Enhanced electrical and photocatalytic properties of porous TiO2 thin films decorated with Fe2O3 nanoparticles

Abstract

In this work, we developed a facile synthetic process for the fabrication of porous heterojunction Fe2O3/TiO2 using a two-step method to be employed as a visible light photocatalyst. In the first step, porous TiO2 thin films were successfully prepared by a sol–gel method using polyethylene glycol (PEG). The porous TiO2 thin film was further annealed and then decorated with nanoparticles of Fe2O3 using the direct electrodeposition method. The photocatalysts were structurally investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy. The Fe2O3/TiO2 heterojunction presented both an anatase TiO2 phase and rhombohedric structure of hematite α-Fe2O3. The optical properties have been investigated for all the materials, in which the TiO2 material present in porous heterojunction exhibited a remarkable absorption and red shift in the visible region from 3.2 to 3.0 eV compared to the pure heterojunction Fe2O3/TiO2. Moreover, the electrochemical behavior of the samples was investigated. Photocatalytic activity was assessed from methylene blue degradation with remarkable degradability performance under visible light. The photodegradation of the porous heterojunction Fe2O3/TiO2 exhibited an enhanced photodegradation up to 70% after 150 min of irradiation.