黑色二氧化钛纳米材料的结构和产氢机制的理论研究

Photo-catalytic technique is a new, energy-efficient and environmental friendly technique. TiO2 is attracting great attention because of its high photo-catalytic activity, low toxicity and high stability. In 2011，a new type of highly reduced black TiO2 nanomaterials has been observed. It has much higher efficiency in photo-catalytic water dissociation and some other processes, therefore became a new research hot spot in photo-catalytic materials. In recent years, great progresses have been made in the experimental side. However, due to the complexity of the black TiO2 system and the lacking of the enough techniques, the detailed structure feature of the materials, the reason of the high photo absorption efficiency, and mechanism of high H2 production efficiency are not well understood yet. Theoretical studies are therefore highly desired to accompany with the experimental works to get further improvements. In this project state-of-art theoretical methods will be used to study the detailed structure feature of black TiO2 nanomaterials containing high concentration of O defections and H doping. Then we will investigate the reasons behind the high photo absorption efficiency and the mechanism of H2 production in black TiO2 nanomaterials. With these results, we will discuss which type of structure is needed for black TiO2 to have good performance in photo-catalytic reactions, and try to provide theoretical support and valuable suggestions for design better black TiO2 nanomaterials. Our research experiences on the structure and reactivity of TiO2 surface, the mechanism of H2 production, as well as the cluster chemistry will provide a solid basis for the success of this project.

光催化技术是一种高效节能的现代绿色环保技术，二氧化钛以其良好的光催化性能、低毒以及高稳定性被广泛使用和关注。2011年科学家发现一类包含高还原性缺陷的黑色二氧化钛纳米材料在光解水产氢等过程中表现非常优异，并迅速成为近期光催化材料的一个研究热点。目前该领域已积累了大量的实验成果，但由于其体系的复杂性以及实验手段的制约，对其结构、高光吸收效率和高产氢效率的机制的认识还非常不足，亟需相关理论研究的跟进与配合。本项目将利用当前先进的理论化学方法，首先研究含有高浓度氧空位和高浓度氢掺杂的黑色二氧化钛纳米团簇材料的结构特征，继而系统研究黑色二氧化钛材料高光吸收效率的机制及其产氢的机理，探索这些优良的性质在材料结构上的需求，为设计出具有更优性能的黑色二氧化钛光催化体系提供理论基础和指导意见。我们在二氧化钛表面结构、产氢机制以及团簇化学方面的研究积累将为本项目的顺利实施提供坚实的基础。

二氧化钛具有良好的光催化性能，且具有廉价、低毒以及高稳定性等优点，在光催化领域受到广泛关注。近年来一类包含高还原性缺陷的黑色二氧化钛纳米材料在光解水产氢等过程中表现优异，并迅速成为研究热点。在本项目的资助下，我们对二氧化钛纳米团簇体系开展了系统的理论研究。在团簇的结构、稳定性、缺陷分布方面，我们发现了多个小团簇的大量新低能异构体和个别团簇的新基态结构，发现团簇和表面中氧空位形成的尺寸效应并解释了其内在原因，探讨了氧空位的聚集行为。在光催化和产氢方面，我们研究了团簇和表面的光催化特征，产氢及其影响机制，C-H活化机制等。这些研究成果加深了对理解黑色二氧化钛的结构和功能的理解，为进一步的研究提供了基础，并对其改性研究提供了一些理论参考。