SURFACE STRESS CURVES FOR PLATINUM

Electrocapillary-type curves were measured for platinum ribbon electrodes in aqueous salt solutions using an extensometer instrument previously developed. A surface stress maximum was observed which varied with pH with a slope of about −50 mV/pH. This surface stress maximum is attributed to formation of a surface platinum hydride. Immediately positive of this maximum is a region about 0.15-0.4V wide in which platinum exhibits classical electrocapillary behavior. At potentials more positive than this region, the surface stress decreases rapidly due to formation of surface oxides. A surface stress maximum is found for the oxide surface at +1.8V. © 1979, The Electrochemical Society, Inc. All rights reserved.