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Researchers in South Korea have developed a cobalt-iron (CoFe)-based non-noble metal ammonia decomposition catalyst, advancing eco-friendly hydrogen production. The work is in the Chemical Engineering Journal.

The research team led by Dr. Su-Un Lee and Dr. Ho-Jeong Chae from the Korea Research Institute of Chemical Technology (KRICT) has successfully developed a high-performance ammonia decomposition catalyst by incorporating cerium oxide (CeO₂) into a cobalt-iron-based layered double oxide (LDO) structure. This innovation enables high ammonia decomposition efficiency at lower temperatures.

Ammonia (NH₃) is gaining attention as a carbon-free hydrogen carrier due to its high hydrogen storage capacity and transport efficiency.

However, extracting hydrogen from ammonia requires a high-temperature decomposition process, typically facilitated by catalysts. Ruthenium (Ru) catalysts demonstrate the highest efficiency in this reaction, but their high cost and the need for elevated temperatures pose significant barriers to large-scale application.

To overcome these challenges, the research team developed a CoFe-based non-noble metal catalyst enhanced with cerium oxide (CeO₂). This catalyst offers high ammonia decomposition efficiency at lower temperatures, ensuring cost efficiency and long-term stability.

Advantages of cerium oxide incorporation:

• Prevents particle agglomeration: Adjusts the surface structure of CoFe-based LDO catalysts, preventing metal nanoparticle sintering.
• Enhances catalytic properties: Utilizes Ce³⁺/Ce⁴⁺ redox transitions to modulate the electronic characteristics of the catalyst.

Facilitating the rate-determining step:

• The rate-determining step in ammonia decomposition is nitrogen recombination-desorption from the catalyst surface.
• The newly developed catalyst optimizes this process, significantly accelerating ammonia decomposition even at lower temperatures.

Thanks to these advancements, the catalyst achieved 81.9% ammonia conversion at 450°C, surpassing previous non-noble metal catalysts.

This marks a significant improvement compared to a 2022 nickel-based catalyst, which exhibited only 45% conversion at 450°C.

Furthermore, long-term stability tests at 550°C demonstrated that the catalyst maintained structural integrity and hydrogen production efficiency even after prolonged operation.

The research team aims to further enhance low-temperature hydrogen production efficiency through additional studies, targeting commercialization by 2030.

"This catalyst can be applied to large-scale ammonia-based hydrogen production, hydrogen power plants, hydrogen fueling stations, and maritime industries," Dr. Su-Un Lee stated.