Good Vibrations Turbo Charge Green Hydrogen Production

Source: Sally Wood

Engineers in Melbourne recently used sound waves to boost production of green hydrogen by 14 times, through electrolysis to split water.

The team believe their invention offers a promising way to tap into a plentiful supply of cheap hydrogen fuel for transportation and other sectors, which could radically reduce carbon emissions and help fight climate change.

By using high-frequency vibrations to divide and conquer individual water molecules during electrolysis, the team managed to split the water molecules to release 14 times more hydrogen.

Electrolysis involves electricity running through water with two electrodes to split water molecules into oxygen and hydrogen gases, which appear as bubbles.

This process produces green hydrogen, which represents just a small fraction of hydrogen production globally due to the high energy required. Most hydrogen is produced from splitting natural gas, known as blue hydrogen, which emits greenhouse gases into the atmosphere.

Associate Professor Amgad Rezk from RMIT University 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.”

“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,” Rezk said.

The ability to use low-cost electrode materials and avoid the use of highly corrosive electrolytes are gamechangers for lowering the costs of producing green hydrogen.

The team recently secured an Australian provisional patent application to protect the new technology.

First author Yemima Ehrnst said the sound waves also prevented the buildup of hydrogen and oxygen bubbles on the electrodes, which greatly improved its conductivity and stability.

“Electrode materials used in electrolysis suffer from hydrogen and oxygen gas build-up, forming a gas layer that minimises the electrodes’ activity and significantly reduces its performance,” said Ehrnst, who is also a PhD researcher at RMIT’s School of Engineering.

As part of their experiments, the team measured the amount of hydrogen produced through electrolysis with and without sound waves from the electrical output.

“The electrical output of the electrolysis with sound waves was about 14 times greater than electrolysis without them, for a given input voltage. This was equivalent to the amount of hydrogen produced,” Ehrnst said.

The Potential Applications of The Team’s Work

Distinguished Professor Leslie Yeo, who was one of the lead senior researchers, said the team’s breakthrough opened the door to using the acoustic platform for other applications.

“Our ability to suppress bubble buildup on the electrodes and rapidly remove them through high-frequency vibrations represents a major advance for electrode conductivity and stability,” said Yeo.

“With our method, we can potentially improve the conversion efficiency leading to a net-positive energy saving of 27 per cent.”

While the innovation is promising, the team hopes to overcome challenges with integrating the sound-wave innovation through existing electrolysers to scale up the work.

University of Queensland | Brisbane, Australia | 29 - 31 October 2023

The fifth International Materials Innovations in Surface Engineering (MISE) conference will be convened in Brisbane, Australia. The conference will be located at the state-of-the-art St Lucia Campus of the University of Queensland: twenty minutes from the centre of Brisbane.

MISE2023 features eminent academic and industrial plenary, keynote and invited speakers who encompass the engineering modification of a material’s surface to improve its performance.

The conference will cover topics such as:

> Coatings and Thin Films for Extreme Industrial Environments

> Surface Modification for Industrial Applications

> Surface Modification for Biomedical Applications

> Modelling and Simulation related to Surface Engineering

> Vacuum Deposition Coatings and Technologies: PVD and CVD

> Thermal Spray Coatings and Technologies

> Weld Overlays and Technologies

> Laser Processing and Technologies

> Characterisation of Surfaces, Coatings and Films

> New Horizons in Coatings and Thin Films

> Educational and Training of Early Career Researchers in Surface Engineering

> Case Histories for Surface Engineering, including Failure Analysis

> Corrosion, Bio-corrosion and Coatings for Corrosion Protection

> Wear of Materials

> Surface modification for Wear and Corrosion Resistance

Abstracts

Abstracts open 1 December 2022 and can be submitted online through the MISE website - www.mise2023.com.au

• Guidelines and an abstract template can be downloaded

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Enquiries

Tanya Smith

Materials Australia

+61 3 9326 7266 imea@materialsaustralia.com.au

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