Papers by Keyword: Nanosized Ni Powders

Abstract: Nano-Nickel (Ni0) powders have been successfully prepared via the reduction of nanosized NiO powders by the solid state reaction. And the nanosized NiO powders were derived from low temperature (350°C) calcinations in muffle in air of nanosized Ni(OH)2 powders firstly prepared by the room temperature solid state reaction between NiSO4•6H2O and NaOH by H2 at 400°C for 4 h. The crystallinity, microstructure of surface and xps property of obtained nickel powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, the catalytic activity of the obtained nanosized Ni powders for hydrogenation of nitrobenzene to aniline was investigated. The results show that the spherical Ni parepared in particle sizes ranges from 20 to 25 nm and achieves enhanced catalytic activity for hydrogenation of nitrobenzene to aniline compared with Raney Ni.

Abstract: Monodispersed and nano-sized Ni powders were synthesized from aqueous Ni sulfate hexahydrate (NiSO4· 6H2O) inside sucrose as a nonionic polymer network by using wet chemical reduction process. The influence of a nonionic polymer network on the particle size of the Ni powders were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). The Ni powders obtained by adding of sucrose were nearly spherical in shape and seemed to be nano-sized, typically in the range of 100 nm with not being agglomerated. As the sucrose content increased, the particle size of Ni powders steeply decreased and reached the minimum value, however, the particle size increased again with a further increase of sucrose content. This is believed to be due to the pore size of the swollen polymer network. As a result, the particle size of the Ni powders prepared by the reduction inside polymer network was strongly dependent of the sucrose content.