Electrolysis with a cheap metal that can produce 10x more hydrogen

Green hydrogen, produced from renewable energy sources by electrolysis of water, is the great promise of the energy sector. Countries like Spain are banking on this energy carrier for their future, but further research is needed to ensure that it can be produced on a sustainable scale. And on this point, Japan has a head start. In recent years, PEM electrolysers, which use a proton exchange membrane as the electrolyte, have become increasingly popular for hydrogen production because of their greater efficiency and their ability to respond rapidly to intermittent energy sources.

The problem with PEM electrolysers is that they are more expensive. They require efficient catalysts that resist corrosion in acid, and therefore use platinum or iridium, which are rare and expensive metals. Iridium catalysts can prolong the oxygen conversion reaction and produce large quantities of hydrogen. And the question was, is there a cheap material capable of doing the same thing? Researchers at the RIKEN Institute in Japan took a common metal, manganese, and modified its three-dimensional structure to make the first efficient and sustainable PEM electrolyser without rare metals.

Everything is hidden in its 3D structure

Researchers have developed a manganese oxide (MnO2) catalyst by manipulating the lattice structure of the material so that it forms stronger bonds with oxygen atoms. The improved MnO2 is much more stable than other non-noble metal catalysts and maintains the reaction with water for much longer. 1,000% more hydrogen. According to a study published in Nature Catalysis, MnO2 increases the lifespan of other cheap catalysts by a factor of 40. The material is more resistant to dissolution in acid and more stable during the reaction. In laboratory tests, the catalyst operated for more than 1,000 hours at 200 mA/cm², producing 10 times more hydrogen than other materials.

Of course, this is just the beginning. There is still work to be done before the new material can be installed in industrial electrolysers, but the researchers believe that their discovery will play a crucial role in the sustainable production of hydrogen. Future modifications to the manganese structure could further increase the current density supported by the material and the lifetime of the catalyst, with the long-term aim of making water electrolysis iridium-free.