Boron doped titaniumdioxide nanotube arrays: production,characterization and photocatalytic properties

In numerous studies, regularly oriented anatase titanium dioxide nanotube arrays (TNTAs), obtained through electrochemical anodization, have been employed as catalyst surfaces for photocatalytical applications. However, in many practical applications the phocatalytical activities are restricted due to their wide band gaps. This work shows that photocatalytical activity of TNTAs can be improved by a novel approach which provides boron incorporation into TiO₂ structure during anodization process without any further treatment. Anodization was performed in an aqueous solution containing hydrofluoric acid, oxalic acid and sodium fluoroborate (NaBF₄) at room temperature on titanium (Gr2) substrates. The anodized samples were annealed at 480?°C for 2 h in air in order to obtain anatase transformation and intended crystalline structure. As-prepared B-doped TNT structure was characterized by field emission scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, atomic force microscopy and ultraviolet–visible light diffuse absorbance spectroscopy. The photocatalytic kinetics of B-doped TNTAs for the degradation of methylene blue (MB) under visible light irradiation were evaluated in details.