Researchers in Australia develop low-cost water-splitting catalyst that offers comparable performance to platinum
A team of researchers in Australia has developed a Janus nanoparticle catalyst with a nickel–iron oxide interface and multi-site functionality for a highly efficient hydrogen evolution reaction with a comparable performance to the benchmark platinum on carbon catalyst. (Janus particles feature surfaces with two or more distinct properties.) An open-access paper on their work is published in the journal Nature Communications.
Schematic representation of the Ni and Fe nanoparticles and the Ni-Fe Janus nanoparticles synthesis through the oleate-assisted micelle formation and the illustration on the HER across the Ni-γ-Fe2O3 interface in alkaline medium. Suryanto et al.
Iron and nickel, which are found in abundance on Earth, would replace precious metals ruthenium, platinum and iridium that up until now are regarded as benchmark catalysts in the water-splitting process.
Density functional theory calculations reveal that the hydrogen evolution reaction catalytic activity of the nanoparticle is induced by the strong electronic coupling effect between the iron oxide and the nickel at the interface.
Remarkably, the catalyst also exhibits extraordinary oxygen evolution reaction activity, enabling an active and stable bi-functional catalyst for whole cell water-splitting with, to the best of our knowledge, the highest energy efficiency (83.7%) reported to date.—Suryanto et al.
In 2015, UNSW School of Chemistry’s Professor Chuan Zhao’s team invented a nickel-iron electrode for oxygen generation with a record-high efficiency. However, Prof Zhao says that on their own, iron and nickel are not good catalysts for hydrogen generation, but where they join at the nanoscale is “where the magic happens”.
The nanoscale interface fundamentally changes the property of these materials. 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.—Prof Zhao
Iron and nickel are currently priced at $0.13 and $19.65 a kilogram. By contrast, ruthenium, platinum and iridium are priced at $11.77, $42.13 and $69.58 per gram—in other words, thousands of times more expensive.
… this work demonstrates that the introduction of asymmetry in an electrocatalyst structure could induce unprecedented synergistic effect for electrocatalysis. Through this approach, we have overcome the practical limitation of Ni–Fe mixed oxides for overall water electrolysis due to the poor HER activity. Additionally, having similar active sites for both OER and HER results 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.
Beyond, it is also our hope that this multi-site functionality catalyst design can help to expedite the conception-to-commercialization process of other multi-metallic nanoparticle electrocatalysts with different compositions and structures that exhibit distinct interfaces for various electrolytic applications such as CO2 reduction reactions and nitrogen reduction reactions.—Suryanto et al.
Bryan H. R. Suryanto et al. (2019) “Overall electrochemical splitting of water at the heterogeneous interface of nickel and iron oxide,” Nature Communications doi: 10.1038/s41467-019-13415-8