MECHANOCHEMICALLY INDUCED SYNTHESIS OF La2O3

Abstract

Lanthanum(III)-oxide (La2O3) powders were synthesized by a mechanochemically induced solvent-deficient method using lanthanum nitrate, and ammonium bicarbonate as precursors. The precursor mixture was calcined for one hour at either 600 or 800 °C. This study included an investigation of the formation reactions, crystal structure, specific surface area, and optical properties of synthesized La2O3. The proposed mechanism indicates a complex synthesis with several reactions, some of which are mechanochemically induced. The size of the La2O3 nanocrystallites, as determined by XRD, is 22.15±3.9 nm (by using the Williamson-Hall plot, it is determined that the strain is 1.4×10−3 and crystallite size 30.81 nm) while the specific surface is set to 7.04 m2g-1. The direct bandgap value obtained from reflectance measurement is determined to be 5.37 eV.