Self-cleaning and depollution of fiber reinforced cement materials modified by neutral TiO2/SiO2 hydrosol photoactive coatings

Environmental pollution has an evidently adverse impact on the buildings that are constructed by the glass fiber reinforced cement (GRC) materials. In the present work, the stable, neutral TiO2/SiO2 hydrosols were prepared by using the Ti(SO4)2 as titanium source, HNO3 as peptizing agent, and SiO2 as stabilizer through a simple and low cost process. The morphologies and structures of TiO2/SiO2 hydrosol were further characterized by the TEM, SEM, XRD, and FTIR measurement. In the synthetic hydrosol, lots of nanoparticles with the diameters in the range of 10-20 nm can be observed. TiOSi band were formed, as observed from the FTIR spectrum. The Na2O·SiO2 was detected from the SEM. After drying the TiO2/SiO2 hydrosol, the XRD shown that the TiO2 has an anatase structure and the SiO2 is amorphous. The TiO2/SiO2 hydrosol can be compactly coated on the GRC surface due to the existence of Na2O·SiO2 binder and exhibited high photocatalytic activity and stability in the degradation of Rhodamine B.