Enhancing the photocatalytic activity of TiO2 nanocrystalline thin film by doping with SiO2

Nanocrystalline films of TiO2:XSiO2 (X = mol percent) with high photocatalytic activity was prepared on glass substrate via the sol–gel method. The films were subjected to high temperature treatment at 500 °C for growing TiO2 crystals. Energy Dispersive X-ray Spectroscopy (EDS) was used to indicate the elements in the films. The EDS result showed that besides Ti, O and Si elements, there were small amounts of Ca, Na and Mg. X-ray diffraction (XRD) analysis indicated that TiO2:XSiO2 films contain only anatase phase. Scanning electron microscopy (SEM) was used to study the films surface morphology. The TiO2:SiO2 films that were contacted with methyl orange (MO) in the aqueous solution (10 mg L−1) and irradiated with UV showed a high photocatalytic activity. UV spectrophotometry technique was used to monitor the degradation of methyl orange (MO) by the reduction of main absorbance peak at 464 nm. The results showed that complete degradation was achieved after 1.5 h.

► TiO2 grain size controlling with adding SiO2, that high content of SiO2 restrain the crystallization of TiO2.
► Photocatalytic activity of TiO2:SiO2 was higher in compare with pure TiO2.
► Higher photocatalytic activity of TiO2 is because of small grain size and small grain size was achieved with adding SiO2.