Carbon-Doped TiO2 Nanotube Array Platform for Visible Photocatalysis

Carbon-doped TiO2 nanotube arrays (NTAs) are fabricated by electrochemical anodization followed by annealing in argon without extrinsic precursors. Ethylene glycol (EG) from the electrolyte adsorbs onto the nanotube (NT) wall during anodization and serves as the carbon source. The C atoms are distributed uniformly along the entire nanotube surface forming C-doped TiO2 NTAs and the bandgap of the C-doped NTAs shifts towards the visible range. By removing the accumulated carbon around the mouth of the NT, the NTAs exhibit high visible light photocatalytic activity as a result of the high separation efficiency of photogenerated electrons and holes. The favorable properties stem from the synergistic effects between the carbon sensitizer and one-dimensional TiO2 structure.