Researchers at the University of Delaware have developed an environmentally friendly way to recycle one of the world’s rarest and most valuable metals from hydrogen energy devices.
The new method can recover precious metals while also preserving key parts of the devices, helping reduce waste and support the growing clean energy industry.
The research focuses on proton exchange membrane (PEM) electrolyzers and fuel cells. These technologies play an important role in the future of hydrogen energy.
PEM electrolyzers use electricity to split water into hydrogen and oxygen. PEM fuel cells do the opposite by turning hydrogen back into electricity to power vehicles, equipment, or buildings.
Both technologies rely on expensive precious metals as catalysts. Platinum and iridium help speed up the chemical reactions that make the systems work efficiently.
While platinum is already scarce, iridium is even rarer. Only about eight tonnes of iridium are produced worldwide each year, making it one of the biggest challenges for expanding hydrogen technology.
Instead of depending only on mining, the University of Delaware team believes recycling used hydrogen devices can provide another important source of these valuable materials.
Doctoral researcher Safina-E-Tahura Siddiqui, working with Professor Ajay Prasad, created a new spray-jet recycling process. Professor Prasad compares the technique to pressure washing the outside of a house.
A controlled spray gently removes the catalyst layer from the membrane without damaging the material underneath.
Unlike many existing recycling methods, the new approach does not use harsh chemicals such as sulfuric or nitric acid. It also avoids burning the used membranes, a process that can release harmful emissions into the environment.
Instead, the researchers use a carefully controlled mixture of isopropyl alcohol and water. This solution removes the catalyst layers safely while producing very little waste, making the process much more environmentally friendly.
Another important advantage is that the method preserves the membrane itself. These membranes make up about 20% to 30% of the cost of a PEM device. They are also made from PFAS materials, often called “forever chemicals” because they remain in the environment for many years.
Reusing these membranes could reduce both costs and environmental pollution.
The process also removes platinum and iridium separately from opposite sides of the membrane. Keeping the two metals apart makes them much easier to recycle and reuse.
Developing the technique required hundreds of experiments. The researchers carefully adjusted factors such as temperature, spray strength, solvent mixture, and spraying time.
They also solved a problem where the membranes expanded and became fragile by designing a heated vacuum platform that held the material flat during cleaning.
The next step is to test how well the recovered metals and membranes perform in new hydrogen devices.
If successful, this recycling method could reduce the need for new mining, lower manufacturing costs, and create a more sustainable supply of materials for the growing hydrogen economy.
