Dresden 2014 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 36: Topical Session: Thermodynamics at the nano scale IV - Electrochemistry and strain
MM 36.1: Topical Talk
Wednesday, April 2, 2014, 10:15–10:45, BAR 205
First-principles prediction of the equilibrium shape of nano particles under realistic electrochemical conditions — •Nicola Marzari1 and Nicephore Bonnet2 — 1Theory and Simulations of Materials, EPFL — 2AIST and University of Tokyo
A first-principles model of the electrochemical double layer is applied to study surface energies and surface coverage under realistic electrochemical conditions and to determine the equilibrium shape of metal nanoparticles as a function of applied potential. The potential bias is directly controlled by adding electronic charge to the system, while total energy calculations and thermodynamic relations are used to predict electrodeposition curves and changes in surface energies and coverage. This approach is applied to Pt surfaces subject to hydrogen underpotential deposition. The shape of Pt nanoparticles under a cathodic scan is shown to undergo an octahedric-to-cubic transition, which is more pronounced in alkaline media due to the interaction energy of the pH-dependent surface charge with the surface dipole.
References: N. Bonnet and N. Marzari, Phys. Rev. Lett. 110. 086104 (2013).