The structure of the Au(111) surface in contact with a recast Nafion film was studied as a function of potential by using grazing incident angle X-ray diffraction. The high penetration depth of X-ray made it possible to probe the electrode surface covered by a 1 to 3μm thick Nafion film. The Nafion-coated Au(111) electrode surface was not reconstructed at open circuit potential. However, the (23 x √3) reconstruction could be generated at sufficiently negative potentials. In comparison with the Au(111) electrode in NaClO4 solution, the lifting of reconstruction was shifted positively by about 0.2V. This fact supports the view of the primary effect of surface charge on the Au(111) reconstruction lifting. Adding chloride to the solution shifts the phase transition potential negatively after several hours, indicating a moderate ion permselectivity of the Nafion film in NaCl solution. These results demonstrate that the Nafion coating was stable over a large potential range and was suitable for studying surface properties and the effects of ion distribution on surface electrochemical processes at single crystal surfaces.

Surface Reconstruction at Metal/Solid Polymer Electrolyte Interfaces - Au(111)|Nafion Interface. J.X.Wang, R.R.Adžić: Journal of Electroanalytical Chemistry, 1998, 448[2], 205-10