Towards an understanding of the surface photocatalytic decomposition of H2O: Electronic structure and femtosecond electron dynamics

该项目旨在从根本上了解吸附在Ru和Ru氧化物表面上的水的光刺激分解，这对利用太阳光将水转化为氢的可再生能源的开发具有关键意义。我们将与莱顿、剑桥和伦敦的研究小组合作，使用飞秒时间分辨光谱技术和理论模型来研究这一过程的动力学和机制。特别是，我们将重点研究裸表面和水/衬底界面的电子结构和电荷转移动力学。我们的目标是确定启动水的光催化分解的相关能级，并表征吸附-底物界面上的激发寿命和竞争电子弛豫动力学。利用吸附在单晶Ru(001)表面、全氧覆盖(1x1)O/Ru(001)表面和Ru氧化物薄层上的水以及共吸附的碱原子，表面的复杂性将以受控和系统的方式变化。作为实验技术，我们将使用紫外光电子能谱(UPS)和飞秒时间分辨双光电子能谱(2PPE)，这使得我们可以同时研究激发态的能级和动力学。

This project aims towards a fundamental understanding of the photostimulated decomposition of water adsorbed on ruthenium and Ru-oxide surfaces, which is of key relevance for development of renewable energy sources by conversion of water to hydrogen using sunlight. In collaboration with the groups in Leiden, Cambridge and London we will use femtosecond time-resolved spectroscopic techniques and theoretical modeling to investigate the dynamics and mechanism of this process. In particular, we will focus on the electronic structure and the charge transfer dynamics of both the bare surface and the water/substrate interface. Our goal is to identify the relevant energy levels that initiate the photocatalytic decomposition of water and characterize the excited lifetimes and the competing electron relaxation dynamics at the adsorbate-substrate interface. The complexity of the surface will be varied in a controlled and systematic way using of water adsorbed on a single crystal Ru(001) surface, on a fully oxygen-covered (1x1)O/Ru(001) surface and on thin Ru-oxide layers as well as co-adsorbed alkali atoms. As experimental techniques we will use ultraviolet photoelectron spectroscopy (UPS) and femtosecond time-resolved two-photoemission (2PPE), which allows to study both the energetics and the dynamics of the excited state.