A novel and economical method for preparing CaO-based high-temperature CO2 absorbents for sorption-enhanced hydrogen production is introduced. CaO-MgO absorbents prepared by the co-precipitation method show excellent cyclic stability but poor absorption capacity (similar to 8-14 g CO2/100 g absorbent). An additional hydration process provided spacious CO2 pathways resulting in a significant increase of the absorption capacity (similar to 17.4-47.8 g CO2/100 g absorbent) with excellent cyclic stability. As the MgO content increased, the absorption ratio of the absorbent and the degree of CaO conversion also increased. In addition, XRD analysis revealed that the hydration process followed by calcination at 900 degrees C led to the formation of a partial solid solution in the CaO-MgO absorbent containing 25 wt% MgO. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.