The reliance on noble metal elements, such as platinum, ruthenium and iridium, as cathodes and anodes raises the cost of hydrogen production by electrochemical water splitting. Earth-abundant iron and nickel can serve as efficient, economical catalysts, according to Australian researchers.

Nickel-iron oxide nanoparticles were tested as both the anode and cathode in a whole cell water electrolyzer. Electrocatalytic hydrogen evolution reaction activity was comparable to that of benchmark platinum on carbon catalyst. Multi-site functionality was also unexpectedly observed in the form of improved oxygen evolution reaction activity.

The nanoparticle structure has similar active sites for both oxygen and hydrogen evolution reactions, resulting in the preservation of catalyst structure and activity against electrode corrosion induced by power interruptions, which is ideal for a water electrolyzer powered by intermittent renewable energy sources. An 83.7% energy efficiency for the nickel-iron nanoparticle is determined, based on a calculated hydrogen and oxygen evolution reaction Faradaic efficiency of 100% at a current density of 10 mA/cm².

Researchers from University of New South Wales and Swinburne University of Technology contributed to this study, which is published in Nature Communications.

Earth-abundant iron and nickel can substitute for platinum and other noble metal-based catalysts used in electrochemical water splitting.