Abstract: The photocatalyst NaTaO₃, owing to its notable chemical and thermal stability as well as environmental friendliness, emerges as a versatile candidate capable of meeting diverse demands across various fields. Through ion doping, it is feasible to modulate the electronic structure and performance of NaTaO₃. In this study, employing density functional theory (DFT), electronic structure and optical properties of perovskite-type Na_0.75B_0.25TaO₃ (where B=Cr, Mn, Fe, Cu, Zn) were systematically investigated, elucidating the impact of different transition metal dopants on the band structure and electron density of states in NaTaO₃. The investigation reveals that Cr, Mn, Fe, and Zn doping induces metallic properties, while Na_0.75Cu_0.25TaO₃ exhibits semiconductor characteristics, accompanied by a narrowed bandgap of 1.35 eV. The introduction of Cu introduces new energy levels (Cu 3d and Cu 4s) within the bandgap, positioned at its center, resulting in an upward shift of the valence band. Furthermore, the absorption spectra in the Cu-doped system exhibit a redshift, extending the light absorption wavelength up to 800 nm. Subsequently, the photocatalytic antibacterial performance of NaTaO₃ and Na_0.75Cu_0.25TaO₃ was explored, demonstrating a bactericidal efficiency of 99.99% against Staphylococcus aureus (S. aureus) following Cu ion modulation. Finally, an analysis of potential antibacterial mechanisms was undertaken.

Key words: NaTaO₃, density functional theory, transition metal doping, electronic structure, optical property, photocatalytic antimicrobial