TiO_2@酵母菌草莓结构型光催化剂的合成及其催化性能

调节水相悬浮液的pH值,使得酵母菌主体粒子和P25-TiO2客体粒子表面带相反电荷,通过静电自组装法一步合成了草莓结构的TiO2@酵母菌复合光催化剂。FESEM,EDS,FT-IR,XRD,UV-VIS表征了催化剂的物化结构。FESEM结果表明产品具有椭球形态,长度为(3.6±0.50)μm,宽度为(2.4±0.45)μm,分散性好。X射线粉末衍射表明TiO2客体粒子为锐钛矿和金红石矿晶型。紫外-可见光漫反射光谱证实催化剂对紫外光具有光响应。FT-IR分析表明TiO2@酵母草莓结构的形成与酵母细胞表面和TiO2粒子的表面化学官能团有关,其形成机理可概括为静电自组装过程。沉降性能测试表明该复合催化剂具有较好的悬浮性能,这有利于催化剂的分离回收。在光催化降解刚果红染料水溶液中,TiO2@酵母光催化剂表现出了较高的光催化活性。

Fabrication of TiO2@ yeast photocatalyst with raspberry-like structure and their catalytic performance

The opposite zeta-potentials of P25-TiO2 nanoparticles(guest particles) and yeasts(host particles) were achieved by adjusting pH of their own aqueous suspensions.Then TiO2@ yeast hybrid micro-spheres with raspberry-like structure were prepared by electrostatic interaction-driven self-assembly.The products obtained were characterized by field emission scanning electron microscopy(FESEM),Energy Dispersive Spectrometer(EDS),X-ray diffraction(XRD),and ultraviolet-visible spectrophotometry(UV-VIS),and fourier transform infrared spectroscopy(FT-IR),respectively.FESEM indicates that the resulting samples retain ellipsoid shape,with the uniform size length(3.6±0.50) μm,width(2.4±0.45) μm] and good dispersity.XRD pattern indicates that the main crystal structure of as-synthesized TiO2@ yeast microsphere is consisted of anatase and rutile.UV-VIS shows that the samples obtained have a good responding to UV light.FT-IR presents the possible formation mechanisms of TiO2@ yeast hybrid micro-spheres,which can be interpreted by the one-step electrostatic attraction self-assembly.The unique surface traits of the primitive yeast and TiO2 nanoparticles are responsible for the fabrications of TiO2@ yeast hybrid microspheres.The settling ability of particles indicates that the composite catalysts are good for recycling and reusing.They also exhibit a high photocatalytic activity for the degradation of Congo red dye aqueous solutions.