Ni/SBA-15 catalysts that are used in ammonia decomposition to produce COx-free hydrogen were prepared by a deposition-precipitation (DP) method and investigated by N-2 adsorption/desorption, XRD, TEM and H-2-TPR techniques. The results show that not only the nano-sized nickel particles with narrow distribution could be obtained, but also the ordered mesostructures of the Ni/SBA-15. catalysts could be achieved during the preparation process. The amount of formed nickel phyllosilicate increases with prolonging the DP time, while surface areas and pore sizes of samples decrease relatively. These Ni/SBA-15 catalysts exhibit higher performance than other Ni-based catalysts and even some supported Ru catalysts. Ammonia conversion is more than 96% at 873 K with GHSV(NH3) of 46,000 ml/h g-cat. Additionally, the Ni/SBA-15 catalyst is very stable during catalytic evaluation operation due to the strong interactions between nickel grains and SBA-15 support. (c) 2007 Elsevier B.V. All rights reserved.