Some Electrochemical Consequences of Potential-Induced Surface Reconstruction on Au(100): Double-Layer Nonuniformity and Electrode Kinetics
PURDUE UNIV LAFAYETTE IN DEPT OF CHEMISTRY
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Some consequences of potential-induced surface reconstruction upon the double-layer structure and electrocatalytic properties of Au100 in aqueous perchloric acid have been explored by means of cyclic voltammetry and differential capacitance measurements, along with in-situ scanning tunneling microscopy STM . Initially unreconstructed i.e. 1 x 1 Au100 yields capacitance-potential C-E profiles in dilute 1 mM perchloric acid in the vicinity of the potential of zero charge, E sub pzc, which are consistent with the presence of an essentially uniform distribution of electronic charge across the surface. Upon forming electrochemically induced hexagonal surface reconstruction by holding the potential below -0.2 V for periods up to ca 20 min, these C-E minima are broadened substantially. The latter observation implicates the presence of electrostatically distinct surface domains with local E sub pzc values that are significantly 0.1-0.2 V lower as well as higher than that for unreconstructed Au100, having dimensions at least comparable to the Debye length of the diffuse layer, ca 9.5 nm, in 1 mM HC104.
- Physical Chemistry