Al-water reaction promoted by catalysts is a promising hydrogen generation technology. In this work, a high-activity M-B/gamma-Al2O3 (M = Co, Ni) catalyst is prepared by wet chemical reduction method. It is found that M-B/gamma-Al2O3 catalyst significantly promotes the Al-water reaction and decreases the induction time. When the molar ratio of gamma-Al2O3 to Co-M in Co-B/gamma-Al2O3 catalyst is 1:1, the induction time is only 0.43 h. The catalytic activity of M-B/gamma-Al2O3 is proportional to its active area. SEM analyses show that M-B particles are dispersed on gamma-Al2O3 surface, which reduces the agglomeration of M-B and increases the active surface of M-B/gamma-Al2O3, leading to a high catalytic activity. A possible mechanism is proposed, which shows that the dissociation of water molecules on gamma-Al2O3 surface and the microgalvanic interaction between M-B and Al can promote the hydration process of passive oxide film on Al particle surface, speeding up the Al-water reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.