炭气凝胶孔结构对其负载的TiO2光催化降解甲基橙性能的影响

摘要

选用两种孔径不同的炭气凝胶CA125和CA500制备了碳含量为20%的TiO2/CA光催化剂,采用X射线衍射、扫描电镜和N2吸附-脱附对催化剂进行了表征,并考察了其光催化降解甲基橙反应性能.结果表明,TiO2/CA样品中TiO2主要以锐钛矿相存在,伴随有少量的金红石相,且均匀分散于炭气凝胶的表面.催化剂的孔隙率分析表明,孔结构直接影响到催化剂的光催化活性,以中孔为主的TiO2/CA125活性要远高于TiO2/CA500.这主要源于中孔良好的吸附性能及其合适的空间限域效应.%Two kinds of carbon aerogel (CA). CA125 and CA500, with pore diameters of ～18 nm and ＞ 50 nm. respectively, were used as supports to prepare TiO2/CA photocatalysts with the CA content of 20％. X-ray diffraction. scanning electron microscopy and N2 adsorption-desorption were used to characterize the crystal structure. morphology, and pore structures of the TiO2/CA photocatalysts, respectively.The loaded TiO2 was mainly anatase with a little amount of rutile. which was homogeneously dispersed on the CA support. The activity of TiO2/CA125 was much higher than that of TiO2/CA500 in the photodegradation of methyl orange. The photodegradation rate over TiO2/CA is mainly influenced by the pore structure of the catalysts. The favorable adsorption and suitable confinement effect of mesopore structure are beneficial to the photodegradation of methyl orange. Therefore. TiO2/CA125 with the large amount of mesopores displays the higher photocatalytic activity than TiO2/CA500.