Redox materials with high thermal stabilities, comprising iron oxide with alumina were synthesized from ultrasonic spray pyrolysis method. Their catalytic activities towards the redox evolution of hydrogen from water were evaluated and compared with that of pure iron oxide, which decreased rapidly after 1 cycle due to its low thermal stability. The samples containing alumina sustained their total and relative hydrogen evolutions over three redox cycles, while maintaining their original surface morphologies, thus demonstrating their thermal stability. (C) 2012 Elsevier Ltd. All rights reserved.