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钌和钌氧化物表面上的水的光刺激分解，这对于通过利用阳光将水转化为氢来开发可再生能源具有关键意义。在与莱顿，剑桥和伦敦的小组合作，我们将使用飞秒时间分辨光谱技术和理论建模来研究这个过程的动力学和机制。特别是，我们将专注于裸露表面和水/基板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，并表征在吸附物-衬底界面处的激发寿命和竞争电子弛豫动力学。表面的复杂性将以受控和系统的方式变化，使用在单晶Ru（001）表面上、在完全氧覆盖的（1x 1）O/Ru（001）表面上和在薄Ru氧化物层上吸附的水以及共吸附的碱原子。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发射（2 PPE），这使得研究能量和激发态的动力学。

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 timeresolved 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.