Direct Methanol Fuel Cells (DMFC) have yet another argument in their battle for wide-entrance to the market. Instead of using pure hydrogen, these ones use methanol, which is much easier to transport and store than hydrogen. The backside of methanol is that it contains carbon, but that’s also fixable (recycled carbon dioxide can be used to make it).
MIT researchers, along with their colleagues from the Brookhaven National Laboratory and the Japan Institute of Science and Technology have found a method of decreasing the amount of platinum used in DMFCs by increasing the efficiency of the fuel cell’s electrodes. Others have tried to replace the platinum on the cathode with a liquid regenerating catalyst system (catholyte solution).
The MIT researchers deposited platinum nanoparticles on the surface of multiwall carbon nanotubes, and discovered that to increase the fuel cell’s efficiency they have to change the surface texture of the electrode, and not the size of the particle, as they previously had thought. In order to do that, they crated many tiny step-like shapes of the surface instead of leaving it smooth. The result was that the amount of electricity doubled.
The researchers found that the surface steps on the platinum nanoparticles correlate with the electrochemical activity and stability, which can be over hundreds of cycles. The activity of carbon monoxide and methanol electro-oxidation were enhanced with the step surface. The researchers reported that increasing surface steps on the platinum nanoparticles of around 2 nm leads to enhanced activity of up to about 200% for electro-oxidation of methanol.
Further development of the surface texture promises to yield more electricity from the fuel cell with the same amount of platinum used.