MCM-41 supported Co, Mo and Co-Mo bimetallic catalysts with different Co/Mo atomic ratios were prepared by incipient wetness impregnation, and the channels of MCM-41 acted as nano-reactor. The catalysts without pre-nitridation treatments were directly used to catalyze ammonia decomposition. The characterization of the catalysts was carried out by N-2 physisorption, H-2-TPR, Raman, XRD, TEM and XPS. The results show that the catalysts have the similar size distribution of metallic particles. Due to the synergistic effect between Co and Mo, MCM-41 supported Co-Mo bimetallic catalysts show higher ammonia decomposition activity compared to Co or Mo alone. The Co-Mo bimetallic catalyst with the Co/Mo atomic ratio of about 7/3 exhibits the highest NH3 conversion. Moreover, the Co7Mo3/MCM-41 catalyst shows good thermal stability. (C) 2012 Elsevier B.V. All rights reserved.