Scientists find way to mass-produce high-performance hydrogen catalysts like pulling noodles

UNIST develops continuous manufacturing technology for carbon fiber electrodes embedded with ruthenium catalyst

From left: UNIST professors Chae Han-ki and Baek Jong-beom, KAUST professor Zafar Yavuz, UNIST doctoral researcher Lee Ga-hyeon, and KAUST research professor Kim Seok-jin. [UNIST]

South Korean researchers have developed a technology that allows catalyst electrodes for hydrogen production to be manufactured in bulk — much like pulling strands of noodles.

A joint research team from Ulsan National Institute of Science and Technology (UNIST) — led by professors Chae Han-ki of the Department of Materials Science and Engineering and Baek Jong-beom of the Department of Energy and Chemical Engineering — announced Sunday that they had developed a fiber-type hydrogen production electrode technology in collaboration with professor Zafar Yavuz of King Abdullah University of Science and Technology (KAUST). The technology uniformly embeds ruthenium catalysts inside carbon fibers.

The efficiency and lifespan of water electrolysis devices depend heavily on the performance of the electrodes where the hydrogen evolution reaction takes place. Electrodes in such devices are typically made by coating a catalyst onto an electrically conductive substrate, a process that requires mixing in a binder. That binder can obscure the catalyst surface and impede the reaction. Catalysts are also prone to clumping and detaching during prolonged operation.

Carbon fiber electrodes, by contrast, allow the fibers themselves to serve as conductors, while also enabling water and electrolytes to flow freely between fibers and hydrogen gas to escape rapidly.

The newly developed technology makes it possible to mass-produce such electrodes by incorporating the catalyst directly into the fiber during fabrication — rather than coating it onto the fiber after the fact.

The process involves pushing a thick liquid mixture of a polymer solution — the raw material for carbon fiber — and a ruthenium catalyst precursor through a nozzle to draw out thread-like strands, which are then heat-treated. During this process, the ruthenium forms small catalyst particles both inside and on the surface of the carbon fibers.

Precursor solution design and manufacturing process for the ruthenium-embedded carbon fiber electrode (Ru-EFEC). [UNIST]

The research team completed the electrode by applying oxygen plasma treatment to expose more of the embedded catalyst on the fiber surface. Tests using the finished electrode in a water electrolysis device showed strong durability even under high-current conditions — the electrode operated continuously for 170 hours at a current density of 500 mA cm⁻², maintaining its structural form throughout hydrogen generation. In separate tests evaluating the intrinsic performance of the catalyst, it outperformed commercial platinum catalysts.

"The key feature of this technology is that it uniformly embeds metal catalysts inside carbon fibers, enhancing the structural stability of the electrode," Chae said. "Going forward, it could be used as a highly durable fiber-type electrode material in hydrogen production, fuel cells and energy storage devices."

The research was supported by the Ministry of Science and ICT and the Ministry of Education through the Mid-Career Researcher Support Program and the Leading Researcher Support Program, both administered by the National Research Foundation of Korea. It was published May 19 in ACS Nano, an international journal in nanoscience and materials science published by the American Chemical Society.

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