Synthesis and characterization of Fe-doped TiO2 hollow nanospheres prepared by carbon sphere as hard template

Abstract Fe-doped TiO2 hollow nanospheres (THs-Fe) with various Fe-dopant concentrations (0.25, 0.50, 0.75 and 1.00 mol%) were prepared using carbon spheres as templates. After calcination, the obtained hollow structure TiO2 were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDS) and ultraviolet-visible spectroscopy (UV-Vis). The analysis results revealed that the crystallite size and crystallinity of the samples decreased with increasing Fe content. Morphology and particle size were investigated by electron microscopic techniques and the results showed that dopant concentrations had a significant influence on average particle size. The average diameter of hollow spheres decreased from 146.92 to 61.57 nm when Fe-content increased from 0.25 to 1.00 mol%. The UV-Vis absorption spectra exhibited that the absorption edge of THs-Fe was shifted toward the visible light region with increased Fe content. The energy gap (Eg) was decreased from 2.85 to 1.84 eV when the dopant content increased from 0.25 to 1.00 mol%.