Photocatalytic Oxidation of Benzene to Phenol and Dye Over N and S Doped Ferromagnetic Nanosize TiO2

In the present investigation, we report the presence of N, S and Ti3+ in the TiO2 samples and the surface exhibits acidic characteristics. Synthesized TiO2 samples were also found to be ferromagnetic in nature at room temperature and show high photocatalytic activity in comparison to commercially available TiO2 (DP-25). Nanosize TiO2 with a high surface area was obtained by a simple sol-gel method of synthesis and during the synthesis hydrazine sulphate was used as fuel. Synthesized TiO2 was found to be with N and S doping and surface defects were present due to cationic and anionic vacancies. The presence of defects was confirmed from the Raman, Infra-Red (IR), Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDAX), Photoluminescence (PL) analysis. The presence of Ti3+ in the TiO2 samples was confirmed by the Electron Spin Resonance spectroscopy (ESR) and X-ray Photoelectron Spectroscopy (XPS) Spectra. XPS also showed the presence of nitrogen and sulphur doping in the TiO2 samples. Synthesized TiO2 possesses an acidic surface and surface acidity was measured from the pyridine adsorption and Ammonia-Temperature Programme Desorption (NH3-TPD) studies. The ferromagnetic behavior of the synthesized samples was confirmed by the Vibrating Sample Magnetometer (VSM) measurements. Synthesized samples were further studied for their photocatalytic activity towards methylene blue dye and 4-nitrophenol degradation and for photo-oxidation of benzene to phenol conversion. We report the synthesis of the simultaneous presence of nitrogen and sulphur doping in the ferromagnetic TiO2 and its high activity toward photocatalytic oxidation reactions.