Portal de Periódicos da CAPES

Real-Time Surface X-ray Scattering Study of Au(111) Electrochemical Dissolution

2010; American Chemical Society; Volume: 114; Issue: 43 Linguagem: Inglês

10.1021/jp107101a

1932-7455

Klaus Krug, Daniel M. Kamiński, Frederik Golks, Jochim Stettner, Olaf M. Magnussen,

Advanced Materials Characterization Techniques

Direct in situ surface X-ray scattering studies of electrochemical dissolution at technologically relevant rates are presented using Au(111) electrodes in acidic chloride-containing solutions as an example. The dissolution process was investigated with high time resolution by monitoring the time-dependent X-ray intensity at selected positions in reciprocal space and by simultaneously recording high-quality electrochemical data. With increasing electrode potential, transitions from step-flow to layer-by-layer dissolution, manifesting as layering oscillations in the X-ray intensity as well as in electrochemical current−time transients, are observed prior to surface passivation. A quantitative analysis based on an atomic-scale structural model reveals that the dissolution process proceeds via progressive vacancy island nucleation in the whole active dissolution regime with next-layer nucleation occurring at comparatively low critical coverages between θc = 0.29 and θc = 0.44. This dissolution behavior shows the same characteristics as the intermediate "smooth multilayer growth" regime recently introduced in kinetic growth theories.