Investigations of the influence of non-metal dopants on the electronic and photocatalytic properties of ZrTiO₄ by density functional theory calculations

In this work, the electronic and photocatalytic properties of non-metal-doped ZrTiO4 are computed using the DFT + U method. This method allows for calculations of the systems with strong correlation electronic effects like several metal oxides, which the standard DFT fails to give the correct predictions. Applying on-site Coulomb energy (U) correction to bulk pristine ZrTiO4 yields an orthorhombic unit cell lattice parameter a = 4.804 angstrom, b = 5.509 angstrom, and c = 5.041 angstrom, which is in good agreement with the experiment. The calculated band gap energy (Eg) for pristine ZrTiO4 with DFT + U is 3.60 eV, which is in excellent agreement with the experimental value of 3.65 eV. Substitutional doping is more likely to occur at the O site than at the Zr or Ti site in the X-doped ZrTiO4 model. F substitution at O atom and Si substitution at Ti or Zr atom are thermodynamically favorable with negative formation energy. Substitutional doping of S at the O site, Se at the Ti site, or S/Se at the Zr site in ZrTiO4 can enhance the photooxidation and photoreduction ability. These materials are expected to have good catalytic activity for water decomposition, CO2 reduction, and N-2 fixation in the visible light region.