Srinivasan Sarangapani

Electrochemical characterization of unsupported high area platinum dispersed on the surface of a glassy carbon rotating disk electrode in the absence of Nafion † or other additives

Abstract A method is described herein to immobilize dispersed unsupported high area Pt particles (ca. 30 m 2 g −1 ) on the surface of a glassy carbon (GC) disk of a rotating Pt(ring)/GC(disk) electrode (RRDE) assembly, without the use of Nafion® or other additives, allowing electrochemical measurements to be performed under forced convection with only minimal losses of Pt from the surface. Diffusion limiting currents, I lim , and half-wave potentials for O 2 reduction recorded with dispersed Pt/GC electrodes at the highest attainable loadings (ca. 8.3 equivalent Pt monolayers and rotation rates 400≤ ω ≤2500 rpm, were found to be differ only slightly from those observed with a bulk Pt RDE of the same cross sectional area, e.g. I lim (Pt) ca. 1.06 I lim (Pt/GC), under otherwise identical conditions. In addition, this novel strategy enables in situ surface modification of dispersed Pt particles on the GC disk of the RRDE by ad-atoms and subsequent voltammetric and electrocatalytic characterization for a wide spectrum of redox reactions.