Cheaper Fuel Cells

Carbon nanotubes could replace expensive platinum catalysts and help finally make fuel cells economical. By Prachi Patel-Predd

Better than platinum: A scanning electron microscope image shows an array of vertical carbon nanotubes that are doped with nitrogen. The array could replace the expensive platinum catalyst used in fuel-cell electrodes. Credit: Science

Researchers have shown that arrays of vertically grown carbon nanotubes could be used as the catalyst in fuel cells. The carbon nanotubes, which are doped with nitrogen, would be much cheaper and longer lasting than the expensive platinum catalysts used now.

More than half the cost of fuel-cell stacks comes from platinum, according to the Department of Energy. "Fuel cells haven't been commercialized for larger-scale applications because platinum is too expensive," says Liming Dai, a materials-engineering professor at the University of Dayton, in Ohio, who led the work. "For electrodes, you need a cheaper material that still has a high performance."

Dai and his colleagues make electrodes by depositing the carbon-nanotube arrays on a composite film of polymer and carbon nanotubes. In a Science paper, the researchers show that using the material as a cathode gives four times higher current densities than do conventional platinum-coated electrodes. "There has been very limited success to finding a replacement for platinum, and [carbon nanotubes] could be one," says Prashant Kamat, a chemistry professor at the University of Notre Dame.

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