The nanoparticles of Ni-Co alloy/MgAlOx nanosheets were supported on monolithic macroporous gamma-Al2O3 by calcining and reducing a layered double hydroxide which contains elements of Mg, Ni, Co and Al. This precursor was in situ grown on the macropores' walls of the gamma-Al2O3 support by sharing the sole Al source. The catalysts and their precursors were characterized by using the techniques of XRD, TPR, TEM, SEM, ICP-OES, TG and N-2 adsorption/desorption. The results indicate that small Ni Co alloy nanoparticles were highly dispersed on the MgAlOx nanosheets and the porous structure with the open access of active sites should be beneficial for the mass transfer. The resultant catalysts exhibited excellent catalytic performance for ethanol steam reforming. The new preparation approach described here provides a practical and efficient method to support nano-bimetallic catalysts. The results suggest that this type of material possesses tremendous potential for future applications. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.