A Ni-nano-CaO sorption complex catalyst was modified with ZrO(2) to improve its stability for use in hydrogen production from steam methane reforming (SMR). Nano-ZrO(2) was introduced into a support containing nano-CaCO(3) and Al(2)O(3). The sorption complex catalyst, ZrO(2)-Ni-nano-CaO, was prepared by infusing Ni into the ZrO(2)-nano-CaO support, followed by calcination. The catalyst was evaluated with a bench-scale fixed bed reactor under the following reaction conditions: a temperature of 600 degrees C, a steam-carbon mole ratio of 4:1, a gas hourly space velocity of 1800 h(-1), and a regeneration temperature of 800 degrees C. The reaction was performed under an atmosphere of nitrogen. The ZrO(2)-modified sorption complex catalyst could achieve 20 cyclic runs of ReSER hydrogen production, while the sorption complex catalyst without the ZrO(2) modification rapidly deactivated after three cyclic runs. Brunauer Emmer Teller analysis showed that the catalyst surface area of the new catalyst had increased. Furthermore, the addition of ZrO(2) could prevent the formation of NiAl(2)O(4) in the sorption complex catalyst, which we believe to be the main cause of the improvement in the catalyst stability. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.