The thermochemical two-step water-splitting cycle using transition element-doped cerium oxide (M CeO2-delta; M=Fe, Co, Ni, Mn) powders was studied for hydrogen production from water. The oxygen/hydrogen productivity and repeatability of M CeO2-delta materials with M doping contents in the 5-15 mol% range were examined using a thermal reduction (TR) temperature of 1500 degrees C and water decomposition (WD) temperatures in the 800-1150 degrees C range. The temperature, steam partial pressure, and steam flow rate in the WD step had an impact on the hydrogen productivity and production rate. 5 mol% Fe- and Co-doped CeO2-delta enhances hydrogen productivity by up to 25% on average compared to undoped CeO2, and shows stable repeatability of stoichiometric oxygen and hydrogen production for the cyclic thermochemical two-step water-splitting reaction. In addition, 5 mol% Mn-doped CeO2-delta, 10 and 15 mol% Fe- and Mn-doped CeO2-delta show near stoichiometric reactivities. (C) 2015 Elsevier B.V. All rights reserved.