Enhanced photocatalytic activity and stability of nano-scaled TiO2 co-doped with N and Fe

Titanium dioxide (TiO2) nanoparticles co-doped with N and Fe were prepared via modified sol–gel process. The products were characterized by transmission electron microscopy (TEM), N2 adsorption, X-ray diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS). It is shown that the prepared TiO2 particles were less than 10 nm with narrow particle size distribution. The addition of MCM-41 caused the formation of Ti–O–Si bond which fixed the TiO2 on MCM-41 surface, thus restricted the agglomeration and growth of TiO2 particles. The photocatalytic performance in the degradation of methylene blue showed that N, Fe co-doped TiO2 exhibited much higher photocatalytic activity than doped sample with nitrogen or Fe3+ alone under both UV and visible light. N, Fe co-doping decreased the loss of doping N during the degradation reaction, thus increased the photocatalytic stability. It was also found that the nitridation time had significant influence on the photocatalytic activity of prepared TiO2 catalysts.