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Aluminum (Al) is a material considered susceptible to corrosion, but it could become key to core technology in producing clean hydrogen energy. A POSTECH research team succeeded in dramatically improving the performance of hydrogen production catalysts using this unstable metal.

The research is in the journal ACS Catalysis.

Hydrogen is being spotlighted as a clean energy source that could replace fossil fuels. In particular, research on alkaline water electrolysis using alkaline solution as an electrolyte is being actively conducted, as it is cost-effective and suitable for mass production.

Water electrolysis requires a catalyst that accelerates two important reactions. One of them is the hydrogen evolution reaction (HER), which produces hydrogen gas (H₂) by combining hydrogen ions (H⁺) and electrons. The other is the oxygen evolution reaction (OER), which produces oxygen gas (O₂) as hydroxyl ions (OH^-) lose electrons. Nickel-iron (Ni-Fe) is a catalyst mainly used in the oxygen production reaction; however, it has had difficulties in commercializing due to its lack of activity and durability.

The research team solved the problem using aluminum. Aluminum is generally known to be easily corroded in alkaline environments, but the research team overcame the problem by designing it to form a stable structure on the surface of an electrode. As a result, aluminum efficiently controlled the existing catalytic electron structure without corrosion, accelerating the oxygen production reaction.

Experiments conducted in an alkaline water electrolysis cell showed that the nickel-iron-aluminum (Ni-Fe-Al) catalyst improved performance by approximately 50% compared to existing catalysts. The research team confirmed that the aluminum catalyst maintained high current density even at low voltage. Additionally, it was proven to be applicable in a large-scale hydrogen production process, as it maintained excellent stability in long-term operation.

Professor Yong-Tae Kim, the leader of this research, said, "This research broke the stereotypes of existing catalyst designs. By using this innovative approach of utilizing aluminum, we were able to drastically improve the performance of catalysts used in a hydrogen production system. I expect this research will substantially advance the hydrogen economy age and become a new milestone in eco-friendly energy technology."