Showing papers on "Nickel published in 2008"
Book•
01 Jan 2008
TL;DR: In this paper, the authors discuss the effect of stress on the properties of metal oxidation and tarnish, and present a list of the most important properties of metals in soil.
Abstract: Definition and Importance. Electrochemical Mechanisms. Corrosion Tendency and Electrode Potentials. Polarization and Corrosion Rates. Passivity. Iron and Steel. Effect of Stress. Atmospheric Corrosion of Iron and Other Metals. Corrosion of Iron and Other Metals in Soil. Oxidation and Tarnish. Stray--Current Corrosion. Cathodic Protection. Metallic Coatings. Inorganic Coatings. Organic Coatings. Inhibitors and Passivators. Treatment of Water and Steam Systems. Alloying for Corrosion Resistance. Stainless Steels. Copper and Copper Alloys. Aluminum and Magnesium. Lead. Nickel and Nickel Alloys. Cobalt and Cobalt Alloys. Titanium, Zirconium, and Tantalum. Silicon--Iron and Silicon--Nickel Alloys. Problems. Appendix. Index.
634 citations
TL;DR: Electrodeposited Ni(OH)(2) on nickel foam with porous and 3D nanostructures has ultrahigh capacitance in the potential range -0.05-0.45 V, and a maximum specific capacitance as high as 3152 F g (-1) can be achieved in 3% KOH solution at a charge/discharge current density of 4 A g(-1).
540 citations
TL;DR: In this article, a microwave-assisted hydrothermal method was used to obtain the typical α-phase of Ni(OH)2 and showed that the flakes were built up from many uniform flowerlike architectures with diameters of 700 nm−1µm which consisted of the aggregated flakes.
Abstract: Nickel hydroxide has received increased attention especially due to its electrochemical properties and potential applications in rechargeable Ni-base alkaline batteries, e.g., Ni/Cd, Ni/Zn, and Ni/MH. Ni(OH)2 has a hexagonal layered structure with two polymorphs, α- and β-Ni(OH)2. α-Ni(OH)2 shows superior electrochemical properties compared to those of the β-form. Nanosized flowerlike α-nickel hydroxide materials with an interlayer spacing of 7.0 A have been prepared by a microwave-assisted hydrothermal method. The experimental results from XRD and FT-IR showed that the Ni(OH)2 sample prepared by this method had the typical α-phase. FE-SEM images showed many uniform flowerlike architectures with diameters of 700 nm−1µm which consisted of the aggregated flakes. TEM results showed the flakes were built up from many nanocrystals with 2–3 nm diameters. TGA and TPD were employed to investigate thermal stability and gas evolution during the heating process. α-Nickel hydroxide was transferred to NiO with a cubic...
413 citations
TL;DR: In this paper, the ambient temperature equations of state (EoS) of iron, cobalt, nickel, zinc, molybdenum, silver, platinum, and gold were measured by x-ray diffraction.
Abstract: The ambient temperature equations of state (EoS) of iron, cobalt, nickel, zinc, molybdenum, and silver have been measured by x-ray diffraction. These transition metals were compressed using diamond anvil cells with a helium pressure transmitting medium. The maximum pressure reached during these experiments varied between 65 GPa (for cobalt) and 200 GPa (for iron). This work completes previous measurements on six other metals [Phys. Rev. B 70, 094112 (2004)] to quantify the differences between ab initio calculations and experiment on a large experimental set of transition metals. The compression curves of iron, cobalt, nickel, zinc, molybdenum, silver, platinum, and gold are also calculated ab initio within the density-functional theory (DFT) formalism using the projector augmented-wave (PAW) method and different exchange-correlation functionals (LDA, GGA-PBE, GGA-PBEsol). The difference between PAW and available all-electron calculations is found to be negligible up to very high pressures. The success of each exchange-correlation functional is correlated with the atomic number. For all metals, the bulk modulus becomes overestimated at high pressure. In addition, this extended data set of metals' EoS enables to reduce further, but marginally, the systematic uncertainty of the high-pressure metrology based on the ruby standard.
368 citations
TL;DR: The one-pot synthesis of alumina-supported metal oxides via self-assembly of a metal precursor and aluminum isopropoxide in the presence of triblock copolymer (as a structure directing agent) is described in detail for nickel oxide, representing an important step toward the facile and reproducible synthesis of ordered mesoporous aluminium-supported materials.
Abstract: The one-pot synthesis of alumina-supported metal oxides via self-assembly of a metal precursor and aluminum isopropoxide in the presence of triblock copolymer (as a structure directing agent) is described in detail for nickel oxide. The resulting mesoporous mixed metal oxides possess p6 mm hexagonal symmetry, well-developed mesoporosity, relatively high BET surface area, large pore widths, and crystalline pore walls. In comparison to pure alumina, nickel aluminum oxide samples exhibited larger mesopores and improved thermal stability. Also, long-range ordering of the aforementioned samples was observed for nickel molar percentages as high as 20%. The generality of the recipe used for the synthesis of mesoporous nickel aluminum oxide was demonstrated by preparation of other alumina-supported metal oxides such as MgO, CaO, TiO 2, and Cr 2O 3. This method represents an important step toward the facile and reproducible synthesis of ordered mesoporous alumina-supported materials for various applications where large and accessible pores with high loading of catalytically active metal oxides are needed.
350 citations
TL;DR: In this paper, atmospheric leaching of nickel laterite ores with sulphuric acid was examined, specifically the limonite, smectite (clay) and saprolite fractions.
341 citations
TL;DR: In this paper, the microstructure of core/shell (metal/metal oxide) in nanoparticle formed after in situ passivation process was measured in the frequency range of 2-18 GHz.
267 citations
TL;DR: In this article, the growth of carbon nanotubes by a plasma assisted catalytic chemical vapor deposition was investigated using cobalt, nickel and iron catalyst particles of different sizes, and it was shown that the growth mode switches from "tip-growth" for large particles (>>5nm) to "base growth" for smaller ones (
261 citations
TL;DR: Pseudo-second-order model described well the sorption kinetic of nickel and copper ions in comparison to pseudo-first-order and intra-particle diffusion kinetic model.
255 citations
TL;DR: In this article, a cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution.
254 citations
TL;DR: In this paper, the effect of the dispersion on catalyst structure and hydroprocessing performance was studied. And the authors concluded that tetrahedral Ni(1) sites are responsible for DDS while the Ni(2) are highly active sites for the HYD route.
TL;DR: The cationic nickel complex is exceptional in this series in that it does not exhibit any ligand mixed valency, and its electronic structure is consistent with two neutral ligands (L)0 and a monovalent metal center or [(L)2Ni(THF)][B(ArF)4].
Abstract: A series of bis(alpha-iminopyridine)metal complexes featuring the first-row transition ions (Cr, Mn, Fe, Co, Ni, and Zn) is presented. It is shown that these ligands are redox noninnocent and their paramagnetic pi radical monoanionic forms can exist in coordination complexes. Based on spectroscopic and structural characterizations, the neutral complexes are best described as possessing a divalent metal center and two monoanionic pi radicals of the alpha-iminopyridine. The neutral M(L*)2 compounds undergo ligand-centered, one-electron oxidations generating a second series, [(L(x))2M(THF)][B(ArF)4] [where L(x) represents either the neutral alpha-iminopyridine (L)0 and/or its reduced pi radical anion (L*)-]. The cationic series comprise mostly mixed-valent complexes, wherein the two ligands have formally different redox states, (L)0 and (L*)-, and the two ligands may be electronically linked by the bridging metal atom. Experimentally, the cationic Fe and Co complexes exhibit Robin-Day Class III behavior (fully delocalized), whereas the cationic Zn, Cr, and Mn complexes belong to Class I (localized) as shown by X-ray crystallography and UV-vis spectroscopy. The delocalization versus localization of the ligand radical is determined only by the nature of the metal linker. The cationic nickel complex is exceptional in this series in that it does not exhibit any ligand mixed valency. Instead, its electronic structure is consistent with two neutral ligands (L)0 and a monovalent metal center or [(L)2Ni(THF)][B(ArF)4]. Finally, an unusual spin equilibrium for Fe(II), between high spin and intermediate spin (S(Fe) = 2 S(Fe) = 1), is described for the complex [(L*)(L)Fe(THF)][B(ArF)4], which consequently is characterized by the overall spin equilibrium (S(tot) = 3/2 S(tot) = 1/2). The two different spin states for Fe(II) have been characterized using variable temperature X-ray crystallography, EPR spectroscopy, zero-field and applied-field Mossbauer spectroscopy, and magnetic susceptibility measurements. Complementary DFT studies of all the complexes have been performed, and the calculations support the proposed electronic structures.
TL;DR: In this article, the performance of catalysts for aqueous phase reforming of glycerol was investigated using temperature programmed reduction and XPS analysis. But, the results showed that the catalysts showed high APR activities at initial times on stream, but showed significant deactivation rates that deactivate the catalyst after few hours under operation.
Abstract: Hydrogen production from glycerol reforming in liquid (aqueous phase reforming, APR) and vapor (steam reforming SR) phase over alumina-supported nickel catalysts modified with Ce, Mg, Zr and La was studied. Characterization of catalysts by temperature programmed reduction and XPS analyses revealed important structural effects: (i) the intercalation of Mg between nickel and alumina that inhibited the alumina incorporation to nickel phases, (ii) the close contact between Ni and Zr phases and, (iii) the close surface interaction of La and Ce ions with NiO phases. The catalytic activity of the samples studied in this work clearly indicated the different catalyst functionalities necessary to carry out aqueous-phase and vapor-phase steam reforming of glycerol. For aqueous phase reforming of glycerol, the addition of Ce, La and Zr to Ni/Al2O3 improves the initial glycerol conversions obtained over the Ni/Al2O3 supported catalyst. It is suggested that the differences in catalytic activities are related with geometric effects caused by the decoration of Ni phases by Ce and La or by the close interaction between Ni and Zr. In spite that nickel catalysts showed high APR activities at initial times on stream, all samples showed, independently of support, important deactivation rates that deactivate the catalysts after few hours under operation. Catalysts characterization after APR showed the oxidation of the active metallic Ni during reaction as the main cause of the observed deactivation. In the case of the glycerol steam reforming in vapor phase, the use of Ce, La, Mg and Zr as promoters of Ni based catalysts increases the hydrogen selectivity. Differences in activity were explained in terms of enhancement in: surface nickel concentration (Mg), capacity to activate steam (Zr) and stability of nickel phases under reaction conditions (Ce and La).
TL;DR: In this article, the effects of fuel impurity poisoning on Ni-ScSZ cermet anodes have been analyzed and compared, and the degradation of cell performance caused by these impurities was characterized by measuring cell voltage and anode polarization at a constant current density of 0.2 cm − 2 for humidified H 2 and CH 4 fuels.
TL;DR: In this paper, the optimum conditions for biosorption and bioaccumulation of lead and nickel were investigated by using a tolerant bacterial strain isolated from El-Malah canal, Assiut, Egypt, and identified as Pseudomonas aeruginosa ASU 6a.
TL;DR: The anthropogenic nickel cycle for the year 2000 was analyzed using a material flow analysis at multiple levels: 52 countries, territories, or country groups, eight regions, and the planet.
Abstract: The anthropogenic nickel cycle for the year 2000 was analyzed using a material flow analysis at multiple levels: 52 countries, territories, or country groups, eight regions, and the planet. Special attention was given to the trade in nickel-containing products at different stages of the cycle. A new circular diagram highlights process connections, the role and potential of recycling, and the relevance of trade at different life stages. The following results were achieved. (1) The nickel cycle is dominated by six countries or territories: USA, China and Hong Kong, Japan, Germany, Taiwan, and South Korea; only China also mines some of its nickel used. (2) Nickel is mostly used in alloyed form in stainless steels (68%). (3) More scrap is used for the production of stainless steels (42%) than for other first uses (11%). (4) Industrial machinery is the largest end use category for nickel (25%), followed by buildings and infrastructure (21%) and transportation (20%). (5) 57% of discarded nickel is recycled within the nickel and stainless steel industries, and 14% is lost to other metal markets where nickel is an unwanted constituent of carbon steel and copper alloy scrap.
TL;DR: In this paper, the state of the nickel in a Ni/CeO 2 catalyst during hydrogen reduction, steam and dry reforming of methane, was studied by means of in situ XAS spectroscopy.
TL;DR: The use of type 316 stainless steels in gaseous hydrogen infrastructure motivated the work on hydrogen-assisted fracture in this paper, where the tensile ductility of 316 stainless steel is reduced by internal hydrogen contents of 136 wppm that have been generated by thermal precharging in hydrogen gas.
TL;DR: Mesoporous nanocrystalline zirconia with high surface area and pure tetragonal crystalline phase has been prepared by the surfactant-assisted route, using Pluronic P123 block copolymer surfactants as discussed by the authors.
Abstract: Mesoporous nanocrystalline zirconia with high-surface area and pure tetragonal crystalline phase has been prepared by the surfactant-assisted route, using Pluronic P123 block copolymer surfactant. The synthesized zirconia showed a surface area of 174 m2 g−1 after calcination at 700 °C for 4 h. The prepared zirconia was employed as a support for nickel catalysts in dry reforming reaction. It was found that these catalysts possessed a mesoporous structure and even high-surface area. The activity results indicated that the nickel catalyst showed stable activity for syngas production with a decrease of about 4% in methane conversion after 50 h of reaction. Addition of promoters (CeO2, La2O3 and K2O) to the catalyst improved both the activity and stability of the nickel catalyst, without any decrease in methane conversion after 50 h of reaction.
TL;DR: The nickel hydroxide nanosheets exhibited charge-discharge properties in strong alkaline electrolyte and the morphology of the nanosheet changed during the electrochemical reaction.
Abstract: One-nanometer-thick nickel hydroxide nanosheets were prepared by exfoliation of layered nickel hydroxides intercalated with dodecyl sulfate (DS) ions. The shape of the nanosheets was hexagonal, as was that of the layered nickel hydroxides intercalated with DS ions. The nickel hydroxide nanosheets exhibited charge-discharge properties in strong alkaline electrolyte. The morphology of the nanosheet changed during the electrochemical reaction.
TL;DR: In this article, the electrical conductivity and specific surface area of the synthesized nickel hydroxide/oxide film was investigated by cyclic voltammetry and electrochemical impedance spectroscope methods.
TL;DR: In this paper, Ni and nickel matrix composite deposits containing nano-SiC particles were produced under both direct and pulse current conditions from an additive-free nickel Watts' type bath, and the study of the textural perfection of the deposits revealed that the presence of nano-particles led to the worsening of the observed [1/0/0] preferred orientation.
TL;DR: Nickel phosphide, nickel selenide thin films and their heterostructure were deposited from a newly synthesized single source precursor {Ni[iPr2P(S)NP(Se) iPr2]2 just by altering the deposition temperature using CVD.
Abstract: Nickel phosphide, nickel selenide thin films and their heterostructure (Ni0.85Se/Ni2P) were deposited from a newly synthesized single source precursor {Ni[iPr2P(S)NP(Se)iPr2]2} just by altering the deposition temperature using CVD.
TL;DR: In this paper, an iron-nickel oxide catalyst that can eliminate oxygen overvoltage in the electrolysis of alkaline water is described, which is the largest source of energy loss in water electrolysis.
Abstract: This paper describes an iron-nickel oxide catalyst that can eliminate oxygen overvoltage in the electrolysis of alkaline water Oxygen overvoltage is the largest source of energy loss in water electrolysis A method for cathodic electrodeposition of first-row transition metal oxides for use as catalysts is described, and the effects of the electrodeposition variables on catalytic performance and catalyst composition were explored The NiFe oxide catalyst achieved a nearly ideal anodic electron-transfer coefficient, αa = 00082 (148 mV/decade) in a 1 M KOH solution The metal oxide catalysts reported here could produce hydrogen and oxygen from water at approximately the thermodynamic potential for small currents Both transmission electron microscopy and X-ray photoelectron spectroscopy experiments indicated that the NiFe oxide was composed of small crystals (∼1 nm) connected with an amorphous phase and contained a highly disordered arrangement of all nonmetallic nickel and iron oxidation states Changes
TL;DR: An efficient nickel catalyst system for the carboxylation of organozinc reagents with CO(2) under very mild conditions has been developed and enables the direct synthesis of various saturated carboxylic acid derivatives from the corresponding alkylzinc reagent reagents andCO(2).
TL;DR: In this article, the adsorption mechanism of nickel at a molecular level was attributed to chemical interaction between nickel and the surface functional groups of MWCNTs and surface adsorbed SDBS.
TL;DR: The results indicated that the biosorption of nickel(II) ion on to baker's yeast was spontaneous and exothermic in nature.
TL;DR: Most existing hydrometallurgical processes for the leaching of nickel laterites employ sulphuric acid. Alternative technologies that utilize other leaching agents such as hydrochloric acid and various organic acids are currently being examined and developed, and are the topics of as discussed by the authors.
TL;DR: The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated and the proposed procedure was applied to the analysis of biological, natural and wastewater, soil and blood samples.
TL;DR: In this article, the hydrogen storage capacity of two different high surface area carbon materials of templated carbon (TC) and superactivated carbon (AX-21) doped with three different metals (Ru, Pt, and Ni) have been studied.
Abstract: Hydrogen adsorption properties of two different high surface area carbon materials of templated carbon (TC) and superactivated carbon (AX-21) doped with three different metals (Ru, Pt, and Ni) have been studied. The equilibrium hydrogen storage capacities followed the order of Ru/C > Pt/C > Ni/C on both TC and AX-21. Ru doped on templated carbon (Ru/TC) showed a hydrogen storage capacity of 1.43 wt % at 298 K and 10.3 MPa. Furthermore, a thermal reduction method was applied to increase the contacts between the Ru metal particles and the carbon support, and in turn, to facilitate hydrogen spillover. The ruthenium-doped templated carbon by thermal reduction (Ru/TC-T) showed the highest hydrogen storage of 1.56 wt % at 298 K and 10.3 MPa, resulting in an enhancement factor of 2 compared with that of the undoped carbon. These experimental results were interpreted by using a simple mechanistic model for hydrogen spillover.