Researchers have identified a way to balance the trade-off between catalytic activity and long-term durability in hydrogen fuel cell catalysts by pairing platinum alloys with a two-dimensional material called MXene. The work, published in Progress in Energy, compared platinum-copper (PtCu) and platinum-iron (PtFe) nanoparticles supported on MXene, a graphene-like material that helps anchor the nanoparticles and improve their stability.
Hydrogen fuel cells convert hydrogen into electricity with water as the only by-product, making them an important low-carbon technology for vehicles, backup power systems and other applications. A key limitation is the oxygen reduction reaction at the cathode, which is relatively slow and constrains overall fuel-cell performance. Platinum catalysts accelerate this reaction but are expensive and degrade over time, so much research focuses on reducing platinum content while improving both activity and lifetime.
Platinum alloys, in which a cheaper metal is mixed with platinum, can improve efficiency. However, the alloying metal can gradually leach out, causing the catalyst to lose activity. The new study investigated whether MXene supports could help address this trade-off by stabilising the alloy nanoparticles and modifying their catalytic behaviour.
PtCu/MXene showed the highest catalytic activity. According to the researchers, copper modifies the platinum surface in a way that improves oxygen reduction and accelerates the reaction. PtFe/MXene was less active but more durable, with strong Fe-O-MXene interactions helping to stabilise the catalyst during long-term operation.
To understand these differences, the team used in-situ X-ray spectroscopy to observe the catalysts while they were operating. This allowed them to identify the structural and electronic changes responsible for performance differences, revealing how alloy composition and catalyst supports influence both activity and durability.
The findings provide a roadmap for developing improved catalysts for future fuel cells. By decoupling activity from durability, the study suggests that alloy composition and support interactions can be tuned to meet different performance priorities, potentially reducing reliance on platinum while extending catalyst life.
The research was conducted by Sharon Benny Alex and colleagues and published in Progress in Energy. The work adds to ongoing efforts to make hydrogen fuel cells more commercially viable by addressing the cost and longevity of platinum-based catalysts.
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