Promotion effect of Al2O3-SiO2 interlayer and Pt loading on TiO2/nickel-foam photocatalyst for degrading gaseous acetaldehyde

TiO2 photocatalysts coated on foam nickel were prepared by sol-gel method. Al2O3-SiO2 films introducing as transition interlayer between TiO2 and nickel metal foam were used to promote the photocatalytic activity of TiO2. The results show that TiO2/Al2O3-SiO2 composite films have much higher photocatalytic activity and stability for degradation of gaseous acetaldehyde than TiO2 films. The significant enhancement effect arises from the large specific surface area of Al2O3-SiO2, which provides more active sites for subsequent TiO2 loading and photocatalytic reaction. The Al2O3-SiO2 interlayer also inhibits the transfer of photo-generated electron from TiO2 to Ni metal and improves the photocatalytic activity of photocatalysts. Furthermore, Pt loading on TiO2 by photo-deposition was carried out to improve photocatalytic efficiency. The acetaldehyde degradation rate on Pt-loaded TiO2 photocatalyst is more than three times than that of TiO2 without Pt loading. The optimum Pt concentration is 0.3 wt%. XRD, UV-vis and SEM were used to characterize the structural, physical and chemical features of all the samples and to reveal the mechanism of the improvement of the photocatalytic activity. The effects of photocatalyst preparation parameters along with their photocatalytic behavior in deactivation and reactivation are also presented in the present study. (C) 2008 Elsevier B.V. All rights reserved.