The structural "memory effect" of a hydrotalcite (HT)-derived mixed oxide is utilized to prepare a shell-core Ni/Mg-Al catalyst for ethanol steam reforming (ESR). The reconstruction proceeds rapidly in a Ni2+ nitrate solution on the outer layer of the Mg-Al mixed oxide particle, being accompanied with the growth of large flake-like sheets. A part of Ni2+ ions can incorporate into the reconstructed HT-like structure, leading to the formation of the shell-type Ni loading catalyst after calcination. At 700 degrees C, the shell-core catalysts with much lower Ni contents perform better activities than that of the bulk Ni/Mg-Al catalyst prepared directly via the calcination of the HT-like precursor. Further investigations reveal that temperature and space-time significantly affect the contribution of WGS, CH4 reforming reactions to the product distribution in the ESR reaction. Most interestingly, C2H4 is observed in the reactions carried out at 700 degrees C and very low space-time. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.