Exploring efficiency and durability in fuel cell catalysts

Researchers have demonstrated that platinum-copper and platinum-iron catalysts supported on MXene can enhance fuel-cell performance and durability.

Hydrogen fuel cells represent a crucial low-carbon technology, applicable in vehicles, backup power systems, and other areas. These cells convert hydrogen into electricity, emitting only water as a by-product. A critical process within the cell is the oxygen reduction reaction, where oxygen is reduced at the cathode. This reaction is relatively slow, limiting the overall performance of the fuel cell.

Platinum catalysts are used to accelerate this reaction. Despite their effectiveness, platinum is costly and degrades over time. Consequently, research focuses on minimizing platinum usage while enhancing performance and catalyst longevity. One strategy involves using platinum alloys, which combine platinum with a less expensive metal to boost efficiency. However, these metals can leach out, reducing catalyst activity over time.

The researchers explored the balance between catalytic activity and durability by studying two alloy catalysts: platinum-copper (PtCu) and platinum-iron (PtFe). These catalysts were supported on MXene, a two-dimensional material akin to graphene, which enhances performance and stabilizes the nanoparticles. PtCu/MXene exhibited the highest catalytic activity, as copper alters the platinum surface to improve oxygen reduction. Conversely, PtFe/MXene was less active but more durable, with strong Fe-O-MXene interactions stabilizing the catalyst during prolonged use.

Using in-situ X-ray spectroscopy, the researchers observed the catalysts in operation, identifying structural and electronic changes that influence performance. This study highlights how alloy composition and catalyst supports affect activity and durability, providing a roadmap for developing advanced catalysts for future fuel cells.