Hydrogen, the lightest element, is increasingly sought after for its potential as a sustainable resource during the energy transition. Researchers from Leipzig University and TU Dresden, part of the Hydrogen Isotopes 1,2,3H Research Training Group, have made a significant advancement in the effective and economical extraction of isotopes. Hydrogen comes in three natural forms: protium, deuterium, and tritium. The international research team has made great progress in achieving their goal to separate these hydrogen isotopes at room temperature without high costs. Their research findings have just been published in the journal Chemical Science.
Protium, also known as hydrogen-1, is the most prevalent form of hydrogen. Deuterium, referred to as heavy hydrogen, is becoming increasingly valuable, particularly in creating more stable and effective pharmaceuticals. A combination of deuterium and tritium, termed “super-heavy” hydrogen, acts as fuel for nuclear fusion, which presents a sustainable energy option for the future. A major challenge in hydrogen research lies in producing these isotopes in a highly pure form efficiently and affordably, as their physical characteristics are very similar. The existing methods for isotope separation are quite inefficient, requiring large amounts of energy.
“For nearly 15 years, it’s been acknowledged that porous metal-organic frameworks can theoretically be used to purify and separate hydrogen isotopes. But this process has only been feasible at extremely low temperatures, around minus 200 degrees Celsius, which is challenging and expensive for industrial applications,” explains Professor Knut Asmis from the Wilhelm Ostwald Institute for Physical and Theoretical Chemistry at Leipzig University and spokesperson for the Research Training Group. He adds that the separation process relies on the preferential adsorption of one of the isotopes onto free metal sites in the porous material. Adsorption is when particles from a gas or liquid stick to a solid, often porous, surface.
The doctoral researchers from the 1,2,3H Research Training Group—Elvira Dongmo, Shabnam Haque, and Florian Kreuter—who are part of a research team led by Professors Thomas Heine (TU Dresden), Knut Asmis, and Ralf Tonner-Zech (both from Leipzig University), have gained new insights into how the environment of the framework affects binding selectivity. This addresses why one isotope tends to attach more readily than the other. Their current study details this through a collaborative approach using advanced spectroscopy, quantum chemical calculations, and chemical binding analysis on a model system. “For the first time, we’ve demonstrated how the individual atoms in the framework compounds influence adsorption. This allows us to specifically optimize them to create materials with high selectivity at room temperature,” states Heine.
The 1,2,3H Research Training Group, supported by the German Research Foundation (DFG) with 5.4 million euros over 4.5 years, has been training over 20 doctoral candidates since October 2021. It unites the expertise of Leipzig University, TU Dresden, the Helmholtz-Zentrum Dresden-Rossendorf, and the Leibniz Institute of Surface Engineering to develop innovative materials, more effective medications, and advanced detection techniques by consolidating resources for fundamental research and training in hydrogen isotopes. The upcoming cohort of approximately 15 to 20 doctoral candidates will start their three-year structured doctoral program on October 1, 2024.
