Noble Metal Deposition And The Photocatalytic Activity Study Of Three-dimensional Ordered Mesoporous TiO₂ Film

Titania is widely used in various fields, due to its many advantages including non-toxicity, chemical stability, low price, facile preparation, environmental friendliness, and excellent performance. But in photocatalysis, because of the limitation of the titania material itself, its utilization of solar energy is not high. The photocatalytic activity of titania photocatalyst appears only under the ultraviolet light, which restricts the development of titania in the field of photocatalysis study. In this paper, by using the template method and sol-gel method, successfully prepared a three-dimensional ordered mesoporous TiO2 microspheres array photonic crystal films, and modified the material by noble metal deposition, effectively improve the photocatalytic preformance of titania under visible light. The main work is as follows:Through the soap free emulsion polymerization, by controlling the temperature of polymerization reaction, synthesis the PS microspheres with uniform size and good monodisperse. Using the PS microspheres as template, obtain the high quality silica inverse opal template with different diameter through the one-step template method. Filling the silica inverse opal template with titania precursor containing PI23 as a mesoporous agent, and then by aging and calcinations, obtain three-dimensional ordered mesoporous TiO2 microspheres array photonic crystal films with different grain size. Because of the characteristics of photonic crystal structure, and the increase of the specific surface area brought by mesoporous, the photocatalytic performance of the titania has been greatly improved.By chemical reduction method, using sodium borohydride as a reducing agent, obtain the noble metal nanoparticles deposition TiO2 precursor. Through it finally prepare the noble metal deposition three-dimensional ordered mesoporous TiO2 microspheres array photonic crystal film. Select two kinds of noble metal:Pt and Au, the initial template diameter is 330 nm. The average size of Pt particle on obtained Pt-TiO2 material is 5 nm with uniform distribution. XPS characterization displayed that Pt element in the Pt-TiO2 materials found in elemental Pt. The photocatalytic properties test results showed that Pt deposition mesoporous titania material reflect a better degradation rate to organic dye RhB under visible light. The best deposition of Pt is 0.4wt%, degradation rate to RhB is 73%.The average size of Au particle on obtained Au-TiO2 material is 7 nm with uniform distribution. XPS characterization displayed that Au element in the Au-TiO2 materials found in elemental Au. The photo- catalytic properties test results showed that the best deposition of Au is 0.4wt%, degradation rate to RhB is 88%. The improvement of mesoporous TiO2 microspheres array material photocatalytic performance under visible light by deposition Au is better than those by deposition Pt. With the same best deposition 0.4wt%, degradation rate to RhB under visible light increase 15%.