二氧化钛材料的氧空位调制及光催化降解室内气相污染物应用

Recently, non-stoichiometric TiO2-x, such as Black TiO2 and Ti3+-self-doping TiO2, has drawn much attention. It contains abundant oxygen vacancies in its lattice, and thus exhibits strong visible light absorbance and high visible light photocatalytic activity. The oxygen vacancies in the TiO2 materials are crucial to its photoexcitation, carrier dynamics as well as the surface reaction. However, the understanding towards the fundamental characteristics of the oxygen vacancies, as well as the interaction mechanism of different oxygen vacancy clusters to the photocatalytic performance of the TiO2 materials, is still insufficiently clear. In this project, vacuum-calcination method, as well as caicination under H2 flow, is adopted to prepare the TiO2 materials rich in oxygen vacancies. By selecting the raw nano-TiO2, changing the calcination parameters, the regulation to the amount and shape of the oxygen vacancies (clusters) can be achieved. Further, on the issues of the poor stability of the surface oxygen vacancies in TiO2, surface impurity (chemically adsorbed F- anion or surface hydroxyl group) modification, RuO2 load and deposition of noble metal clusters are used to study the effects of as-formed heterogeneous junction or surface modification towards the formation, the life-time of oxygen vacancies, as well as the photocatalytic performance of the TiO2 materials. The optimization of the oxygen vacancies-containing TiO2 as well as TiO2 composites is then carried out, and applied for the photocatalytic oxidation of indoor gaseous pollutants.

近年来，非计量比TiO2-x如黑色TiO2和Ti3+自掺杂TiO2等深受关注。此类TiO2富含氧空位缺陷，因此具有很好的可见光吸收和可见光光催化活性。TiO2材料的氧空位对其光致激发、载流子动力学乃至表面反应至关重要。然而，对于TiO2氧空位的基本特性以及不同形态的氧空位在光催化过程中的作用机制，目前人们的理解仍然不够清晰。在本项目中，拟利用真空煅烧或还原气氛煅烧的方法，制备富含氧空位的TiO2材料。通过TiO2原料的选择，煅烧工艺的改变，实现对TiO2中氧空位的数量和形态的调控。进而，针对TiO2表面氧空位稳定性不足的问题，采用表面杂质（F离子或表面羟基）修饰、二氧化钌负载，贵金属原子簇沉积等手段，考察上述手段形成的异质结结构或表面修饰对TiO2的表面氧空位的生成、寿命和光催化性能的影响。对含氧空位的TiO2及其复合物催化剂进行优选，并将其应用于室内气相污染物的光催化氧化降解处理。

近年来，含氧空位（Ov）非计量比TiO2-x在光催化材料制备及其环境应用中深受关注。本项目分别从商品TiO2、实验室自制无定形TiO2出发，利用真空煅烧的方法，制备了富含Ov的TiO2催化剂材料。通过TiO2原料的选择、煅烧工艺的改变,实现了对TiO2中Ov数量和形态的调控。TiO2表面Ov能够有效稳定TiO2表面沉积的二氧化钌和贵金属Pt纳米簇，改善其在催化领域的应用；进一步地，发现了TiO2表面的Ov作为活性位点促进了催化剂表面Pt纳米簇的光致尺寸调制，进一步改善催化剂的性能；通过表面杂质（F离子或表面羟基）修饰实现了对Ov的稳定化，进而改善了Ov-TiO2的光催化性能；发现表面杂质如F离子可通过占位效应，实现对于F-V-TiO2/Pt中表面Ov的化学稳定，获得了相对于无F改性催化剂的更为稳定的光催化活性。UV预处理4.0 h时间下，F-V-TiO2/Pt催化剂表现出了最高的CO光催化氧化速率常数，是未经UV预处理活化时的4.2倍。本项目的研究对于我们进一步了解Ov在TiO2光催化中的作用以及如何通过Ov获得性能更为优异的光催化材料，提供了实验和理论参考。