Thermochemical two-step water-splitting using CeO2 (cerium oxide) particles was studied to examine oxygen and hydrogen productivity and repeatability at thermal reduction (T-R) temperatures of 1300-1550 degrees C and water decomposition (W-D) temperatures of 400-1000 degrees C for the production of hydrogen from water using concentrated solar radiation as the energy source. The temperature dependency of oxygen and hydrogen productivity and the cyclic repeatability of CeO2 are reported in this paper. The characteristic features of CeO2 particles in the thermochemical two-step water-splitting cycle are compared with the well-known highly active reactive mediums of zirconia-supported Ni-ferrites (NiFe2O4/m-ZrO2 and NiFe2O4/c-YSZ) and unsupported NiFe2O4. Copyright (C) 2013, Hydrogen En ergy Publications, LLC. Published by Elsevier Ltd. All rights reserved.