Structural and Optical Properties of Co-precipitated Mn-doped TiO2 Nanoparticles

Abstract

Mn-doped TiO2 nanoparticles have been synthesized by conventional co-precipitation process with different dopant concentrations. As-synthesized products were calcined at 400-700 ºC for 3 h in order to improve their crystallinity. The crystalline phase structure, surface morphology and optical properties of Mn doped TiO2 nanoparticles were investigated by X-ray diffraction, Scanning electron microscope and UV-Vis spectroscopy. The phase transformation from anatase to rutile occurred when the calcination temperature increases beyond specific temperature. SEM images revealed the agglomerated spherical shapes of the product. XRD results were shown the crystalline sizes of TiO2 decreased depending on high Mn doping due to the influence of Mn charge and ionic radius incorporated into Ti lattice. The optical spectra of doped products exhibit a noticeable red shift of absorption edge toward visible region. This occurrence may imply the decrease of the optical band gap with increasing Mn doping content.