Mechanism of Non-Contact Reduction of MoO3 to Prepare MoO2

In this present study, carbothermic reduction process of MoO3 to produce MoO2 has been carried to investigate the influences of reaction temperature and distance between activated carbon and MoO3 on phase composition of reduction products by controlling carbon diffusion. Results show that the reduction degree increases with the increase of temperature and the decrease of distance between activated carbon and MoO3. MoO3 can be completely reduced to MoO2 at 680°C with the carbon distance of 1 mm. It is found that the transformation from MoO3 to MoO2 is a process of crystal cracking and growth by observing the phase transition and morphological evolution during the reduction. The massive MoO3 is first decomposed into a platelet-shaped MoOx (2.75 < x < 3), then the platelet-shaped MoOx changes into a needle-like shape or irregular platelet-like Mo4O11, and finally Mo4O11 changes into irregular granular or irregular platelet-like shaped crystals, which form MoO2 powders.