Hydrogen Electrolysers: The Race of Noble Metals vs. Stainless Steel

As the demand for clean energy soars, hydrogen has emerged as a vital solution to decarbonize hard-to-abate industries and reshape the global energy landscape. According to the International Energy Agency (IEA), clean hydrogen could account for up to 10% of total final energy consumption by 2050 if current momentum and policies continue. Central to this growth are hydrogen electrolysers, which split water into hydrogen and oxygen. This article looks at one key aspect of electrolyser design: the material race between noble metals and stainless steel—which one holds the key to scalable, cost-effective, and durable solutions?

1. The Importance of Material Selection in Electrolysers

Electrolysers operate in challenging environments. They deal with:

• High temperatures
• Corrosive electrolytes
• Constant voltage and current stresses

As a result, the choice of material for the electrolyser’s core components (electrodes and stack materials) directly impacts performance, longevity, and overall system economics.

2. Noble Metals: Platinum and Beyond

Advantages

1. Excellent Corrosion Resistance Noble metals such as platinum, iridium, and ruthenium have superior chemical stability, making them highly resistant to corrosive conditions inside electrolysers (especially in PEM electrolysers).
2. Exceptional Electrocatalytic Properties These metals exhibit very high catalytic activity, which improves hydrogen production efficiency and can lower overall power consumption.

Disadvantages

1. High Cost and Limited Availability Platinum-group metals are expensive and subject to supply constraints. As hydrogen production scales, availability and pricing are crucial concerns for large-scale deployment.
2. Recycling and Recovery Complexity While recycling programs do exist, recovering noble metals from spent catalysts is complex, energy-intensive, and not always cost-effective.

3. Stainless Steel: The Contender for Cost-Effectiveness

Advantages

1. Cost Efficiency Stainless steel (SS) is widely available and far less expensive than noble metals, allowing for more budget-friendly electrolyser designs.
2. Mechanical Strength SS has good structural integrity and can withstand high pressures, making it well-suited for alkaline electrolysers and certain PEM electrolyser components.

Disadvantages

1. Corrosion Challenges While stainless steel resists corrosion well in many environments, the aggressive conditions of some electrolyser types (particularly acidic PEM systems) can still pose challenges.
2. Lower Catalytic Activity Stainless steel does not match the catalytic performance of noble metals, potentially resulting in lower efficiency and a higher operational cost over time.

4. Striking the Right Balance

Recent research from institutions such as the National Renewable Energy Laboratory (NREL) and ongoing industry developments suggest a hybrid approach. Novel coatings, alloys, and composites aim to combine the best properties of both stainless steel (mechanical strength and cost-effectiveness) and noble metals (corrosion resistance and high catalytic activity). For example, using thin layers of iridium or platinum on a stainless-steel substrate can drastically reduce the quantity of noble metal while maintaining necessary performance metrics.

5. Market Outlook and Future Innovations

Companies are racing to refine material technologies to unlock large-scale, low-cost hydrogen production. Here’s what to watch:

1. Cost Reduction Through Innovation As manufacturing scales and R&D advances, we can expect price drops in catalysts and stack materials.
2. Resource Diversification The discovery and development of alternative, abundant catalysts will help mitigate supply chain risks associated with precious metals.
3. Sustainability Focus Greater attention on the full lifecycle of electrolyser components—from raw material extraction to end-of-life recycling—will accelerate the push for stainless-steel-based and hybrid solutions.

Conclusion

The choice between noble metals and stainless steel in hydrogen electrolyser manufacturing is not a one-size-fits-all question. Noble metals deliver top-tier efficiency and durability but come with high costs and resource constraints. Stainless steel offers a more affordable path with robust mechanical properties but faces limitations in catalytic performance and corrosion under harsh conditions. Hybrid approaches—leveraging cost-effective substrates and advanced thin-film coatings—promise to bridge the gap.

As the hydrogen economy continues to scale, material innovation will be pivotal. By striking the balance between performance, cost, and sustainability, manufacturers, policymakers, and investors can collectively drive the emergence of hydrogen as a cornerstone of our low-carbon future.