Molecular dynamics (MD) and ab initio molecular dynamics (AIMD) simulations were conducted in order to define the structure of Nafion/Pt interface and to probe the mechanisms of oxygen reduction and hydrogen oxidation reactions. The results indicate that the interface can be characterized by a few layers of orderly distributed molecules. The periodicity in the first layer on the surface of Pt is broken at the boundaries between hydrophilic and hydrophobic domains. In addition, the periodically distributed molecules in the first layer on top of the Pt also form a superlattice. This ordered layer favors oxygen reduction but does not favor hydrogen oxidation. The oxygen reduction path is 2Pt + O 2 + H3O+ + e- → 2Pt-OH + H2O or 2Pt-OH2 + O2 + 2H3O+ + 2e- → 2Pt-OH + 4H2O→ The hydrogen oxidation path is 2Pt-H2 + H 2O → 2Pt-H- + H3O+.
ASJC Scopus subject areas