One Step Closer to Green Hydrogen Era: New Material Boosts Production Efficiency and Reduces Costs

# Green hydrogen, produced through water electrolysis, is a next-generation eco-friendly energy source as it does not generate pollutants like carbon dioxide during production. Catalysts play a crucial role in the water electrolysis process, splitting water into hydrogen and oxygen. The efficiency of green hydrogen production largely depends on the performance of these catalysts. Therefore, the commercialization of green hydrogen hinges on the development of cost-effective catalysts capable of maintaining high performance over extended periods.

Researchers in Korea have successfully developed a new material that significantly enhances the efficiency of green hydrogen production while reducing costs.

The Korea Research Institute of Standards and Science (KRISS) has developed a high-performance base metal catalyst for use in anion exchange membrane (AEM) water electrolysis.* The newly developed catalyst is not only more affordable than precious metal-based alternatives but also exhibits superior performance, bringing the commercialization of green hydrogen a step closer.
^{* AEM Water Electrolysis: Among various water electrolysis methods, AEM electrolysis is drawing attention as a next-generation technology. It theoretically allows the use of cost-effective non-metallic catalysts to produce large quantities of hydrogen.}

Currently, AEM water electrolysis systems predominantly rely on precious metal catalysts such as platinum (Pt) and iridium (Ir). However, the high cost of these materials and their susceptibility to degradation significantly increase the cost of hydrogen production. To overcome this challenge, the development of durable and affordable base metal catalysts is essential.

The KRISS Emerging Material Metrology Group has succeeded in developing base metal catalysts by introducing a small amount of ruthenium (Ru) into a molybdenum dioxide with nickel molybdenum (MoO2-Ni4Mo) structure. While molybdenum dioxide offers high electrical conductivity, its use as a water electrolysis catalyst has been limited due to degradation in alkaline environments.

Through comprehensive structural analysis, the researchers identified hydroxide ion (OH-) adsorption on molybdenum dioxide as the primary cause of degradation. Building on these findings, they devised a method to incorporate ruthenium at an optimal ratio to prevent molybdenum dioxide degradation. The resulting ruthenium nanoparticles, measuring less than 3 nanometers, form a thin layer on the catalysts’ surface, preventing degradation and enhancing durability.

Performance evaluations revealed that the newly developed catalysts offers four times the durability and more than six times the activity compared to existing commercial materials. Moreover, when integrated with a perovskite-silicon tandem solar cell, the catalysts achieved a remarkable solar-to-hydrogen efficiency of 22.8%, highlighting its strong compatibility with renewable energy sources.

The catalysts also demonstrated high activity and stability in saline water, producing high-quality hydrogen. This capability is expected to significantly reduce the costs associated with desalination.

Dr. Sun Hwa Park, a principal researcher at the KRISS Emerging Material Metrology Group, commented, “Currently, producing green hydrogen requires purified water, but using actual seawater could substantially lower costs associated with desalination. We plan to continue our research in this area.”

This research was supported by the KRISS MPI Lab Program and conducted in collaboration with Professor Ho Won Jang’s team at Seoul National University and Dr. Sung Mook Choi’s team at the Korea Institute of Materials Science. The findings were published in the July edition of Applied Catalysis B: Environmental and Energy (IF: 20.2), a leading journal in the field of chemical engineering.