Article pubs.acs.org/JPCC
Site Selectivity for CO Adsorption and Stripping on Stepped and Kinked Platinum Surfaces in Alkaline Medium Manuel J. S. Farias, Enrique Herrero, and Juan M. Feliu* Instituto de Electroquímica, Universidad de Alicante, Ap. 99, E-03080, Alicante, Spain ABSTRACT: This work reports experimental evidence that the adsorption of CO on Pt surfaces composed by (111) terraces and steps and/or kinks in alkaline media occurs faster on sites with (100) symmetry, followed by (110) sites. On the other hand, the (111) terrace has the lowest adsorption rate. CO electrooxidation demonstrates the existence of a close relationship between the preferential site CO occupancy and the peak multiplicity observed in CO stripping voltammetry. For the stepped Pt(554) and Pt(544) and kinked Pt(875) single crystal surfaces, the CO stripping process takes place at high potentials (∼0.80 V vs RHE) when only the (110) or (100) step sites are blocked by CO. However, when the terrace sites with (111) symmetry are fully occupied, new CO stripping peaks appear at lower potentials (
