Characterization of carbon-supported Pt catalyst prepared from colloidal Pt particles capped with sodium polyacrylate

Abstract

Colloidal Pt nanoparticles, which contained 23% tetrahedral particles, 8% cubic particles, 49% other polyhedral particles, and 20% unidentified particles, were prepared through the reduction of Pt cations by dissolved H2 in the presence of sodium polyacrylate (SPA). The Pt particles were supported on carbon black and heated at 260°C in N2 flow. The prepared catalyst (Pt/C-SPA) contained 18% tetrahedral particles, 5% cubic particles, 29% other polyhedral particles, and 48% unidentified particles. Although the mean Pt particle size of Pt/C-SPA estimated by transmission electron microscopy (TEM) (9.1 nm) was larger than that of a conventional electrocatalyst (Pt/C-ref) (2.4 nm) for oxygen reduction reaction (ORR), the specific activities of Pt/C-SPA for ORR based on the particle size measured from the TEM image and on its electrochemical surface area were 1.8 and 1.6 times as high as those of Pt/C-ref, respectively.