Influence of molybdenum on the stability of iron oxide materials for hydrogen production with cyclic water gas shift process

The redox behavior of iron oxide modified with various amount of molybdenum (Mo) was investigated in the present study. The modified iron oxides were prepared by co-precipitation using urea hydrolysis method. The influence of Mo on the hydrogen production capacity and the material stability was studied in detail employing temperature-programmed reduction (TPR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET analysis. Furthermore, the activity and the stability of the samples were tested in repeated reduction and re-oxidation for 100 cycles with diluted H2 and H2O. The results indicate that Mo enhances the stability of iron oxide material by mitigating the sintering process. The positive influence of Mo in stabilizing the iron oxide material is attributed to the dispersion of Fe–Mo oxide material. The dispersion in turn inhibits the neck formation responsible for the sintering.