As phosphoric acid fuel cells move towards commercialisation capital cost is one of the factors influencing their economic viability. Platinum metals catalysts are used in the power section where the conversion of chemical fuel into electric energy takes place, and efforts to improve the performance of the catalysed electrodes continue. Interestingly, a recent study of platinum on carbon catalysts made at Stanford University, suggests that the optimum crystallite diameter for the most efficient use of platinum in fuel cell cathodes is about 3 nanometres (“Oxygen Reduction on Small Supported Platinum Particles”, M. Peuckert, T. Yoneda, R. A. Dalla Betta and M. Boudart, J. Electrochem. Soc., 1986, 133, (5), 944–947).