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

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(R) 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 400less than or equal toomegaless than or equal to2500 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. 1.06I(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. (C) 2002 Elsevier Science B.V. All rights reserved.