Effect of low Fe 3+ doping on characteristics, sonocatalytic activity and reusability of TiO 2 nanotubes catalysts for removal of Rhodamine B from water

Abstract

Fe-doped titanium dioxide (TiO 2) nanotubes were prepared using sol-gel followed by hydrothermal methods and characterized using various methods. The sonocatalytic activity was evaluated based on oxidation of Rhodamine B under ultrasonic irradiation. Iron ions (Fe 3+) might incorporate into the lattice and intercalated in the interlayer spaces of TiO 2 nanotubes. The catalysts showed narrower band gap energies, higher specific surface areas, more active surface oxygen vacancies and significantly improved sonocatalytic activity. The optimum Fe doping at Fe:Ti=0.005 showed the highest sonocatalytic activity and exceeded that of un-doped TiO 2 nanotubes by a factor of 2.3 times. It was believed that Fe 3+ doping induced the formation of new states close to the valence band and conduction bands and accelerated the separation of charge carriers. Leached Fe 3+ could catalyze Fenton-like reaction and led to an increase in the hydroxyl radical (OH) generation. Fe-doped TiO 2 nanotubes could retain high degradation efficiency even after being reused for 4 cycles with minimal loss of Fe from the surface of the catalyst. © 2012 Elsevier B.V.