Kinetics of gas phase reduction of nickel chloride in preparation for nickel nanoparticles

We investigated the chemical kinetics of NiCl₂ reduction to apply to the synthesis of nickel nanoparticles in a tubular furnace reactor. The conversion of NiCl₂ increased monotonically with reaction temperature up to 99% at 950 °C, and in turn, the rate constant of the reaction increased from 78 to 286 with an increase in the temperature from 800 to 950 °C. The reaction rate was estimated to be the first order with respect to chloride concentration, and the rate constant obeyed the Arrhenius law, of which the activation energy and pre-exponential factor were 103.79 kJ/mol and 7.34 × 10⁶ min⁻¹, respectively. Taking advantage of the kinetics, we synthesized crystalline nickel nanoparticles with average primary particle size ranging from 31 to 106 nm by systematically controlling the reactor temperature and chloride concentration.