Novel silica gel supported TiO2 photocatalyst synthesized by CVD method

TiO2 in anatase crystal phase is a very effective catalyst in the photocata lytic oxidation of organic compounds in water. To improve the recovery rate of TiO2 photocatalysts, which in most cases are in fine powder form, the c hemical vapor deposition (CVD) method was used to load TiO2 onto a bigger p article support, silica gel. The amount of titania coating was found to dep end strongly on the synthesis parameters of carrier gas flow rate and coati ng time. XPS and nitrogen ads/desorption results showed that most of the Ti O2 particles generated from CVD were distributed on the external surface of the support and the coating was stable. The photocatalytic activities of T iO2/silica gel with different amounts of titania were evaluated for the oxi dation of phenol aqueous solution and compared with that of Degussa P25. Th e optimum titania loading rate was found around 6 wt % of the TiO2 bulk con centration. Although the activity of the best TiO2/silica gel sample was st ill lower than that of P25, the synthesized TiO2/silica gel catalyst can be easily separated from the treated water and was found to maintain its TiO2 content and catalytic activity.