Research Published in 'ACS Energy Letters', Supported by Ministry of Science and ICT

The cover of the June 2024 issue of "ACS Energy Letters" (KIST)

A research team of the Korea Institute of Science and Technology (KIST) has successfully developed a high-efficiency water electrolysis catalyst that significantly reduces the amount of iridium used to one-twentieth of that in commercial catalysts. This innovation addresses a major hurdle in the global scale-up of water electrolysis facilities, where the high price of iridium catalysts has been a significant barrier.

The research was led by Dr. Kim Myung-geun and Dr. Yoo Seong-jong from the institute's Hydrogen and Fuel Cell Research Center. The results were published as a cover paper in "ACS Energy Letters," highlighting the significance and recognition of this breakthrough within the scientific community. The monthly scientific journal is published by the American Chemical Society.
 

The newly developed catalyst incorporates a highly durable carbon support, which is crucial as existing carbon supports are prone to oxidation at the operational voltage of 1.6-2V for water electrolysis reactions. By using hydrophobic carbon, which has minimal interaction with water, the team was able to reduce iridium usage while suppressing carbon corrosion reactions. Additionally, selenium was introduced onto the carbon support to enhance durability. Selenium forms a thin hydroxide layer on the iridium surface, inhibiting changes in iridium during reactions and suppressing iridium dissolution.

When applied to commercial water electrolysis facilities, the low-iridium catalyst demonstrated a reduction in iridium usage to one-twentieth of the existing amount while improving performance. A membrane electrode assembly (MEA) with 0.05 mg of iridium per unit area was fabricated, and a polymer electrolyte membrane water electrolysis (PEMWE) experiment was conducted. The experiment recorded a current density of 3.18 A/cm² at 1.9V, outperforming the existing commercial catalyst, which recorded 2.45 A/cm².

Dr. Kim stated, "We have presented a strategy for the development of supports and the securing of catalyst performance for the implementation of low-iridium catalysts." He added, "By integrating large-scale catalyst synthesis technology, we aim to lower the production cost of green hydrogen and contribute to the transition to a hydrogen society."

This research was supported by the Ministry of Science and ICT and was carried out as part of KIST's major projects and the Nano Material Technology Development Project.

Green hydrogen production, which uses renewable energy sources to split water into hydrogen and oxygen through electrolysis, is considered environmentally friendly as it does not produce carbon emissions. The efficiency and cost of this process are heavily influenced by the catalysts used. Iridium, a rare and expensive metal, has been the catalyst of choice due to its excellent performance and durability. However, its scarcity and high cost have posed significant challenges for large-scale green hydrogen production.
 

Read the full article at:  KIST's New Catalyst Reduces Iridium Use for Green Hydrogen Production - Businesskorea