A South Korean research team has achieved a significant breakthrough in hydrogen production by developing a platinum-free water electrolysis system. This innovation addresses a major hurdle in the widespread adoption of green hydrogen, offering a more cost-effective and sustainable alternative to traditional methods.
The Quest for Green Hydrogen
Green hydrogen, produced through water electrolysis using renewable energy sources, is considered a promising clean energy carrier. However, the high cost and limited efficiency of current electrolysis technologies have hindered its widespread adoption. A significant contributor to these challenges is the reliance on expensive precious metal catalysts, particularly platinum, to facilitate the water-splitting process.
KAIST and KIER Collaboration
Researchers led by Hee-Tak Kim from the Department of Chemical and Biomolecular Engineering at the Korea Advanced Institute of Science & Technology (KAIST), in collaboration with Gisu Doo of the Korea Institute of Energy Research (KIER), have successfully developed a platinum-free water electrolysis technology. This innovative system promises to significantly reduce the cost of hydrogen production while maintaining high efficiency.
Tackling the Platinum Challenge
Platinum is a highly effective catalyst for hydrogen production, but its scarcity and high cost pose a significant barrier to the large-scale commercialization of water electrolysis technologies. To overcome this limitation, researchers have been exploring alternative materials and methods to reduce or eliminate the need for platinum.
AEM Water Electrolysis and the Catalyst Breakthrough
The Korean team focused on anion exchange membrane (AEM) water electrolysis, a next-generation technology that has the potential to use non-precious metal catalysts. While AEM electrolysis offers the promise of lower costs, most existing systems still rely on platinum and iridium, both expensive and scarce metals.
The team’s breakthrough involves engineering a base metal catalyst by incorporating a small amount of ruthenium (Ru) into a molybdenum dioxide-nickel molybdenum (MoO2-Ni4Mo) structure. This innovative approach overcomes a major limitation of molybdenum dioxide—its tendency to degrade in alkaline environments—by stabilizing its structure. Through extensive structural analysis, the research team identified that hydroxide ion (OH-) adsorption on molybdenum dioxide was the primary cause of degradation.
Key Benefits of the Platinum-Free System
The newly developed platinum-free system offers several key advantages:
- Cost Reduction: By eliminating the need for platinum, the system significantly reduces the cost of hydrogen production, making it more competitive with traditional fossil fuel-based methods.
- Improved Efficiency: The ruthenium-based catalyst demonstrates high efficiency in splitting water into hydrogen and oxygen, comparable to or even exceeding that of platinum-based catalysts.
- Enhanced Stability: The catalyst’s unique structure provides excellent stability in alkaline environments, ensuring long-term performance and durability.
- Scalability: The system is designed for industrial-scale applications, paving the way for large-scale green hydrogen production.
UNIST’s Ionomer-Free Catalyst-Coated Membrane
Another notable development comes from Professor Youngkook Kwon’s team at UNIST (Ulsan National Institute of Science and Technology), who have created a novel in-situ, ionomer-free catalyst-coated membrane (m-CCM) fabrication method. This method enables the synthesis and integration of a catalyst layer between the anion exchange membrane (AEM) and the gas diffusion layer without needing anion exchange ionomers.
Using a platinum group metal-free benchmark anode catalyst, the Anion Exchange Membrane Water Electrolyzer (AEMWE) fabricated through the m-CCM method has demonstrated remarkable performance superiority over its MEA (membrane electrode assembly) counterparts. This innovative approach optimizes interfacial resistance, maximizes catalyst utilization, and establishes intimate contact, enabling an industrially relevant current density of 1 A cm–2 at a moderate cell voltage of 1.79 Vcell. Furthermore, it exhibits exceptional durability, withstanding over 200 hours of continuous electrolysis at 50 °C in 1 M KOH electrolyte.
Ruthenium Nanocluster Catalyst
A team led by Professor Jin Young Kim from Seoul National University (SNU), in collaboration with Professor Chan Woo Lee from Kookmin University and Dr. Sung Jong Yoo from the Korea Institute of Science and Technology (KIST), has developed a ruthenium-based nanocluster catalyst with a core-shell structure. This catalyst achieves “world-class performance” and exceptional stability while using a minimal amount of precious metal. When applied to industrial-scale water electrolysis equipment, it demonstrated “remarkable efficiency”. The research was published in Energy & Environmental Science. By reducing the catalyst size to below 2 nanometers (nm) and minimizing the amount of precious metal to just one-third of what is used in conventional platinum-based electrodes, the team achieved superior performance surpassing that of existing platinum catalysts.
The newly developed catalyst demonstrated 4.4 times higher performance than platinum catalysts with the same precious metal content, setting a new benchmark in hydrogen evolution reaction efficiency. Additionally, it recorded the highest performance ever reported among hydrogen evolution catalysts.
Implications for a Hydrogen Economy
These breakthroughs in platinum-free hydrogen electrolysis have significant implications for the development of a hydrogen economy. By reducing the cost and improving the efficiency of hydrogen production, these technologies can accelerate the transition to a cleaner and more sustainable energy future.
Industries reliant on fossil fuels, such as steel production, transportation, and heavy manufacturing, could finally have a cleaner, more economical alternative. This research represents a major leap forward in the quest for sustainable energy solutions.
The Role of AEM Water Electrolysis
Anion Exchange Membrane Water Electrolysis (AEMWE) is gaining attention as a next-generation technology due to its ability to produce high-purity hydrogen. However, for AEMWE to be commercially viable, it requires catalysts that offer both high efficiency and long-term stability.
A Step Towards a Sustainable Future
With cost-effective catalysts and improved efficiency, green hydrogen is rapidly moving from concept to reality. As research continues to refine AEM electrolysis, the dream of large-scale, affordable green hydrogen production edges closer to becoming an industry standard. The world is in dire need of sustainable energy solutions, and these breakthroughs represent a major leap forward.
Other Approaches to Hydrogen Production
While AEM water electrolysis is promising, other methods are also being explored. Proton Exchange Membrane Water Electrolysis (PEMWE) is another technology that offers high efficiency and ionic conductivity. PEMWE systems typically use platinum-based electrodes and a proton exchange membrane to produce hydrogen.
Ion-solvating membrane water electrolysis (ISWE) is another emerging technology that utilizes an aqueous alkaline electrolyte to achieve ionic conductivity. ISWE offers the potential for improved energy efficiency and higher hydrogen conversion rates compared to conventional water electrolysis.
The Path Forward
The development of platinum-free hydrogen electrolysis systems is a significant step towards a sustainable energy future. As research continues and these technologies are refined, green hydrogen has the potential to play a major role in decarbonizing the global economy. The Korean team’s breakthrough, along with other advancements in the field, paves the way for a cleaner, more affordable, and more sustainable hydrogen economy.
