PhD researcher Yemima Ehrnst with the acoustic device used to boost hydrogen production. Image: RMIT University
Engineers at Australia’s RMIT University have demonstrated the potential of sound waves to boost green hydrogen production in the electrolysis process.
With the high frequency (10MHz) vibrations during the electrolysis, the engineers were able to split the water molecules to release 14 times more hydrogen compared with standard electrolysis techniques, along with a net positive energy saving of over 27%.
This then offers the prospect of lowering the production cost and opening the way for plentiful supply of cheap green hydrogen.
Associate Professor Amgad Rezk from RMIT University’s School of Engineering, who led the work, said the team’s innovation tackles big challenges for green hydrogen production.
“One of the main challenges of electrolysis is the high cost of electrode materials used, such as platinum or iridium,” he commented.
“With sound waves making it much easier to extract hydrogen from water, it eliminates the need to use corrosive electrolytes and expensive electrodes such as platinum or iridium. As water is not a corrosive electrolyte, we can use much cheaper electrode materials such as silver.”
Another notable finding in the work, which has been published in the journal Advanced Energy Materials, was that the sound waves also prevented the build-up of hydrogen and oxygen bubbles on the electrodes.
Typically the hydrogen and oxygen gas build-up can form a gas layer that lowers the electrodes’ activity and significantly reduces their performance.
An Australian provisional patent application has been filed on the technology, which also is expected to have use for other applications, especially where bubble build-up on the electrodes is a challenge.
In the next step, the research team hope to collaborate with industry partners to address the challenges with integrating the sound-wave innovation with existing electrolysers in order to scale up its use.
