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

Abstract

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 Å, b = 5.509 Å, and c = 5.041 Å, 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 N2 fixation in the visible light region.