Preparation of oriented SiO32− doped TiO2 film and degradation of methylene blue under visible light irradiation

SiO32− doped TiO2 films with oriented nanoneedle and nanorectangle block structure has been firstly synthesized by hydrothermal synthesis method. The prepared samples are characterized, X-ray diffraction (XRD) results demonstrate that the SiO32− doped TiO2 films are rutile and brookite phases. The scanning electron microscope (SEM) analysis reveals that the quantity of O2 affects the morphology of the SiO32− doped TiO2 films (SiTiA films prepared with unmodified substrate). The SiO32− doped TiO2 films (SiTiB films prepared with modified substrate) display two layers, one is porous structure, the other is nanoneedle structure. UV–vis, IR, transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) microscopy all prove that SiO32− have been doped in the TiO2 crystal structure. They have remarkable red shift and higher photocatalytic activity of degradation of methylene blue than P-25 under visible light (λ > 420 nm) irradiation. Besides, photocatalytic activity of the film is stable during 4 times recycling.