM"−"1 cm"−"2, and a possible mechanism was also given in the paper.

3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

Energy Technology Data Exchange (ETDEWEB)

Huang, Wei; Cao, Yang, E-mail: caowang507@163.com; Chen, Yong; Zhou, Yang; Huang, Qingyou

2015-12-30

Graphical abstract: The enzyme-less amperometric sensor based on 3-D periodic mesoporous NiO nanomaterials used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM{sup −1} cm{sup −2}. - Highlights: • Microwave-assisted method was used to fabricate the 3-D periodic mesoporous NiO particles. • The mesoporous nickel oxide was applied to nonenzymatic uric acid biosensor. • The detection limit is 0.005 μM over wide linear detection ranges up to 0.374 mM. • The sensitivity is 756.26 μA mM{sup −1} cm{sup −2}. - Abstract: 3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N{sub 2} adsorption–desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM{sup −1} cm{sup −2}, and a possible mechanism was also given in the paper.

Nickel as a catalyst for the electro-oxidation of methanol in alkaline medium

Science.gov (United States)

Abdel Rahim, M. A.; Abdel Hameed, R. M.; Khalil, M. W.

The use of Ni as a catalyst for the electro-oxidation of methanol in alkaline medium was studied by cyclic voltammetry. It was found that only Ni dispersed on graphite shows a catalytic activity towards methanol oxidation but massive Ni does not. Ni was dispersed on graphite by the electro-deposition from acidic NiSO 4 solution using potentiostatic and galvanostatic techniques. The catalytic activity of the C/Ni electrodes towards methanol oxidation was found to vary with the amount of electro-deposited Ni. The dependence of the oxidation current on methanol concentration and scan rate was discussed. It was concluded from the electro-chemical measurements and SEM analysis that methanol oxidation starts as Ni-oxide is formed on the electrode surface.

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.

Preparation of Reduced Graphene Oxides as Electrode Materials for Supercapacitors

KAUST Repository

Bai, Yaocai

2012-01-01

Reduced graphene oxide as outstanding candidate electrode material for supercapacitor has been investigated. This thesis includes two topics. One is that three kinds of reduced graphene oxides were prepared by hydrothermal reduction under different

Electrochemical reduction and oxidation pathways for Reactive Black 5 dye using nickel electrodes in divided and undivided cells

International Nuclear Information System (INIS)

Méndez-Martínez, Ana J.; Dávila-Jiménez, Martin M.; Ornelas-Dávila, Omar; Elizalde-González, María P.; Arroyo-Abad, Uriel; Sirés, Ignasi; Brillas, Enric

2012-01-01

Highlights: ► Ni electrodes were used for the mild degradation of the azo dye Reactive Black 5. ► Potentiostatic degradation was performed in undivided and divided cells. ► Degradation by-products were detected and monitored by RP-HPLC and LC–MS/MS. ► Small alkylsulfonyl phenol and isoxazole derivatives were identified. ► The cathodic and anodic degradation pathways for Reactive Black 5 were elucidated. - Abstract: The cathodic reduction and anodic ·OH-mediated oxidation of the azo dye Reactive Black 5 (RB5) have been studied potentiostatically by using undivided and divided cells with a Ni-polyvinylchloride (Ni-PVC) composite cathode and a Ni wire mesh anode. Solutions of 50–100 cm 3 of 20–80 mg dm −3 RB5 in 0.1 mol dm −3 KOH were degraded to assess the effect of electrolysis time and electrode potentials on the infrared and absorbance spectra, as well as on the decay of the total organic carbon and chemical oxygen demand. Reversed-phase high performance liquid chromatography (RP-HPLC) with ion-pairing and diode array detection (ion pair chromatography), along with coupling to tandem mass spectrometry (LC–MS/MS), were used for the identification of the aromatic degradation by-products and monitoring their time course. These analyses revealed the progressive conversion of the RB5 dye to simpler molecules with m/z 200, 369.5 and 547 under the direct action of the electron at the cathode and the formation of polar compounds such as alkylsulfonyl phenol derivatives with m/z 201, 185 and 171 by the ·OH mediation at the anode. From these results, the electrochemical reduction and oxidation pathways for the RB5 dye were elucidated.

Study and optimisation of manganese oxide-based electrodes for electrochemical supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Staiti, P.; Lufrano, F. [CNR-ITAE, Istituto di Tecnologie Avanzate per l' Energia ' ' Nicola Giordano' ' , Via Salita S. Lucia n. 5, 98126 S. Lucia, Messina (Italy)

2009-02-01

A manganese oxide material was synthesised by an easy precipitation method based on reduction of potassium permanganate(VII) with a manganese(II) salt. The material was treated at different temperatures to study the effect of thermal treatment on capacitive property. The best capacitive performance was obtained with the material treated at 200 C. This material was used to prepare electrodes with different amounts of polymer binder, carbon black and graphite fibres to individuate the optimal composition that gave the best electrochemical performances. It was found that graphite fibres improve the electrochemical performance of electrodes. The highest specific capacitance (267 F g{sup -1} MnO{sub x}) was obtained with an electrode containing 70% of MnO{sub x}, 15% of carbon black, 10% of graphite fibres and 5% of PVDF. This electrode, with CB/GF ratio of 1.5, showed a higher utilization of manganese oxide. The results reported in the present paper further confirmed that manganese oxide is a very interesting material for supercapacitor application. (author)

A transparent nickel selenide counter electrode for high efficient dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Dong, Jia; Wu, Jihuai, E-mail: jhwu@hqu.edu.cn; Jia, Jinbiao; Ge, Jinhua; Bao, Quanlin; Wang, Chaotao; Fan, Leqing

2017-04-15

Highlights: • Ni{sub 0.85}Se was obtained by hydrothermal way and the film was gained by spin-coating. • Ni{sub 0.85}Se film has good conductivity and excellent electrocatalytic activity. • DSSC based on transparent Ni{sub 0.85}Se counter electrode obtains PCE of 8.96%. • The PCE reaches 10.76% when putting a mirror under Ni{sub 0.85}Se counter electrode. - Abstract: Nickel selenide (Ni{sub 0.85}Se) was synthesized by a facile one-step hydrothermal reaction and Ni{sub 0.85}Se film was prepared by spin-coating Ni{sub 0.85}Se ink on FTO and used as counter electrode (CE) in dye-sensitized solar cells (DSSC). The Ni{sub 0.85}Se CEs not only show high transmittance in visible range, but also possess remarkable electrocatalytic activity toward I{sup −}/I{sub 3}{sup −}. The electrocatalytic ability of Ni{sub 0.85}Se films was verified by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization curves. The DSSC using Ni{sub 0.85}Se CE exhibits a power conversion efficiency (PCE) of 8.96%, while the DSSC consisting of sputtered Pt CE only exhibits a PCE of 8.15%. When adding a mirror under Ni{sub 0.85}Se CE, the resultant DSSC exhibits a PCE of 10.76%, which exceeds that of a DSSC based on sputtered Pt CE (8.44%) by 27.49%.

Kinetic and geometric aspects of solid oxide fuel cell electrodes

DEFF Research Database (Denmark)

Mogensen, Mogens Bjerg; Skaarup, Steen

1996-01-01

The paper gives an overview of the main factors controlling the performance of the solid oxide fuel cell (SOFC) electrodes, emphasizing the most widely chosen anodes and cathodes, Ni-YSZ and LSM-YSZ. They are often applied as composites (mixtures) of the electron conducting electrode material...

Energy Harvesting by Nickel Prussian Blue Analogue Electrode in Neutralization and Mixing Entropy Batteries.

Science.gov (United States)

Gomes, Wellington J A S; de Oliveira, Cainã; Huguenin, Fritz

2015-08-11

Some industries usually reduce the concentration of protons in acidic wastewater by conducting neutralization reactions and/or adding seawater to industrial effluents. This work proposes a novel electrochemical system that can harvest energy originating from entropic changes due to alteration in the concentration of sodium ions along wastewater treatment. Preparation of a self-assembled material from nickel Prussian blue analogue (NPBA) was the first step to obtain such electrochemical system. Investigation into the electrochemical properties of this material helped to evaluate its potential use in neutralization and mixing entropy batteries. Assessment of parameters such as the potentiodynamic profile of the current density as a function of the concentration of protons and sodium ions, charge capacity, and cyclability as well as the reversibility of the sodium ion electroinsertion process aided estimation of the energy storage efficiency of the system. Frequency-domain measurements and models and the proposed charge compensation mechanism provided the rate constants at different dc potentials. After each charge/discharge cycle, the NPBA electrode harvested 12.4 kJ per mol of intercalated sodium ion in aqueous solutions of NaCl at concentrations of 20 mM and 3.0 M. The full electrochemical cell consisted of an NPBA positive electrode and a negative electrode of silver particles dispersed in a polypyrrole electrode. This cell extracted 16.8 kJ per mol of intercalated ion after each charge/discharge cycle. On the basis of these results, the developed electrochemical system should encourage wastewater treatment and help to achieve sustainable growth.

Coating manganese oxide onto graphite electrodes by immersion for electrochemical capacitors

International Nuclear Information System (INIS)

Lin, C.-C.; Chen, H.-W.

2009-01-01

In this study, manganese oxide was coated on a graphite electrode by immersion. Durations for immersion were varied to control the amount of manganese oxide coated onto the electrode surface. Maximum capacitance of 556 mF cm -2 was obtained in 0.5 M LiCl and with better/superior conditions (immersion time = 80 min and potential scan rate = 10 mV s -1 ). In addition, cyclic voltammograms of the prepared electrode at different potential scan rates exhibited the approximately rectangular and symmetric current-potential characteristics of a capacitor. Furthermore, the chronopotentiometry (CP) charge-discharge curves of the electrode prepared at 80 min of immersion time with a constant current of 1 mA were symmetric and similar isosceles triangles, which demonstrate its high electrochemical reversibility and good stability. Finally, under scanning electron microscope (SEM), the surface of the electrode prepared at 80 min of immersion time and after 1500 cycles of potential cycling revealed that numerously three-dimensional network of macropores appeared on large spherical grains

OXIDATIVE-REFORMING OF METHANE AND PARTIAL OXIDATION OF METHANE REACTIONS OVER NiO/PrO2/ZrO2 CATALYSTS: EFFECT OF NICKEL CONTENT

Directory of Open Access Journals (Sweden)

Y. J. O. Asencios

Full Text Available Abstract In this work the behavior of NiO-PrO2-ZrO2 catalysts containing various nickel loadings was evaluated in the partial oxidation of methane and oxidative-reforming reactions of methane. The catalysts were characterized by X-Ray Diffraction Analysis (in situ-XRD, Temperature Programmed Reduction (H2-TPR, Scanning Electron Microscopy (SEM/EDX and Adsorption-Desorption of nitrogen (BET area. The reactions were carried out at 750 °C and 1 atm for 5 hours. The catalysts were studied with different nickel content: 0, 5, 10 and 15% (related to total weight of catalyst, wt%. In both reactions, the catalyst containing the mixture of the three oxides (NiO/PrO2/ZrO2 with 15% nickel (15NiPrZr catalyst showed the best activity for the conversion of the reactants into Syngas and showed high selectivity for H2 and CO. The results suggest that the promoter PrO2 and the Niº centers are in a good proportion in the catalyst with 15% Ni. Our results showed that low nickel concentrations in the catalyst led to high metallic dispersion; however, very low nickel concentrations did not favor the methane transformation into Syngas. The catalyst containing only NiO/ZrO2 in the mixture was not sufficient for the catalysis. The presence of the promoter PrO2 was very important for the catalysis of the POM.

Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films.

Science.gov (United States)

Sun, Ke; Saadi, Fadl H; Lichterman, Michael F; Hale, William G; Wang, Hsin-Ping; Zhou, Xinghao; Plymale, Noah T; Omelchenko, Stefan T; He, Jr-Hau; Papadantonakis, Kimberly M; Brunschwig, Bruce S; Lewis, Nathan S

2015-03-24

Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide protective layers on a variety of technologically important semiconducting photoanodes, including textured crystalline Si passivated by amorphous silicon, crystalline n-type cadmium telluride, and hydrogenated amorphous silicon. Under anodic operation in 1.0 M aqueous potassium hydroxide (pH 14) in the presence of simulated sunlight, the NiOx films stabilized all of these self-passivating, high-efficiency semiconducting photoelectrodes for >100 h of sustained, quantitative solar-driven oxidation of water to O2(g).

Metal hydride electrode and nickel hydrogen storage battery; Suiso kyuzo gokin denkyoku oyobi nikkeru-suiso chikudenchi

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Y.; Tamagawa, H. [Shin-Kobe Electric Machinery Co. Ltd., Tokyo (Japan); Ikawa, A.; Muranaka, R. [Hitachi Ltd., Ibaraki (Japan). Hitachi Research Lab.

1996-04-16

Water soluble polymers such as cellulose derivatives and polyvinylalcohol have been used conventionally as binders for metal hydride electrode used for nickel-hydrogen storage batteries. The shortcomings of those binders, however, are low flexibility, and poor binding property for hydrogen absorbing alloy powder and the conductive supporting substrate. This invention relates to the use of ethylene-vinyl copolymer with less than -10{degree}C Tg as the binder for hydrogen absorbing alloy powder. It is desirable that the ethylene-vinylacetate copolymer is selected out of ethylene-vinyl acetate-acryl copolymer and ethylene-vinyl acetate-long chain vinyl ester copolymer, and that the addition is larger than 0.1wt% and less than 1wt% against the weight of hydrogen absorbing alloy in the electrode. The use of this binder results in strong binding of hydrogen absorbing alloy powder to the conductive supporting substrate, providing flexibility as well. 4 figs., 5 tabs.

Recycling of the rare earth oxides from spent rechargeable batteries using waste metallurgical slags

Directory of Open Access Journals (Sweden)

Tang K.

2013-01-01

Full Text Available A high temperature process for recycling spent nickel-metal hydride rechargeable batteries has been recently developed at SINTEF/NTNU. The spent battery modules were first frozen with liquid nitrogen for the de-activation and brittle fracture treatment. The broken steel scraps and plastics were then separated by the mechanical classification and magnetic separation. The remaining positive and negative electrodes, together with the polymer separator, were heated to 600-800oC in order to remove the organic components and further separate the Ni-based negative electrode. XRF analyses indicate that the heat-treated materials consist mainly of nickel, rare earth and cobalt oxides. The valuable rare earth oxides were further recovered by the high-temperature slagging treatment. The waste metallurgical slags, consist mainly of SiO2 and CaO, were used as the rare earth oxide absorbent. After the high temperature slagging treatment, over 98% of nickel and cobalt oxides were reduced to the metal phase; meanwhile almost all rare earth oxides remain in the molten slags. Furthermore, EPMA and XRF analyses of the slag samples indicate that the rare earth oxides selectively precipitate in the forms of solid xSiO2•yCaO•zRe2O3. The matrix of slag phase is Re2O3 deficient, typically being less than 5 wt%. This provides a sound basis to further develop the high-temperature process of concentrating the Re2O3 oxides in slags.

Electrode Reaction Pathway in Oxide Anode for Solid Oxide Fuel Cells

Science.gov (United States)

Li, Wenyuan

Oxide anodes for solid oxide fuel cells (SOFC) with the advantage of fuel flexibility, resistance to coarsening, small chemical expansion and etc. have been attracting increasing interest. Good performance has been reported with a few of perovskite structure anodes, such as (LaSr)(CrMn)O3. However, more improvements need to be made before meeting the application requirement. Understanding the oxidation mechanism is crucial for a directed optimization, but it is still on the early stage of investigation. In this study, reaction mechanism of oxide anodes is investigated on doped YCrO 3 with H2 fuel, in terms of the origin of electrochemical activity, rate-determining steps (RDS), extension of reactive zone, and the impact from overpotential under service condition to those properties. H2 oxidation on the YCs anodes is found to be limited by charge transfer and H surface diffusion. A model is presented to describe the elementary steps in H2 oxidation. From the reaction order results, it is suggested that any models without taking H into the charge transfer step are invalid. The nature of B site element determines the H2 oxidation kinetics primarily. Ni displays better adsorption ability than Co. However, H adsorption ability of such oxide anode is inferior to that of Ni metal anode. In addition, the charge transfer step is directly associated with the activity of electrons in the anode; therefore it can be significantly promoted by enhancement of the electron activity. It is found that A site Ca doping improves the polarization resistance about 10 times, by increasing the activity of electrons to promote the charge transfer process. For the active area in the oxide anode, besides the traditional three-phase boundary (3PB), the internal anode surface as two-phase boundary (2PB) is proven to be capable of catalytically oxidizing the H2 fuel also when the bulk lattice is activated depending on the B site elements. The contribution from each part is estimated by switching

Absolute determination by X-ray diffraction of a binary or ternary mixture: nickel oxide and fluoride in a nickel powder (1960); Dosage absolu par diffraction X d'un melange binaire ou ternaire: oxyde et fluorure de nickel dans une poudre de nickel (1960)

Energy Technology Data Exchange (ETDEWEB)

Charpin, P; Hauptman, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

The method employed is based upon the comparison between computed and measured intensities for conveniently selected X-Ray diffraction lines of each component of the powder. Care must be taken to allow for absorption, both inside each grain and in overall sample. This method has been applied to the determination of nickel oxide and fluoride in a nickel powder. (author) [French] La methode utilisee, dite 'absolue' est basee sur le calcul des intensites theoriques de raies de diffraction convenablement choisies. Elle n'est applicable que si l'absorption est negligeable a travers chaque grain constituant l'echantillon et a travers l'echantillon total. Elle a ete employee pour doser, ensemble ou separement, de l'oxyde et du fluorure de nickel dans une poudre de nickel. (auteur)

Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes

Directory of Open Access Journals (Sweden)

Shozo Yanagida

2015-05-01

Full Text Available Mesoscopic anatase nanocrystalline TiO2 (nc-TiO2 electrodes play effective and efficient catalytic roles in photoelectrochemical (PEC H2O oxidation under short circuit energy gap excitation conditions. Interfacial molecular orbital structures of (H2O3 &OH(TiO29H as a stationary model under neutral conditions and the radical-cation model of [(H2O3&OH(TiO29H]+ as a working nc-TiO2 model are simulated employing a cluster model OH(TiO29H (Yamashita/Jono’s model and a H2O cluster model of (H2O3 to examine excellent H2O oxidation on nc-TiO2 electrodes in PEC cells. The stationary model, (H2O3&OH(TiO29H reveals that the model surface provides catalytic H2O binding sites through hydrogen bonding, van der Waals and Coulombic interactions. The working model, [(H2O3&OH(TiO29H]+ discloses to have a very narrow energy gap (0.3 eV between HOMO and LUMO potentials, proving that PEC nc-TiO2 electrodes become conductive at photo-irradiated working conditions. DFT-simulation of stepwise oxidation of a hydroxide ion cluster model of OH−(H2O3, proves that successive two-electron oxidation leads to hydroxyl radical clusters, which should give hydrogen peroxide as a precursor of oxygen molecules. Under working bias conditions of PEC cells, nc-TiO2 electrodes are now verified to become conductive by energy gap photo-excitation and the electrode surface provides powerful oxidizing sites for successive H2O oxidation to oxygen via hydrogen peroxide.

Catalytic Water Oxidation by a Bio-inspired Nickel Complex with a Redox-Active Ligand.

Science.gov (United States)

Wang, Dong; Bruner, Charlie O

2017-11-20

The oxidation of water (H 2 O) to dioxygen (O 2 ) is important in natural photosynthesis. One of nature's strategies for managing such multi-electron transfer reactions is to employ redox-active metal-organic cofactor arrays. One prototype example is the copper tyrosinate active site found in galactose oxidase. In this work, we have implemented such a strategy to develop a bio-inspired nickel phenolate complex capable of catalyzing the oxidation of H 2 O to O 2 electrochemically at neutral pH with a modest overpotential. Employment of the redox-active ligand turned out to be a useful strategy to avoid the formation of high-valent nickel intermediates while a reasonable turnover rate (0.15 s -1 ) is retained.

In-line monitoring of an oxide ion in LiCl molten salt using a YSZ based oxide ion selective electrode

International Nuclear Information System (INIS)

Cho, Young Hwan; Jeon, Jong Seon; Yeon, Jei Won; Choi, In Kyu; Kim, Won Ho

2004-01-01

The electrode potential characteristics of a YSZ based membrane metal oxide electrode have been studied in molten LiCl at 700 .deg. C by the potentiometric method. The electrode exhibited a good potential response to log[O 2 ] and data reproducibility. The calibration plot (potential vs. log[O 2 ] was found to be linear, obeying the nernst equation. The electrode potential showed a good reversibility corresponding to increase/decrease of the oxide ion present in the molten LiCl. The physical and chemical durability appeared to be sound after several repeated uses, resulting in reproducible results. However, 'the proposed electrode' failed when metallic Li was present in the melt

Reduction of nickel oxide particles by hydrogen studied in an environmental TEM

DEFF Research Database (Denmark)

Jeangros, Q.; Hansen, Thomas Willum; Wagner, Jakob Birkedal

2013-01-01

In situ reduction of nickel oxide (NiO) particles is performed under 1.3 mbar of hydrogen gas (H2) in an environmental transmission electron microscope (ETEM). Images, diffraction patterns and electron energy-loss spectra (EELS) are acquired to monitor the structural and chemical evolution of the...

X-ray diffraction on nanoparticles chromium and nickel oxides obtained by gelatin using synchrotron radiation

International Nuclear Information System (INIS)

Menezes, Alan Silva de; Medeiros, Angela Maria de Lemos; Miranda, Marcus Aurelio Ribeiro; Almeida, Juliana Marcela Abraao; Remedios, Claudio Marcio Rocha; Silva, Lindomar R.D. da; Gouveia, S.T.; Sasaki, Jose Marcos; Jardim, P.M.

2003-01-01

Full text: Cr 2 O 3 nanoparticles has many applications like green pigments, wear resistance, and coating materials for thermal protection. Several methods to produce chromium oxide nanoparticles have already been studied, gas condensation, laser induced pyrolysis, microwave plasma, sol-gel and gamma radiation methods. Many applications for this kind of material can be provide concerning the particle size. For instance, particle size approximately of 200 nm are preferable as pigment due to its opacity and below 50 nm can be used as transparent pigment. In this work we have demonstrated that chromium and nickel oxide nanoparticles can be prepared by gelatin method. X-Ray diffraction (XRD) show that mean particle size for chromium oxide of 15-150 nm and nickel oxide of 90 nm were obtained for several temperature of sintering. The X-Ray powder diffraction pattern were performed using Synchrotron Radiation X-Ray source at XRD1 beamline in National Laboratory of Light Synchrotron (LNLS). (author)

Redox Response of Reduced Graphene Oxide-Modified Glassy Carbon Electrodes to Hydrogen Peroxide and Hydrazine

Directory of Open Access Journals (Sweden)

Jun-ichi Anzai

2013-05-01

Full Text Available The surface of a glassy carbon (GC electrode was modified with reduced graphene oxide (rGO to evaluate the electrochemical response of the modified GC electrodes to hydrogen peroxide (H2O2 and hydrazine. The electrode potential of the GC electrode was repeatedly scanned from −1.5 to 0.6 V in an aqueous dispersion of graphene oxide (GO to deposit rGO on the surface of the GC electrode. The surface morphology of the modified GC electrode was characterized by scanning electron microscopy (SEM and atomic force microscopy (AFM. SEM and AFM observations revealed that aggregated rGO was deposited on the GC electrode, forming a rather rough surface. The rGO-modified electrodes exhibited significantly higher responses in redox reactions of H2O2 as compared with the response of an unmodified GC electrode. In addition, the electrocatalytic activity of the rGO-modified electrode to hydrazine oxidation was also higher than that of the unmodified GC electrode. The response of the rGO-modified electrode was rationalized based on the higher catalytic activity of rGO to the redox reactions of H2O2 and hydrazine. The results suggest that rGO-modified electrodes are useful for constructing electrochemical sensors.

Electrochemistry behavior of endogenous thiols on fluorine doped tin oxide electrodes

Energy Technology Data Exchange (ETDEWEB)

Rojas, Luciana; Molero, Leonard; Tapia, Ricardo A.; Rio, Rodrigo del; Valle, M. Angelica del; Antilen, Monica [Departamento de Quimica Inorganica, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Av Vicuna Mackenna 4860, Casilla 306, Correo 22, Macul, Santiago (Chile); Armijo, Francisco, E-mail: jarmijom@uc.cl [Departamento de Quimica Inorganica, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Av Vicuna Mackenna 4860, Casilla 306, Correo 22, Macul, Santiago (Chile)

2011-10-01

Highlights: > The first time that fluorine doped tin oxide electrodes are used for the electrooxidation of endogenous thiols. > Low potentials of electrooxidation were obtained for the different thiols. > The electrochemical behavior of thiols depends on the pH and the ionic electroactive species, the electrooxidation proceeds for a process of adsorption of electroactive species on FTO and high values the heterogeneous electron tranfer rate constant of the reaction were obtained. - Abstract: In this work the electrochemical behavior of different thiols on fluorine doped tin oxide (FTO) electrodes is reported. To this end, the mechanism of electrochemical oxidation of glutathione (GSH), cysteine (Cys), homocysteine (HCys) and acetyl-cysteine (ACys) at different pH was investigated. FTO showed electroactivity for the oxidation of the first three thiols at pH between 2.0 and 4.0, but under these conditions no acetyl-cysteine oxidation was observed on FTO. Voltammetric studies of the electro-oxidation of GSH, Cys and HCys showed peaks at about 0.35, 0.29, and 0.28 V at optimum pH 2.4, 2.8 and 3.4, respectively. In addition, this study demonstrated that GSH, Cys and HCys oxidation occurs when the zwitterion is the electro-active species that interact by adsorption on FTO electrodes. The overall reaction involves 4e{sup -}/4H{sup +} and 2e{sup -}/2H{sup +}, respectively, for HCys and for GSH and Cys and high heterogeneous electron transfer rate constants. Besides, the use of FTO for the determination of different thiols was evaluated. Experimental square wave voltammetry shows a linear current vs. concentrations response between 0.1 and 1.0 mM was found for HCys and GSH, indicating that these FTO electrodes are promising candidates for the efficient electrochemical determination of these endogenous thiols.

Electrochemical oxidation of butein at glassy carbon electrodes.

Science.gov (United States)

Tesio, Alvaro Yamil; Robledo, Sebastián Noel; Fernández, Héctor; Zon, María Alicia

2013-06-01

The electrochemical oxidation of flavonoid butein is studied at glassy carbon electrodes in phosphate and citrate buffer solutions of different pH values, and 1M perchloric acid aqueous solutions by cyclic and square wave voltammetries. The oxidation peak corresponds to the 2e(-), 2H(+) oxidation of the 3,4-dihydroxy group in B ring of butein, given the corresponding quinone species. The overall electrode process shows a quasi-reversible behavior and an adsorption/diffusion mixed control at high butein bulk concentrations. At low butein concentrations, the electrode process shows mainly an adsorption control. Butein surface concentration values were obtained from the charge associated with the adsorbed butein oxidation peaks, which are in agreement with those values expected for the formation of a monolayer of adsorbate in the concentration range from 1 to 5μM. Square wave voltammetry was used to perform a full thermodynamic and kinetics characterization of the butein surface redox couple. Therefore, from the combination of the "quasi-reversible maximum" and the "splitting of the net square wave voltammetric peak" methods, values of (0.386±0.003) V, (0.46±0.04), and 2.7×10(2)s(-1) were calculated for the formal potential, the anodic transfer coefficient, and the formal rate constant, respectively, of the butein overall surface redox process in pH4.00 citrate buffer solutions. These results will be then used to study the interaction of butein, and other flavonoids with the deoxyribonucleic acid, in order to better understand the potential therapeutic applications of these compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

Thermogravimetric study of the reduction of oxides of nickel and chromium

Science.gov (United States)

Herbell, T. P.

1973-01-01

The effectiveness of hydrogen, carbon and hydrogen-carbon in reducing NiO, Cr2O3, mixed NiO-Cr2O3 and oxidized Ni-20Cr was evaluated by thermogravimetry. NiO was effectively reduced by all three atmospheres, Cr2O3 only by hydrogen-carbon, NiO-Cr2O3 by hydrogen and hydrogen-carbon and oxidized Ni-20Cr by hydrogen, hydrogen-carbon and partially by carbon alone. The results indicate that nickel and carbon promote the reduction of Cr2O3.

Ultrasmall Dispersible Crystalline Nickel Oxide Nanoparticles as High-Performance Catalysts for Electrochemical Water Splitting

Czech Academy of Sciences Publication Activity Database

Fominykh, K.; Feckl, J. M.; Sicklinger, J.; Döblinger, M.; Böcklein, S.; Ziegler, J.; Peter, L.; Rathouský, Jiří; Scheidt, E.-W.; Bein, T.; Fattakhova-Rohlfing, D.

2014-01-01

Roč. 24, č. 21 (2014), s. 3123-3129 ISSN 1616-301X Institutional support: RVO:61388955 Keywords : electrocatalysis * nickel oxide * nanocrystals Subject RIV: CG - Electrochemistry Impact factor: 11.805, year: 2014

Electrodes as Terminal Electron Acceptors in Anaerobic Ammonium Oxidation

Science.gov (United States)

Ruiz-Urigüen, M.; Jaffe, P. R.

2017-12-01

Anaerobic ammonium (NH4+) oxidation under iron (Fe) reducing conditions is a microbial- mediated process known as Feammox. This is a novel pathway in the nitrogen cycle, and a key process for alleviating NH4+ accumulation in anoxic soils, wetlands, and wastewater. Acidimicrobiaceae-bacterium A6, phylum Actinobacteria, are one type of autotrophic bacteria linked to this process. The Feammox-bacteria obtain their energy by oxidizing NH4+ and transferring the electrons to a terminal electron acceptor (TEA). Under environmental conditions, iron oxides are the TEAs. However, in this study we show that electrodes in Microbial Electrolysis Cells (MECs) or electrodes set in the field can be used as TEAs by Feammox-bacteria. The potential difference between electrodes is the driving force for electron transfer, making the reaction energetically feasible. Our results show that MECs containing Feammox cultures can remove NH4+ up to 3.5 mg/L in less than 4 hours, compared to an average of 9 mg/L in 2 weeks when cultured under traditional conditions. Concomitantly, MECs produce an average current of 30.5 A/m3 whilst dead bacteria produced low (Actinobacteria when compared to bulk soil. Electrodes as TEAs enhance electrogenic bacteria recovery and culturing. The use of MECs for the productions of Feammox-bacteria eliminates the dependence of Fe, a finite electron acceptor, therefore, allowing for continuous NH4+ removal. Finally, Fe-free Feammox-bacteria can be applied to reduce other metals of environmental concern; therefore, opening the range of possible application of Feammox-bacteria.

Binder-free manganese oxide/carbon nanomaterials thin film electrode for supercapacitors.

Science.gov (United States)

Wang, Ning; Wu, Chuxin; Li, Jiaxin; Dong, Guofa; Guan, Lunhui

2011-11-01

A ternary thin film electrode was created by coating manganese oxide onto a network composed of single-walled carbon nanotubes and single-walled carbon nanohorns. The electrode exhibited a porous structure, which is a promising architecture for supercapacitors applications. The maximum specific capacitances of 357 F/g for total electrode at 1 A/g were achieved in 0.1 M Na(2)SO(4) aqueous solution.

The Development of Nano-Composite Electrodes for Solid Oxide Electrolyzers

Energy Technology Data Exchange (ETDEWEB)

Gorte, Raymond J.; Vohs, John M.

2014-03-26

Solid oxide fuel cells (SOFC) and electrolyzers (SOE) offer an attractive means for converting between electrical and chemical energy. Because they operate at high temperatures and are usually based on electrolytes that are oxygen-ion conducting ceramics, such as yttria-stabilized zirconia (YSZ), they are equally capable of converting between CO and CO2 as between H2 and H2O. When operated in the SOFC mode, they are able to operate on hydrocarbon fuels so long as there are no materials within the anode that can catalyze carbon formation. Compared to other types of electrolyzers, SOE can exhibit the highest efficiencies because the theoretical Nernst potential is lower at high temperatures and because the electrode overpotentials in SOE tend to be much lower. Finally, pure H2 can be produced without an external electrical source by electrolysis of steam at one electrode and oxidation of any fuel at the other electrode through a process known as Natural-Gas Assisted Steam Electrolysis. This final report describes results from studies of novel electrodes for SOE and SOFC prepared by infiltration methods.

Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films

KAUST Repository

Sun, Ke

2015-03-11

Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide protective layers on a variety of technologically important semiconducting photoanodes, including textured crystalline Si passivated by amorphous silicon, crystalline n-type cadmium telluride, and hydrogenated amorphous silicon. Under anodic operation in 1.0 M aqueous potassium hydroxide (pH 14) in the presence of simulated sunlight, the NiOx films stabilized all of these self-passivating, high-efficiency semiconducting photoelectrodes for >100 h of sustained, quantitative solar-driven oxidation of water to O2(g). © 2015, National Academy of Sciences. All rights reserved.

Performance-Enhanced Activated Carbon Electrodes for Supercapacitors Combining Both Graphene-Modified Current Collectors and Graphene Conductive Additive

Science.gov (United States)

Wang, Rubing; Qian, Yuting; Li, Weiwei; Zhu, Shoupu; Liu, Fengkui; Guo, Yufen; Chen, Mingliang; Li, Qi; Liu, Liwei

2018-01-01

Graphene has been widely used in the active material, conductive agent, binder or current collector for supercapacitors, due to its large specific surface area, high conductivity, and electron mobility. However, works simultaneously employing graphene as conductive agent and current collector were rarely reported. Here, we report improved activated carbon (AC) electrodes (AC@G@NiF/G) simultaneously combining chemical vapor deposition (CVD) graphene-modified nickel foams (NiF/Gs) current collectors and high quality few-layer graphene conductive additive instead of carbon black (CB). The synergistic effect of NiF/Gs and graphene additive makes the performances of AC@G@NiF/G electrodes superior to those of electrodes with CB or with nickel foam current collectors. The performances of AC@G@NiF/G electrodes show that for the few-layer graphene addition exists an optimum value around 5 wt %, rather than a larger addition of graphene, works out better. A symmetric supercapacitor assembled by AC@G@NiF/G electrodes exhibits excellent cycling stability. We attribute improved performances to graphene-enhanced conductivity of electrode materials and NiF/Gs with 3D graphene conductive network and lower oxidation, largely improving the electrical contact between active materials and current collectors. PMID:29762528

Performance-Enhanced Activated Carbon Electrodes for Supercapacitors Combining Both Graphene-Modified Current Collectors and Graphene Conductive Additive.

Science.gov (United States)

Wang, Rubing; Qian, Yuting; Li, Weiwei; Zhu, Shoupu; Liu, Fengkui; Guo, Yufen; Chen, Mingliang; Li, Qi; Liu, Liwei

2018-05-15

Graphene has been widely used in the active material, conductive agent, binder or current collector for supercapacitors, due to its large specific surface area, high conductivity, and electron mobility. However, works simultaneously employing graphene as conductive agent and current collector were rarely reported. Here, we report improved activated carbon (AC) electrodes (AC@G@NiF/G) simultaneously combining chemical vapor deposition (CVD) graphene-modified nickel foams (NiF/Gs) current collectors and high quality few-layer graphene conductive additive instead of carbon black (CB). The synergistic effect of NiF/Gs and graphene additive makes the performances of AC@G@NiF/G electrodes superior to those of electrodes with CB or with nickel foam current collectors. The performances of AC@G@NiF/G electrodes show that for the few-layer graphene addition exists an optimum value around 5 wt %, rather than a larger addition of graphene, works out better. A symmetric supercapacitor assembled by AC@G@NiF/G electrodes exhibits excellent cycling stability. We attribute improved performances to graphene-enhanced conductivity of electrode materials and NiF/Gs with 3D graphene conductive network and lower oxidation, largely improving the electrical contact between active materials and current collectors.

Roentgenoelectronic investigation into oxidation of iron-chromium and iron-chromium-nickel alloys

International Nuclear Information System (INIS)

Akimov, A.G.; Rozenfel'd, I.L.; Kazanskij, L.P.; Machavariani, G.V.

1978-01-01

Kinetics of iron-chromium and iron-chromium-nickel alloy oxidation (of the Kh13 and Kh18N10T steels) in oxygen was investigated using X-ray electron spectroscopy. It was found that according to X-ray electron spectra chromium oxidation kinetics in the iron-chromium alloy differs significantly from oxidation kinetics of chromium pattern. Layer by layer X-ray electron analysis showed that chromium is subjected to a deeper oxidation as compared to iron, and accordingly, Cr 2 O 3 layer with pure iron impregnations is placed between the layer of mixed oxide (Fe 3 O 4 +Cr 2 O 3 ) and metal. A model of the iron-chromium alloy surface is suggested. The mixed oxide composition on the steel surface is presented as spinel Fesub(2+x)Crsub(1-x)Osub(y)

Oxygen Reduction Kinetics of La2-xSrxNiO 4+delta Electrodes for Solid Oxide Fuel Cells

Science.gov (United States)

Guan, Bo

In the development of intermediate temperature solid oxide fuel cell (IT-SOFC), mixed ionic-electronic conductors (MIEC) have drawn big interests due to their both ionic and electronic species transport which can enlarge the 3-dimension of the cathode network. This thesis presents an investigation of MIEC of Ruddlesden-popper (RP) phases like K2NiF4 type La2NiO4+delta (LNO)-based oxides which have interesting transport, catalytic properties and suitable thermal expansion coefficients. The motivation of this present work is to further understand the fundamental of the effect of Sr doing on the oxygen reduction reaction (ORR) kinetics of LNO cathode. Porous symmetrical cells of La2-xSrxNiO4+delta (0≤x≤0.4) were fabricated and characterized by electrochemical impedance spectroscopy (EIS) in different PO2 from temperature range of 600˜800°C. The spectra were analyzed based on the impedance model introduced by Adler et al. The rate determining steps (RDS) for ORR were proposed and the responsible reasons were discussed. The overall polarization resistances of doped samples increase with Sr level. Surface oxygen exchange and bulk ionic diffusion co-control the ORR kinetics. With high Sr content (x=0.3, 0.4), oxygen ion transfer resistance between nickelate/electrolyte is observed. However for porous symmetrical cells it is hard to associate the resistance from EIS directly to each ORR elementary processes because of the difficulty in describing the microstructure of the porous electrode. The dense electrode configuration was adopted in this thesis. By using the dense electrode, the surface area, the thickness of electrode, the interface between electrode and electrolyte and lastly the 3PB are theoretically well-defined. Through this method, there is a good chance to distinguish the contribution of surface exchange from other processes. Dense and thin electrode layers in thickness of ˜40 mum are fabricated by using a novel spray modified pressing method. Negligible

Adsorptive Stripping Determination of Trace Nickel Using Bismuth Modified Mesoporous Carbon Composite Electrode

Science.gov (United States)

Ouyang, Ruizhuo; Feng, Kai; Su, Yongfu; Zong, Tianyu; Zhou, Xia; Lei, Tian; Jia, Pengpeng; Cao, Penghui; Zhao, Yuefeng; Guo, Ning; Chang, Haizhou; Miao, Yuqing; Zhou, Shuang

Novel bismuth nanoparticle-modified mesoporous carbon (MPC) was successfully prepared on a glassy carbon electrode (Bi@MPC/GCE) for the adsorptive stripping voltammetric determination of nickel by complexing with dimethylglyoxime (DMG). The presence of MPC obviously improved the properties of Bi particles like the electron transfer ability, particle size and hydrophicility, important parameters to achieve preferable analytical performances of Bi@MPC/GCE toward Ni(II). The best electrochemical behaviors of Bi@MPC/GCE was obtained for the stripping determination of Ni(II), compared with electrodes individually modified with Bi and MPC. The synergic effect between metallic Bi and ordered MPC (forming a 3D array like Bi microelectrodes) made major contribution to such improved electrochemical properties of Bi@MPC/GCE for Ni(II) sensing. The good linear analytical curve was achieved in a Ni(II) concentration range from 0.1μM to 5.0μM with a correlation coefficient of 0.9995. The detection limit and sensitivity were calculated to be 1.2nM (S/N=3) and 1410μAmM-1cm-2, respectively. The new method was successfully applied to Ni(II) determination in soybean samples with recoveries higher than 99% and proved to be a simple, efficient alternative for Ni(II) monitoring in real samples.

Wustite-based photoelectrodes with lithium, hydrogen, sodium, magnesium, manganese, zinc and nickel additives

Science.gov (United States)

Carter, Emily Ann; Toroker, Maytal Caspary

2017-08-15

A photoelectrode, photovoltaic device and photoelectrochemical cell and methods of making are disclosed. The photoelectrode includes an electrode at least partially formed of FeO combined with at least one of lithium, hydrogen, sodium, magnesium, manganese, zinc, and nickel. The electrode may be doped with at least one of lithium, hydrogen, and sodium. The electrode may be alloyed with at least one of magnesium, manganese, zinc, and nickel.

High-temperature conversion of methane on a composite gadolinia-doped ceria-gold electrode

DEFF Research Database (Denmark)

Marina, O.A.; Mogensen, Mogens Bjerg

1999-01-01

Direct electrochemical oxidation of methane was attempted on a gadolinia-doped ceria Ce(0.6)Gd(0.4)O(1.8) (CG4) electrode in a solid oxide fuel cell using a porous gold-CG4 mixture as current collector Gold is relatively inert to methane in contrast to other popular SOFC anode materials such as n......Direct electrochemical oxidation of methane was attempted on a gadolinia-doped ceria Ce(0.6)Gd(0.4)O(1.8) (CG4) electrode in a solid oxide fuel cell using a porous gold-CG4 mixture as current collector Gold is relatively inert to methane in contrast to other popular SOFC anode materials...... such as nickel and platinum. CG4 was found to exhibit a low electrocatalytic activity for methane oxidation as well as no significant reforming activity implying that the addition of an electrocatalyst or cracking catalyst to the CG4 anode is required for SOFC operating on methane. The methane conversion...... observed at the open-circuit potential and low anodic overpotentials seems to be due to thermal methane cracking in the gas phase and on the alumina surfaces in the cell housing. At high anodic overpotentials, at electrode potentials where oxygen evolution was expected to take place, the formation of CO(2...

Mechanistic interaction study of thin oxide dielectric with conducting organic electrode

International Nuclear Information System (INIS)

Sharma, Himani; Sethi, Kanika; Raj, P. Markondeya; Gerhardt, R.A.; Tummala, Rao

2012-01-01

Highlights: ► Thin film-oxide dielectric-organic electrode interface studies for investigating the leakage mechanism. ► XPS to elucidate chemical-structural changes on dielectric oxide surface. ► Correlates structural characterization data with capacitor leakage current and impedance spectroscopy characteristics. - Abstract: This paper aims at understanding the interaction of intrinsic conducting polymer, PEDT, with ALD-deposited Al 2 O 3 and thermally oxidized Ta 2 O 5 dielectrics, and the underlying mechanisms for increase in leakage currents in PEDT-based capacitors. Conducting polymers offer several advantages as electrodes for high surface area capacitors because of their lower resistance, self-healing and enhanced conformality. However, capacitors with in situ polymerized PEDT show poor electrical properties that are attributed to the interfacial interaction between the organic electrode and the oxide dielectric. This study focuses on characterizing these interactions. A combination of compositional, structural and electrical characterization techniques was applied to polymer-solid-state-capacitor to understand the interfacial chemical behavior and dielectric property deterioration of alumina and tantalum-oxide films. XPS and impedance studies were employed to understand the stiochiometric and compositional changes that occur in the dielectric film on interaction with in situ deposited PEDT. Based on the observations from several complimentary techniques, it is concluded that tantalum-pentoxide has more resistance towards chemical interaction with in situ polymerized PEDT. The thermally oxidized Ta 2 O 5 -PEDT system showed leakage current of 280 nA μF −1 at 3 V with a breakdown voltage of 30 V. On the other hand, Al 2 O 3 -PEDT capacitor showed leakage current of 50 μA μF −1 and a breakdown voltage of 40 V. The study reports direct evidence for the mechanism of resistivity drop in alumina dielectric with in situ polymerized PEDT electrode.

Engineered Nickel Oxide Nanoparticle Causes Substantial Physicochemical Perturbation in Plants

Directory of Open Access Journals (Sweden)

Indrani Manna

2017-11-01

Full Text Available Concentration of engineered nickel oxide nanoparticle (NiO-NP in nature is on the rise, owing to large scale industrial uses, which have accreted the scope of its exposure to plants, the primary producers of the ecosystem. Though an essential micronutrient for the animal system, supported by numerous studies confirming its toxicity at higher dosages, nickel oxide is graded as a human carcinogen by WHO. A few studies do depict toxicity and bioaccumulation of nickel in plants; however, interaction of NiO-NP with plants is not well-elucidated. It is known that exposure to NiO-NP can incite stress response, leading to cytotoxicity and growth retardation in some plants, but a defined work on the intricate physicochemical cellular responses and genotoxic challenges is wanting. The present study was planned to explore cytotoxicity of NiO-NP in the model plant, Allium cepa L., its internalization in the tissue and concomitant furore created in the antioxidant enzyme system of the plant. The prospect of the NiO-NP causing genotoxicity was also investigated. Detailed assessments biochemical profiles and genotoxicity potential of NiO-NP on A. cepa L. was performed and extended to four of its closest economically important relatives, Allium sativum L., Allium schoenoprasum L., Allium porrum L., and Allium fistulosum L. Growing root tips were treated with seven different concentrations of NiO-NP suspension (10–500 mg L−1, with deionised distilled water as negative control and 0.4 mM EMS solution as positive control. Study of genotoxic endpoints, like, mitotic indices (MI, chromosomal aberrations (CAs, and chromosome breaks confirmed NiO-NP induced genotoxicity in plants, even at a very low dose (10 mg L−1. That NiO-NP also perturbs biochemical homeostasis, disrupting normal physiology of the cell, was confirmed through changes in state of lipid peroxidation malonaldehyde (MDA, as well as, in oxidation marker enzymes, like catalase (CAT, super oxide

High Temperature Oxidation of Nickel-based Cermet Coatings Composed of Al2O3 and TiO2 Nanosized Particles

Science.gov (United States)

Farrokhzad, M. A.; Khan, T. I.

2014-09-01

New technological challenges in oil production require materials that can resist high temperature oxidation. In-Situ Combustion (ISC) oil production technique is a new method that uses injection of air and ignition techniques to reduce the viscosity of bitumen in a reservoir and as a result crude bitumen can be produced and extracted from the reservoir. During the in-situ combustion process, production pipes and other mechanical components can be exposed to air-like gaseous environments at extreme temperatures as high as 700 °C. To protect or reduce the surface degradation of pipes and mechanical components used in in-situ combustion, the use of nickel-based ceramic-metallic (cermet) coating produced by co-electrodeposition of nanosized Al2O3 and TiO2 have been suggested and earlier research on these coatings have shown promising oxidation resistance against atmospheric oxygen and combustion gases at elevated temperatures. Co-electrodeposition of nickel-based cermet coatings is a low-cost method that has the benefit of allowing both internal and external surfaces of pipes and components to be coated during a single electroplating process. Research has shown that the volume fraction of dispersed nanosized Al2O3 and TiO2 particles in the nickel matrix which affects the oxidation resistance of the coating can be controlled by the concentration of these particles in the electrolyte solution, as well as the applied current density during electrodeposition. This paper investigates the high temperature oxidation behaviour of novel nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in a nickel matrix and produced by coelectrodeposition technique as a function of the concentration of these particles in the electrolyte solution and applied current density. For this purpose, high temperature oxidation tests were conducted in dry air for 96 hours at 700 °C to obtain mass changes (per unit of area) at specific time

Nickel-regulated heart rate variability: The roles of oxidative stress and inflammation

International Nuclear Information System (INIS)

Chuang, Hsiao-Chi; Hsueh, Tzu-Wei; Chang, Chuen-Chau; Hwang, Jing-Shiang; Chuang, Kai-Jen; Yan, Yuan-Horng; Cheng, Tsun-Jen

2013-01-01

Heart rate variability (HRV) has been reported to be a putative marker of cardiac autonomic imbalance caused by exposure to ambient particulate matter (PM). Our objective in this study was to determine the effects on HRV from exposure to nickel, an important chemical component of ambient PM that results in oxidative stress and inflammation. HRV data were collected for 72 h before lung exposure (baseline) and 72 h after intratracheal exposure (response) to nickel sulphate (NiSO 4 ; 526 μg) in Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. The antioxidant N-acetyl-L-cysteine (NAC) and the anti-inflammatory celecoxib were intraperitoneally injected to examine post-exposure oxidative and inflammatory responses. Self-controlled experiments examined the effects of NiSO 4 exposure on average normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to-normal intervals (LnSDNN) and root mean square of successive differences of adjacent normal-to-normal intervals (LnRMSSD); the resulting data were sequentially analysed using the generalised estimating equation model. HRV effects on NiSO 4 -exposed SH rats were greater than those on NiSO 4 -exposed WKY rats. After adjusted the HRV responses in the WKY rats as control, ANN and LnRMSSD were found to be quadratically increased over 72 h after exposure to NiSO 4 . Both NAC and celecoxib mitigated the NiSO 4 -induced alterations in HRV during the exposure period. The results suggest that concurrent Ni-induced oxidative stress and inflammatory responses play important roles in regulating HRV. These findings help bridge the gap between epidemiological and clinical studies on the plausible mechanisms of the cardiovascular consequences induced by chemical components in ambient PM. -- Highlights: ► To determine the effects on HRV from exposure to nickel. ► ANN and LnRMSSD were found to be quadratically increased after exposure to Ni. ► NAC and celecoxib mitigated the Ni

Nickel-regulated heart rate variability: The roles of oxidative stress and inflammation

Energy Technology Data Exchange (ETDEWEB)

Chuang, Hsiao-Chi, E-mail: r92841005@ntu.edu.tw [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Tzu-Wei, E-mail: r95841015@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, Department of Public Health, National Taiwan University, Taipei, Taiwan (China); Chang, Chuen-Chau, E-mail: nekota@tmu.edu.tw [Department of Anaesthesiology, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan (China); Hwang, Jing-Shiang, E-mail: jshwang@stat.sinica.edu.tw [Institute of Statistical Science, Academia Sinica, Taipei, Taiwan (China); Chuang, Kai-Jen, E-mail: kjc@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Yan, Yuan-Horng, E-mail: d97841006@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, Department of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Medical Research, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City, Taiwan (China); Cheng, Tsun-Jen, E-mail: tcheng@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, Department of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China)

2013-01-15

Heart rate variability (HRV) has been reported to be a putative marker of cardiac autonomic imbalance caused by exposure to ambient particulate matter (PM). Our objective in this study was to determine the effects on HRV from exposure to nickel, an important chemical component of ambient PM that results in oxidative stress and inflammation. HRV data were collected for 72 h before lung exposure (baseline) and 72 h after intratracheal exposure (response) to nickel sulphate (NiSO{sub 4}; 526 μg) in Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. The antioxidant N-acetyl-L-cysteine (NAC) and the anti-inflammatory celecoxib were intraperitoneally injected to examine post-exposure oxidative and inflammatory responses. Self-controlled experiments examined the effects of NiSO{sub 4} exposure on average normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to-normal intervals (LnSDNN) and root mean square of successive differences of adjacent normal-to-normal intervals (LnRMSSD); the resulting data were sequentially analysed using the generalised estimating equation model. HRV effects on NiSO{sub 4}-exposed SH rats were greater than those on NiSO{sub 4}-exposed WKY rats. After adjusted the HRV responses in the WKY rats as control, ANN and LnRMSSD were found to be quadratically increased over 72 h after exposure to NiSO{sub 4}. Both NAC and celecoxib mitigated the NiSO{sub 4}-induced alterations in HRV during the exposure period. The results suggest that concurrent Ni-induced oxidative stress and inflammatory responses play important roles in regulating HRV. These findings help bridge the gap between epidemiological and clinical studies on the plausible mechanisms of the cardiovascular consequences induced by chemical components in ambient PM. -- Highlights: ► To determine the effects on HRV from exposure to nickel. ► ANN and LnRMSSD were found to be quadratically increased after exposure to Ni. ► NAC and

A glassy carbon electrode modified with a nickel(II) norcorrole complex and carbon nanotubes for simultaneous or individual determination of ascorbic acid, dopamine, and uric acid