A sol–gel route using propylene oxide as a gelation agent to synthesize spherical NiAl 2O 4 nanoparticles

Abstract

Spherical NiAl 2O 4 nanoparticles with large surface area were successfully synthesized by a sol–gel method using propylene oxide as a gelation agent. The formation process of the resulting nanoparticles is described and characterized by TG-DTA, XRD, BET and TEM. A pseudo-spinel structure was formed at 700 °C and a spinel NiAl 2O 4 structure was formed at 800 °C by the reaction of NiO at the surface of amorphous alumina particles. It was found that the presence of NiO or NiAl 2O 4 on the surface of the alumina retards the crystallization of amorphous alumina to γ-Al 2O 3. The obtained nanoparticles experienced the decrease of particle size from 700 to 800 °C accompanying the structure transformation from pseudo-spinel to NiAl 2O 4 spinel.