Effect of synthesis conditions on preparation of nickel metal nanopowders via hydrothermal reduction technique

Synthesis of nickel nanopowders from aqueous solution using hydrothermal reduction method with hydrazine hydrate as a reducing agent and Cetyl trimethyl ammonium bromide (CTAB) as a surfactant was investigated. Statistical design was used to study the effects of reaction time, concentration of nickel chloride, and concentration of surfactant on the nickel particles size. Formed nickel particles were characterized using XRD and SEM. The formation of nickel single phase was revealed from XRD patterns. On the other hand, SEM showed that the nickel particles are in nanosized ranges from 55 nm to 250 nm. The analysis of the results indicated that the reaction time and surfactant addition were the controlling factors. The reduction of nanocrystalline nickel hydroxide Ni(OH) 2 into Ni is the possible formation mechanism. 3-D cubic graph for Ni particle size in studied regions revealed that particle size, which ranged from 35–225 nm could be produced. The smallest particle size 35 nm can be obtained at two different conditions, i.e., at high levels and low levels of main parameters. On the other hand, the highest particle size, 225 nm, can be achieved at high level of reaction time and low levels of both NiCl 2 and surfactant concentrations. [Display omitted]