探索影响共掺杂金属氧化物光电催化性能的内在限制因素及其性能优化

Compared with mono-doping, co-doping with metal and non-metal elements could effectively narrow the bandgaps of metal oxide semiconductors such as TiO2; however, experimental research finds that the introduced visible light absorption by co-doping cannot be efficiently utilized in the photocatalytic process. Currently, the investigation on co-doped metal oxides still mainly focuses on the theoretical prediction, while the experiment research only reports the observed phenomenon and superficial analysis of the photocatalyic performance. The intrinsic limiting factors in the co-doping metal oxides for photocatalysis are still unknown and also there is no clear guidance to help design effective strategies to improve the performance of co-doped metal oxides. In this proposal, we will use TiO2 and typical co-doped systems such as Cr-N, V-N and Mo-C as the main studying materials, and employ x-ray photoelectron spectroscopy (XPS),ultraviolet photoelectron spectroscopy (UPS), time resolved transient absorption spectroscopy (TR-TAS) and quasi in-situ synchrotron x-ray absorption fine structure spectroscopy (XAFS) to elucidate the intrinsic limiting factors of co-metal oxides for photoelectrochemical (PEC) activity from the perspectives of optics, spectroscopy dynamics, electronics and the local micro-structures of dopants, and finally develop effective approaches to improve the PEC water splitting performance of co-doped metal oxides.

相比单个元素掺杂，金属-非金属共掺杂能够有效缩小金属氧化物半导体如TiO2的能带间隙；但是实验发现共掺杂引入的可见光并不能被光电催化过程有效利用。当前对共掺杂金属氧化物的研究更多是从理论模拟上的预测，而实验上的研究依然主要停留在对实验现象的报道和简单的催化性能分析，以至于限制共掺杂金属氧化物光电催化性能的内在因素尚不清楚，以及如何设计有效策略进一步提升其光电催化性能也没有明确的指导。在这个项目中，申请人拟以常见的金属氧化物TiO2和一些典型的共掺杂体系（Cr-N, V-N和Mo-C）作为主要研究对象，利用X射线光电子能谱（XPS）、真空紫外光电子能谱（UPS）、准原位同步辐射X射线吸收精细结构分析光谱(XAFS) 以及时间分辨瞬态吸收光谱等技术手段，从光学、光谱动力学、电学以及掺杂元素局部微观结构等方面, 理清限制共掺杂金属氧化物光电催化性能的关键因素，进而设计有效方法提升其光电催化性能。

利用光、电驱动电解水制氢是实现氢能经济的关键，催化材料是其中的核心组件也是影响性能的关键因素。针对限制光、电催化水分解性能的内在关键因素不清楚的科学问题，本项目借助多种物理化学精细结构表征手段，如X射线光电子能谱，真空紫外光电子能谱以及同步辐射X射线精细结构吸收谱等，通过关联催化剂微观局域结构、电子结构和催化性能，系统理清限制催化性能提升的内在关键因素，进而设计新颖的掺杂体系以提高催化剂的光、电催化性能。该项目按照计划执行，并进一步拓展金属氧化物催化剂到其他非氧化物催化剂如硫化物、氮化物、磷化物和贵金属等，系统研究了轨道结构与催化性能之间的构-效关系，揭示了限制催化性能提升的关键因素；项目执行过程中一共发表论文15篇，包括3篇Nature Communications，1篇Science Advances，2篇Advanced Materials，1篇Angewandate Chemie International Edition，1篇Advanced Energy Materials。该项目的研究为发展新型高性能的光、电催化剂提供一定的实验基础和理论依据。