Valence Photoelectron and Auger-Emission Spectroscopy from the Solid-Aqueous Solution Interface under Operando Photochemical Conditions

原位光化学条件下固体-水溶液界面的价光电子和俄歇发射光谱

• 批准号: 319327379
• 负责人: Dr. Robert Seidel
• 金额: --
• 依托单位: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB)
• 依托单位国家: 德国
• 项目类别: Independent Junior Research Groups
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/319327379?language=en
• 关键词: Valence; Photoelectron; Auger; Emission; Spectroscopy

Solar energy is an inexhaustible natural source of energy, and hence plays an exceptional role in our search for future solutions to the global energy needs due to an increasing world population and increasing demand in clean energy. Here, the main challenge is an efficient collection and storage of solar energy in chemical bonds, in so-called solar fuels. This is analogous to the ability of plants' ability to convert sunlight, water and CO2 into usable forms of energy through photosynthesis. One of the most promising processes for technological application, which eventually replaces the technologies based on traditional non-renewable energy sources, is the splitting of (abundant) water at a semiconductor surface acting as a catalyst, in the presence of sunlight. The device to realize such processes is a photoelectrochemical cell (PEC), consisting of an aqueous electrolyte, a semiconductor anode exposed to light, and a metal cathode. Two principle reactions characterize the water decomposition, the evolution reaction of molecular oxygen, O2, (at the photoanode) and the evolution reaction of hydrogen gas, H2, at the cathode. The work proposed here focuses largely on the former half-reaction. From the technologic point of view the crucial issues are the development of stable, inexpensive and abundant materials for high-performance PEC electrodes, especially the improvement of the photoanode properties for efficient water splitting. Such a material optimization must however go hand in hand with an in-depth understanding of the underlying atomic-level interactions at the solid-water interface, both with and without illumination. It is undisputed that one of the most powerful experimental tools to access the desired electronic-structure information is photoelectron (PE) spectroscopy which however only now has been developed for application to the solid-water interface. This field of spectroscopy is still very young, and perhaps a dozen scientific works have been reported, and among the most recent accomplishments is the application of PE spectroscopy from an actual PEC. My aim is to investigate recently discovered aspects of PE spectroscopy from a liquid microjet (based on the detection of Auger and valence electrons) from neat aqueous solutions to advance our understanding of the atomic-level processes at the solid-solution interface. This is an important step, and complementary to previous PE spectroscopy studies, in uncovering mechanisms of photocatalytic water splitting towards developing improved solar-converted energy concepts.

太阳能是一种取之不尽用之不竭的天然能源，因此在我们寻求未来解决方案以满足全球能源需求方面发挥着特殊作用，因为世界人口不断增加，对清洁能源的需求不断增加。在这里，主要的挑战是有效地收集和储存化学键中的太阳能，即所谓的太阳能燃料。这类似于植物通过光合作用将阳光、水和二氧化碳转化为可用能量的能力。技术应用中最有前途的方法之一，最终取代基于传统不可再生能源的技术，是在阳光下，在半导体表面作为催化剂分解（丰富的）水。实现这种过程的装置是光电化学电池（PEC），其由含水电解质、暴露于光的半导体阳极和金属阴极组成。两个主要反应表征了水的分解，即分子氧O2的析出反应（在光阳极处）和氢气H2的析出反应（在阴极处）。这里提出的工作主要集中在前半反应。从技术的角度来看，关键问题是开发稳定，廉价和丰富的高性能PEC电极材料，特别是提高光电阳极的性能，以有效地分解水。然而，这样的材料优化必须与深入了解固体-水界面处的潜在原子级相互作用密切相关，无论是否有照明。毫无疑问，获得所需电子结构信息的最强大的实验工具之一是光电子（PE）光谱，但现在才被开发用于固体-水界面。光谱学的这一领域仍然非常年轻，也许已经报道了十几项科学工作，其中最新的成就是从实际PEC中应用PE光谱。我的目的是调查最近发现的方面的PE光谱从液体微射流（基于俄歇和价电子的检测）从纯水溶液，以推进我们的理解的原子级过程在固溶体界面。这是重要的一步，并补充以前的PE光谱研究，在揭示光催化水分解机制，以发展改进的太阳能转换能源的概念。