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Research
More hydrogen using ultra-thin layer
Research
More hydrogen using ultra-thin layer
Christoph Bäumer develops catalysts for hydrogen production. To do this, he needs seven steps, as he explains (in German) in our Jülich blog: fzj.de/woran-forscht-baeumer
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An unexpected effect could help to considerably reduce the cost of hydrogen production in the future.
If water is split in an electrolysis system using electricity from renewable sources in a climate-neutral way, so-called “green hydrogen” is produced. It is considered an important component of energy transition because, among other things, wind or solar energy can be stored in it and released again when needed. However, producing hydrogen is expensive. This impedes its widespread use. Researchers from Jülich, Aachen, Stanford and Berkeley have discovered an effect by means of which the amount of hydrogen produced can be doubled in a model system – without increasing the required energy and costs. The effect is caused by a layer just 200 billionths of a millimetre thick.
Picture above: Christoph Bäumer develops catalysts for hydrogen production. To do this, he needs seven steps, as he explains (in German) in our Jülich blog: fzj.de/woran-forscht-baeumer
THE SURFACE DOES THE TRICK
The layer referred to here is the surface of an electrode: during electrolysis, hydrogen is formed at the negatively charged electrode (cathode), while oxygen is formed at its positive counterpart (anode). Both processes can only co-occur, so that facilitating the formation of oxygen also increases hydrogen production.
Lanthanum nickelate (LaNiO3) is an established catalyst that promotes this electrolytic formation of oxygen. In its crystal structure, nickel oxide and lanthanum oxide layers alternate. Normally, it is a coincidence which layer forms the surface of the anode. The German-American research team has developed a method with which they can determine whether a layer of lanthanum oxide or one of nickel oxide is on top.
Inside the electrolysis cell
Nickel oxide layer
Lanthanum oxide layer
Hydrogen
Oxygen
Surface of the anode: nickel oxide
Surface of the anode: lanthanum oxide
Twice as much oxygen is produced at the anode with the nickel oxide surface (left) as at the lanthanum oxide variant (right). Likewise, because the processes are coupled, more hydrogen is formed at the cathode.
“Surprisingly, this makes a huge difference,” says physicist Dr. Christoph Bäumer from the Peter Grünberg Institute (PGI-7), who was significantly involved in the research, both in Jülich and Aachen and in the USA. The researchers found that an anode with a nickel oxide surface produced twice as much oxygen in the same time as the other variant. The reason: during electrolysis, only this surface develops a disordered, catalytically very active layer that encourages the formation of oxygen.
“So far, our results only constitute basic research. However, they suggest that when developing better catalysts, one must also bear in mind for other materials that the uppermost atomic layer can be decisive for the electrochemical processes that take place under operating conditions,” says Bäumer.
Frank Frick
Photo: Forschungszentrum Jülich/Sascha Kreklau, Illustrations: SeitenPlan