Preparation of platinum nanoparticles on carbon black with mixed binary surfactants: Characterization and evaluation as anode catalyst for low-temperature fuel cell

Abstract

Platinum nanoparticles supported on Vulcan XC-72R prepared by a surfactant-stabilized colloidal method exhibit excellent properties as an anode catalyst for a low-temperature fuel cell. A Pt/C catalyst prepared with a 10-fold critical micelle concentration of mixed non-ionic surfactants [polyoxyethylene (23) lauryl ether + polyoxyethylene (20) sorbitan monolaurate (Brij 35 + Tween 20)] shows the highest catalytic activity and the greatest electrochemical surface-active area among those prepared. The maximum current density of this catalyst is much higher than that of a commercial Pt/C catalyst (E-TEK). Moreover, X-ray diffraction and transmission electron microscopy analyses reveal that Pt/C prepared with Brij 35 + Tween 20 has an average particle size of 2.4 nm with quite a narrow distribution between 2 and 3 nm, which is the smallest among all the catalysts prepared. This is attributed to the formation of more compact micelles. Mixtures of non-ionic and anionic surfactants result in less compact micelles.