Researchers at the University of Twente have shown how to improve the efficiency of hydrogen production in an experimental setup. They showed that the magnetic order of the molecules plays a critical role.
In the search for green hydrogen, the design of efficient catalyst materials that increase the efficiency and speed of the chemical reaction that produces (green) hydrogen is essential. Theoretically, several studies already implied that the magnetic properties of the catalyst affect this efficiency and speed. However, experimental evidence for these enhancements is still sparse, especially for the role of magnetic properties which exist without external magnetic fields.

Aligning tiny magnets
Until now! The researchers aligned the magnetic ‘spins’ of the atoms in the catalyst while the reaction was happening. They saw that aligning all these tiny magnets increased the reaction speed. “Although we’re working on a fundamental scale, this research can have important implications for efficient hydrogen production”, says first author Emma van der Minne.

To align the magnetic spins while the reaction was running, the researchers used a simple approach. Van der Minne explains: “We decreased the temperature during the reaction. By comparing the changes in the reaction speed during this decrease for two catalysts with a different magnetic state, we found that the activity is really increased by this so-called magnetic order. The fact that this happens even without the application of a magnetic field is something that was unclear before. Our research thus gives us new ways to improve the design of catalysts in large-scale hydrogen production.”

External magnetic field
But that’s not all. The researchers also found that if they applied an external magnetic field, it made the catalyst even better at its job. The direction of this magnetic field mattered. It had to line up just right with the material's magnetic properties. Understanding how both the magnetism inside the catalyst and its reaction to external magnetic fields affect the reactions involved in hydrogen production brings us one step closer to a greener future.

More information
Emma van der Minne is a PhD student in the research group Inorganic Material Science (IMS; Faculty of S&T). She studies the effect of magnetic interactions on surface chemistry. She is supervised by Dr. Chris Baeumer. They published their findings in an article, entitled ‘The effect of intrinsic magnetic order on electrochemical water splitting’, in the scientific journal Applied Physics Reviews, where it was selected as ‘one of the journal's best’ and published as a Featured Article.
DOI: 10.1063/5.0174662