Rate control mechanism for the hydrogen reduction of MoO3 to MoO2

The rate control mechanism for the reduction of MoO3 to MoO 2 is estimated based on shrinking core model (SCM). The rate controlling step for reduction is either the diffusion of reducing gas or the actual chemical reaction between reducing gas and metal oxide. The experimental data follows the trend for reduction mechanism controlled by diffusion of reactant gas through outer gas film. The finding is in very good agreement with general understanding of the reduction mechanism of MoO3. It is widely accepted that the reduction of MoO3 is controlled by chemical vapor transport and progresses from outside to the inside of the MoO3 particles. It is concluded for the analysis that the reduction of MoO 3 follows by a shrinking core model with the reduction gas transport being the rate limiting mechanism.