Scientists at the University of New South Wales (UNSW) have developed an inexpensive yet sturdy oxygen-producing electrode (conductor) for splitting water. The new technology can be potentially scaled up for industrial production of hydrogen – a clean energy fuel.
Hydrogen production is a rapidly growing industry as it does not exist naturally in its pure form. The cleanest way of producing it — by electrolysis (where the water is split into hydrogen and oxygen using an electrical current) — is extremely expensive and energy-intensive. This continues to be one of the major barriers to the widespread commercial production of hydrogen. As such, the majority of hydrogen is still produced using fossils fuels such as natural gas, oil and coal.
Unlike other water electrolysers that use costly precious metals, UNSW’s electrode is made from non-precious and abundant metals – nickel foam coated with nickel-iron. Microscopic holes in the coating prevent oxygen bubbles from sticking to the electrode allowing them to successfully split through larger holes in the foam. “The larger bubbles of oxygen can escape easily through the big holes in the foam. As well, the smaller holes make the electrode surface ‘wetter’, so the bubbles do not stick to it, which is a common problem that makes electrodes less efficient,” says Associate Professor Chuan Zhao, of the UNSW School of Chemistry.
Hydrogen has long been considered preferable to carbon-based fuel sources because it produces water when it burns. Theoretically, hydrogen can fuel cars and power stations, heat homes and store excess electricity without emitting toxins or warming the atmosphere. Although UNSW are bringing us a step closer to a cleaner future, scientists also need to develop more efficient techniques of storing pressurised hydrogen before the ‘hydrogen economy’ could become a reality.
An artist’s impression of the water splitting electrode.
A scanning electron microscope image showing the porous structure of the nickel foam electrode, which has holes in it about 200 micrometres across.