Researchers from Japan have found a way to produce hydrogen while reducing the use of rare metals

Researchers in Japan have presented a way to save on the use of the rare metal iridium in hydrogen production, which could allow the gas to be produced on a large scale, according to a study published this Thursday.

Large-scale production of green hydrogen, important for the energy transition to sustainable technologies, is difficult because it requires iridium, an extremely rare metal, but the method presented by researchers led by Ryuhei Nakamura at the RIKEN Center for Resources Science (CSRS), in Japan, reduces the amount of iridium needed for a chemical reaction by 95% without changing the rate of hydrogen production.

Researchers have been able to stabilize the production of green hydrogen (so-called if produced using renewable energy) at a relatively high level by using a form of manganese oxide as a catalyst for a chemical electrolysis reaction that extracts hydrogen from water. However, they acknowledge that it will be many years before industrial production levels can be achieved in this way.

“This discovery could revolutionize our ability to produce green hydrogen and help create a carbon-neutral hydrogen economy,” the researchers say in the study, which will be published Friday in the journal Science, recalling that hydrogen is an existing source of renewable energy. on a large scale, although its production still does not compete with fossil fuels.

To extract hydrogen from water, a catalyst is needed to cause a chemical reaction. The most effective catalysts are rare metals, with iridium being the most effective, but it is so rare that using it to make hydrogen would take 40 years to achieve the terawatt scale of energy production produced today from fossil fuels, Shuang Kong said. co-author of the investigation.

“We need a way to bridge the gap between rare metal electrolyzers and common metal electrolysers (…) so that green hydrogen is completely sustainable,” said Ryuhei Nakamura.

The technique presented in the study does this by combining manganese with iridium. The researchers found that the distribution of iridium atoms in manganese oxide allowed the hydrogen production rate to be maintained at the same level as using iridium alone, but with 95% less iridium.

With the new catalyst, continuous hydrogen production was possible for more than 3,000 hours (about four months) with an efficiency of 82% without decomposition.

“The unexpected interaction between manganese oxide and iridium was the key to our success,” said study co-author Ailong Li.