The global nature of the climate change problem requires the development of technologies that are not only effective in one specific country but are economically attractive anywhere in the world. All efforts to defossilize global energy systems are under considerable time pressure to reduce fossil CO2 emissions as quickly as possible.
 
Hydrogen technologies play an important role in the transformation of global energy systems. They are particularly well suited to the storage, transport and on-demand supply of large quantities of clean energy. In addition to the handling of elemental hydrogen in gas networks or cryogenic tanks, the various approaches to chemical hydrogen storage offer safe and cost-effective storage and transportation of hydrogen in the form of hydrogen derivatives that can further utilize the existing fuel infrastructure.
 
The presentation will discuss chemical hydrogen storage in the form of ammonia, alcohols, ethers, and so-called LOHC systems (LOHC = Liquid Organic Hydrogen Carrier). Particular emphasis is placed on the dimethyl ether/CO2 cycle [1] and the use of various classes of LOHC systems. The latter consist of pairs of hydrogen-poor and hydrogen-rich organic liquids that can store hydrogen through repeated catalytic hydrogenation and dehydrogenation cycles. Aromatic/alicyclic LOHC systems [2] are compared with diol/lactone systems [3,4] in terms of thermodynamics, catalyst selection, application-relevant properties and potential areas of application. The presentation covers the scientific principles of chemical hydrogen storage, outlines key findings from ongoing development work, and presents selected application and demonstration examples.
 
 
References:
P. Schühle, R. Stöber, M. Semmel. A. Schaadt, R. Szolak, S. Thill, M. Alders, C. Hebling, P. Wasserscheid, O. Salem, Energy Environ. Sci., 2023, 16, 3002-3013. F. Siegert, M. Gundermann, L. Maurer, S. Hahn, J. Hofmann, M. Distel, J. Schühle, K. Müller, M. Wolf, P. Preuster, F. Auer, M. Geisselbrecht, P. Wasserscheid, Int. J. Hydrogen Ener., 2024, 91, 834-842. Y. Chen, X. Kong, C. Yang, Y., G. Gao, R. Ma, M. Peng, W. Shao, H. Zheng, H. Zhang, X. Pan, F. Yang , Y Zhu, Z. Liu, Y. Cao, D. Ma, X. Bao, Y. Zhu, Nat. Energy, 2025, 10, 971–980. P. Wasserscheid, Nat. Energy, 2025, 10(8), 924-925.

While chemo-, bio-, and photocatalysis are well-established methodologies, integrating them into continuous flow processes remains still a major challenge. Similarly, there is a shift in pharmaceutical crystallization from isolated batch operation to an integrated element of end-to-end processing. While batch processing dominates due to operational flexibility, continuous flow crystallization offers enhanced batch-to-batch reproducibility, increased control over particle size and morphology, seamless scalability, and superior resource efficiency.
This contribution outlines various strategies for integrating different catalytic methodologies within continuous flow processes, as well as the synergy between continuous crystallization and enabling technologies such as automation, real-time analysis, and process optimization. First, photobiocatalytic applications using cyanobacteria in tubular1 and 3D-printed reactors2 are highlighted. Next, a continuous multistep cascade combining chemo-, photo-, and biocatalysis is detailed, featuring the synthesis of an α-CF3-substituted ketone substituted ketone in a self-designed photoreactor followed by enzymatic ketoreduction to yield chiral trifluoromethylated alcohols.3 The interface between catalysis and particle formation is further extended to a three-step biocatalytic process for polycaprolactone (PCL) production.4 Finally, additive manufacturing for tailored crystallizer designs in cooling crystallization is showcased5, alongside an in-house optical flow cell6 serving as an in-line PAT tool for automated monitoring and process optimization.
1 Valotta, A., Malihan-Yap L., Hinteregger K., R. Kourist R., Gruber-Woelfler H., ChemSusChem, 2022, 15, e202201468
2 Malihan-Yap, L.; Schmedler, L.; Pint, D.; Medipally, H.; Lackner, L.; Fedrigotti, S.; Kargl, R.; Stana Kleinschek, K.; Kourist, R.; Gruber-Woelfler, H. ACS Sustainable Chem. Eng. 2026 14 (14)6599–6612,
3 Valotta A., Maderbacher J., Stelzer D., Reiter T., Kroutil W., Gruber-Woelfler, H., Chemical Papers, 2024, 78, 7973-7986
4 Valotta, A., Stelzer, D., Reiter, T., Kroutil, W., Gruber-Woelfler, H., React. Chem. Eng., 2024, 9, 713-727
5 Nys N., Koenig M., Neugebauer P., Jones M.J., Gruber-Woelfler H., Org. Process Res. Dev, 2023, 27, 1455 – 1462
6 Soritz S., Nys N., Thierrichter M., Buchgraber L., Amering R., Neugebauer P., Gruber-Woelfler H., Org. Process Res. Dev., 2024, 28, 3940–3949