Nanoneedles of Lanthanum Oxide (La₂O₃): A Novel Functional Material for Microwave Absorber Material

Abstract

Synthesis and characterization of La2O3 nanoneedles have been successfully carried out by using hydrolysis reaction with NH4OH as a solvent. La2O3 was prepared from LaCl3 solution. LaCl3 was preheated on a hotplate and stirred by using a magnetic stirrer, then added solution of NH4OH 1 M with the variation speed drops of 3 ml, 6 ml and 9 ml to obtain white precipitation La(OH)3 until a pH of 9. Stirring was continued until 1 hour. A white precipitate formed is separated from the effluent by centrifugation method with 3000 rpm and neutral pH. Then, the precipitate was dried in an oven at a temperature of 70 °C and sintered at 1000 °C to get La2O3 nanoneedles. The identification of sample phase was carried out by using X-ray diffractometer (XRD). The refinement results of X-ray diffraction pattern shows that the samples have a single phase of La2O3. The morphology of the nanoneedles was observed by using the transmission electron microscope (TEM). Meanwhile, the reflection and transmission of electromagnetic wave were measured by using the vector network analyzer (VNA) at X-band frequency.