表面键联型TiO2/SiO2固定化催化剂的结构及催化性能

 采用浸渍法制备了表面键联型TiO2／SiO2固定化光催化剂．XRD\r\n，FT－IR，XPS和BET比表面积测定结果表明，TiO2通过Ti－O－Si联结\r\n负载于多孔硅胶的表面，由此提出TiO2／SiO2的结构模型．考察了多孔\r\n硅胶的粒度及氧化钛负载量对催化剂活性的影响．对活性艳红K－2G（\r\nR15）的光催化脱色反应，最佳的光催化剂30％TiO2／SiO2（Ims30）比\r\nB－TiO2粉末的催化速率快3倍．随着载体粒度的减小，催化剂的比表面\r\n积增大，催化活性升高；多孔硅胶不仅起着支持体的作用，而且具有分\r\n散的作用；多孔硅胶具有很好的透光性．经ξ－电位测定，所制备催化\r\n剂的等电点为3．0pH单位，表明催化剂表面呈酸性．

Structure and Photocatalytic Performance of Surface Bond-Conjugated TiO2/SiO2 Catalyst

Surface bond conjugated TiO 2/SiO 2 catalyst was prepared by means of impregnation method with cyclohexane solution of tetrabutyl titanate. The catalyst overcomes the difficulty of liquid solid separation owing to the formation of milky dispersion after mixing the powdered TiO 2 in water. Based on the results of XRD, FT IR, XPS and BET measurements, the growth of TiO 2 (predominantly anatase) on the SiO 2 support seems to occur by anchoring the TiO 2 phase through Ti O Si cross linking bonds. The structure model of TiO 2/SiO 2 was proposed. Compared with B TiO 2, the most efficient catalyst is 30%TiO 2/SiO 2 (Ims 30), which showed three times higher photoactivity for degradation of reactive brilliant red K 2G(R15). In addition, the catalyst had higher photoactivity and bigger specific surface area on SiO 2 with smaller particle size than on that with larger particle size. SiO 2 gel plays the basic roles of dispersion and support for powder TiO 2. Meanwhile, SiO 2 gel has better transmission for light. The isoelectronic point of the catalyst was 3.0 pH units by measurement of zeta potential, indicating the presence of acidity on the catalyst surface.