Structural and optical properties of transition metal ion-doped ordered mesoporous TiO2 prepared by chelating-assisted evaporation induced self-assembly method

Abstract

This paper demonstrates the fabrication of highly ordered mesoporous titanium dioxide (OMT) with different transition metals (TM: Fe, Mn, and Ni) by employing a self-assembly surfactant template route. The ordered TM-loaded mesoporous TiO2 (TM-OMT) has uniform mesopores (3–5 nm pore diameter), and a crystalline framework is successfully prepared via soft template strategy by employing Pluronic® F127 triblock copolymer as a chelating and structural directing agent. The structural and optical characteristics of the TM-OMT hybrids have been examined by scanning electron microscopy (SEM), transmission electron microscope (TEM), XRD, N2-sorption isotherms, UV/visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS) reveals the successful incorporation of TM ions over the highly ordered mesostructured OMT. The XRD pattern evidenced that the obtained TM-doped OMT samples are pure anatase of the crystalline phase. By employing TEM analysis, the average particle size is estimated to be 2–2.7 nm, whereas diffraction patterns have evidenced the polycrystalline features of the mesoporous structure. The bandgap energy of TM-doped mesoporous decreases according to the particular metal and its amount due to the reduced particle size. This cost-effective method provides the exceptional potential to tune the optical features for TM-doped mesoporous TiO2 materials for its optoelectronic applications and show more significant promise for energy conversion technologies.