A Key to Producing Green Hydrogen
A layer as thin as a single atom makes a huge difference: On the surface of an electrode, it doubles the amount of water split in an electrolysis system without increasing the energy requirements.
Researchers from Jülich, Aachen, Stanford, and Berkeley have studied the layered structure of a catalyst material and found that an atomically thin surface layer can double the activity for the water splitting reaction. Thus, the ultrathin layer also doubles the amount of hydrogen produced without increasing costs.
"By studying a model material we were able to gain a more detailed understanding of how the properties of a catalytically active electrode result from its structure," says Christoph Bäumer, first author of the study. Funded by a "Global Fellowship" from the Marie Skłodowska-Curie Actions he performed his research in Jülich and Aachen, as well as in the USA. "With this expanded understanding, we hope that better catalysts can be developed in the future to produce green hydrogen more energy-efficiently and thus more cost-effectively," the materials scientists explains.
What makes hydrogen green?
The colorless hydrogen gas is known as green hydrogen if it is produced in a climate-neutral way, using electricity from renewable sources for the electrolysis of water. Hydrogen is considered an essential component of the energy transition, in part because it can store wind and solar energy in times of an oversupply to be released later. However, electrolytic hydrogen production at the negatively charged electrode (cathode) cannot take place without oxygen generation at the positively charged electrode (anode). Thus, catalysts that favour this kind of oxygen generation make the overall process more energy-efficient. The high energy requirements have been one of the main obstacles for a broad use of hydrogen so far.