云母（001）晶面结构对低维TiO2的诱导效应

In this project, considering that the ordered distribution of Si-O tetrahedron on the (001) face of mica substrate might display inducing effect on TiO2 film, large mica pieces of the first grade level was employed as supporting material of TiO2, in order to investigate the mechanism of cooperating effect between TiO2 film and high crystallized SiO2, which is useful in improving the combination-strength of these two substances and the photo-activity of loaded TiO2. As known, the arrangement of Si-O tetrahedron on the (001) face of mica is in ordered hexahydroxy net work. Such special crystalline structure and surface condition of mica substrate might influence many properties of loaded TiO2, such as the crystalline structure, the light-absorption ability, the photo-induced super-hydrophilic performance, and the photo-catalytic activity. In order to understand the relationship between the crystallization degree of SiO2 substrate and the photo-activity of TiO2 film, many properties of mica should be examined before and after activation treatment, such as the crystalline structure, the chemical component, the surface -OH condition, and the located acid site. All of these are helpful to reveal the interrelation among the catalytic-active sites of TiO2, the surface active sites of mica, and the crystal structure of mica substrate. The results of this project would provide theoretical foundation for the mineral loaded TiO2 which has higher photo-activity, lower cost, and better combination. It is also helpful to improve the combination-strength between mica powder and its surface coating materials, and even provide promising method in improving the photocatalytic activity of TiO2 loaded on other layer-structure silicates of 2:1 type. All of these are meaningful for promoting the additional value of natural mineral products in both theoretical and practical view.

为研究TiO2与高结晶度SiO2载体之间的界面结合及协同作用机制，改善二者的结合强度及TiO2光活性，本项目以大尺寸优质云母片为载体，利用云母(001)晶面上规则的Si、O排布诱导TiO2覆膜。探讨云母载体自身结构及表面状态对TiO2薄膜晶体结构、吸收光谱、光诱导超亲水性、光催化活性的影响，分析基底晶体结构及活化程度与低维TiO2光活性之间的关系。通过测试各种云母基片活化前后的成分、结构、表面-OH、固体酸中心等特征，分析TiO2催化活性点位、云母表面活性位置、以及载体晶面结构特征之间的联系，研究云母(001)晶面规则六元网状结构对TiO2薄膜结构及催化中心分布的诱导作用，为制备高活性、低成本、结合牢固的矿物负载型TiO2提供理论依据。其成果同样适用于改善云母表面包覆层的牢固性，也可为其它2:1型层状硅酸盐矿物负载高活性TiO2提供思路，对促进天然矿物高附加值产品开发具有理论和实践意义。

为研究TiO2与高结晶度SiO2载体之间的界面结合及协同作用机制，改善二者的结合强度及TiO2光活性，本项目以天然优质云母为载体，利用云母(001)晶面上规则的Si、O排布诱导TiO2覆膜。同时对比了多种2:1型层状硅酸盐矿物，探讨云母载体自身结构及表面状态对TiO2薄膜晶体结构、吸收光谱、光诱导超亲水性、光催化活性的影响，研究矿物(001)晶面成分、结构等对TiO2形貌、结构、性能的诱导作用，为制备高活性、低成本、结合牢固的矿物负载型TiO2提供理论依据。. 通过负载前后TiO2的相变规律的研究，结果显示天然硅酸盐矿物能够显著抑制TiO2的晶粒生长和相变过程，而普通玻璃或者化学合成SiO2则不具备这样的性能。尤其是在使用水解沉淀法和水热法的情况下，矿物负载后TiO2由锐钛矿向金红石的相转变温度可提升200~400℃，粘土矿物的脱羟过程不会诱发TiO2相变，而且结晶程度好且与TiO2的结合较为牢固的矿物载体（如云母化程度较高的伊利石）对TiO2相变的延迟作用更为显著。说明矿物载体晶面的长程有序结构能够对TiO2的晶格调整过程产生影响，显著提升这一相变过程的动力学势垒，这对改善锐钛矿型TiO2光催化剂的热稳定性非常有益。. 通过对比分析TiO2在不同2:1型粘土矿物片层表面的铺展规律，结果表明云母层间的钾会削弱TiO2与矿物之间的键合，而云母片层中的铝有助于改善TiO2与矿物之间的键合。通过对负载前后TiO2光催化活性及光诱导超亲水性的变化规律进行分析，表明云母改变了TiO2体内光生载流子的传输过程特征。其它矿物负载后也有类似的效果，但不同种类矿物对TiO2光催化氧化能力的影响规律有一定差异，相关数据还在进一步整理过程中，该方面的研究将有助于探讨矿物载体与TiO2协同作用的根源与机制。