Surface step enhanced H2 splitting on Ti-doped Al(1Â 1Â 1) surface

► The doping of Ti in surface step region can gain ∼0.36 eV higher doping energy. ► Activation energy is reduced to as low as 0.45 eV for aluminum hydrogenation. ► Ti doped in the lowest energy structure could remain as recycling active catalyst. ► H2 in intermediate state gains 0.3 e charge due to Kubas interaction mechanism.