An electrochemical strategy of doping Fe 3+ into TiO 2 nanotube array films for enhancement in photocatalytic activity

Abstract

Highly ordered Fe 3+-doped TiO 2 nanotube array films were fabricated directly by the electrochemical anodic oxidation of pure titanium in an HF electrolyte solution containing iron ions. The morphology, structure and composition of the as-prepared nanotube array films were characterized by SEM, Raman and XPS. The effects of dopant amount on the morphologies, structure, photoelectrochemical property and photoabsorption of the TiO 2 nanotube array film were investigated. The results showed that Fe 3+ was successfully introduced into the nanotube array film. Compared with the undoped TiO 2 nanotube array film, the photocurrent of Fe 3+-doped TiO 2 nanotube array films increased obviously. The absorption edge of Fe 3+-doped TiO 2 nanotube array films appeared to be red shifted. The photocatalytic activity of Fe 3+-doped TiO 2 nanotube array films was evaluated by the removal of methylene blue (MB) aqueous solution. A maximum enhancement of photocatalytic activity was achieved for Fe 3+-doped TiO 2 nanotube array film prepared in 0.10 M Fe(NO 3) 3+0.5% HF electrolyte under UV irradiation, which attributes to the effective separation of photogenerated electron–hole upon the substitutional introduction of appropriate Fe 3+ amount into the anatase TiO 2 structure.