Solid solutions of hematite (alpha-Fe2O3) and corundum (alpha-Al2O3) have been synthesized by coprecipitation. The resulting particles have been used as oxygen carriers for the production of hydrogen by chemical looping and characterized using X-ray diffraction (XRD), temperature programmed reduction (TPR), specific surface area measurements (BET), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDXS). The particles were repeatedly (i) reduced with, e.g., CO to, nominally, Fe, (ii) then oxidized with steam to Fe3O4 to produce hydrogen, (iii) then returned to Fe2O3 by oxidizing with air. The optimum loading of Al2O3 in the composite particles was found to be 25 wt % for the production of hydrogen over 50 cycles, resulting in an average yield (mole H-2 formed/theoretical amount possible on reduction to Fe and oxidation to Fe3O4) of hydrogen of similar to 48%. It was found that although Al2O3 is often thought of as inert, it participates in the oxidation and reduction reactions by forming FeAl2O4 and various solid solutions with the iron oxides. This behavior has been explained with the help of phase diagrams, and the applicability of these particles for the production of hydrogen by chemical looping is discussed.