Sb/Cu/Zn tri-doped BaTiO₃ semiconductor: colossal dielectric and high photodegradation activities for crystal violet, diclofenac sodium, and Congo red contaminants

This research aims to develop the energy storage and photocatalytic functions of perovskite BaTiO₃ material by improving its permittivity and the visible light absorption properties. Both goals were realized by using a mixture of three dopants including Sb, Cu, and Zn elements. By using the solid-state method, pure and Sb/Cu/Zn tri-doped BaTiO₃ samples were successfully synthesized. The tetragonal phase of perovskite BaTiO₃ was confirmed by X-ray diffraction analysis. The crystallite and grain sizes of BaTiO₃ powder were reduced due to the addition of Sb/Cu/Zn dopants. The oxidation states of the elements were identified by X-ray photoelectron spectroscopy (XPS) as Ba (+2), Ti (+4), Sb (+5), Cu (+2) and Zn (+2). Owing to the incorporation of Sb/Cu/Zn ions, the stability and values of the dielectric constant of BaTiO₃ were enhanced with varying the frequency and significantly increased from 2518 to 10,027 at 50 Hz. The optical characteristics of Sb/Cu/Zn tri-doped BaTiO₃ powder displayed a wide visible light absorption properties with measured band gap energy of 2.79 eV. The photocatalytic studies proved the rapid decolorization and mineralization of crystal violet, diclofenac sodium, and Congo red contaminants by Sb/Cu/Zn tri-doped BaTiO₃ catalyst under sunlight spectrum. The trapping tests specified that the hydroxyl radicals (·OH) are the key energetic species in the photodegradation reactions. The reuse tests established the high stability of Sb/Cu/Zn tri-doped BaTiO₃ catalyst for wastewater treatment.