The perturbation energy: A missing key to understand the “nobleness” of bulk gold

Abstract

The nobleness of gold surfaces has been appreciated since long before the beginning of recorded history. Yet, the origin of this phenomenon remains open because the so far existing explanations either incorrectly imply that silver should be the noblest metal or would fail to predict the dissolution of Au in aqua regia. Here, based on our analyses of oxygen adsorption, we advance that bulk gold's unique resistance to oxidation is traced to the large energy cost associated with the perturbation its surfaces undergo upon adsorption of highly electronegative species. This fact is related to the almost totally filled d-band of Au and relativistic effects, but does not imply that the strength of the adsorbate-Au bond is weak. The magnitude of the structural and charge-density perturbation energy upon adsorption of atomic oxygen—which is largest for Au—is assessed from first-principles calculations and confirmed via a multiple regression analysis of the binding energy of oxygen on metal surfaces.

On the Elusive Link between Adsorbate's Binding Energy and Bond Strength: An Illustration from CO Adsorption on Metal-Doped Graphene

“…(3), E B has for the most part been assumed to exactly represent bond strength: E B =E BF and, as a consequence, rational tuning of E B has been tackled through models addressing only the connection between bond strength, E BF , and the electronic structure of potential catalyst surfaces . Nevertheless, contrary to these premises and practices, recent studies show that E rx is comparable to E B for atomic oxygen adsorption on metal nanoparticles, and it is significant for other systems ,,. For example, E rx amounts up to 0.25 eV for Au(111) upon adsorption of atomic oxygen .…”

“…Nevertheless, contrary to these premises and practices, recent studies show that E rx is comparable to E B for atomic oxygen adsorption on metal nanoparticles, and it is significant for other systems ,,. For example, E rx amounts up to 0.25 eV for Au(111) upon adsorption of atomic oxygen . Clearly, E rx cannot be neglected in such cases.…”

“…While E rx has also been obtained in various studies, to our knowledge, the total energy increase associated with the electronic perturbation ( E elec ) was considered only very recently . The electronic contribution to E pert may be critical for catalytically relevant systems.…”

“…The electronic contribution to E pert may be critical for catalytically relevant systems. For example, for oxygen adsorption on various transition metals surface, it has been found that E elec , may be high and varies significantly from metal to metal …”