Application of surfactants for the synthesis of qualitative hydroxide and metallic cobalt nanopowders
In this work, Co(OH)<sub>2</sub> nanopowders (NP) were obtained by chemical precipitation from aqueous solutions of cobalt nitrate Co(NO3)<sub>2</sub> and alkali NaOH (10 wt. %) using surfactants - sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC) (0.1 wt. %). Regardless of the preparation conditions, the Co(OH)<sub>2</sub> particles have the form of fiakes with an irregular shape and have a size in the nanometer range. It was shown that Co(OH)<sub>2</sub> NP obtained with the addition of 0.1 % SDS is the best quality product, since its dispersion increases by more than 2 times as compared to the samples obtained in the presence of 0.1 % CPC and without surfactants. The Co(OH)<sub>2</sub> NP synthesized under the condition of adding 0.1 % SDS was chosen to obtain metallic cobalt NP. It was found that for the Co NP sample obtained by hydrogen reduction of Co(OH)<sub>2</sub> NP with 0.1 % SDS at 280 °C, the maximum on the histogram of the particle size distribution is in the range 41-50 nm. The obtained Co NP is characterized by a narrow particle size distribution and represents spherical particles sintered with each other.