Conference paper

Characterization of the Surface of High-Area Ni(OH)2 and NiO

C. Cronan ; Center for Surface and Coatings Research Lehigh University, Bethlehem, Pennsylvania, USA
F . J. Micale ; Center for Surface and Coatings Research Lehigh University, Bethlehem, Pennsylvania, USA
H. Leidheiser ; Center for Surface and Coatings Research Lehigh University, Bethlehem, Pennsylvania, USA
M. Topić ; Center for Surface and Coatings Research Lehigh University, Bethlehem, Pennsylvania, USA
A. C. Zettlemoyer ; Center for Surface and Coatings Research Lehigh University, Bethlehem, Pennsylvania, USA

Abstract

The surface propertij:ls of Ni(OH)2, and the mechanism of decomposition
of Ni(OH)2 to NiO were investigated by a variety , of
experimental approaches including gas adsorption, heats of immersion
and diffuse ir reflectance. The N~(OHh samples were
prepared by bubbling ammonia gas through a Ni(N03)2 solution at
different temperatures. Ni(OHh is relatively hydrophobic while
NiO is completely hydrophilic. A relatiQIIlShip was estabhlshed between
the specific surface areas of rthe parent Ni(OH)2 and Its
decomposition product NiO which supports a mechanism of dehydration
at 200 °c involving separation along the hexagona~ planes.
This mechanism was confirmed by electron micrographs during
decomposmon of Ni(OHh to NiO.
Gravimetric studies of the decomposition of Ni(OH)2 at 200 °c
iindicated that approximately 14°/o of the hydroxyl groups are not
removed. Diffuse ir reflectance studies showed that surface hydroxyls
were not removed. Physical adsorption of water vapor on
Ni(OHh as a function of surface area supports the hypo·thesis that
the basal planes are hydrophobic and the crystal edges are hydrophilic.

Keywords

Hrčak ID:

196443

URI

https://hrcak.srce.hr/196443

Publication date:

22.12.1976.

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