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Nickel

About: Nickel is a research topic. Over the lifetime, 79308 publications have been published within this topic receiving 1210058 citations. The topic is also known as: Ni & element 28.


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TL;DR: The ion-bombardment cleaning method has been successfully applied to the (100) faces of germanium, silicon, and nickel, and to the(0001) face of titanium as mentioned in this paper.
Abstract: The ion‐bombardment cleaning method has been successfully applied to the (100) faces of germanium, silicon, and nickel, and to the (0001) face of titanium. Conditions and precautions necessary for the production of clean surfaces are described. Tests have been made for contamination from the ambient during the cleaning procedure for germanium. It has been shown that contamination approximating one‐half monolayer does not occur under the conditions which were obtained, and that the method is capable of producing surfaces which are atomically clean.Results for clean (100), (111), and (110) germanium faces and the (100) silicon face indicate that the atomic positions in the surface planes are not the same as the corresponding positions in the bulk structure. For (100) nickel and (0001) titanium, the positions of the atoms in the surface planes are in agreement with x‐ray data. In the case of titanium, an unidentified surface structure was present until after several cycles of alternate heating and ion bombardment. In the case of nickel, a double‐spaced surface monolayer and in some cases a single‐spaced, simple‐square structure, attributed to carbon, was present until after several cycles of alternate heating and ion bombardment.

187 citations

Journal ArticleDOI
TL;DR: In this paper, a nickel powder (0.5-1-μm) was used as a substitute for the platinum catalysts in microbial electrolysis cells (MECs).

187 citations

Journal ArticleDOI
TL;DR: In this article, a nanometer-scale catalysts based on nanometerscale nickel particles prepared from a hydrotalcite-like anionic clay precursor have been designed and tested to fit the process goals.
Abstract: From the decomposition of methane, hydrogen without carbon oxides can be produced with a high energy-efficiency, which is attractive for its suitability of utilization in the fuel cells. At a same time nanocarbon materials with attractive texture and structure can be produced in a large amount. Toward a simultaneous bulk production of hydrogen and nanocarbon, catalysts based on nanometer-scale nickel particles prepared from a hydrotalcite-like anionic clay precursor have been designed and tested to fit the process goals. For hydrogen production, as the equilibrium methane conversion of the reaction increases with the increase of the reaction temperature, the process is commercially more attractive if it can be operated at a temperature higher than 1073 K. However, a nickel catalyst has a maximum activity for nanocarbon production at 923 K. Modification of the catalyst with doping of copper increased the activation temperature and leads to a production of nanocarbon with an attractive structure. The feasib...

187 citations

Journal ArticleDOI
TL;DR: In this paper, the rotational coefficient in nickel and cobalt has been investigated and the authors propose a method to find the optimal value for each element in terms of the rotation coefficient.
Abstract: (1881). XVIII. On the “Rotational Coefficient” in nickel and cobalt. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 12, No. 74, pp. 157-172.

187 citations

Journal ArticleDOI
TL;DR: In this paper, a combinatorial self-regulating acid etching and topotactic transformation strategy is developed to unprecedentedly prepare vertically stacked ultrathin 2D non-layered nickel selenide nanosheets.
Abstract: DOI: 10.1002/aenm.201702704 bulky counterparts.[1–11] In particular, 2D nonlayered materials are expected to show intriguing properties, as their sur­ faces are occupied with dangling bonds, unlike the layered materials.[12–15] The 3D atomic bonding in an unconven­ tional dimensionality enables chemi­ cally active surface, thus reinforcing the catalytic capability.[16,17] Nickel selenides (NiSe2 and NiSe), as nonlayered metal chalcogenides, have emerged as pro­ mising catalysts for water electrolysis, due to their favorable electrochemical reactivity toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER).[18–24] Thus, integrating overall water splitting based on the low­ cost ultrathin 2D nonlayered nickel sele­ nide electrocatalysts, especially in alkaline intermediates for submissive industrial requirements, is promising. Unfortu­ nately, engineering ultrathin 2D non­ layered nickel selenide is considerably challenging and rare, due to its intrinsic lack of anisotropic growth driving force of the nonlayered structure.[14–17] Although epitaxial growth of 2D nonlayered nickel sele­ nide has been achieved in­between ZnSe film and Ni foil very recently,[25] the rigorous requirements (lattice­matched sub­ strate, high temperature, and vacuum), poor thickness con­ trollability (over tens of nanometers), and limited surface area (parallel to the planar substrate) make it a suboptimal strategy. Other than that, composition transition through postseleni­ zation of the as­prepared precursors (e.g., nickel hydroxides, Ni(OH)2) provides new possibilities for achieving nanostruc­ tured nickel selenides.[26–34] Yet, the structural deformation is inevitable during the selenization process due to the collec­ tive lattice expansion of individual layers (e.g., ≈58% incre­ ment in volume per unit cell as hexagonal Ni(OH)2 converts to hexagonal NiSe) and crystal phase transformation, leading to the formation of nanoparticles or deformed thick sheet struc­ tures. In comparison, ultrathin 2D structures may render a well­retained structural framework in view of topotactic reac­ tion on the surfaces that induces limited epitaxial lattice expan­ sion and swelling of a few monolayer thick structure.[6,35–39] Thus, ultrathin 2D nonlayered nickel selenide is expected to be conceptualized, originating from the ultrathin layered Ni(OH)2 counterparts. However, conventional synthetic pro­ tocols of Ni(OH)2 under alkaline conditions practically result in thick sheets due to the fast and insubordinate hydrolysis Fabrication of ultrathin 2D nonlayered nanomaterials remains challenging, yet significant due to the new promises in electrochemical functionalities. However, current strategies are largely restricted to intrinsically layered materials. Herein, a combinatorial self-regulating acid etching and topotactic transformation strategy is developed to unprecedentedly prepare vertically stacked ultrathin 2D nonlayered nickel selenide nanosheets. Due to the inhibited hydrolyzation under acidic conditions, the self-regulating acid etching results in ultrathin layered nickel hydroxides (two layers). The ultrathin structure allows limited epitaxial extension during selenization, i.e., the nondestructive topotactic transformation, enabling facile artificial engineering of hydroxide foundation frameworks into ultrathin nonlayered selenides. Consequently, the exquisite nonlayered nickel selenide affords high turnover frequencies, electrochemical surface areas, exchange current densities, and low Tafel slopes, as well as facilitating charge transfer toward both oxygen and hydrogen evolution reactions. Thus, the kinetically favorable bifunctional electrocatalyst delivers advanced and robust overall water splitting activities in alkaline intermediates. The integrated methodology may open up a new pathway for designing other highly active 2D nonlayered electrocatalysts.

186 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20233,184
20226,229
20211,949
20202,693
20193,234
20183,107