Preparation Of Graphite / TiO 2 Catalyst And Its Photocatalytic Activity

The combination of TiO₂ with graphite（G） could solve the problem of recombination of the photogenerated electron-hole. In this work, G/TiO₂ composite was synthesized via a sol-gel method, meanwhile, G/TiO₂/foam-Ni and G/TiO₂/PTFE were prepared by using the foam nikel as the support and PTFE latex as binder, and the photocatalytic performance of three photocatalysts has been investigated.The G/TiO₂ composite were characterized by XRD, Raman, BET, XPS, SEM and TEM. The results showed that TiO₂ in composite was anatase phase, and dispersed uniformly on the surface of the graphite with average diameter of 10 nm.The photoelectrochemical properties of G/TiO₂ were investigated by UV-visible diffuse reflectance spectrum（DRS） and surface photovoltage spectrum（SPS）. The results showed that the absorption edge of G/TiO₂ exhibited a remarkable red-shift of20-25 nm and the stronger photoabsorbance over the whole visible light region as well as the significantly improved separation efficency of photogenerated electron-hole in comparison with the pristine TiO₂.Photocatalytic systems were established with the methyl orange（MO） as the target pollutant, the 500 W Xenon lamp as simulated solar light and the G/TiO₂,G/TiO₂/foam-Ni and G/TiO₂/PTFE as photocatalysts. The results showed that when the graphite content was 0.03 g, the calcination temperature was 350℃, the ratio of the powder G/TiO₂ and PTFE latex of the G/TiO₂/foam-Ni was 1:3, the ratio of the powder G/TiO₂ and PTFE latex of the G/TiO₂/PTFE was 1:5, the catalysts exhibited the best photocatalytic effect. Under illumination for 120 min, the MO degradation rate over G/TiO₂, G/TiO₂/foam-Ni and G/TiO₂/PTFE was 77.5%, 85.1% and 95.6%, respectively.