Showing papers on "Nickel published in 1981"
TL;DR: Several series of nickel (or Co) molybdenum oxide catalysts supported on X-ray photoelectron and Raman spectroscopy have been studied by as discussed by the authors, where the combination of these two techniques is a complementary approach to the alumina coverage, the nature of the deposited species, and the interaction between these species.
Abstract: Several series of nickel (or Co) molybdenum oxide catalysts supported on ..gamma..-Al/sub 2/O/sub 3/ have been studied by X-ray photoelectron and Raman spectroscopy. The combination of these two techniques is a complementary approach to the alumina coverage, the nature of the deposited species, and the interaction between these species. In particular, the characteristics of the monolayer coverage by the nickel species appear somewhat different from cobalt in systems without molybdenum. When molybdenum is present, formation of a phase similar to (a) NiMoO/sub 4/ is observed. No bulk NiO or Ni(OH)/sub 2/ phases are detected. Comparison with Co-Mo or Ni-Mo-..gamma..-Al/sub 2/O/sub 3/ industrial catalysts is also presented.
237 citations
TL;DR: In this article, the application of H2 chemisorption, X-ray diffraction (XRD) line broadening, and transmission electron microscopy (TEM) to the determination of metal crystallite size and size distribution in Ni SiO 2, Ni Al 2 O 3, and Ni TiO 2 catalysts having wide ranges of nickel loadings and dispersions was investigated.
203 citations
TL;DR: Several molybdenum compounds were prepared and their catalytic properties in the methanation of CO at 350 °C were investigated and compared with those of nickel and iron as mentioned in this paper.
197 citations
193 citations
TL;DR: In this paper, the interfaces formed by evaporating copper, nickel, and chromium layers on polystyrene, polyvinyl alcohol, polyethylene oxide, polymethyl methacrylate have been studied with x-ray photoemission spectroscopy (XPS).
Abstract: The interfaces formed by evaporating copper, nickel, and chromium layers on polystyrene, polyvinyl alcohol, polyethylene oxide, polyvinyl methyl ether, polyvinyl acetate, and polymethyl methacrylate have been studied with x‐ray photoemission spectroscopy (XPS). The adhesion strengths of the metal films to the polymers were measured by a tensile‐pull test. At submonolayer coverages of the metals, the peak positions and widths of the metallic electron core levels measured with XPS vary significantly from one polymer substrate to another. Most of these variations can be accounted for in terms of changes in the atomic and extra‐atomic relaxation energies during the photoemission process. Much of this change is brought about when the metal atom deposited on an oxygen‐containing polymer interacts with the substrate oxygen and forms a metal‐oxygen‐polymer complex. The presence of this complex is verified by changes in the photoemission lineshapes of the substrate carbon and oxygen atoms. The XPS signatures of th...
181 citations
TL;DR: In this paper, room temperature adsorption of CO on bare and carbided (111), (100) and (110) nickel surfaces has been studied by vibrational electron energy loss spectroscopy (EELS) and thermal desorption.
181 citations
Patent•
01 Jun 1981TL;DR: In this paper, a nickel layer is prepared by applying a nickel salt and a reducing agent for reducing said nickel salt, on a substrate and reducing said salt by a chemical reaction, in the presence of at least one compound selected from the group consisting of diethylenetriamine, and imidazole.
Abstract: A nickel layer is prepared by applying a nickel salt and a reducing agent for reducing said nickel salt, on a substrate and reducing said nickel salt by a chemical reaction. The chemical reduction is carried out in the presence of at least one compound selected from the group consisting of diethylenetriamine, and imidazole.
180 citations
TL;DR: In this paper, the intrinsic rates and product distributions for CO2 hydrogenation on Ni SiO 2 were determined at 500-575 K, 140-2500 kPa, and a range of space velocities.
168 citations
166 citations
TL;DR: The nickel-dependent chemolithoautotrophic growth of Alcaligenes eutrophus is apparently due to a requirement of nickel for active hydrogenase formation, and a specific activity of soluble and membrane-bound hydrogenase which was severalfold higher than the normal autotrophic level.
Abstract: The nickel-dependent chemolithoautotrophic growth of Alcaligenes eutrophus is apparently due to a requirement of nickel for active hydrogenase formation. Cells grown heterotrophically with fructose and glycerol revealed a specific activity of soluble and membrane-bound hydrogenase which was severalfold higher than the normal autotrophic level. The omission of nickel from the medium did not affect heterotrophic growth, but the soluble hydrogenase activity was reduced significantly. In the presence of ethylenediaminetetraacetic acid (EDTA), almost no hydrogenase activity was detected. The addition of nickel allowed active hydrogenase formation even when EDTA was present. When chloramphenicol was added simultaneously with nickel to an EDTA-containing medium, almost no hydrogenase activity was found. This indicates that nickel ions are involved in a process which requires protein synthesis and not the direct reactivation of a preformed inactive protein. The formation of the membrane-bound hydrogenase also appeared to be nickel dependent. Autotrophic CO2 assimilation did not specifically require nickel ions, since formate was utilized in the presence of EDTA and the activity of ribulosebisphosphate carboxylase was not affected under these conditions.
159 citations
TL;DR: In this article, electron microprobe techniques were used to examine the deposition patterns of nickel, vanadium, iron, and coke in 1/16 in. extrudate (unspecified) catalysts aged in hydrotreating pilot plants.
Abstract: Deposition patterns of nickel, vanadium, iron, and coke in 1/16 in. extrudate (unspecified) catalysts aged in hydrotreating pilot plants were examined by electron microprobe techniques. Iron deposited mostly on the outer catalyst surface; coke deposited in an outer annulus initially and then its levels in the catalyst interior increased linearly with time; and nickel and vanadium deposited in the interior in a manner consistent with diffusion-limited demetalation. With increasing temperature or hydrogen partial pressure, nickel and vanadium deposition occurred nearer the catalyst surface. The metals distribution in the catalyst varied with crude source. The metals diffused further into catalysts with larger pores. The distribution of deactivation processes in the catalyst bed suggested that poisoning of surface sites and pore plugging both take place and that the rate at which pore plugging moves through the bed depends on the extent of surface poisoning and on the axial distribution of the metal deposits along the reactor length. The tests were conducted with six feedstocks containing 1.7-4.3% sulfur, 29-630 ppm vanadium, 8-48 ppm nickel, and 3-15% iron.
TL;DR: A series of materials containing nickel and aluminium ions has been prepared by coprecipitation with alkaline solutions, under various conditions, from solutions of the nitrates as discussed by the authors, and the composition and structure of the precipitates has been examined using a number of techniques including chemical analysis, X-ray diffraction, thermogravimetry and infrared spectroscopy.
Abstract: A series of materials containing nickel and aluminium ions has been prepared by coprecipitation with alkaline solutions, under various conditions, from solutions of the nitrates. The composition and structure of the precipitates has been examined using a number of techniques including chemical analysis, X-ray diffraction, thermogravimetry and infrared spectroscopy. The precipitates have structures typical of minerals of the hydrotalcite group and particularly of the nickel-aluminium compound, takovite. They consist of brucite-like layers of composition [NixAl1–x(OH)2](1–x)+ and interlayers containing CO2–3, NO–3 or OH– ions, or combinations of these, depending on the preparation conditions, together with molecular water; the anions balance the excess charge of the brucite layers. It is concluded that the aluminium ions are randomly substituted for nickel ions in the brucite layers and that the structure of these layers is independent of the anions in the interlayer. For freshly precipitated samples, 0.5 ⩽x≲ 0.85, but for hydrothermally aged materials, 0.66 ⩽x⩽ 0.75; outside these ranges, boehmite or Ni(OH)2 from as separate phases. The results are compared with those for precipitates prepared from ammoniacal solutions and it is concluded that the two types of material are indistinguishable.
TL;DR: In this article, the reaction of oxygen with atomically clean nickel surfaces is reviewed, and the reaction consists of three stages: chemisorption, oxide nucleation and lateral growth to coalescence, and thickening of coalesced oxide.
Abstract: The reaction of oxygen with atomically clean nickel surfaces is reviewed. The reaction consists of three stages—chemisorption, oxide nucleation and lateral growth to coalescence, and thickening of coalesced oxide. Chemisorption is dissociative and nonreconstructive in general. However, a reconstructed chemisorbed phase is detected on Ni (110). NiO nucleates and grows laterally as islands displacing the chemisorbed phase, and finally coalescing to passivate the nickel surface. The conditions and rates at which the coalesced oxide thickens have not been well defined.
TL;DR: In this article, the authors compared the results obtained from X-ray diffraction (XRD) and transmission electron microscopy (TEM) to those obtained from typical NiSiO2 and NiAl2O3 catalysts, and showed that oxygen monolayer coverage on NiO2-supported nickel does not exceed unity regardless of crystallite size.
Journal Article•
TL;DR: Results suggest that nickel particles were broken down in the cytoplasm to a size range no longer detectable with the electron microscope and then subsequently entered the nucleus, suggesting that nickel binds strongly to cellular macromolecules.
Abstract: Divisionof Toxicologyol the Departmentof PharmacologyÂiM. C., J. S-H.), Departmentof PathologyÂiC. W.M. B.), and the Analytical ChemistryCenter IJ. B., R. M. C.), TheUniversityof TexasMedical School of Houston,Houston, Texas77025 ABSTRACT The uptake, toxicity, and morphological transformation effi cacy of various water-insoluble nickel compounds were ex amined in tissue culture. Particles (2.2 to 4.8 firn) of crystalline Ni3S2, crystalline NiS, and crystalline Ni3Se2 were actively phagocytized by cultured cells as determined by light and electron microscopy. However, particles of similar size con sisting of amorphous NiS and metallic nickel were not signifi cantly phagocytized despite long exposure periods to high concentrations. X-ray fluorescence spectrometry measure ments of metal levels in subcellular fractions isolated from cells treated with crystalline Ni3S2, crystalline NiS, or amorphous NiS confirmed that amorphous NiS did not significantly enter the cells, either as a phagocytized particle or in a solubilized form, while the other two crystalline nickel compounds were actively taken up. Cells treated with amorphous NiS contained nickel levels generally less than 10% of the nickel levels in whole cells and in cytoplasmic fractions, or nuclear fractions of cells treated with either crystalline NiS or crystalline Ni3S2. The phagocytized nickel particles were always observed in the cytoplasm with light and electron microscopy, but substantial nickel levels were measured in the nuclear fraction. These and other results suggest that the nickel particles were broken down in the cytoplasm to a size range no longer detectable with the electron microscope and then subsequently entered the nucleus. Control experiments suggest that at least 20% of the nickel measured in the nucleus isolated from cells treated with Ni3S2is no longer part of a sedimentatale particle with the same particle size and/or solubility properties of the parent compound. A substantial portion of the nickel associated with the nuclear fraction coprecipitated with trichloroacetic acid- insoluble material, suggesting that nickel binds strongly to cellular macromolecules. The phagocytized particulate nickel compounds were more cytotoxic as determined by reduction of cell-plating efficiency and induced more morphological transformations in the Syrian hamster embryo cell transforma tion assay than did the particulate nickel compounds which were not phagocytized. Manganese dust inhibited the morpho logical transformation induced by Ni3S2and also reduced the phagocytosis of Ni3S2particles.
TL;DR: The addition of nickel and cobalt to anaerobic fixed-film digestors, which treat food processing waste, greatly enhanced reactor performance and tests showed that reactor performance was increased because trace nutrient addition allowed accumulation of a thicker methanogenic fixed film.
Abstract: The conversion of acetic acid to methane and carbon dioxide by a mixed methanogenic population from an anaerobic fixed-film digestor was stimulated by the addition of nickel (100 nM) and cobalt (50 nM) and especially by the addition of these elements in combination. Molybdenum addition (50 nM) was only slightly stimulatory when added in combination with both nickel and cobalt. The addition of these trace metals to anaerobic fixed-film digestors, which treat food processing waste, greatly enhanced reactor performance. Total gas and methane productions were increased 42%, greater volumes of waste could be effectively treated, and reactor residence time was shortened. However, the lag period for reactor start-up was not reduced. Tests showed that reactor performance was increased because trace nutrient addition allowed accumulation of a thicker methanogenic fixed film.
TL;DR: The surface properties of mixed copper and mixed copper-nickel aluminates have been investigated by means of optical spectroscopy, magnetic susceptibility, gravimetric carbon monoxide adsorption, thermal desorption.
TL;DR: In this article, an analysis of the impedance of nickel deposition was carried out and the electrode kinetics was shown to be dependent on the type of anion, where the ad-ion NiadsI acts as both a reaction intermediate and a catalyst associated with a propagating kink site.
TL;DR: In this article, the total and metallic nickel areas of a series of coprecipitated nickel-alumina catalysts prepared and pretreated in different ways were analyzed. And the high stability of the catalysts was attributed to the presence in the unreduced catalyst of nickel oxide rich phases containing dissolved aluminium ions.
Abstract: Results are presented for the total and metallic nickel areas of a series of coprecipitated nickel–alumina catalysts prepared and pretreated in different ways. The total areas of the samples decrease on reduction and with increasing reduction temperature, while the nickel area increases with reduction temperature. Increasing calcination temperature causes a decrease in total and nickel areas, this being particularly marked at high temperatures of calcination. A model for the catalyst system is proposed, based on these results and on complementary structural investigations. The high stability of the catalysts is attributed to the presence in the unreduced catalyst of nickel oxide rich phases containing dissolved aluminium ions; on reduction, alumina crystallises on the surface of the growing nickel crystallites, preventing sintering of the catalysts except under extreme conditions.
TL;DR: In this article, the authors investigated the loss of methanation activity of alumina-supported nickel catalysts at pressures up to ca. 600 kPa and temperatures from 400 to 740 K. Deactivation is attributed primarily to growth in nickel particle size.
TL;DR: The known ratio of 20 thiolate ligands to 7 metal ions, in conjunction with the spectral evidence for tetrathiolate coordination in metallothionein, represents good evidence that these metal thiolates are organized in clusters.
Abstract: The zinc and cadmium of native rabbit metallothionein-1 were replaced stoichiometrically with either cobalt (II) or nickel (II). The electronic, magnetic circular dichroic (MCD), and electron spin resonance spectra of Co (II)-metallothionein reflect distorted tetrahedral coordination of the cobalt atoms. Both the d-d and charge-transfer spectral regions closely resemble those of simple cobalt-tetrathiolate complexes, implying that their coordination chemistry is analogous. Ni (II) complex ions and Ni (II)-metallothionein similarly exhibit analogous MCD bands in the d-d region. The circular dichroic bands associated with ligand-metal charge-transfer transitions in the non-d-d region of Co (II)- and Ni (II)-metallothionein afford additional evidence for the similarity in tetrahedral microsymmetry of the two metal derivatives. The known ratio of 20 thiolate ligands to 7 metal ions, in conjunction with the spectral evidence for tetrathiolate coordination in metallothionein, represents good evidence that these metal thiolates are organized in clusters.
TL;DR: In this paper, the intercalation of nickel chloride into graphite in presence of chlorine gas has been studied in the temperature range 390 − 750 °C with an apparatus allowing the measurement of the chlorine pressure during interalation.
TL;DR: The high temperature parts of the published sulfur chemisorption measurements are also well described by this expression as discussed by the authors, and it is suggested that the absence of a coverage dependence in the entropy term is due to subsurface chemistry.
TL;DR: In this paper, a polysilicate-based coating is applied to polysilicon-based paints containing particles of the desired metals and the coating is sintered into a porous structure which is bonded firmly to the substrate.
Abstract: Electrodes for alkaline water electrolysis have been made by applying high specific surface area coatings of nickel or nickel‐iron alloy to steel or nickel substrates. The coatings are applied as polysilicate‐based paints containing particles of the desired metals. The coating is sintered into a porous structure which is bonded firmly to the substrate. The present electrode preparation method has been used to coat a variety of substrate forms, such as flat plates or wire screens, and is compatible with commercial alkaline electrolysis equipment. The resulting electrodes were found to be particularly effective as anodes for oxygen evolution. The efficiency of the electrodes was greatly influenced by coating microstructure. This microstructure, in turn, could be controlled by adjusting the sintering conditions. Electrochemical operating characteristics of the electrodes in at 80°C were determined. Comparable oxygen evolution efficiencies were obtained with coatings made from nickel powders, nickel flake, and nickel‐iron alloy powder.
TL;DR: In this paper, general models applicable to the electrocrystallisation of nickel are analyzed and the relevant current-time transients for the initial stages of deposition are derived, based on which the authors derive a model for the first stages of nickel deposition.
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IBM1
TL;DR: A previously developed theory of the magnetism of iron, based upon notion of a randomized exchange field, has now been applied to calculate the properties of nickel as discussed by the authors, and they obtained a Curie temperature of 1200 K, about twice the observed value.
Abstract: A previously developed theory of the magnetism of iron, based upon notion of a randomized exchange field, has now been applied to calculate the properties of nickel. We obtained a Curie temperature of 1200 K, about twice the observed value. The magnetization curve, the paramagnetic susceptibility (a Curie-Weiss law), and the distribution of spin lengths are also calculated. Both similarities and differences from the results of the iron calculations are noted.
TL;DR: In this article, the presence of the sulphate molecule is unambiguously shown by the infra-red spectra, and the observed bands are consistent with the sulfate groups lying in the interlayer with their trigonal axes parallel to c.ssMg0.ls.XH20 for the Unst material.
Abstract: Honessite and hydrohonessite from Unst, Shetland, and Linden, Wisconsin, are sulphate-containing members of the pyroaurite group and are analogous to reevesite. The structural formula can be written (Nis.ssMg0.10Fe2a~s)(OH)16(SO4)l.ls .XH20 for the Unst material, with sulphate groups replacing the inter- layer carbonate groups in reevesite. Microprobe analyses of the Unst materiaJ show amounts of SO 3 in excess of that required to balance all trivalent cations and this may be due to the presence of an amorphous nickel sulphate material. We find no evidence for the presence of trivalent nickel in honessite. The Unst material occurs in both 8.8 (honessite) and 1t.1/~ (hydrohonessite) forms, depending on composi- tion, humidity, and temperature, similar to carrboydite, motukoreaite, and SO4-exchanged takovite. The Wiscon- sin material occurs only with an 8.8 A basal spacing. The increase from the 7.7/~ basal spacing of reevesite is due to the difference in molecular geometry of carbonate and sulphate groups. The presence of the sulphate molecule is unambiguously shown by the infra-red spectra, and the observed bands are consistent with the sulphate groups lying in the interlayer with their trigonal axes parallel to c. The Unst material is found intimately mixed in variable proportions with reevesite, distributed in patches on chromite, and the mixed nature is revealed by X-ray powder diffraction, by variations in total SO3 content, and by the presence of absorptions due to both SO~- and CO )- in the infra-red spectra.