2014 Volume 55 Issue 4 Pages 735-738
Microelectrochemical polarization measurements of polycrystalline Pt were performed to clarify the effect of the crystal orientation and grain boundary on the surface oxidation of Pt. Cyclic voltammograms (CV) for Pt(100)-like and Pt(110)-like grains on polycrystalline Pt after mechanical polishing showed no anodic peak below 1.35 V, which is similar to that for well-annealed Pt(111) single crystal. The anodic current of Pt(110)-like grain was significantly larger than Pt(100)-like. A small but concrete current increase appeared around 1.05–1.3 V in the CV of the surface including grain boundaries. This suggests the grain boundary may be the preferential site for the dissolution.