Morphology Modification of MoO₃ Powders by Hydrogen Reduction and Re-Oxidation Process

An optimum route to fabricate the MoO₃ nanoparticles with modified morphology was investigated. Microstructure analysis for the MoO₃ powder prepared by high-energy ball milling process for 25 h showed that the plate-shaped raw powders are mostly converted into equiaxed fine particles, but exist as large agglomerates. However, the powder fabricated by the hydrogen reduction at 775℃ of raw powder and re-oxidation at 450℃ exhibits equiaxed fine particles with a size of about 260 nm and relatively small agglomerates. Additionally, the re-oxidized particles show a unimodal particle size distribution with measured values ranging from 0.18 to 0.42 µm. These results indicated that the reduction and re-oxidation process can significantly decrease the particle size and modify the powder morphology into an equiaxed shape.