Promotion effect of Al 2O 3–SiO 2 interlayer and Pt loading on TiO 2/nickel-foam photocatalyst for degrading gaseous acetaldehyde

Abstract

TiO 2 photocatalysts coated on foam nickel were prepared by sol–gel method. Al 2O 3–SiO 2 films introducing as transition interlayer between TiO 2 and nickel metal foam were used to promote the photocatalytic activity of TiO 2. The results show that TiO 2/Al 2O 3–SiO 2 composite films have much higher photocatalytic activity and stability for degradation of gaseous acetaldehyde than TiO 2 films. The significant enhancement effect arises from the large specific surface area of Al 2O 3–SiO 2, which provides more active sites for subsequent TiO 2 loading and photocatalytic reaction. The Al 2O 3–SiO 2 interlayer also inhibits the transfer of photo-generated electron from TiO 2 to Ni metal and improves the photocatalytic activity of photocatalysts. Furthermore, Pt loading on TiO 2 by photo-deposition was carried out to improve photocatalytic efficiency. The acetaldehyde degradation rate on Pt-loaded TiO 2 photocatalyst is more than three times than that of TiO 2 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.