O2 reduction on on ink-type rotating disk electrode using Pt supported on high-area carbons

Abstract

The kinetics of O2 reduction has been examined on an ink-type electrode made with Pt supported on high-area carbon. Electrocatalysls with 5-40 mass % of Pt on Black Pearls, Vulcan XC-72, and Shawinigan acetylene black carbons were used. Experiments were performed in 0.1 M solutions of H2SO4, H2PO4, HClO4, and NaOH. Kinetic parameters of O2 reduction were found to be similar as on a smooth Pt surface. No influence of the type of carbon was observed The mass activity of O2 reduction was independent of Pt loading at low currents, but at high currents the mass activity decreased with an increase in Pt loading. It is suggested that mass-transfer limitations are responsible for the different influence of Pt loading on mass activity at low and high currents. Reproducibility of the measurements on the ink electrode was satisfactory, and it is recommended for investigations of dispersed electrocatalysts.