Density Functional Theory Calculations for the Electronic Structure of Carbon and Copper Co-Doped TiO2 Rutile Model

In recent years, a lot of attention has been given to the development of Titanium dioxide (TiO2) semiconductor photocatalyst for an efficient photocatalytic solar hydrogen production. However, wide bandgap of rutile TiO2 (3.0 eV) and meagre visible light absorption hinders its application for the solar driven photocatalytic hydrogen production. Co-doping of TiO2 with metal and non-metal dopants has emerged as an effective strategy for the band gap reduction than mono-doping. Therefore, in this work, we theoretically designed the Carbon-Copper (C-Cu) co-doped TiO2 rutile model using first principles density functional theory (DFT) calculations. The optoelectronic properties of the TiO2 rutile model were investigated to reduce the band gap to an optimal range and improve the visible light absorption. Plane-wave pseudopotential DFT approach with Hubbard�s modified Perdew�Burke�Ernzerhof assisted generalized gradient approximation (GGA+PBE+U) exchange correlational functional is employed to simulate the characteristics of the model. The simulation results indicate that C-Cu co-doping of TiO2 exhibits a significant band gap reduction from 2.98 to 2.21 eV for undoped TiO2 and C-Cu co-doped TiO2 model respectively, confirmed by the band structure plots and density of states diagrams. Bandgap reduction and the red shift of the optical absorption edge towards higher wavelength in the visible range suggest that the electrons in the TiO2 rutile model can be effortlessly excited from conduction band to the valence band. Overall, the C-Cu co-doping could be a promising approach to significantly boost up the photocatalytic performance of TiO2 under visible light irradiation. © 2022 American Institute of Physics Inc.. All rights reserved.