By performing first-principles calculations, H-2 splitting processes on pure and transition metal (TM) atom substituted Al (111) surfaces were examined. Corrected reaction pathways with splitting energy barriers (0.99 eV) lower than those in previous studies (1.28 eV) were obtained. By further analyzing the H-2 splitting process on the 3d-TM-atom-doped Al (111) surface, the relationship of the catalysis effect and the electron donation-back donation process on TM 3d orbitals were examined in detail. Finally, to confirm the possibility of reducing the partially oxidized Al (111) surface with an H2 molecule, the surface reduction process was studied by using the climb-image nudged elastic band (CI-NEB) method systematically. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.