UNSW scientists say they have key to unlock low-cost green hydrogen

Research from Australian scientists appears to have unlocked new techniques for the production of renewable hydrogen from electrolysis, that they believe could lead to significantly reduced costs.

In a paper published in the journal Nature Communications, researchers from UNSW, Griffith University and the Swinburne University of Technology have invented a new method of coating electrodes used in the electrolysis process to produce hydrogen.

Using electrolysis, hydrogen can be extracted by water using electricity, with the electricity working to split the hydrogen atoms in water from the oxygen atoms to which are bonded.

Electricity is passed through water using electrodes which have been traditionally consisted of precious metals like platinum and iridium, which allow for high energy efficiencies in the electrolysis process but are hugely expensive.

The research led by scientists at the UNSW found that it was possible to achieve improvements in energy efficiency while using common, low-cost, metals like iron and nickel as the electrolysis catalysts. These materials are thousands of times cheaper than materials like platinum, and their use could contribute to driving down the costs of hydrogen production.

The research team has invented a process to coat the electrodes with a nano-material, which establishes an interface at the nano-scale between the electrodes and the water, which facilitates the splitting of water into hydrogen and oxygen while requiring significantly less energy.

“What we do is we coat the electrodes with our catalyst to reduce energy consumption,” UNSW’s professor Chuan Zhao said.

“On this catalyst there is a tiny nano-scale interface where the iron and nickel meet at the atomic level, which becomes an active site for splitting water. This is where hydrogen can be split from oxygen and captured as fuel, and the oxygen can be released as an environmentally friendly waste.

“The nanoscale interface fundamentally changes the property of these materials,” Zhao added. “Our results show the nickel-iron catalyst can be as active as the platinum one for hydrogen generation.

“An additional benefit is that our nickel-iron electrode can catalyse both the hydrogen and oxygen generation, so not only could we slash the production costs by using Earth-abundant elements, but also the costs of manufacturing one catalyst instead of two.”

When the electrolysis process is powered using renewable electricity, it offers a source of zero-emissions hydrogen that can then be used as a transport fuel, stored as a backup supply of energy or as a source of thermal heat used in industrial processes.

“At the moment in our fossil fuel economy, we have this huge incentive to move to a hydrogen economy so that we can be using hydrogen as a clean energy carrier which is abundant on Earth,” professor Zhao said.

“We’ve been talking about the hydrogen economy for ages, but this time it looks as though it’s really coming.”

Last month, Australia’s chief scientist Dr Alan Finkel delivered the National Hydrogen Strategy to the COAG Energy Council, that both Finkel and the energy ministers hope will provide a pathway to Australia seizing the multi-billion dollar potential that a hydrogen production industry could provided to Australia.

“We’re hoping our research can be used by stations like these to make their own hydrogen using sustainable sources such as water, solar and these low cost, yet efficient, catalysts,” Zhao added.