Fuel cells have been hailed as saviours of the environment, because they can cleanly and efficiently turn hydrogen and other fuels into electricity. But so far this technology has been hobbled by the high cost of the platinum catalysts needed to make it work.
Now a new type of fuel cell based on carbon nanotubes promises to be much cheaper, as well as more compact and more efficient.
A team led by Liming Dai of the University of Dayton, Ohio, has discovered that a bundle of nanotubes doped with nitrogen can act as the catalyst, helping oxygen to react inside the fuel cell.
Hydrogen gas, for example, is pumped past one electrode (the anode), where it is split into its constituent electrons and protons. The electrons then flow out of the anode, providing electrical power, while the protons diffuse through the cell. Electrons and protons both end up at a second electrode (the cathode), where they combine with oxygen to form water.