A first principles analysis of the electro-oxidation of CO over Pt(111)

作者：Janik Michael J; Neurock Matthew^*

来源：Electrochimica Acta, 2007, 52(18): 5517-5528.

DOI：10.1016/j.electacta.2007.01.060

• CO electro-oxidation
• Pt(111)
• direct methanol fuel cells
• PEMFC
• density functional theory

First principle density functional theoretical calculations carried out within a constant potential half-cell formalism were used to model the electro-oxidation of CO over Pt(1 1 1). The method involves tuning the potential by the addition or removal of electrons from the system. The free energy for different adsorbed species within the double-layer is analyzed over a range of different potentials to establish the lowest energy states and the reaction energies that connect these states. The potentials are calculated based on a novel double-reference approach [J.S. Filhol, M. Neurock, Angew. Chem. Int. Ed. 45 (2006) 402] discussed earlier. The potential -dependent reaction energies are reported for the elementary steps of water activation in the presence of co-adsorbed CO and CO oxidation over the model Pt(1 1 1) surface. The potential-dependent activation barriers are computed for the key elementary steps in CO oxidation to develop a detailed reaction energy profile as a function of electrode potential. The results suggest that the coupling of co-adsorbed CO and OH controls the rate. Water activation, however, is necessary to supply a critical coverage of the surface OH oxidant.

• 出版日期2007-5-10