Preparation And Characterization Of Composite Photocatalyst

All the works of this research were supported by key Technology R&D Program of China (NO. 2007BAE42B04). In this study, the photocatalyst compound by photosensitizers and nano TiO2 were prepared. (ferric stearate- P25, ferrocene-P25, nickel N,N-dibuty dithiocarbamate(NiDBC)-P25). Absorption intensities and surface morphology of these photocatalyst were investigated by Diffuse Reflectance Spectroscopy (DRS) and Scanning Electron Microscopy(SEM).Innovatively, methylene blue (MB) was used as model pollutant to study the photocatalytic activity of these photocatalyst compounds. The study indicated that:(1) NiDBC showed the best absorption activity at the scale of 400-800 nm, and adding ferric stearate into nano TiO₂ increased the absorption in the range of 400-600 nm, the reflect rate decreased from 35% to 18%。Furthermore, adding NiDBC could extend the range of absorption of ferric stearate,ferrocene and TiO₂,to the wavelength 600nm and 700nm, respectively.(2) Ferric stearate and ferrocene showed few absorb activity for MB solution. Even after being stirred 80 minutes without light, the absorption rate was only 2%. NiDBC had better absorption activity than Ferric stearate and ferrocene, the absorption rate could achieve 6%. P25 showed the best absorption activity. However, the result showed that these photocatalyst showed the same activity when the mass was 0.05 g.(3) The result of degradation of the methylene blue solution irradiated under a xenon lamp showed that NiDBC has the best photocatalitic activity for MB in these photosensitizers. After being irradiated 120 minutes, the solution which had been added into 0.1 g NiDBC had been degraded 8.53%. In which added ferric stearate were 4.8%. Hydro-gen peroxide showed huge influence on photocatalytic activity of photocatalyst. After being added hydro-gen in, irradiated 120 minutes, the degraded rate of solution was increased from 18.5% to 64.5%.(4) MB solution could be degraded 97% by NiDBC after being irradiated 275 hours, and 44% by ferric stearate, 40% by ferrocene. When the sun light was used as light resource, the activity of photocatalytic regularity was ferric stearate-P25 > ferrocene-P25 > NiDBC-P25 (photosensitizer/P25=5:1); ferrocene-P25 > ferric stearate-P25 > NiDBC-P25 (photosensitizer/P25=2:1); ferric stearate-P25> ferrocene-P25> NiDBC -P25(photosensitizer/P25=1:1).