Original synthesis of chromium (III) oxide nanoparticles

Nanosized chromium (Cr2O3) oxide was prepared by the common thermal decomposition of Cr(NO3)3·9H2O chromium (III) nitrate nonahydrate. Prior to the heat treatment at 550 °C, the commercial reagent was first dissolved in a colloidal silica solution and then dried at a low temperature to slowly evaporate the aqueous solvent. The SiO2/Cr(NO3)3·9H2O weight ratio (R) was changed from 0 to 2. The various Cr2O3 powders were characterized by XRD, FTIR, nitrogen adsorption, SEM and TEM techniques. A maximum specific surface area of 113 m2 g−1, associated with a pore volume of 0.72 cm3 g−1, was obtained for the Cr2O3 powder prepared with R = 2. These pristine chromium oxide nanoparticles, with a slightly sintered sphere-shaped morphology, exhibited a 10 nm particle size with a monocrystalline character as demonstrated by the TEM and XRD correlation.