Monodisperse CuNi nanoparticles are conveniently prepared by the reduction of cupric acetate and nickel(II) acetylacetonate in the presence of oleylamine and borane tributylamine under inert gas atmosphere. It is found that among the CuNi system, Cu0.9Ni0.1 shows the best performance for catalyzing the dehydrogenation of ammonia borane. In total, 2.5 equiv. of hydrogen per ammonia borane is generated even at room temperature with an initial turnover frequency value of 212.3 mol of H-2 (mol of Cu0.9Ni0.1)(-1).h(-1), which is comparable to the best Pd-based catalyst ever reported. The remarkable catalytic performance is attributed to the mild affiliation of oleylamine (OAm) to NPs, which not only stabilizes NPs to maintain good dispersion but also leaves sufficient surface active sites to facilitate the catalytic reaction. This low-cost and high catalytic performance catalyst makes it an exciting alternative towards the application of ammonia borane as a hydrogen storage material for fuel cell applications. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.