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

全球变暖的后果威胁着我们今天的日常生活。必须找到创新的解决方案，以减少二氧化碳和甲烷等危害气候的工业和废气。与此同时，必须尽快解决实施能源转型的主要问题之一：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通过可再生能源将工业气体和废气(CO2、CH4、H2、CO)转化为有价值的可运输燃料(甲醇CH3OH、乙醇C2H5OH等能源丰富的碳氢化合物)。然而，纯热或电供应的活化能通常不会导致所需的反应路径。一个有希望的解决方案是另外用光或用光和催化剂(光催化剂)来控制过程。然而，目前复杂反应的基本相互关系还没有被充分了解，还需要进一步的研究，所申请的基础设施将创造创新的可能性，利用在IAP(AG Nolte/Ackermann)建立的拉曼光谱，特别是FS-CARS，来解决光催化中的公开问题。CARS测量允许现场以高动力学和空间分辨率同时确定所涉及气体的温度和浓度，从而在详细研究复杂转化反应的中间步骤方面具有极大的优势。因此，要在IAP获得适当的气体反应器，除了在实际工艺条件下(在操作中)测量拉曼信号外，还将允许灵活地选择不同光催化剂和气体混合物的光激发。为了在国际比较中对结果进行定量评估，有必要扩展该设备，采用标准测量方法来确定气体浓度和转化率。因此，该装置将配备一台气相色谱仪，以便以最高的精度测定反应产物。借助于所应用的重力平衡，可以测定反应气体在光催化剂上的吸附，这是对所涉及的物质进行全面、定量表征所必需的。具体地，将涉及以下主题：-发展原位FS-CARS光谱以研究光催化反应过程。-作为激发光的性质(波长、脉冲长度、脉冲频率、强度、……)的函数的这些过程的色层研究-开发，选择性可控的高效光催化剂的制备和优化-基于改进的机理研究和过程优化的数据库，对气相光催化反应进行模拟。

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.