Abstract
The synthesis and evaluation of low platinum loading-reduced graphene oxide (Pt/rGO) electrocatalyst with high surface area and electrochemical activity for the oxygen reduction reaction (ORR) is presented in this work. Pt nanoparticles were synthesized via colloidal method by simultaneous chemical reduction of metallic salts in presence of poly (N-vinyl-2-pyrrolidone). First he GO was obtained by exfoliation of graphite layers using the modified Hummers methodology. The exfoliation process allowed getting GO of a few layers (around 5). The well dispersed Pt particles (around 10 nm) were deposited in small amounts (1 to 10%) over the GO using incipient wetness in an ultrasonic bath. It is expected that due to the surface functionalization (side step during the exfoliation process); the anchorage sites for the Pt particles between layers are created facilitating the deposition. Afterwards, the material obtained was treated at different temperatures (300, 500 y 800 °C) under inert atmosphere in order to improve the reduction degree and the electrical conduction of the rGO layers. The obtained electrocatalysts were characterized physically and chemically using X-ray diffraction (including Rietveld analysis), Raman and UV-Vis spectroscopies as well as scanning electron microscopy. The electrochemical performance of low loading Pt/rGO materials towards the ORR was studied using cyclic and linear voltammetry with a rotating disk electrode, in a typical three electrode cell using O2-satured acid solution as electrolyte, glassy carbon as substrate for the working electrode, Ag/AgCl (KCl sat) as reference and a Pt wire as counter electrode. Low metal loading materials exhibited interesting behaviors and will be presented and discussed at the conference.