Influence of cerium doping on the structural, electronic, and optical properties of rutile titanium dioxide: A DFT approach

This study employs density functional theory to explore the effects of cerium (Ce) doping on the structural, electronic, and optical properties of rutile titanium dioxide (TiO2). With increasing Ce doping concentration, the lattice constants gradually expand, with the a = b values reaching 4.92, 5.18, and 5.20 Å, and the c axis extending to 3.13, 3.35, and 3.59 Å, respectively. Electronic calculations indicate that Ce doping enhances the electronic structure by shifting the bandgap into the visible spectrum. The dielectric function analysis reveals real static dielectric constants of 5.23, 5.16, 5.10, and 4.80 for the pure material and the three doping concentrations, respectively. Furthermore, Ce doping increases the negative charge on oxygen atoms from −0.66 to −0.70 electrons, enhancing their electron-attracting ability. The positive charge on Ti increases slightly from +1.11 to +1.31 electrons since Ce shares its electron-donating role. Notably, Ce exhibits a significant positive charge (+1.41 to +1.60 electrons), with its 4f orbitals contributing 0.54–0.58 electrons, indicating its dual role in redox reactions. These trends highlight Ce’s effectiveness in modifying the electronic structure, making Ce-doped a suitable material for photocatalysis, wastewater treatment, and gas detection. The findings suggest that TiO2, enhanced by Ce doping, is a compelling choice of material for environmental and energy-related applications.