Stabilization of hexagonal close-packed metallic nickel for alumina-supported systems prepared from Ni(II) glycinate |
| |
Authors: | Vicente Rodrí guez-Gonzá lez,Patricia Beaunier,Cyrille Train |
| |
Affiliation: | a Laboratoire de Réactivité de Surface (UMR 7609 CNRS), Université Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75252Paris Cedex 05, France b Laboratoire de Chimie Inorganique et Matériaux Moléculaires (UMR 7071 CNRS), Université Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75252Paris Cedex 05, France c Institut Universitaire de France, France |
| |
Abstract: | The decomposition in flowing argon of the neutral complex [NiII(glycinate)2(H2O)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 Ni3C, the unit cell parameters (a=0.2493 and ) 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. |
| |
Keywords: | Nickel Alumina Glycinate Hexagonal close-packed arrangement X-ray diffraction Transmission electron microscopy Electron diffraction Magnetic measurements |
本文献已被 ScienceDirect 等数据库收录! |
|