Hydrogen production from water decomposition by redox of Fe2O3 modified with single- or double-metal additives

Iron oxide modified with single- or double-metal additives (Cr, Ni, Zr, Ag, Mo, Mo–Cr, Mo–Ni, Mo–Zr and Mo–Ag), which can store and supply pure hydrogen by reduction of iron oxide with hydrogen and subsequent oxidation of reduced iron oxide with steam (Fe3O4 (initial Fe2O3)+4H2↔3Fe+4H2O), were prepared by impregnation. Effects of various metal additives in the samples on hydrogen production were investigated by the above-repeated redox. All the samples with Mo additive exhibited a better redox performance than those without Mo, and the Mo–Zr additive in iron oxide was the best effective one enhancing hydrogen production from water decomposition. For Fe2O3–Mo–Zr, the average H2 production temperature could be significantly decreased to 276 °C, the average H2 formation rate could be increased to 360.9–461.1 μmol min−1 Fe-g−1 at operating temperature of 300 °C and the average storage capacity was up to 4.73 wt% in four cycles, an amount close to the IEA target.