Mono, dual and tri-doped TiO2: Sunlight photocatalytic, room temperature ferromagnetic and dielectric constant properties

Abstract

In this study, the optical, magnetic and electrical properties of nanostructured TiO2 semiconductor have been investigated for multi-functional applications. Herein, different compositions composed of TiO2, Ti0.985Co0.015O2, Ti0.97Co0.015Mn0.015O2, Ti0.97Co0.015Fe0.015O2 and Ti0.97Co0.01Mn0.01Fe0.01O2 were synthesized by coprecipitation method. The XRD and Rietveld refinement analysis confirmed that TiO2, Ti0.985Co0.015O2, Ti0.97Co0.015Mn0.015O2 and Ti0.97Co0.01Mn0.01Fe0.01O2 powders have mixed phases of rutile and anatase TiO2 structure while Ti0.97Co0.015Fe0.015O2 powder has anatase structure. The incorporation of Co, (Co, Mn), (Co, Fe) and (Co, Mn, Fe) ions into TiO2 lattice decreases the band gap energy from 3.13 eV to 3.05, 2.7, 3.08 and 2.88 eV, respectively. Ti0.985Co0.015O2 and Ti0.97Co0.015Fe0.015O2 samples exhibit high sunlight efficiencies of 73% and 72% for Congo red (CR) dye degradation in 80 min, respectively. The dielectric constant and electrical conductivity of TiO2 were enhanced due to insertion of Co2+, Mn2+ and Fe2+/3+ ions. Among all samples, Ti0.97Co0.015Mn0.015O2 composition reveals the highest dielectric constant value of 5004. On the other hand, notable room temperature ferromagnetism with found in Ti0.97Co0.015Fe0.015O2 composition with magnetization value of 0.056 emu/g and coercivity of 86 Oe. The obtained results confirmed that the incorporation of Co2+, Mn2+ and Fe2+/3+ ions into TiO2 enhances the electrical, magnetic and photocatalytic properties.