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Potential Dependent Structural Memory Effects in Au-Pd Nanoalloys

Jakub S Jirkovský ; Itai Panas (Institutionen för kemi- och bioteknik, Oorganisk miljökemi) ; Simon Romani ; Elisabet Ahlberg ; David Schiffrin
The Journal of Physical Chemistry Letters (1948-7185). Vol. 3 (2012), 3, p. 315–321.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: segregation, nanoparticle, ORR, H2O2, bimetallic, alloy, adsorption

Denna post skapades 2012-01-09. Senast ändrad 2012-03-07.
CPL Pubid: 151890


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Institutioner (Chalmers)

Institutionen för kemi (2001-2011)
Institutionen för kemi- och bioteknik, Oorganisk miljökemi (2005-2014)



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