CeO2 modified Fe2O3 for the chemical hydrogen storage and production via cyclic water splitting

•Fe–Ce chemical interaction could counteract sintering of materials.•Fe–Ce mixed oxides decreased the reaction temperatures of redox process.•Ce–Fe mixed oxides showed good activity for hydrogen production.

The chemical hydrogen storage (hydrogen reduction) and production (water splitting) behaviour of Ce-modified Fe2O3 mixed oxides were investigated. Fe1−xCexO2−δ (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4 and 1) oxides prepared by chemical precipitation were characterized by XRD (X-ray diffraction), H2-TPR (hydrogen temperature-programmed reduction) and H2O-TPO (steam temperature-programmed oxidation) tests. XRD results showed that two kinds of Fe–Ce–O solid solutions (Ce-based and Fe-based) coexisted in Fe–Ce mixed oxides. H2-TPR experiment suggested that Ce addition could reduce hydrogen reduction temperature while H2O-TPO experiments over reduced oxides showed that Fe–Ce mixed oxides could split water to produce hydrogen at a lower temperature and complete in a shorter time. Both redox reactions (hydrogen reduction and water splitting) were sensitive to the temperature and active at a high temperature. The successive redox cycles were carried out over the Fe0.7Ce0.3O2−δ mixed oxide at 750 °C. It kept a stable production of hydrogen in the successive redox process at the condition of serious agglomeration of the materials. The highest hydrogen storage amount was up to 1.51 wt% for the Fe–Ce sample with a 30% substitution of Ce for Fe.