Redox reactions in liquid plasma during iron oxide and oxide-hydroxide nanoparticles synthesis

Abstract

A new synthesis method of iron oxide and iron oxide-hydroxide nanoparticles by pulsed liquid plasma process is presented. The redox reaction rates in liquid phase depend on the relative number densities of oxygen and hydrogen atoms produced in plasma gas phase and on the injected energy per pulse. The oxidation rate was higher than the reduction one in both regimes of plasma operation as glow and arc discharge. An oxidation rate of 0.13 μg mL −1 s −1 and a reduction rate of 0.04 μg mL −1 s −1 of iron ion during the process were obtained when plasma operates in glow discharge regime. The α-Fe 2O 3 and β-FeO(OH) nanoparticles of 80 nm size with a rice-shape morphology can be rapidly synthesized using low energy injected in plasma.