A three-step reaction for the complete extraction of H-2 from H2O molecule using a small Al6Si cluster is determined based on first-principle calculations. All reactants, products, and transition states are found through optimization calculation and confirmed frequency analysis. The intrinsic reaction coordinate is also calculated to validate the reaction process. Charge distribution is used to analyze the novel reaction. The present results show that the entire reaction can be actively started when the H2O molecule is adsorbed on Al6Si cluster because the barrier of the first transition state only 0.1448 eV and the whole process is an exothermic reaction when zero-point energy is included. It is found that Al6Si cluster can strongly capture H2O molecule, as well as extract and store the H-2 molecule, at a favorable temperature. This result may serve as a basis for the development of a more efficient method of generating and storing H-2 from H2O molecule. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.