IMAGINE a car that runs on hydrogen from solar power and produces water instead of carbon emissions. While vehicles like this won’t be on the market any time soon, University of Wisconsin-Madison researchers are making incremental, but important, strides in the fuel-cell technology that could make clean cars a reality.
Materials science and engineering assistant professor Dane Morgan and PhD student Edward (Ted) Holby have developed a computational model that could optimise an important component of fuel cells, making it possible for the technology to have a more widespread use.
Fuel cells are electrochemical devices that facilitate a reaction between hydrogen and oxygen, producing electrical power and forming water.
Though the premise sounds straightforward, there are multiple hurdles to producing efficient fuel cells for widespread use. One of these is the catalyst added to aid the reaction between protons, electrons and oxygen at the cathode. Current fuel cells use platinum and platinum alloys as a catalyst. But platinum is expensive and not very abundant.
To maximise its use, researchers use catalysts made with platinum particles as small as two nanometers, which are about 10 atoms across. These tiny structures have a large surface area on which the fuel-cell reaction occurs. However, platinum catalysts this small degrade very quickly.
But Dane and Ted now think smallest is not necessarily best. Their work shows that if the particle size of a platinum catalyst is increased to four or five nanometers, which is about 20 atoms across, the level of degradation significantly decreases – which means the catalyst and the fuel cell can function for much longer.