Langmuir, Vol.28, No.7, 3658-3663, 2012
Electro-oxidation of COchem on Pt Nanosurfaces: Solution of the Peak Multiplicity Puzzle
An understanding of the oxidation of chemisorbed CO (COchem) on Pt nanoparticle surfaces is of major importance to fuel cell technology. Here, we report on the relation between Pt nanoparticle surface structure and COchem, oxidative stripping behavior. Oxidative stripping voltammograms are obtained for COchem preadsorbed on cubic, octahedral, and cuboctahedral Pt nanoparticles that possess preferentially oriented and atomically flat domains. They are compared to those obtained for etched and thermally treated Pt(poly) electrodes that possess atomically flat, ordered surface domains separated by grain boundaries as well as those obtained for spherical Pt nanoparticles. A detailed analysis of the results reveals for the first time the presence of up to four voltammetric features in COchem oxidative stripping transients, a prepeak and three peaks, that are assigned to the presence of surface domains that are either preferentially oriented or disordered. The interpretation reported in this article allows one to explain all features within the voltammograms for COchem oxidative stripping unambiguously.