Preparation Of Porous TiO₂Composites By Using An Emulsion Liquid Membrane System

As a separation means, emulsion liquid membrane has high selectivity, great flux, high membrane surface area and high mass transfer velocity; while as a preparation method, it can control the morphology of the materials through changing the concentration and structure of surfactantsurface active agent in the emulsion system of structure and concentration, the formation of the six party phase, cubic phase, layer, the cube, the six parties, the liquid crystalline phase, effectively preparation with special structure, the composition, morphology, orderly arrangement of nanometer materials, size and the mass transfer process by internal phase. The pores can act as light transfer paths to introduce more photo energy onto the inner surface of TiO2which can enhance the utilization of light energy of the internal surface of TiO2. Additionally, patterned large channels may facilitate diffusion of reactant molecules within the pores and enhance the reaction rate. However, TiO2has a relatively large band gap (Eg=3.02eV). As well-known, it can only be excited by radiation with ultraviolet light. Such poor solar light absorption capability is of little practical applications for the TiO2photocatalysis. So on the basis of the patterned porous TiO2, it also needs to enhance the utilization ratio of visible light.A novel nanocomposites CdS-TiO2was prepared by the sequential chemical bath deposition(S-CBD) of CdS on patterned porous titania. The influences of the different deposition cycle times on pattered porous TiO2were investigated. The photoactivity of nanocomposites was tested by photodegradation Rhodamine B in aqueous solution under150W metal halide or500W Xe lamp. The photocatalytic activity of CdS-TiO2-3was the best,. After being calculated, the band gap of CdS-TiO2-3was2.03eV. The apparent rate constants of CdS-TiO2-3and pure patterned porous TiO2was K=0.0053min-1and K=0.00451min-1, which indicated that CdS-TiO2-3showed better photocatalytic performance compared with the pure patterned porous TiO2under under150W metal halide.The metal Ag, Au was deposited on the surface of the patterned porous TiO2by reduction. These samples were designated as Ag-TiO2, Au-TiO2. The XRD pattern results of nanocomposites CdS-TiO2indicated that metal Ag, Au was successfully deposited in the TiO2. The photocatalytic activity of Ag-TiO2-1, Au-TiO2-2was the best. The SEM micrographs of TiO2and nanocomposites showed that the patterned channels of nanocomposites were basically unchanged and were not blocked and destroyed by the Ag and Au. The band gap of Ag-TiO2-1, Au-TiO2-2was2.53eV by calculation. The light absorbance of Ag-TiO2and Au-TiO2extends to the visible light region. The degradation rate of Rhodamine B by Ag-TiO2reached100%at100min as well as Au-TiO2.The nanocomposites PPy-TiO2was prepared by means of in-situ photopolymerization in ultraviolet radiation. The patterned porous TiO2as the photosensitizer and template. The band edge of PPy-TiO2-12, PPy-TiO2-24was430nm,450nm and the band gap of them was2.88,2.76eV, respectively.The photodegradation of Rhodamine B of PPy-TiO2-24was the best.. The photocurrent density of the PPy-TiO2-24under simulated solar irradiation and visible light at OV were2.7μ A/cm2and200n A/cm2. The photocurrent density of TiO2Was almost zero.