Crystallographic rearrangement of platinum induced by square wave potentials.
This paper provides experimental evidences of crystalline rearrangements on platinum surfaces by applying square wave potential perturbations. The phenomenon was followed by differential ex situ X-ray diffraction patterns and in situ cyclic voltammetry in sulfuric acid solutions. Various upper and lower potential limits were employed covering anion, hydrogen, and/or oxygen adsorption ranges. When the -0.05 to 1.50 V (vs. reversible hydrogen) potential region is covered an increase in the distribution of (200) planes is observed. However, when the 0.65 to 1.50 V region is used, (220), (311), and (420) planes developed. The development of a longitudinal propagation mode is responsible for this rearrangement. The new equilibrium position of the platinum surface atoms in the lattice was calculated from the minimization of the potential energy expression.
Zinola
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Laboratorio de Electroquímica Fundamental, Iguá 4225, CP 11400, School of Sciences, Universidad de la República, Montevideo, Uruguay. fzinola@yahoo.com
Bello
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