Running Projects

Fundamental Investigations on the Efficiency of Microstructured Photoreactors

The aim of the project is the investigation of microstructured photoreactors in terms of reaction engineering. Therefore not and homogeneous catalyzed photoreactions will be used to characterize the radiation field. Primary objective will be the development of general design rules providing a tool for choosing or developing efficient photoreactor systems. In this context design rules shall be developed both for laboratory and technical scale reactors. With this a systematic optimization approach will be developed to support the currently primarily used empiric optimization. Furthermore the potential of microreactortechnology for large scale use shall be evaluated.

Involved Members: Benjamin Wriedt, Maximilian Sender

Funding: Deutsche Forschungsgemeinschaft (DFG); ZI 1502/4-1

Key Publications:

  1. M. Sender, D. Ziegenbalg, Light Sources for Photochemical Processes -- Estimation of Technological Potentials; Chemie Ingenieur Technik, 2017, 89, 1159-1173, 10.1002/cite.201600191
  2. B. Wriedt, D. Kowalczyk, D. Ziegenbalg, Experimental Determination of Photon Fluxes in Multilayer Capillary Photoreactors, ChemPhotoChem, 2018, 10.1002/cptc.201800106


Heterogeneous photocatalysis has been known for a long time mainly for its applications in degradation of organic impurities and photocatalytic water splitting. However, especially in recent years, photocatalytic reactions have also become important in organic synthesis. The irradiation of semiconductors with light of a suitable wavelength produces very reactive states, so called electron-hole pairs, which can be used for a variety of chemical reactions such as oxidations, reductions or C-C couplings.

Using the example of quinoline synthesis two important directions for the current development of photocatalysis are to be addressed in the present research project. On one side improved and optimized for organic synthesis photocatalysts will be developed and on the other side a scalable photoreactor concept in which the process can be operated continuously is aimed. The results should be applicable not only for the selected target reaction, but also for other heterogeneous photocatalytic reactions.

The work program is handled by three research partners:

At Justus-Liebig-Universität Giessen, the research group Marschall works on the further development of photocatalysts.

At DECHEMA Research Institute, kinetics studies are used to investigate and optimize the reaction behavior.

Photoreactor development is carried out at the research group Ziegenbalg, Institute of Chemical Engineering at Ulm University. Various photoreactor concepts are to be developed and investigated using rapid prototyping. In this case, both approaches in which the photocatalyst is suspended and those which are immobilized on the walls of the photoreactor are tested and compared.

Involved Members:  Fabian Guba 

Collaborators: Dr. Jonathan Z. Bloh, Prof. Dr. Roland Marschall

Funding: Supported by Federal Ministry of Economic Affairs and Energy (BMWi) on the basis of a decision by the German Bundestag within the project within the project IGF 18904 N/3

Key Publications:

  1. F. Guba, Ü. Tastan, K. Gugeler, M. Buntrock, T. Rommel, D. Ziegenbalg, Chemie Ingenieur Technik. 2019, 91 (1–2), 17–29. 10.1002/cite.201800035.

Modular Industrial Scale Conti-Flow Photoreactor (MISCOP)

The project aims on developing an innovative, modular photoreactor by utilizing LEDs. Therewith, especially the energetic efficiency will improved. Furthermore, new degrees of freedom will be opened regarding the reactor design. This allows the installation of equipment to intensify the mass and heat transport without negative effects on the radiation field. This leads to more compact reactors. Through a systematic theoretical and experimental characterization and optimization of the reactor, general design rules will be available by the end of the project. These rules will be used to manufacture a demonstrating reactor. The project is a collaboration with Peschl Ultraviolet GmbH.

Involved Members:  Florian Gaulhofer

Collaborators: Peschl Ultraviolet

Funding: Supported by Federal Ministry of Economic Affairs and Energy (BMWi) on the basis of a decision by the German Bundestag within the project ZF4496701ZG7

Key Publications:

  1. Ü. Taştan, D. Ziegenbalg, Getting the Most out of Solar Irradiation: Efficient Use of Polychromatic Light for Water Splitting, Chemistry - A European Journal, 2016, 22, 18824-18832, 10.1002/chem.201602709.
  2. D. Ziegenbalg, B. Wriedt, G. Kreisel, D. Kralisch,Investigation of Photon Fluxes within Microstructured Photoreactors Revealing Great Optimization Potentials, Chemical Engineering & Technology, 2016, 39, 123-134, 10.1002/ceat.201500498

Unsteady Operation of Photoreactions

Using solar energy faces the substantial challenge of an unsteady photon (energy) supply. From an energetic point of view this leads to the necessity of storage capacities to transform the unsteady energy supply to a steady one. For preparative photochemistry or air and water treatment storing is not a suited option. For such processes reaction control is the key to high yields and efficiencies. The aim of the project is to investigate the influence of a varying photon flux on the performance of different photochemical reactions by means of experimental and theoretical investigations.

Involved Members: Christian Köcheler

Key Publications:

  1. I. Reim, B. Wriedt, Ü. Tastan, D. Ziegenbalg, M. Karnahl, Impact of the Type of Reactor and the Catalytic Conditions on the Photocatalytic Production of Hydrogen using a Fully Noble-Metal-Free System, ChemistrySelect, 2018, 3, 2905-2911, 10.1002/slct.201800289

Project Light-to-Gas

The catalytic conversion of CO2 to methane and other hydrocarbons is suspected to benefit substantially from irradiation with light. Current reports do not cover the relevant interplay between photon absorption, mass transport and heat management. A microchannel reactor is used to maintain a controlled temperature, even under intense irradiation, and to quantify the performances of various catalysts.

Contact: Henning Becker

Collaborators: Prof. Dr.-Ing. Robert Güttel, Prof. Dr. Sven Rau

Funding: Vector Stiftung

Characterization and Control of Photocatalytic Processes within Soft Matter Matrices

Within the Collaborative Research Center TRR 234 CataLight this project aims at developing reaction engineering concepts to quantitively compare the catalytic activity of homogeneous and heterogeneous light-driven catalysts. The second focus will be on transport effects in soft matter-immobilized light-driven catalysis to establish innovative approaches towards highly intensified and more efficient light-driven chemical processes. For this, the impact of a changing radiation field and the mass transport will be studied. Based on this knowledge, control strategies will be established that make use of an imposed unsteady irradiation and an imposed unsteady mass transport.

Involved Members: Daniel Kowalczyk, Pengcheng Li

Funding: Deutsche Forschungsgemeinschaft (DFG); TRR CATALIGHT – Projektnummer 364549901 – TRR234 (project C6)

Key Publications:

  1. I. Reim, B. Wriedt, Ü. Tastan, D. Ziegenbalg, M. Karnahl, Impact of the Type of Reactor and the Catalytic Conditions on the Photocatalytic Production of Hydrogen using a Fully Noble-Metal-Free System, ChemistrySelect, 2018, 3, 2905-2911, 10.1002/slct.201800289


Finished Projects

Photochemical Reactions as Switchable Tool for the Fundamental Investigation of Mass Transfer Processes in Gas-Liquid-Flows

Reactive mass transfer between a gas and a liquid phase plays an important role in chemical industry. Many large scale reactions such as hydrogenations or oxygenations are conducted in bubble columns and can suffer from mass transport limitations. The reaction directly influences the mass transfer. Commonly decoupling of reaction and mass transfer is impossible, as the reaction starts immediately after the gaseous reactant enters the liquid phase. Consequently, investigations of reactive mass transfer are quite challenging.

To gain a deeper understanding of the single processes, photochemical reactions can be used with the benefit that the reaction can be instantaneously on and off. With this, reaction and physical mass transfer can be decoupled to gain insights into to the interaction. Within this project, we apply this concept to the photochlorination of toluene as a benchmark reaction.  

Involved Members: Ümit Tastan

Funding: Deutsche Forschungsgemeinschaft (DFG); ZI 1502/1-1

Key Publications:

  1. Ü. Tastan, F. Guba, F., D. Ziegenbalg, “Switchable” Reactions for the Investigation of Reactive Mass Transfer Processes, Chemical Engineering & Technology, 2017, 40, 1418-1424, 10.1002/ceat.201600586 
  2. Ü. Taştan, J. Dollinger, D. Ziegenbalg, Measurement of UV/VIS-Absorption Spectra of Photochemically Active Solutions in Continuous Flow, Flow Measurement and Instrumentation, 2018, 59, 211-214, 10.1016/j.flowmeasinst.2017.12.012.