Intrinsic reduction kinetics of MoO3 by hydrogen

The reduction kinetics of MoO3 shallow powder beds by hydrogen was investigated by isothermal and non-isothermal thermogravimetric technique. The isothermal reduction was carried out in the temperature range 823 to 973 K, whereas in the case of non-isothermal experiments, the reduction was studied by heating the sample from room temperature up to 1073 K with temperature ramps from 8 to 15 K/min. A mathematical expression based on the chemical reaction control was used to evaluate the activation energy from the non-isothermal experimental data. It was found that the chemical reaction was the rate-controlling step at the beginning of the reduction process. The activation energy for this step evaluated from the isothermal data was found to be 175 kJ/mol, which is in an excellent agreement with the value obtained from the non-isothermal data, 172 kJ/mol.