Elementary Steps in the photocatalytic Water Splitting over TiO2-based Model Electrode Systems

基于 TiO2 的模型电极系统光催化水分解的基本步骤

• 批准号: 220687630
• 负责人: Professor Dr. Timo Jacob
• 金额: --
• 依托单位: Physikalisch-Chemisches Institut
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/220687630?language=en
• 关键词: Elementary; Steps; photocatalytic; Water; Splitting

Hydrogen production through photo-induced splitting of water is a promising avenue for sustainable energy economy, although no cost-effective photocatalytic system has been identified so far. It is believed that a successful search for a new and improved photocatalyst will be based on a molecular understanding of all elementary reaction steps in the photocatalytic water splitting. In the present project model systems for photocatalytic water splitting on the basis of single-crystalline TiO2(110) and TiO2(011) will be prepared and extensively characterized by surface sensitive methods (in-situ) as well as theoretical (ab-initio) photo-electrochemical methods. Single crystallinity of the model systems is required to allow for a direct comparison of ab-initio calculations with corresponding experiments. The choice of TiO2 as photocatalyst material is motivated by its activity, being non-toxic, omnipresent, inexpensive and stable under photochemical reaction conditions. These preconditions are indispensable for the development of a future hydrogen fuel economy. However, the quantum efficiency of TiO2 for sun light is quite low as the band gap is quite wide with more than 3eV. Besides band gap engineering by doping with impurities such as N and Cr, the recently discovered dopant-free TiO2 phase on TiO2(011) with a band gap of only 2.1eV will be in the focus of the present project. The rate determining part in the photocatalytic splitting of water is the oxygen evolution reaction (due to the 4-electron process: OER). Therefore co-catalysts, such as RuO2, the best catalyst known for OER, are frequently co-added. The combined system of single crystalline TiO2-based model photocatalysts and ultrathin RuO2 films provides atomic-scale control of the interface that in turn is highly beneficial for electronic and structural characterization as well as the identification of elementary reaction steps in the photo-induced OER.

光诱导分解水制氢是可持续能源节约的一条很有前途的途径，尽管到目前为止还没有发现经济实惠的光催化系统。人们相信，成功寻找新的和改进的光催化剂将建立在对光催化分解水的所有基本反应步骤的分子理解的基础上。在本项目中，将制备基于单晶二氧化钛(110)和二氧化钛(011)的光催化分解水的模型体系，并用表面敏感方法(原位)和理论光电化学方法(从头算)对其进行广泛的表征。需要模型体系的单晶度才能直接将从头计算与相应的实验进行比较。选择二氧化钛作为光催化剂材料是因为它的活性，无毒，无处不在，价格低廉，在光化学反应条件下稳定。这些前提条件对于发展未来的氢燃料经济是不可或缺的。然而，二氧化钛对太阳光的量子效率很低，因为它的带隙很宽，超过3 eV。除了通过掺杂N和Cr等杂质来实现带隙工程外，最近在TiO2O11上发现的带隙仅为2.1 eV的无掺杂的TiO2相将是本项目的重点。光催化分解水的速率决定部分是析氧反应(由于四电子过程：OER)。因此，共催化剂，如已知的OER最好的催化剂RuO2，经常被添加到一起。基于单晶二氧化钛的模型光催化剂和超薄RuO2薄膜的组合系统提供了对界面的原子尺度控制，这反过来对于电子和结构表征以及识别光诱导OER中的基本反应步骤是非常有利的。