基于微波原位生长方法的介观结构TiO2/CNTs复合材料的制备及其光催化性能研究

In this project, through the design of ferrocene functioned nonion surfactants, the precusors for growth of CNTs will be introduced into the pores of mesostructured TiO2. CNTs can be formed by microwave irradiation where conducting polymers, resulting from the polymerization of pyrrole or thiophene rings of nonion surfactants, act as heating layer and ferrocene decomposes to be both of catalyst and carbon source. The photocatalytic properties of TiO2 will be optimized by studying the effect of structured directing agents and external conditions on the structures of hybrid materials, as well as analyzing their structure-activity relationship. The innovations of this project are summarized as below: First, nonion surfactants, as structure directing agents to prepare mesostructured TiO2, are synthesized by chemical linking the ferrocene and pyrrole or thiophene moieties, which will make the distance between ferrocene and pyrrole or thiophene moieties controllable and benefit the transfer of energy and the growth of uniform CNTs. Second, in-situ growth of CNTs in the pores of mesostructured TiO2, which will be helpful to control the sizes of CNTs and the close contact with TiO2. Therefore, the photocatalytic cooperative action between TiO2 and CNTs can be further improved.

本项目拟通过设计二茂铁功能化的非离子表面活性剂，将合成碳纳米管（CNTs） 所需的前体引入介观结构TiO2 的孔道中，并利用微波法原位生长CNTs，从而制备高度有序的TiO2/CNTs 复合材料。在CNTs 生成的过程中，非离子表面活性剂中的吡咯或噻吩基团聚合产生的导电高分子充当加热层，二茂铁分解为催化剂和碳源。通过研究不同结构导向剂及外界条件对复合材料结构的影响，并分析其结构与性能之间的构效关系，从而优化TiO2 的光催化活性。本项目的创新点在于：将二茂铁催化剂键合到吡咯或噻吩上，并用作制备介观结构的TiO2 的结构导向剂，从而使得二茂铁和导电聚合物之间的距离变得可控，有利于能量的传递，从而生成均匀的CNTs；在介观结构TiO2 的孔道内原位生长CNTs，便于准确控制CNTs 的尺寸及其与TiO2 均匀、紧密的接触，从而更大程度地发挥TiO2 和CNTs 的光催化协同作用。

纳米材料的可控制备及其光催化性能的提高是制约光催化反应发展的关键问题。微波辐射法制备纳米材料具有操作简便，成本低，效率高和环境友好等优点，已被广泛应用于合成碳纳米及其复合材料。本项目采用微波辐射方法，以氧化石墨烯作为吸热源，通过简单的家用微波炉微波加热制备了石墨烯及其复合材料，ZnO/graphene和MWCNTs/graphene，复合材料的电化学性能得到了明显提高。在研究TiO2的光催化性能时，发现通过添加合适的助催化剂可以显著提高TiO2的光电催化水分解速率。另外，项目研究发现通过元素掺杂和自掺杂可以显著提高钙钛矿型半导体的光催化性能。项目表明半导体的光吸收能力和载流子传输速率是影响催化性能的关键因素。