Synthesis of neutral SiO(2)/TiO(2) hydrosol and its photocatalytic degradation of nitric oxide gas

Abstract

A neutral transparent SiO(2)/TiO(2) composite hydrosol was prepared by a coprecipitation-peptisation method using titanium tetrachloride and SiO(2) hydrosol as raw materials. The prepared SiO(2)/TiO(2) hydrosols were characterised by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. The evaluation of photocatalytic activity for nitric oxide degradation showed the optimal weight ratio of SiO(2)/TiO(2) is around 1.5. After heating at 700 degrees C for 1 h, the prepared SiO(2)/TiO(2) hydrosol exhibits much higher photocatalytic activity than the commercial TiO(2) materials, Degussa P25 and ONID TH. The presence of Ti-O-Si bond in the composite hydrosol results in its good thermal stability. The prepared transparent SiO(2)/TiO(2) hydrosols were stable without agglomeration or gelation after storage at room temperature for over 1.5 years. The neutral SiO(2)/TiO(2) hydrosol could be used as the coating material applying for glass or ceramic building materials which must be treated at high temperature.