Preparation and characterization of well-defined colloidal nickel compounds

✍ Scribed by Lily Durand-Keklikian; Ikramul Haq; Egon Matijević

• Book ID: 103967029
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 529 KB
• Volume: 92
• Category: Article
• ISSN: 0927-7757
• DOI: 10.1016/0927-7757(94)02952-0

✦ Synopsis

Uniform colloidal particles of nickel compounds were obtained by aging at elevated temperatures solutions of different nickel salts in the presence of NH,OH, NaOH or urea . The morphology of the resulting dispersed precipitates was dependent on the nature of the base and on the anions present in the reacting systems . Thus, aging Ni(NO 3 )2 solutions containing NH,OH yielded green platelet-type Ni(OH),, particles in the 80 nm size range, whereas in the presence of urea much larger (several microns) particles of similar morphology were generated. In contrast, NiSO,-urea solutions produced large spherical particles which were composed of clearly discernible subunits . On calcination at temperatures of 300°C or above, all original solids transformed into NiO in mixture with a small amount of Ni,O, . The optical properties of the final products were evaluated as a function of the wavelength .