TiO 2 Nanotubes: Nitrogen‐Ion Implantation at Low Dose Provides Noble‐Metal‐Free Photocatalytic H 2 ‐Evolution Activity

Low‐dose nitrogen implantation induces an ion and damage profile in TiO 2 nanotubes that leads to “co‐catalytic” activity for photocatalytic H 2 ‐evolution (without the use of any noble metal). Ion implantation with adequate parameters creates this active zone limited to the top part of the tubes. The coupling of this top layer and the underlying non‐implanted part of the nanotubes additionally contributes to an efficient carrier separation and thus to a significantly enhanced H 2 generation.