A series of activated Mg-based alloys with low-melting-point metals (Zn, Sn, Bi, and In) are prepared by ball milling and characterized by scanning electron microscope and X-ray diffraction. Their hydrogen generation properties are systematically investigated in seawater and methanol. The results demonstrate that the addition of low-melting-point metals can significantly accelerate the reaction of magnesium with seawater and methanol. The alloy Mg-10%In exhibits the excellent hydrolysis properties among all the samples with the maximum hydrogen generation rate of 7.4 mL g(-1) s(-1) and the hydrogen conversion yield of 93% at 30 degrees C in seawater. The excellent hydrolysis performance of Mg-10%In can be attributed to its lower activation energy, lower corrosion potential, and higher corrosion current density. Moreover, the active preservation method of activated Mg alloys by coating dioctyl sebacate is studied. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.