We reported the synthesis and characterization of two trimetallic (Ag@CoFe, and Ag NiFe) core-shell nanoparticles (NPs), and their catalytic activity toward hydrolytic dehydrogenation of ammonia borane (AB) and methylamine borane (MeAB). The as-synthesized trimetallic core-shell NPs were obtained via a facile one-step in situ procedure using methylamine borane as a reducing agent and graphene as the support under ambient condition. The as-synthesized NPs are well dispersed on graphene, and exhibit higher catalytic activity than the catalysts with other conventional supports, such as the SiO2, carbon black, and gamma-Al2O3. Additionally, compared with NaBH4 and AB, the as-synthesized ApCoFe/graphene NPs reduced by MeAB exhibit the highest catalytic activity, with the turnover frequency (TOP) value of 82.9 (mol H-2 min(-1) (mol Ag)(-1)), and the activation energy (E-a) value of 32.79 kJ/mol. Furthermore, the as-prepared NPs exert good durable and magnetically recyclability for the hydrolytic dehydrogenation of AB and MeAB. Moreover, this simple strategic synthesis method can be easily extended to the facile preparation of other graphene supported multi-metal core shell NPs. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.