Gas reactor for in situ studies of photocatalysis and energy conversion processes

全球变暖的后果今天威胁着我们的日常生活。必须找到减少对气候有害的工业和废气（如二氧化碳和甲烷）的创新解决方案。与此同时，实施能源转型的一个主要问题必须尽快解决：无法储存可再生能源。解决这两个问题的一个有希望的方法是将工业废气（CO2, CH4, H2， CO）通过可再生能源转化为有价值的可运输燃料（能量丰富的碳氢化合物，如甲醇CH3OH，乙醇C2H5OH）。然而，纯热或电的活化能供应通常不能导致期望的反应途径。一个很有前景的解决方案是用光或光和催化剂（光催化剂）来额外控制过程。然而，目前对这些复杂反应的基本相互关系还没有充分了解，需要进一步的研究。申请的基础设施将创造创新的可能性，使用在IAP （AG Nolte/Ackermann）建立的拉曼光谱，特别是fs-CARS，来解决光催化中的开放性问题。CARS测量允许在现场，具有高动态和空间分辨率，同时确定所涉及的气体的温度和浓度，因此在复杂转化反应中间步骤的详细研究中具有极大的优势。因此，将在IAP获得一个适当适应的气体反应器，除了在实际工艺条件下（在operando中）测量拉曼信号外，还将同时允许灵活选择不同光催化剂和气体混合物的光激发。为了对结果进行定量评价，也在进行国际比较时，有必要扩展设备，用标准的测量方法来测定气体浓度和转化率。因此，该装置应配备气相色谱仪，以便以最高的精度确定反应产物。利用重力天平可以测定光催化剂上反应气体的吸附量，这是对所涉物质进行全面、定量表征所必需的。特别是，以下主题将讨论：-原位fs-CARS光谱研究光催化反应过程的发展。-色谱研究这些过程作为激发光性质（波长，脉冲长度，脉冲频率，强度等）的函数-开发，制造和优化具有可控选择性的高效光催化剂-基于改进的数据库的气相光催化反应的模拟，用于机理研究和过程的优化。

The consequences of global warming threaten our daily lives today. Innovative solutions to reduce climate-harming industrial and exhaust gases such as CO2 and CH4 must be found. At the same time, one of the main problems in implementing the energy transition must be solved as quickly as possible: the inability to store renewable energy. A promising approach to solve both issues is the conversion of industrial and waste gases (CO2, CH4, H2, CO) by means of regenerative energy into valuable and transportable fuels (energy-rich hydrocarbons such as methanol CH3OH, ethanol C2H5OH). However, the purely thermal or electrical supply of activation energy does not usually lead to the desired reaction pathways. A promising solution is to additionally control the processes with light or with light and catalysts (photocatalysts). However, at present the fundamental interrelationships of the complex reactions are not yet sufficiently understood and further research is needed.The infrastructure applied for will create the innovative possibility to use Raman spectroscopy established at the IAP (AG Nolte/Ackermann), in particular fs-CARS, to solve open questions in photocatalysis. CARS measurements allow in situ, with high dynamics and spatial resolution, to determine the temperature and concentration of the gases involved simultaneously and thus promise extreme advantages in the detailed study of the intermediate steps in the complex conversion reactions. Therefore, an appropriately adapted gas reactor is to be obtained at the IAP, which, in addition to the measurement of the Raman signal under the actual process conditions (in operando), will simultaneously allow flexible options for the light excitation of different photocatalysts and the gas mixtures.For the quantitative evaluation of the results also in the international comparison it is necessary to extend the equipment, by a standard measuring method for the determination of gas concentrations and conversion rates. The setup is therefore to be equipped with a gas chromatograph in order to determine reaction products with the highest precision.With the aid of the gravitational balance applied for, the sorption of the reaction gases on the photocatalysts can be determined, which is necessary for the comprehensive, quantitative characterization of the substances involved.In particular, the following topics will be addressed:- Development of in situ fs-CARS spectroscopy to study photocatalytic reaction processes.- Chromatographic investigation of these processes as a function of the properties of the excitation light (wavelength, pulse length, pulse frequency, intensity, ...)- Development, fabrication and optimization of highly efficient photocatalysts with controllable selectivity- Simulation of gas-phase based photocatalysis reactions based on the improved data base for mechanistic investigation and optimization of the processes.