Gold Nanoparticle Enhancement for Polymer Electrolyte Membrane (PEM) Fuel Cell*

PEM fuel cell is one of the most promising future alternative energy sources. However, its relatively low power output has prevented it from many practical applications. Marvrikakis et al have predicted that gold nanoparticles that are platelet shaped andhave direct contact to the substrate to be the perfect catalysts. In our experiment, hydrophobic, thiol-functionalized gold nanoparticles were synthesized through two-phase method developed by Brust et al. When particle solution is spread at the air water interface, EXAFS spectroscopy indicate that some of the gold atoms are removed, as the water displaces the hydrophobic thiol chains from the particle surface, resulting in platelet shaped particles. Furthermore, after these nanoparticles are spread on the surface of water in a Langmuir-Blodgett trough where surface pressure can be applied to compress them, they form LB film consisting of one or more monolayers. This LB film can then be deposited onto a solid surface, such as the Nafion membrane where the particle surface can make direct contact with electrodes and take effect. We also find that there is an optimal surface pressure for forming gold nanoparticles monolayer to achieve the highest enhancement of output power.