Hydrogen production by water splitting with MnFe2O4/Na2CO3 system was studied at 973 K. An intermediate phase, resulting from decarbonatation of MnFe2O4/Na2CO3 mixture in inert atmosphere, proved to be effective in hydrogen reduction from water with stoichiometric yield. The presence of a highly reactive intermediate phase suggests the feasibility of a high efficiency, three-step, thermochemical cycle for hydrogen production. In fact, the possibility of obtaining CO2 separately from the gases mixture dramatically enhances process efficiency. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.