Optical, structural, morphological and chemical properties of doped TiO₂ nanoparticles with FeCl₃

To achieve high photocatalytic activity, TiO₂ nanoparticles nanoparticles require an excitation source in ultraviolet radiation. Incorporating chemical elements into the TiO₂ lattice can tune its band gap, resulting in an edge-shifted red absorption to reduce energies, improving photocatalytic performance in the visible region of the electromagnetic spectrum. In this research, TiO₂ semiconductor nanoparticles were subjected to a doping process using iron chloride (FeCl₃) powder to activate photocatalysis under visible light and consequently improve pollutant capture. To study the effectiveness of the doping process, the main ratios (1:1), (1:1.622) and (1:3) of TiO₂:FeCl₃ were evaluated using Diffuse Reflectance Spectroscopy (DRS), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The main results of this research show that doping TiO₂ with FeCl₃ shifted the absorption edge to longer wavelength values, changing the optical properties of the material and decreasing the band gap (E_g) of TiO₂ compared to the undoped TiO₂ (reference). There are no relevant differences between the XRD pattern of the samples with TiO₂-FeCl₃ and TiO₂ nanoparticles (reference). The fraction of the anatase phase in doped TiO₂ nanoparticles has the same magnitude as the reference TiO₂. Regarding FTIR, the Fe-doping process alters the TiO₂ reference spectrum, increasing the intensity of hydroxyl bonds and peaks particularly, indicating the Ti-O-Fe bond vibration.