University of New South Wales (UNSW) scientists have developed a highly efficient oxygen-producing catalyzing electrode for splitting water. The electrode has the potential to be scaled up for industrial production of the energy fuel hydrogen. The new technology is based on an inexpensive, specially coated foam material that lets the bubbles of oxygen escape quickly. Unlike other water electrolysers that use precious metals as catalysts, the electrode is made entirely from two non-precious and abundant metals – nickel and iron.

Associate Professor Chuan Zhao, of the UNSW School of Chemistry said, “Our electrode is the most efficient oxygen-producing electrode in alkaline electrolytes reported to date, to the best of our knowledge. It is inexpensive, sturdy and simple to make, and can potentially be scaled up for industrial application of water splitting.”

The research paper by Professor Zhao and Dr Xunyu Lu, has been published in the journal Nature Communications.

Inefficient and costly oxygen-producing electrodes are one of the major barriers to the widespread commercial production of hydrogen by electrolysis, where the water is split into hydrogen and oxygen using an electrical current.

Unlike other water electrolysers that use precious metals as catalysts, the new UNSW electrode is made entirely from two non-precious and abundant metals – nickel and iron.

Nickel Foam. Click image for the largest view.  Image Credit: UNSW Australia.

Nickel Foam. Click image for the largest view. Image Credit: UNSW Australia.

Commercially available nickel foam, which has holes in it about 200 micrometers across, or twice the diameter of a human hair, is electroplated with a highly active nickel-iron catalyst, which reduces the amount of electricity needed for the water-splitting to occur.

This ultra-thin layer of a nickel-iron composite also has tiny pores in it, about 50 nanometers across.
Associate Professor Zhao explained, “The three-dimensional architecture of the electrode means it has an enormous surface area on which the oxygen evolution reaction can occur.”

“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.”

Hydrogen production is a rapidly growing industry, but the majority of hydrogen is still produced using fossils fuels such as natural gas, oil and coal, because those sources are still cheaper than electrolysis of water.

Hydrogen can be a great fuel for powering mobile devices or vehicles, and storing electricity generated from renewable energy, such as solar.

Associate Professor Zhao said, “I think this electrode has great potential for the industrial-scale production of hydrogen. Our next goal is to understand the science behind it and to further improve its performance. Cleaner sources of fuel like hydrogen will be particularly important for reducing carbon dioxide emissions and solving the air pollution problems from the burning of fossil fuels such as coal.”

Like almost all water splitting research the matter of separating the elements and material handling are not covered. Oxygen and hydrogen gases combine very easily releasing a great deal of energy, so getting the water apart and the elements safely separate would make a process that can attract interest.

For now the team is looking at the science and the paper does include worthwhile electric requirements that could be used as comparison to existing processes. Whether that’s enough to compete with fossil fuels that release the hydrogen at very low or no oxygen content in the process is yet to be discovered.


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