Stabilization of hexagonal close-packed metallic nickel for alumina-supported systems prepared from Ni(II) glycinate

Journal Article · Mon Jan 15 00:00:00 EST 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.09.015· OSTI ID:21015614

Rodriguez-Gonzalez, Vicente ^[1]; Marceau, Eric ^[1]; Beaunier, Patricia ^[1]; Che, Michel ^[1]; Train, Cyrille ^[2]

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1. Laboratoire de Reactivite de Surface (UMR 7609 CNRS), Universite Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France)
2. Laboratoire de Chimie Inorganique et Materiaux Moleculaires (UMR 7071 CNRS), Universite Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

The decomposition in flowing argon of the neutral complex [Ni{sup II}(glycinate){sub 2}(H{sub 2}O){sub 2}] leads to a mixture of face-centered cubic (fcc) and hexagonal close-packed (hcp) metallic nickel. The latter is the main phase when the Ni(II) complex is supported on alumina. Unlike most hexagonal Ni phases described earlier, and similar to hexagonal Ni{sub 3}C, the unit cell parameters (a=0.2493 and c=0.4084nm) lead to Ni-Ni distances equal to those encountered in fcc Ni. TEM shows that the nanoparticles are protected by graphite layers, whose elimination by heating in hydrogen results in transformation to the fcc phase and crystal growth. Magnetic measurements provide evidence of the coexistence of superparamagnetic and ferromagnetic nanoparticles. This result is in line with the broad size distribution observed by TEM and is interpreted on the basis of the metallic character of hcp Ni particles.

• OSTI ID: 21015614
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 1; Other Information: DOI: 10.1016/j.jssc.2006.09.015; PII: S0022-4596(06)00523-8; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM OXIDES
ARGON
CRYSTAL GROWTH
DECOMPOSITION
ELECTRON DIFFRACTION
FCC LATTICES
GLYCINE
GRAPHITE
HCP LATTICES
HEATING
HYDROGEN
LAYERS
MIXTURES
NANOSTRUCTURES
NICKEL
NICKEL COMPLEXES
PARTICLES
STABILIZATION
SUPERPARAMAGNETISM
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION