二氧化钛中Ti3+活性物种的形成及其光催化机理的固体NMR研究

In order to promote the photocatalytic activity of TiO2 towards water splitting under solar irradiation, this project aims to develop a simple approach to produce stable and sufficient high Ti3+ in TiO2 by incorporation of boron (B) atoms into TiO2 lattice and further control the concentration and distribution of the active species (Ti3+) by varying the doping amount and synthesis conditions. To gain new insights into the microscopic structure, distribution, and formation mechanism of Ti3+ and B species, the B-TiO2-x photocatalysts will be investigated by advanced solid-state NMR techniques (such as two-dimensional multiple-quantum, and double-quantum MAS NMR correlation techniques) in conjunction with density functional theory (DFT) calculations. Combined with the experiments of visible-light absorption and photocatalytic activity measurements for a series of B-TiO2-x with different structures, the mechanism of (B, Ti3+) synergy and the structure-activity relationship will be clarified. To reveal the active sites on the surface of the photocatalysts, the adsorption and conversion of the reactants will be studied by in-situ 13C and 17O solid-state NMR techniques, which can be used to trace the photocatalytic pathway of water splitting to hydrogen production. Based on the intermediates and products observed in the in-situ NMR experiments, the transition states of the reaction can be studied by theory calculations, which will reveal the molecular-level mechanism of the catalytic reactions on the B-TiO2-x catalysts. All these findings are expected to be the basis for designing new TiO2-based photocatalytic materials with high activity and stability.

本项目拟通过在TiO2的晶格中引入适量的B元素制备出稳定且足量的Ti3+活性物种以提高TiO2对光解水制氢气的活性，通过改变B含量及合成条件实现Ti3+活性物种数量和分布的调控。采用先进的固体NMR技术（包括二维多量子和双量子相关技术等）和XPS、ESR等谱学手段并结合量子化学计算研究这类光催化剂中活性物种(B和Ti3+)的微观结构、分布及形成机制。结合紫外光谱和GC-MS等技术探索不同活性结构对光学特性和光催化活性的调变机制，阐明B和Ti3+活性位在光催化反应过程中的协同机制。利用原位固体NMR技术研究催化剂上光解水制氢气的反应机理，结合理论计算从分子水平阐明催化剂活性增强的微观本质，为稳定高效光催化剂的设计和制备提供依据。

本项目通过在TiO2的晶格中引入适量的B元素制备出稳定且足量的Ti3+活性物种以提高了TiO2对光解水制氢气的活性，通过改变B含量及合成条件实现了Ti3+活性物种数量和分布的调控。采用先进的固体NMR技术（包括二维多量子和双量子相关技术等）和XPS、ESR等谱学手段并结合量子化学计算确定了这类光催化剂中活性物种(B和Ti3+)的微观结构、分布及形成机制。结合紫外光谱和GC-MS等技术探索不同活性结构对光学特性和光催化活性的调变机制，阐明了B和Ti3+活性位在光催化反应过程中的协同机制。利用原位固体NMR技术确定了催化剂上光解水制氢气的反应机理，结合理论计算从分子水平阐明催化剂活性增强的微观本质，为稳定高效光催化剂的设计和制备提供了依据。