Reduced Iridium by 80% and Withstood 1,000 Hours... GIST Breaks Green Hydrogen 'Cost Barrier' [Reading Science]

Significantly Reduced Use of Expensive Catalysts,
Achieving Both Performance and Durability
Published in the International Journal "Advanced Science"

The challenge of dependence on rare metals, long considered the biggest obstacle in green hydrogen production, may be significantly alleviated thanks to a breakthrough by a domestic research team. A water electrolysis electrode has been developed that dramatically reduces the amount of the expensive metal iridium required, while enabling stable long-term operation.

The Gwangju Institute of Science and Technology (GIST) announced on March 25 that a research team led by Professor Chanho Park from the Department of Chemistry has developed a high-performance electrode that uses more than 80% less iridium (Ir)—the essential catalyst for hydrogen production—compared to conventional methods, while operating for over 1,000 hours without performance degradation.

The formation process of iridium oxide, which has two types of crystal structures. Using a spherical template, the synthesis process shows how iridium oxide is created with coexisting crystalline and amorphous structures. During the heat treatment process, the structure rearranges, forming hollow nanostructures inside, which increases the reactive surface area and secures pathways for efficient electron transport, thereby enhancing performance. Provided by the research team

Water electrolysis, a leading technology for hydrogen production, generates hydrogen and oxygen by decomposing water with electricity and emits virtually no carbon, making it a next-generation energy technology of great interest. In particular, polymer electrolyte membrane (PEM) electrolysis is noted in industry as a leading method due to its ability to produce high-purity hydrogen.

The challenge lies with the catalyst. Iridium is a key material that promotes the oxygen evolution reaction in water, but it is expensive and has limited reserves. Furthermore, increasing the reaction rate causes the catalyst to degrade faster, while improving durability tends to reduce performance, creating an "activity-durability trade-off" that has been cited as the biggest barrier to commercialization.

Achieving Both Performance and Durability with Dual-Phase Catalysts

The research team addressed this issue by designing a "dual-phase" iridium oxide catalyst that combines crystalline and amorphous structures.

The catalyst was engineered so that amorphous structures fill the spaces between hollow spherical crystalline structures, thus securing continuous pathways for electron movement. The amorphous structure increases the number of active sites for reactions, while the crystalline structure is responsible for conductivity and structural stability, with each component playing a distinct role.

The team applied this catalyst to a membrane electrode assembly (MEA), a key component of actual water electrolysis devices, to test its performance. When a current at industrial levels (1A) was continuously applied to a 1 cm by 1 cm electrode for over 1,000 hours, the device stably produced hydrogen without any performance loss. The voltage rise was only 31.5 microvolts (μV) per hour, maintaining nearly the same efficiency as at the outset. This demonstrates "commercial-level durability," with performance maintained even during prolonged operation.

From left, Chanho Park, Professor of Chemistry at GIST, Hoseong Yang, Master’s degree. Provided by GIST

This research is highly regarded for dramatically reducing the use of rare metals while simultaneously securing both performance and lifespan, significantly increasing the commercial viability of PEM water electrolysis.

Professor Chanho Park stated, "We have minimized the use of iridium while ensuring stable single-cell operation for over 1,000 hours," adding, "This will help lower the cost of water electrolysis equipment and accelerate the large-scale production of green hydrogen."

This research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea's "Green Hydrogen Technology Independence Project." The results were published online in the international journal Advanced Science on March 10.

This content was produced with the assistance of AI translation services.