Preparation Of Porous BiVO₄with Photonic Crystal Effect And Its Photocatalytic Performance Under Visible Light

Photocatalytic technology which using the sunlight as an energy source could achievethe degradation of pollutants has been widely studied and applied currently. However, themost common photocatalyst TiO2, has a low utilization of visible and low quantum efficiency,which hindered the development of photocatalytic technology. BiVO4has been widely studieddue to its responsive on the visible light. By constructing porous structure, we could enhancethe absorption of light, and improve the photocatalytic performance of BiVO4; Photoniccrystal, as the substrate, could strengthen the effect of catalyst and light by the interface effect,thus contributing to the light absorption. Further, the applied electric field promoted theseparation efficiency of electronic-holes, thus integrating to the photocatalytic efficiencyfinally. The following two aspects were studied in this paper:(1)PS were prepared by a soap-free emulsion polymerization with styrene as monomer.Two sizes of PS were prepared depending on the different alcohol-water ratio,300nm, namedPS(300) and167nm, named PS(167). SEM revealed that the size of PS was uniform. TheTiO2PC was prepared by the template and liquid phase deposition method, PS(193) as atemplate agent and ammonium fluoride titanium as materia. TiO2PC anti-copied the structureof PS template precisely. DRS analysis showed, TiO2PC produced a strong "absorption" invisible region, we called it―photonic band gap‖.(2)Porous BiVO4were prepared by improved metal organic decomposition(MOD),PS(300) as template, bisumuth nitrate pentahydrate and vanadium triisopropylsilyl asmaterials. SEM results showed there were many pores in porous BiVO4. XRD results showedno significant difference in polymorphs of BiVO4and porous BiVO4.DRS analysis showed,porous BiVO4showed stronger absorption capacity than BiVO4in the visible region. TiO2PC/porous BiVO4was made by spin-coating. DRS and photocurrent showed that, when thelayer number of porous BiVO4film was4, TiO2PC/porous BiVO4exhibited the bestabsorption ability. The results of MB degradation under visible light showed that the reactionrate of TiO2PC/porous BiVO4is1.71times that BiVO4in photocatalytic process. In addition, photoelectrocatalysis results showed that the reaction rate of TiO2PC/porous BiVO4is2.38times that BiVO4.