Mechanically treated aluminum-tin (Al-Sn) alloy, a novel hydrogen-generating material, was fabricated and found to react directly and immediately with water at room temperature. The maximum yield of hydrogen per unit volume of alloy was 2259 mL/cm(3) (0.202 g/cm(3)). The mass ratio of the generated hydrogen and the Al-Sn alloy material was 4.86%. This percentage is much higher than that of traditional hydrogen storage alloys and can compete with metal hydrides. The combination of Al-Sn alloy powder and carbon nanotubes (CNTs) produced a new kind of Al-Sn/CNT composite that also reacts with water at room temperature. Al-Sn/CNT composites were synthesized using a high temperature and high-pressure method. When CNT content was held constant, composites with single-walled CNTs had higher reaction rates than those with multi-walled CNTs. The effects of mechanical treatment and CNT addition on enhancing the reaction between Al-Sn alloys or Al-Sn/CNTs and water were also analysed. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.