The mechanism of reduction of iron oxide by hydrogen

Precipitated iron oxide samples were characterized using temperature-programmed reduction. H2 was used as the reduction agents. The two-stage reduction was observed: Fe2O3 was reduced to Fe3O4 and then reduced to metallic Fe. The activation energy for the two reduction steps of iron oxide are 89.13 and 70.412 (kJ mol−1), respectively. The simulation by reduction models of the TPR patterns presents well fitting of unimolecular model for Fe2O3→Fe3O4 reduction and two-dimensional nucleation according to Avarmi–Erofeev model for Fe3O4→Fe.