Defect induced enhanced catalytic activity of Lu doped titanium dioxide (TiO₂) thin films

In this article, we report the property evaluation of Lu doped TiO₂ thin films suitable for catalytic activity. The detailed investigation on the film's structural, optical, and chemical properties was carried out. The structural study using XRD and Raman reveal presence of dominant crystalline anatase phase for Lu doped samples. The spherical grains were observed on the surface of Lu doped films and these act as active centres during catalytic activity. XPS analysis confirm the chemical states of basic elements including Ti, O, and Lu, and a brief discussion on enhanced defects on doping using anion and cation core level spectra is described. Moreover, modified Auger parameter and change in chemical bonding interaction energy also strongly supports enhanced defects in the material. These defect centres may act as a trapping core, extending carrier recombination and increasing photocatalytic activity. Under UV irradiation, sample's photocatalytic performance was tested for methyl orange and methylene blue target dyes. Among the samples deposited, 0.4 at% Lu doped films perform better as a photocatalyst, with high degradation efficiency, high reaction rate, and short half-life time.