Titanium Dioxide Photocatalysis Composite Materials Supported On Carbon Fiber

Preparation of immobilized photocatalytic titanium dioxide materials and further improvement of the photocatalytic activity of the materials are keys to expand the scope of practical application of photocatalytic materials. In this paper, the composite photocatalyst of TiO₂ thin film supported on polyacrylonitile based carbon fiber (PAN-CF) substrates was prepared by sol-gel dip coating technique and a suitable sol-gel process was explored. The effects of the TiO₂ thin film structure and its modification on the photocatalytic performance of the composite photocatalyst of TiO₂ thin film supported on carbon fiber materials were researched.First, the TiO₂/CF photocatalyst materials were prepared by different sol systems and heat treatment processes on the basis of the multicomponent system phase diagram theory of Ti(OC₄H₉)₄-C₂H₅OH-H₂O, and the structures and properties of the materials were studied. The results suggest that the concentration of the sol has significant effects on the morphologies and structures of TiO₂/CF film, the load rate of TiO₂ and load fastness. It also indicated that the catalytic activity of TiO₂/CF film is remarkably influenced by the concentration of the sol and annealing temperature, and the TiO₂/CF prepared from the Ti sol with concentration of 0.5M exhibits better load fastness, higher load rate and excellent catalytic performance. Moreover, The optimum heat treatment process was determined as annealed at 600℃for 2 hours at a rate of 2³â„ƒ/min.Second, in order to make full use of the adsorption properties of carrier, the TiO₂ porous film photocatalysts deposited on carbon fiber were fabricated through the sol-gel dip-coating technology using PEG-modified titanium sol. The adsorption effects of the composites to methyl orange and fuchsin, and the photocatalytic property of the composites to methyl orange were investigated respectively. The results suggest that the adsorption kinetic process of TiO₂/CF composites to methyl orange solution and fuchsin fitted very well with the pseudo-second-order kinetic model. In addition, with the improvement of PEG molecules, the adsorption capacity is increased, and the catalytic performance of porous TiO₂/CF using PEG2000 as a template was increased on some degree that compare with TiO₂/CF by photocatalytic degradation of methyl orange solution.And then, the compound photocatalysis material of TiO₂/SnO₂ films with bilayer structure (TiO₂/SnO₂/CF) and TiO₂-SnO₂ hybrid films supported on carbon fiber(SnO₂-TiO₂/CF) were prepared by sol-gel dip-coating technology, respectively. The study revealed that the photocatalytic activity of the composite is efficiently enhanced by using TiO₂/SnO₂ films with bilayer structure, and the photocatalytic degradation efficiency of TiO₂/SnO₂/CF was improved 13% compare with TiO₂/CF, by photocatalytic degradation of methyl orange solution. The photocatalytic activity of SnO₂-TiO₂/CF with SnO₂ content of 20%(mole fraction) was markedly improved compare with TiO₂/CF, and the degradation efficiency of TiO₂/SnO₂/CF was improved 60% by photocatalytic degradation of acid orangeâ…¡solution.The last, photocatalytic property of the TiO₂ films photocatalysts supported on Pd modified carbon fiber(TiO₂/ Pd-CF) was improved by the method of noble metal Pd modified carrier surface through a facile oxidation-reduction technology. The results indicate that the catalytic activity of TiO₂/Pd-CF exhibited greatly enhanced compare with TiO₂/CF, and the photocatalytic performance of TiO₂/Pd-CF towards the degradation of acid orangeâ…¡was improved 70% when the Pd particles loading is 10.8mg/g. It provides a new idea for improving photocatalytic property of immobilized photocatalytic materials.