Density functional theory study for the influence of non-metals doping on the structural, electrical, optical, and photocatalytic properties of rutile TiO2

In this study, the influence of non-metals (C, F, N, and S) doping on the structural, electronic, and optical properties of rutile TiO ₂ is investigated by introducing Hubbard correction (U) to the density functional theory (DFT) by adopting the Quantum ESPRESSO code. Rutile TiO ₂ is a promising material with potential applications in environmental remediation and renewable energy production, such as solar energy and fuels. However, its large bandgap limits these applications to UV-light regions only. In this work, a single atom of each dopant was replaced at oxygen atom sites to shift the absorption edge of rutile TiO ₂ toward visible light. From the computed band structures, the obtained bandgap of pure rutile TiO ₂ is 3.03 eV, which agrees well with the experimental value. Except for F-doped TiO ₂ , the bandgap of other doped materials showed a redshift. The imaginary part of dielectric function peaks indicates that the absorption edges in C, N, and S-doped TiO ₂ are shifted toward the visible region. The shift in absorption coefficient to the highest wavelength in C, N, and S-doped TiO ₂ reveals the suitability of these materials for photocatalysis applications. The increase in refractive index after doping indicates the existence of excess charges that attenuate the transverse of light in materials. Moreover, this work is extremely important for experimentalists in order to guide them in understanding the effects of non-metal doping on the properties of rutile TiO ₂ for photocatalysis applications.