Composition controllable monodisperse palladium tin nanoparticles (PdxSn100-x NPs, x = 77, 69, 63, 52, 49) were prepared by the thermal reduction of palladium bromide and tin acetate in the presence of trioctylphosphine and oleylamine. The NPs were investigated for their catalytic abilities of hydrogen generation from hydrolysis of ammonia borane complex. Deposited on a carbon support without any further treatment, these NPs were active nanocatalysts for hydrolysis of ammonia borane complex, and their catalytic activities were highly composition dependent. Among these NPs studied, Pd69Sn31 NPs exhibited the highest catalytic activity and stability under mild reaction conditions. Kinetic investigations showed that the catalytic hydrolysis of ammonia borane was first-order with respect to catalyst concentration and zero-order with respect to ammonia borane concentration. The activation energy for the hydrolysis of ammonia borane complex in the presence of Pd69Sn31 NPs was calculated to be 27.22 kJ mol(-1). The PdxSn100-x NPs are promising candidates toward the practical development of the ammonia borane complex as a feasible hydrogen storage medium for fuel cell applications under ambient conditions. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.