Abstract
In the past few years, there has been increasing research interest in photocatalysis. There are two main kinds of photocatalyst, metal oxide and metal sulfide, such as TiO2 and ZnS. Photocatalyst can decompose pollutants by irradiation of light of suitable wavelength, leading to oxidation-reduction by the resulting electron-hole pairs. The most common and effective photocatalyst is TiO2 because of its strong redox ability, cheaper price, intoxicity and chemical stability. There are two parts in this research. The first part: The synthesis and properties of TiO2. TiO2 catalyst is surface modified by gold and obtains better photocatalysis efficiency. The second part: fabrication of porous network TiO2 structure achieved by polymer template. TiO2 catalyst was dispersed in different pH solution and coated TiO2 film by dip coater. TiO2 film was coated in different solutions and compared in photocatalytic efficiency. The negative AuCl4- ion can absorb to the surface of TiO2 particles which are positively charge in aqueous solution. Reduction agent was added to form Au/TiO2 catalyst. TiO2 and Au/TiO2 catalyst were synthesized in different conditions. The catalyst was tested by the deNOx photocatalytic reaction. The results showed that Au/TiO2 catalyst gave 10% higher efficiency than TiO2 catalyst. The porous polymer was dipped in TTIP/ACAC/ETOH solution for several weeks, until the solution filled in the continuous pores. Polymer was burn out at 500℃ and the porous network TiO2 structure was produced. Comparison in photocatalytic efficiency of network TiO2 structure and commercial Degussa P-25 particles at deNOx gas photocatalytic reaction and decomposion of methylene blue liquid reaction. The two samples have almost the same photocatalytic efficiency.