Optical and photocatalytic characteristics of Al and Cu doped TiO2: Experimental assessments and DFT calculations

The goal of this study is to investigate the effects of copper and aluminum atom doping on the microstructure, composition, optical, and photocatalytic characteristics of titanium dioxide (TiO2) films produced using the sol-gel method. The structural, morphological, optical, and photocatalytic properties of the films were thoroughly studied using XRD, SEM, XPS, and a UV-VIS spectrophotometer. Methylene blue aqueous solutions as artificial impurities were decomposed with the purpose of determination the photocatalytic performance of pure and doped TiO2 films under UV light irradiation. Anatase, the photocatalytically active phase of TiO2, was dominantly obtained for all samples. Based on the microstructural analysis, doping has no significant effects on the morphologies of the films. XPS results revealed that Cu and Al elements were incorporated into TiO2 phase. The optical band gap values of prepared films were decreased with the Cu and Al impurities as a result of optical measurements. Finally, doping process played an important role on enhancing the photocatalytic efficiency of the samples. Compared to Cu-doped TiO2, Al-doped TiO2 film performed the highest photocatalytic activity. In addition, density functional theory calculations were performed to analyze the impact of Al or Cu doping on the geometric, electronic structure and photocatalytic properties of TiO2.