A European Project Is Engineering Green Hydrogen Production Without PFAS or Rare Iridium
Green hydrogen - hydrogen produced by splitting water with electricity from renewable sources - is widely regarded as essential for decarbonizing industries that cannot run directly on electricity: steel production, ammonia synthesis, heavy transport, and chemical manufacturing. The problem is that the leading technology for producing it, proton exchange membrane electrolysis, remains expensive and depends on materials with serious environmental and supply chain problems.
The EU-funded SUPREME project is attempting to address both problems simultaneously. Over three years, an international research team led by the University of Southern Denmark, with participation from Graz University of Technology and partners across Europe, will work to develop a PEM electrolysis technology that eliminates the need for PFAS chemicals and drastically reduces reliance on iridium - a platinum-group metal that is among the rarest elements on Earth.
Why current PEM electrolysis falls short
PEM electrolysis has a key practical advantage over alkaline electrolysis, its main alternative: it handles variable power input well. When electricity supply from solar panels or wind turbines fluctuates - which it does constantly - PEM systems can ramp up and down quickly without losing efficiency or stability. This makes them particularly well-suited for renewable energy-linked hydrogen production, where matching power generation to electrolysis demand is a central engineering challenge.
But the current PEM technology has two significant drawbacks. The proton exchange membrane at the heart of the system is made from perfluorosulfonic acid polymers - PFAS materials. These are environmentally persistent compounds that the European Union is moving to restrict or ban. Using them as core components of a technology meant to support the green transition creates an obvious contradiction, and the impending regulatory changes add uncertainty to investments in current-generation PEM systems.
The catalyst layers in PEM electrolysis also require iridium to withstand the harsh electrochemical conditions at the anode, where water is oxidized to produce oxygen and protons. Iridium is produced almost entirely as a byproduct of platinum mining, primarily in South Africa and Russia. Global production is measured in a few tonnes per year. Scaling green hydrogen production to the level needed for industrial decarbonization would require iridium in quantities that current supply chains cannot deliver, at costs that would make the hydrogen economically uncompetitive.
What SUPREME aims to build
Merit Bodner from TU Graz's Institute of Chemical Engineering and Environmental Technology described the scale of hydrogen's role in the coming industrial transition: it is used as a raw material in very large quantities already, and demand will only grow as applications like green ammonia and green steel production scale up. The challenge is not whether green hydrogen will be needed, but whether it can be produced sustainably and affordably enough to displace fossil fuel-based production.
The SUPREME team is researching alternative membrane materials that match or approach the performance of PFAS-based membranes without the environmental persistence. Several classes of hydrocarbon-based and composite membrane materials have shown promise in laboratory settings, though none has yet demonstrated the combination of conductivity, durability, and stability that PFAS-based membranes deliver. The project will investigate what modifications to membrane chemistry and structure are needed to close that performance gap.
On the catalyst side, the research targets iridium reduction rather than complete elimination - the chemistry of water oxidation at the anode is genuinely demanding, and finding materials that perform comparably without any iridium is a longer-term challenge. The nearer-term goal is reducing iridium loading to a small fraction of current levels by using it more efficiently or combining it with more abundant materials in ways that maintain performance.
The economics of sustainable hydrogen
Green hydrogen currently costs substantially more to produce than hydrogen derived from natural gas. The cost gap has been narrowing as renewable electricity prices have fallen and electrolysis technology has improved, but it has not yet closed. Reducing material costs by eliminating expensive PFAS membranes and rare iridium catalysts is one pathway to cost reduction that does not depend on electricity prices falling further.
If SUPREME's approach succeeds at the research level, it would still face a substantial commercialization path. Moving from laboratory-scale demonstrations to industrial electrolyzers that can reliably produce hydrogen at scale requires extensive engineering, testing, and manufacturing development that takes years and substantial investment beyond what a three-year research program can accomplish.
What the project represents is a necessary earlier step: establishing whether the underlying science supports the alternative approaches, and if so, characterizing what trade-offs they involve. The answers will shape whether the pathway to PFAS-free, iridium-light PEM electrolysis is a near-term possibility or a longer-horizon challenge requiring further fundamental research.