Novel synthesis of metastable HCP nickel by water quenching

Bolokang, A.S.; Phasha, M.J.

doi:10.1016/j.matlet.2010.09.045

Cited by 28 publications

(18 citation statements)

References 27 publications

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“…To our knowledge, none of the XRD patterns of substoichiometric phase that could be intermediates in the formation of nickel from the nitride/carbide (Ni 8 N or hexagonal Ni 4 N, for example)10a, 13b, 16 do really fit the features observed here at high temperature. Interestingly, similar diffraction peaks have been attributed to pure hexagonal nickel by Bolokang et al 17. and can be found in few other reports in which, unfortunately, the nature of this phase was not discussed 18.…”

Section: Resultssupporting

confidence: 81%

Easy Access to Ni₃N– and Ni–Carbon Nanocomposite Catalysts

Clavel

Molinari

Kraupner

et al. 2014

Chemistry A European J

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In the search for alternative materials to current expensive catalysts, Ni has been addressed as one of the most promising and, on this trail, its corresponding nitride. However, nickel nitride is a thermally unstable compound, and therefore not easy to prepare especially as nanoparticles. In the present work, a sol-gel-based process (the urea glass route) is applied to prepare well-defined and homogeneous Ni3N and Ni nanoparticles. In both cases, the prepared crystalline nanoparticles (∼25 nm) are dispersed in a carbon matrix forming interesting Ni3N- and Ni-based composites. These nanocomposites were characterised by means of several techniques, such as XRD, HR-TEM, EELS, and the reaction mechanism was investigated by TGA and IR and herein discussed. The catalytic activity of Ni3N is investigated for the first time, to the best of our knowledge, for hydrogenation reactions involving H2, and here compared to the one of Ni. Both materials show good catalytic activities but, interestingly, give a different selectivity between different functional groups (namely, nitro, alkene and nitrile groups).

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Section: Resultssupporting

confidence: 81%

Easy Access to Ni₃N– and Ni–Carbon Nanocomposite Catalysts

Clavel

Molinari

Kraupner

et al. 2014

Chemistry A European J

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“…Ni NPs with the hcp structure and a diameter between 13 and 25 nm are also formed in polyethylene glycol, oleic acid, and oleyl amine . There are also other possibilities to obtain nickel compounds in an hcp phase …”

Section: Resultsmentioning

confidence: 99%

“…[58] There are also other possibilities to obtain nickel compounds in an hcp phase. [59,60,61] Concerning the oxidation of nickel,w en ote that traces of oxygen in the EDX spectrum (signal at 0.52 eV) are ubiquitous and always present, also on noble metal samples and pure carbon grids (from surface oxidation). For Ni NPs in ILs with [BF 4 ] À or [PF 6 ] À anions, small amountso fN iO and NiF 2 are ob-tained in three cases (see Table 1) as identified by phase analysis in the powder X-ray and electron diffractograms (Figures S2.9, S2.16, and S2.29 in the Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Soft, Wet‐Chemical Synthesis of Metastable Superparamagnetic Hexagonal Close‐Packed Nickel Nanoparticles in Different Ionic Liquids

Wegner

Rutz

Schütte

et al. 2017

Chemistry A European J

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The microwave-induced decomposition of bis{N,N'-diisopropylacetamidinate}nickel(II) [Ni{MeC(NiPr) } ] or bis(1,5-cyclooctadiene)nickel(0) [Ni(COD) ] in imidazolium-, pyridinium-, or thiophenium-based ionic liquids (ILs) with different anions (tetrafluoroborate, [BF ] , hexafluorophosphate, [PF ] , and bis(trifluoromethylsulfonyl)imide, [NTf ] ) yields small, uniform nickel nanoparticles (Ni NPs), which are stable in the absence of capping ligands (surfactants) for more than eight weeks. The soft, wet-chemical synthesis yields the metastable Ni hexagonal close-packed (hcp) and not the stable Ni face-centered cubic (fcc) phase. The size of the nickel nanoparticles increases with the molecular volume of the used anions from about 5 nm for [BF ] to ≈10 nm for [NTf ] (with 1-alkyl-3-methyl-imidazolium cations). The n-butyl-pyridinium, [BPy] , cation ILs reproducibly yield very small nickel nanoparticles of 2(±1) nm average diameter. The Ni NPs were characterized by high-resolution transmission electron microscopy (HR-TEM) and powder X-ray diffraction. An X-ray photoelectron spectroscopic (XPS) analysis shows an increase of the binding energy (E ) of the electron from the Ni 2p orbital of the very small 2(±1) nm diameter Ni particles by about 0.3 eV to E =853.2 eV compared with bulk Ni , which is traced to the small cluster size. The Ni nanoparticles show superparamagnetic behavior from 150 K up to room temperature. The saturation magnetization of a Ni (2±1 nm) sample from [BPy][NTf ] is 2.08 A m kg and of a Ni (10±4 nm) sample from [LMIm][NTf ] it is 0.99 A m kg , ([LMIm]=1-lauryl-3-methyl- imidazolium). The Ni NPs were active catalysts in IL dispersions for 1-hexene or benzene hydrogenation. Over 90 % conversion was reached under 5 bar H in 1 h at 100 °C for 1-hexene and a turnover frequency (TOF) up to 1330 mol (mol ) h or in 60 h at 100 °C for benzene hydrogenation and TOF=23 mol (mol ) h .

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“…The lattice parameters for hcp-Re and fcc-Re are a ¼ 0.2761 nm, c ¼ 0.4456 nm, [42] and a ¼ 0.393 AE 0.004 nm, [54] respectively. [56] The lattice parameters of fcc-Ni and metastable hcp-Ni are a ¼ 0.3524 nm, [49] and a ¼ 0.2622 nm, c ¼ 0.4321 nm, [57] respectively. [56] The lattice parameters of fcc-Ni and metastable hcp-Ni are a ¼ 0.3524 nm, [49] and a ¼ 0.2622 nm, c ¼ 0.4321 nm, [57] respectively.…”

Section: Intrinsic Stresses Developed In the Banded Structure Of The mentioning

confidence: 99%

“…While hcp is the only stable phase of pure Re, a metastable fcc-Re phase has occasionally been observed, either experimentally (e.g., by high undercooling [54] or epitaxial growth on a NaCl substrate [55] ) or in atomistic calculations. [56] The lattice parameters of fcc-Ni and metastable hcp-Ni are a ¼ 0.3524 nm, [49] and a ¼ 0.2622 nm, c ¼ 0.4321 nm, [57] respectively. Cohen-Sagiv et al [9] reported the formation of the hcp-Ni phase in Re-Ir-Ni electrodeposits based on XRD data.…”

Section: Intrinsic Stresses Developed In the Banded Structure Of The mentioning

confidence: 99%

Atomic‐Scale Structural and Chemical Study of Columnar and Multilayer Re–Ni Electrodeposited Thermal Barrier Coating

et al. 2016

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Rhenium alloys exhibit a unique combination of chemical, physical, and mechanical properties that makes them attractive for a variety of applications. Herein, we present atomic-scale structural and atomic part-per-million level three-dimensional (3D) chemical characterization of a Re-Ni coating, combining aberration-corrected scanning transmission electron microscopy (STEM) and atom-probe tomography (APT). A unique combination of a columnar and multilayer structure is formed by singlebath dc-electroplating and is reported here for the first time. Alternating thicker Re-rich and thinner Ni-rich layers support a mechanism in which Ni acts as a reducing agent. The multilayers exhibit hetero-epitaxial growth resulting in high residual shear stresses that lead to formation of corrugated interfaces and an outer layer with mud-cracks. IntroductionRhenium (Re) is a refractory metal with a unique combination of chemical, physical, and mechanical properties that makes it attractive for high-temperature, catalytic, energy, electrical, biomedical, and other applications, in spite of its high cost. [1,2] Interest in electroless deposition [3,4] and electrodeposition [5][6][7][8][9][10][11][12][13][14][15][16] of Re and its alloys has recently emerged. Electroplating of pure Re yields poor deposition results. The addition of salts of the iron-group metals (Ni, Fe, and Co) to the plating bath improves, however, the coating dramatically, allowing deposition of thick layers of the

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Novel synthesis of metastable HCP nickel by water quenching

Cited by 28 publications

References 27 publications

Easy Access to Ni₃N– and Ni–Carbon Nanocomposite Catalysts

Easy Access to Ni₃N– and Ni–Carbon Nanocomposite Catalysts

Soft, Wet‐Chemical Synthesis of Metastable Superparamagnetic Hexagonal Close‐Packed Nickel Nanoparticles in Different Ionic Liquids

Atomic‐Scale Structural and Chemical Study of Columnar and Multilayer Re–Ni Electrodeposited Thermal Barrier Coating

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Novel synthesis of metastable HCP nickel by water quenching

Cited by 28 publications

References 27 publications

Easy Access to Ni3N– and Ni–Carbon Nanocomposite Catalysts

Easy Access to Ni3N– and Ni–Carbon Nanocomposite Catalysts

Soft, Wet‐Chemical Synthesis of Metastable Superparamagnetic Hexagonal Close‐Packed Nickel Nanoparticles in Different Ionic Liquids

Atomic‐Scale Structural and Chemical Study of Columnar and Multilayer Re–Ni Electrodeposited Thermal Barrier Coating

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Product

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Easy Access to Ni₃N– and Ni–Carbon Nanocomposite Catalysts

Easy Access to Ni₃N– and Ni–Carbon Nanocomposite Catalysts