Electrosynthesis of mesoporous Pt-Au alloy electrode for direct methanol fuel cell

Mesoporous Pt-Au alloy films were successfully fabricated on ITO-coated glass from an aqueous mixture of H2PtCl6 and HAuCl4 by electrodeposition method using proper amount of poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (P123) as a templating agent. For comparison, nonporous Pt and mesoporous Pt were electrodeposited. Crystallinity of synthesized film was investigated by X-ray diffraction (XRD) analysis, and film composition was determined by energy dispersive X-ray spectroscopy (EDS). Scanning electron microscopy (SEM) was utilized to examine surface morphology and it was observed that the addition of P123 affected the particle growth, resulting in a significant change of surface morphology. The mesoporous structure was confirmed by transmission electron microscopy (TEM), and it was concluded that the formation of mesoporous structure strongly depended on electrodeposition conditions, such as deposition voltage, deposition time, temperature and P123 concentration. Compared with pure Pt electrodes, mesoporous Pt-Au film showed higher catalytic activities and stability for methanol oxidation. (C) 2007 Elsevier Ltd. All rights reserved.