The Ti catalyst doped in the vicinity of surface step could split H-2 with 0.37 eV activation energy and the resulting hydrogen atom could diffuse by overcoming 0.45 eV barrier. Our analysis on the energies of the Ti doping and the surface etching phenomenon suggest that Ti can remain as recycling active catalyst during the aluminum hydrogenation. The electronic properties of the intermediate state could account for the enhanced splitting properties. These studies on the role of surface step could contribute to the understanding of the mechanism of transition metal catalyzed hydrogen uptake in aluminum. (C) 2013 Elsevier B.V. All rights reserved.