Mapping Catalyst Failure to Advance Clean Hydrogen Fuel Production

Hydrogen is the most abundant element in the universe. When it meets with oxygen in combustive reactions, massive amounts of energy can be generated, and water, as steam or liquid, is the only byproduct. This makes hydrogen an appealing alternative to fossil fuels for powering everything from vehicles to power plants.

A promising way to produce hydrogen is electrolysis—splitting water using electricity—but this approach is both expensive and energy-intensive and relies on rare materials such as iridium oxide (IrO₂) to act as a catalyst to speed up reactions.

But IrO₂ is among the rarest non-radioactive elements in the Earth’s crust. And not unlike how metals rust over time, iridium oxide catalysts slowly degrade during these reactions, as the harsh acidic and high-voltage conditions required “eat away at” the surface of IrO₂ crystals.

This is why understanding exactly how iridium oxide degrades is a crucial step toward designing more durable materials that require significantly less of this precious metal while helping to reduce carbon emissions in the energy and chemical industries worldwide.

Now, a new study co-led by Aleksandra Vojvodic of the University of Pennsylvania and collaborators at Duke University offers an unprecedented view of that degradation process, capturing how IrO2 nanocrystals dissolve and change shape during electrolysis. The findings, published in the Journal of the American Chemical Society, provide critical insight into why today’s best catalysts still fail and how future materials might last longer.

“Historically, scientists often treated the binding sites of catalysts as perfect static surfaces that just sit there while a reaction happens on top of them,” says Vojvodic, the Rosenbluth Professor at the Department of Chemical and Biomolecular Engineering at Penn Engineering. But the team’s combined computational modeling and physical imaging prove there’s far more to the story; the iridium oxide actively changes its shape, transforming under differing conditions before completely decomposing.

Read More at Penn Today