具有高效太阳光活性的氢化TiO2异相结构设计与光催化作用机制

The photocatalytic technology with high efficiency under the sunlight is the goal for which people are always seeking. The latest reported hydrogenated TiO2 photocatalyst could open a new door to improve solar photocatalytic performance. However, the relationship between microstructure-performance and photocatalytic mechanism has not yet come to a very clear conclusion. It is not yet understood how to modulate the microstructure and the energy band of TiO2 by controlling hydrogenation process. Especially, the single phase hydrogenated TiO2 can't realize the photocatalytic overall water-splitting. To address these critical scientific issues, the regulation and control of electronic properties and dimensional microstructures of hydrogenated TiO2 catalysts are considered as the staring point. A innovative hydrogenation-reduction method using the H2 and/or CO as reductive gas is designed to modulate the energy band structure of hydrogenated TiO2 and to reveal the relationship between microstructure and performance. Combining their different characteristics of the hydrogenated rutile and anatase TiO2, this project is to design and prepare the new hydrogenated TiO2 heterophase structures, which have the characteristics of the solar photocatalytic overall water-splitting and enhanced photocatalytic efficiency due to easy separation of electrons and holes in the space. Using a variety of modern characterization techniques and theoretical calculations, the goal is to elucidate the photocatalytic mechanism under UV-Vis irradiation, and further propose the rationally designing method for the efficient hydrogenated TiO2 photocatalyst. This project will provides a new direction for the practical technology of photocatalytic water-splitting into hydrogen using sunlight efficiently, which has very important scientific significance and wide application prospects in the field of energy and environment.

具有高效太阳光活性的光催化技术一直是人们追求的目标，最近报道的氢化TiO2，在提高太阳能光催化性能方面打开新的一扇门。但目前微观结构-性能与催化机制的关系尚不清晰，如何控制氢化过程调变TiO2微观结构与能带尚未认识，特别是受到单一相氢化TiO2的不能实现光催化全分解水的限制。针对这些关键科学问题，项目从调控电子性能与空间微观结构出发，创新设计H2与CO的组合的氢化-还原方法，调变氢化TiO2的能带结构，明晰微观结构与性能的关系；结合金红石与锐钛矿TiO2氢化的不同特征，设计与制备氢化TiO2异相结构，使其具有太阳光全分解水的特性，同时使电子和空穴在空间上分离，提高光催化效率；通过多种现代表征技术结合理论计算阐明其紫外-可见光下的光催化机制，在此基础上提出氢化TiO2催化剂理性设计新方法。该研究为高效利用太阳光的光解水制氢实用技术突破提供新的方向，在能源、环境领域具有非常重要的科学意义。

氢化TiO2光催化剂的发现为高效利用太阳光的光催化技术开辟了一个新的方向，但目前微观结构与催化机制的关系尚不清晰，如何控制氢化过程调变TiO2微观结构与能带来提高紫外-可见光催化性能仍需深入研究。本项目采用新的氢化-还原方法，结合金红石相与锐钛矿相TiO2氢化的不同特征，调变其能带与空间微观结构，明晰微观结构与性能的关系；设计界面氢化的TiO2异相结构催化剂，大大提高了太阳光的利用效率，探索了氢化TiO2异相结构光电催化机理；以氢化TiO2为基础发展了一系列高活性的光催化制氢催化体系。主要研究进展与成果： (1) 首次通过“水热合成-氢化-分枝”三步成功合成了界面氢化的锐钛矿/金红石型TiO2异相结薄膜，在模拟太阳光下其制氢效率每小时达到136.5 微摩尔/平方厘米，是TiO2异相结4.3倍，是表面氢化TiO2异相结的2倍，采用多种技术系统研究了不同氢化形式的TiO2光催化剂的微观结构、能带分布与光电性能的本质联系；（2）创新采用CO和H2对TiO2还原进行比较研究，制备得到不同结构的还原TiO2光催化剂，研究了无序层厚度、晶型、氧空位、Ti3+、Ti-OH以及Ti-H与光催化性能的关系，提出体相氧空穴与表面Ti-OH协同作用是氢化TiO2高活性的主要原因，发展了提高氢化TiO2材料可见光催化活性的设计方法；（3）在氢化的TiO2纳米棒阵列上负载非贵金属MoS2助催化剂替代贵金属Pt，用于光电催化分解水制氢展现了与贵金属相当的效率，基于此发展了低成本且可重复使用的光电催化制氢系统；（4）探究了异质结光催化剂的电子传递过程，开发了原位光电化学-KPFM表征的分析方法。该研究为有效利用太阳光的光催化材料提供新的方向，在能源、环境催化领域具有重要的科学意义与应用前景。以此为依托发表学术论文20篇，其中JCR 1区论文12篇；申请发明专利3项，授权1件；毕业博士2人，硕士4人。