Molybdenum-doped TiO2 nanoparticles for enhanced photocatalytic activity: a combined experimental and theoretical study

The theoretical calculations and hydrothermal techniques were adapted to explore the redshift of the TiO 2 light absorption edge through Mo-doping. The band gap and reflectance curves were determined using the Kubelka-Munk transformation and the UV–Vis absorption spectra. DFT calculations revealed that doping of Mo narrowed the TiO 2 band gap by creating impurity states (Mo 4d) below the conduction band. This is due to the closeness of orbital energies of Mo 4d and Ti 3d. Pinning of the Fermi level inside the conduction band verified doping of Mo in TiO 2 (n-type) and boosted its absorbance within the visible light range. TiO 2 nanoparticles, with and without Mo, were prepared by a hydrothermal route. Diffuse reflectance spectroscopy (DRS) data showed a systematic band gap decrease from the UV to the visible region (3.48 eV to 2.79 eV) by appropriate doping of Mo in TiO 2 . The experimental observations are verified by the theoretical predictions