Gold based core-shell nanoparticles as fuel cell catalysts

The preparation of Au and Au alloy nanoparticles as electrocatalysts in several reactions including methanol oxidation, CO oxidation, and oxygen reduction was studied to explore the potential use of such nanoparticles as fuel cell catalysts. Both electrochemical and thermal approaches were used to activate the catalysts. For the electrochemically-activated gold nanoparticles assembled on glassy carbon electrodes, which involved the application of a polarization potential to 800 mv, an anodic wave was observed for the oxidation of methanol in alkaline electrolytes, which closely matched the potential for Au oxide formation. In electrochemical quartz crystal nanobalance measurements, a mass wave was detected corresponding to this current wave, implying an initial product release followed by formation of surface oxygenated species. In comparison with the electrochemically-activated catalyst, similar results were observed for thermally activated Au catalysts. The catalytic activity upon activation was dependent on the nature of the molecular-wire agent used to assemble the nanoparticle catalysts.