A technology has been developed to improve the performance and durability of hydrogen production devices using inexpensive catalysts that do not require platinum, which is expected to help produce low-cost green hydrogen in the future.

Professor Seung-Geol Lee's research team from the Department of Materials Science and Engineering at UNIST (President Jong-Rae Park) has presented a new anion exchange membrane electrolysis technology using a low-cost non-platinum metal catalyst.

This reduces the direct contact between the potassium and the ionomer by allowing it to adhere to the catalyst surface. Preventing the ionomer from oxidizing can reduce the cost of hydrogen production.

In general hydrogen production devices, the properties of the ionomer that transfers ions change over time and become weak. This leads to a decrease in hydrogen production efficiency and a shortened lifespan of the device.

The research team utilized the fact that the adsorption energy of potassium is three times greater than that of organic compounds. They discovered that substances such as potassium hydroxide and sodium hydroxide can improve the performance and stability of anion exchange membrane electrolysis systems.

Cationic substances were adsorbed on the catalyst surface, reducing direct contact between the ionomer and the catalyst. Ultimately, it was proven through density functional theory (DFT), which calculates the electronic structure of the material, that the hydrogen production performance can be maintained by preventing oxidation of the ionomer.

There have been attempts to improve performance using strong alkaline potassium hydroxide and sodium hydroxide aqueous solutions in the past, but the specific principles have not been elucidated. However, the competitive adsorption strategy identified in this study is expected to greatly increase the possibility of commercializing low-cost catalysts.

“The competitive adsorption strategy is effective in reducing the electrochemical oxidation of ionomer materials that occurs at the contact surface with the catalyst,” emphasized first author Researcher Lim Ji-hoon.

Professor Seung-Geol Lee said, “This study will provide directions for improving the performance and stability of various energy devices, including high-performance alkaline anion exchange membrane electrolysis systems.”

The research results were published online on June 2 in ACS Energy Letters, a world-renowned energy academic journal. The research was conducted jointly by Dr. Yu Seung Kim’s research team at Los Alamos National Laboratory in the United States and Professor Shannon Boettcher of Berkeley University and Berkeley Lab in the United States, and was supported by the U.S. Department of Energy and the National Research Foundation of Korea.