First-principles prediction of enhanced photocatalytic activity in Cu-doped ZnTiO₃ by replacing zinc and titanium

The most abundant, clean, renewable, and environmentally friendly energy source is sunlight. In numerous environmental applications, the photocatalytic activity of oxide-based semiconductor particles has been proven. Adding new energy levels between and modifying the conduction band minima (CBM) and valence band maxima (VBM) is an efficient way of elemental doping to adjust the band gap of TiO₂. Cu doping in ZnTiO₃ is anticipated to alter absorbance, as well as other physical or chemical characteristics of the material, due to the altered electronic shell structure. The impact of Cu doping on the ZnTiO₃ system's electronic structure and photocatalytic activity was examined through the utilization of the density-functional-theory-based open-source software Quantum Espresso.

In this work, the effects of copper doping on the properties of zinc titanate were studied. The optoelectronic characteristics of pure and doped ZnTiO₃ with copper and the compatibility of Cu to replace Ti or Zn in doping were the main focuses of this research. The formation energies of Cu-doped ZnTiO₃, in which Cu substitutes Zn and Ti, were found to be -188.3019486 eV and -177.7992517 eV, respectively. Studies found that replacing Zn with Cu is more practical than replacing Ti with Cu. Band gaps were 2.92 eV for ZnTiO₃, 2.44 eV for Cu-substituted Zn, and 1.68 eV for Cu-substituted Ti from the band structures of ZnTiO₃ and Cu-doped ZnTiO₃. By generating an accepter level in ZnTiO₃, copper increases the feasibility of ZnTiO₃ for photocatalysis under visible light.

When compared to pure ZnTiO₃, the Cu-doped system shows light absorption activity in the visible range. Cu-doped ZnTiO₃ demonstrated higher photo-catalytic potential because they showed intermediate states in the band structure and density of states, which is better suited to the particular requirements for photocatalysis powered by solar radiation.