The Intriguing Promise of Nanowires

What do jewelry and batteries have in common?

If a pair of Yale engineers have a say, quite a lot. Jan Schroers and Andre Taylor are using microscopic wires made of “bulk metallic glass”—a platinum alloy—to make fuel cells work better.

Their paper on the fuel cell is on the cover of this month’s ACS Nano, a scientific journal.

The alloy, a combination of platinum and other materials, acts as the catalyst for the fuel cell. While catalysts are traditionally made of carbon black and platinum particles, Schroers said, over time the carbon basically overwhelms the metal. But the nanoparticles in the new wires, he said, have a bigger surface area, and so let the catalyst work longer and more efficiently.

“There’s no platinum that disappears,” Schroers said. “In fact, the opposite happens. You get more platinum on the surface than in the alloy.”

After 1,000 cycles, the catalyst maintains 2.4 times as much performance as traditional catalysts made of carbon and platinum, according to the paper.

Materials made from nano-sized particles, like these, are a promising field of engineering. A nanometer is a billionth of a meter, and some of these super-tiny materials have amazing properties, from making bike frames stronger (carbon nanotubes) to making sunscreen more transparent on the skin (titanium dioxide). Scientists are struggling to figure out just how the properties of these substances change when they’re shrunk to the near-atomic level, and how or whether those changes impact people, animals or the environment.

Substances like the alloy Schroers and Taylor are working with, in which the nanoparticles are effectively encased in a larger structure, are of less concern than applications that allow the nanomaterials to be released more easily, such as sprays or fabric treatments.

READ MORE