Preparation of Ultrafine β-MoO₃ from Industrial Grade MoO₃ Powder by the Method of Sublimation

Abstract

This study reports a novel strategy to obtain ultrafine metastable monoclinic molybdenum trioxide (β-MoO 3 ) powder by the method of sublimation in the temperatures range of 1123–1373 K using the industrial grade MoO 3 as raw material. The vapor-phase MoO 3 could rapidly condensate and deposit in the bag filter after being quenched. It is found that the particle size has no obvious regularity with the sublimation temperature and the as-prepared β-MoO 3 appears to be perfectly spherical. Impurities such as SiO 2 in raw MoO 3 samples have a significant retarding influence on the sublimation rate. Both the mechanisms of sublimation of industrial grade MoO 3 as well as the nucleation and growth process of ultrafine β-MoO 3 have been shed light. This work may have a guide role in the large-scale production of ultrafine spherical β-MoO 3 catalyst.