PEM Electrolysis Breakthrough: New Ruthenium Catalyst Slashes Iridium Use, Boosts Hydrogen Production

The race to a sustainable hydrogen economy just got a major boost. With the Hydrogen Council projecting 175 GW of announced hydrogen production capacity by 2030, and a significant 40% of that relying on Proton Exchange Membrane (PEM) electrolysis, a critical bottleneck has emerged: iridium scarcity. But a groundbreaking innovation is here to change the game. A new ruthenium-based catalyst promises to drastically reduce the reliance on this rare and expensive precious metal, paving the way for more affordable and scalable green hydrogen production.

The Iridium Challenge: Why It Matters

Iridium, a platinum group metal (PGM), is essential for PEM electrolyzers. Its exceptional resistance to oxidation and high catalytic efficiency make it the preferred choice for the oxygen evolution reaction (OER) at the anode, where water molecules are split to produce hydrogen. However, iridium is one of the rarest elements on Earth, with annual production limited to approximately 9 tons. This scarcity translates to high costs, with prices soaring to $176,370 per kilogram, making hydrogen generation more expensive.

Currently, building one gigawatt (GW) of PEM electrolysis capacity requires approximately 400 kg of iridium. To avoid supply bottlenecks and ensure the widespread adoption of green hydrogen, this number needs to be reduced to less than 100 kg per GW. The good news is that researchers and companies are actively seeking solutions to lessen our reliance on iridium, and a ruthenium-based catalyst is proving to be a promising alternative.

Ruthenium to the Rescue: An 85% Reduction in Iridium Use

The new ruthenium-based catalyst, developed by Heraeus Precious Metals in collaboration with Sibanye-Stillwater, offers a potential 85% reduction in iridium usage compared to traditional iridium oxide catalysts. This breakthrough addresses the iridium supply problem and makes economic sense, significantly reducing capital expenditure needed per GW.

Ruthenium, another PGM, is 3.5 times more abundant than iridium. While ruthenium possesses superior catalytic activity, it has historically lacked the stability required for the harsh conditions within a PEM electrolyzer. The innovative solution combines ruthenium and iridium oxide in a novel manner, enhancing stability while maintaining the increased catalytic activity provided by ruthenium.

How Does It Work?

The ruthenium-iridium oxide material class delivers an unprecedented activity boost, achieving up to 50 times higher mass activity than iridium oxide alone. Unlike ruthenium oxide alone, it remains stable in operational conditions.

The precise mechanism involves a core-shell nanocluster catalyst based on ruthenium (Ru), which is more than twice as cost-effective as platinum. A precise low-temperature thermal treatment induces atomic-level diffusion, forming the core-shell structure. During the hydrogen evolution reaction, an electrochemical reduction process further enhances the material’s properties, resulting in a ruthenium metal core encapsulated by a porous reduced titania monolayer, with metallic molybdenum atoms positioned at the interface.

Stability and Performance: Key Advantages

The stability of ruthenium-based catalysts has been a major focus of research. Strategies for enhancing stability include:

Chemical Modification: Doping ruthenium perovskites with potassium (K) stabilizes ruthenium in a higher oxidation state, improving durability.
Combining with Other Elements: Merging ruthenium with elements like tungsten oxide (Ru-WO3-x) enhances performance and stability for the Hydrogen Evolution Reaction (HER).

Accelerated degradation tests have confirmed the stability of the new ruthenium-based catalyst, showing significantly lower activity loss than ruthenium oxide and on par with iridium oxide after 30,000 cycles.

Economic Benefits: A Game Changer

Beyond addressing supply concerns, the ruthenium-based catalyst offers significant commercial advantages. By implementing this breakthrough, a significant 90% reduction in capital expenditure on material costs can be achieved, ensuring hydrogen production becomes more economically feasible and efficient.

Dr. Philipp Walter, EVP New Business Development at Heraeus Precious Metals, stated that the dramatic reduction in capital expenditure needed per GW enabled by their new ruthenium-based catalyst not only addresses the iridium supply problem but also makes economic sense.

PEM Electrolysis Market: Growth and Trends

The global PEM electrolyzer market is poised for substantial growth, driven by the increasing demand for hydrogen as a clean and sustainable energy source. The market is expected to reach USD 4.104 billion by 2032, expanding at a CAGR of 30.04%. This growth is attributed to government initiatives, technological advancements, and the rising adoption of hydrogen in various industries, including transportation, power generation, and industrial processes.

Recent trends in the PEM electrolyzer market include:

Continuous improvement of system efficiency and durability.
Increasing focus on large-scale electrolysis projects.
Advanced membrane technologies improving efficiency and durability.
Growing government support and regulations promoting hydrogen adoption.
Commercialization of PEM electrolyzers and their compatibility with intermittent renewable energy sources.

PEM Electrolysis Applications: A Versatile Solution

PEM electrolyzers are finding applications in various sectors, including:

Green Hydrogen Production: Meeting the rising demand for clean energy sources and government initiatives to reduce carbon emissions.
Power-to-Gas: Converting excess renewable energy into hydrogen for storage and transportation.
Grid Stabilization: Providing flexibility to the grid by balancing supply and demand.
Transportation: Powering fuel cell electric vehicles (FCEVs) and reducing reliance on fossil fuels.
Industrial Feedstock: Supplying hydrogen for various industrial processes, such as ammonia production and steel manufacturing.

Overcoming Challenges and Future Directions

While the ruthenium-based catalyst represents a significant step forward, challenges remain in the PEM electrolysis field. These include:

Further reducing iridium loading without compromising catalyst activity.
Improving the efficiency of PEM electrolyzers through membrane-specific pressure optimization.
Developing novel membrane materials to reduce gas crossover and improve performance.
Optimizing cell design, materials, and system integration to enhance electrolyzer performance and lifespan.

The Bottom Line

The PEM Electrolysis Breakthrough, with the new Ruthenium Catalyst, slashes Iridium use and boosts Hydrogen Production. This innovation is a game-changer for the hydrogen economy, offering a pathway to more sustainable, affordable, and scalable green hydrogen production. By addressing the iridium bottleneck and reducing capital expenditure, this technology paves the way for a cleaner energy future.