New Highly Stable Fuel-Cell Catalyst Gets Strength from its Nano Core
Palladium core protects precious platinum; enhances reactivity/stability
Story content courtesy of U.S. Department of Energy's Brookhaven National Laboratory
Scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory have developed a new electrocatalyst that uses a single layer of platinum and minimizes its wear and tear while maintaining high levels of reactivity during tests that mimic stop-and-go driving. The research may greatly enhance the practicality of fuel-cell vehicles and may also be applicable for improving the performance of other metallic catalysts.
The newly designed catalysts are composed of a single layer of platinum over a palladium (or palladium-gold alloy) nanoparticle core. "Our studies of the structure and activity of this catalyst - and comparisons with platinum-carbon catalysts currently in use - illustrate that the palladium core 'protects' the fine layer of platinum surrounding the particles, enabling it to maintain reactivity for a much longer period of time," explained Brookhaven Lab chemist Radoslav Adzic, who leads the research team.
In conventional fuel-cell catalysts, the oxidation and reduction cycling - triggered by changes in voltage that occur during stop-and-go driving - damages the platinum. Over time, the platinum dissolves, causing irreversible damage to the fuel cell. In contrast, platinum was almost unaffected, except for a small contraction of the platinum monolayer.
The fundamental science leading to the development of the new electrocatalyst and early scale-up work was funded by the DOE Office of Science. Additional funding came from the Toyota Motor Corporation.