Facile fabrication, characterization, and enhanced photoelectrocatalytic degradation performance of highly oriented TiO2 nanotube arrays

Highly ordered TiO2 nanotube arrays were successfully fabricated using ethanol and water mixture electrolytes (40 vol% ethanol and 0.2 wt% hydrofluoric acid) by a facile electrochemical anodization method. The as-prepared nanotube arrays were grown perpendicular to the titanium substrate with about 90 nm in diameter, 20 nm in wall thickness, and around 500 nm in length. The formation mechanism of the samples is briefly discussed. A blue shift in the spectrum of UV-Vis absorption was observed with respect to a piece of the sol-gel derived TiO2 film. Moreover, photocurrent response and photoelectrocatalytic degradation of methyl orange under ultraviolet light irradiation were adopted to evaluate the photoelectrocatalytic properties of the TiO2 nanotube arrays. We demonstrate that the highly ordered TiO2 nanotube arrays possess much better photoelectrocatalytic activity than the sol-gel derived TiO2 film and good stability.