Potential Dependent Structural Memory Effects in Au-Pd Nanoalloys
Artikel i vetenskaplig tidskrift, 2012

Alloying of metals offers great opportunities for directing reactivity of catalytic reactions. For nanoalloys, this is critically dependent on near-surface composition, which is determined by the segregation energies of alloy components. Here, Au-Pd surface composition and distribution of Pd within a Au0.7Pd0.3 nanoalloy were investigated by monitoring the electrocatalytic behavior for the oxygen reduction reaction used as a sensitive surface ensemble probe. A time dependent selectivity towards formation of H2O2 as the main oxygen reduction product has been observed, demonstrating that the applied potential history determines surface composition. DFT modeling suggests that these changes can result both from Pd surface diffusion and from exchange of Pd between the shell and the core. Importantly, it is shown that these reorganizations are controlled by surface adsorbate population, which results in a potential dependent Au-Pd surface composition and in remarkable structural memory effects.

segregation

alloy

bimetallic

ORR

nanoparticle

adsorption

H2O2

Författare

Jakub S Jirkovský

Göteborgs universitet

Itai Panas

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Simon Romani

University of Liverpool

Elisabet Ahlberg

Göteborgs universitet

David Schiffrin

University of Liverpool

Journal of Physical Chemistry Letters

1948-7185 (eISSN)

Vol. 3 3 315-321

Ämneskategorier

Kemiska processer

Teoretisk kemi

DOI

10.1021/jz201660t