The Research On Synthesis And Modification Of Mesoporous TiO₂ Photocatalyst

Nano-titanium dioxide(Ti O2) photocatalytic technology, utilizing renewable solar energy stimulates photocatalysis reaction, has been regarded as a potential technology to deal with both environmental and energy problems. However, many challenges still need to be overcome, such as poor photodegradtion activity, low visible light utilization, and difficult recovery. In order to expand solar spectrum absorption and improve the photocatalytic activity of Ti O2, well-difined mesoporous Ti O2 microspheres were synthesized by sol-gel processing assisted hydrothermal, and then doped with metal ion and composited with graphene oxide(GO). The main contents included:Well-difined mesoporous Ti O2 microspheres were synthesized with F127 as template, isopropyl titanate as the titanium source. The as-prepared Ti O2 was characterized by small and wide XRD, N2 adsorption-desorption, TEM, and FESEM. The results indicated that the optimum preparation conditions includ: V(H2O):V(Ti)=8:1, water-bath temperature and time are 55 ℃ and 10 h, respectively, hydrothermal temperature and time are 90 ℃ and 10 h, respectively, addition amounts of F127 are 14%, the heat treatment temperature is 450 ℃. Mesoporous Ti O2 microspheres are formed by nanoparticles accumulating, and the pore diameter and specific surface areas are up to 9.641 nm and 158.236m2/g, respectively, the mesoporous Ti O2 microspheres exhibite higher photocatalytic activity than commercial P25.La3+-Ti O2 and co-doped Fe3+/La3+-Ti O2 mesoporous microspheres were systhesized and characterized by UV-visible diffuse reflectance spectroscopy. The results indicated that absorption of doped Ti O2 mesoporous microspheres in the visible regions are enhanced obviously. The Photodegradation efficiency of MB under UV irradiation for 30 min reaches 100% when the dopant of La3+ and Fe3+ for is 1% and 2%, respectively.GO-Ti O2 and GO/Fe3+/La3+-Ti O2 mesoporous microspheres were synthesized by hydrothermal and characterized by XPS, Raman spectrum, TEM, UV-Vis spectrophotometer. The photocatalysts(5wt.% GO) with the highest photocatalytic activity are achieved and the degradation efficiency under UV irradiation for 20 min is almost 99.8%.