多金属氧酸盐/TiO2介孔杂化材料的合成及光催化性能研究

采用蒸发诱导自组装法合成了介孔TiO2,并将表面含有Si-OH基团的钨磷酸盐衍生物(Bu4N)3PW11O39-[O(SiOH)2](TBAPW11Si2)嫁接到乙醇回流脱模的介孔TiO2上,合成了TBAPW11Si2/TiO2介孔杂化材料.采用IR、XRD、N2吸附-脱附、TEM、ICP-AES对样品的结构和组成进行了表征.结果表明,TBAPW11Si2与TiO2之间的共价键联是通过表面Si-OH和Ti-OH间的缩合进行的;TiO2表面足够的Ti-OH基团和一定温度的焙烧是这一缩合的必要条件.与TiO2载体相比,嫁接了TBAPW11Si2的杂化样品,锐钛矿相的结晶度略有增加;但表面积、孔容和孔径均有所减小,且随TBAPW11Si2负载量的增加而降低.光催化降解甲基橙的结果显示,杂化样品表现出比载体TiO2高得多的催化活性,甚至与高结晶度的商品光催化剂P25相当,显示出多金属氧酸盐-TiO2协同作用的优越性.

Synthesis of Polyoxometalate/TiO2 Mesoporous Hybrid Materials and Their Photocatalytic Performance

A tungstophosphate derivative,(Bu4N)3PW11O39[O(SiOH)2](TBAPW11Si2),with Si-OH groups on the surface was grafted on mesoporous TiO2 synthesized by an evaporation-induced self-assembly method.Such TBAPW11Si2/TiO2 mesoporous hybrid materials were characterized by IR,XRD,N2 adsorp-tion-desorption,TEM and ICP-AES techniques.It was shown that the covalent linkage between TBAPW11Si2 and TiO2 formed by condensation of Si-OH on TBAPW11Si2 with Ti-OH on TiO2.Enough Ti-OH groups on TiO2 surface and the calcination at a certain temperature were necessary for the condensa-tion.Compared with TiO2 support,the hybrid samples had a little higher crystallinity of anatase,but the sur-face area,pore volume and pore size decreased as TBAPW11Si2 loading increased.In the degradation of methyl orange,these hybrid samples exhibited higher photocatalytic activities than anatase TiO2 support,and their activities were even comparable with that of Degussa P25 with much higher crystallinity,which can be mainly attributed to a synergistic effect between polyoxometalate and TiO2.