共价键联的PW11/TiO2介孔杂化材料的合成及其光催化性能

采用二次嫁接的方法，将Keggin结构的缺位钨磷酸盐PW11嫁接到介孔TiO2的表面，得到PW11/TiO2杂化样品。采用IR、低温N2吸附、XRD、TEM和ICP-AES等对样品的结构、PW11负载量以及键联机理进行了表征和研究，对样品光催化降解甲基橙的性能进行了考察。 结果显示，用蒸发诱导自组装法合成的TiO2，焙烧前结构松散，可部分水解并与PW11反应，生成PW11Ti物种，后者与TiO2骨架缩合，从而实现PW11的键联嫁接。 与纯TiO2相比，杂化样品中锐钛矿相的结晶度稍有降低，孔径、孔容减小，但是对甲基橙的光催化降解活性却明显增加，显然这是PW11和TiO2间发生了“协同效应”所致。

Synthesis of Covalent Bonded PW11/TiO2 Mesoporous Hybrid Materials and Their Photocatalytic Activity

Covalent bonded PW11/TiO2 mesoporous hybrid materials were prepared by grafting a lacunary tungstophosphate PW11 with Keggin structure onto the surface of mesoporous TiO2 that was synthesized using evaporation-induced self-assembly(EISA) method.The structure,PW11 loading and the mechanism for grafting were characterized and studied by means of IR,N2 adsorption-desorption,XRD,TEM and ICP-AES techniques.The photocatalytic activities of the hybrid samples for methyl orange degradation were also investigated.It was shown that as-prepared TiO2 via EISA method before calcinations had an incompact framework.It can partially hydrolyze and react with PW11 to form PW11Ti species,which could condense with TiO2 framework to lead to covalent linkage of PW11 on TiO2.Compared with pure TiO2 support,the crystallinity of anatase was lowered slightly,the pore size and the pore volume decreased in the hybrid samples.However,the activities for methyl orange degradation increased significantly,which can be attributed to the synergistic effect between polyoxometalate and TiO2.