The catalytic properties of single-phase Ni3Sn powder in the production of hydrogen via the decomposition of methanol were investigated in isothermal tests at 713, 793, and 873 K. The catalytic activity of Ni3Sn significantly increased with time at 793 and 873 K, but not at 713 K, suggesting that Ni3Sn is spontaneously activated at temperatures above 793 K. At these temperatures, Ni3Sn showed high selectivity for H-2 and CO production and low selectivity for CH4, CO2, and H2O production, indicating that methanol decomposition was the main reaction, and that side reactions such as methanation and water gas shift reaction were suppressed. Surface analysis revealed that fine Ni3Sn particles were formed during the reaction, accompanied by a small amount of deposited carbon. The formation of these particles was suggested to be the cause for the spontaneous activation of Ni3Sn. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved,