Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5424167 | Surface Science | 2008 | 7 Pages |
Abstract
The surface stress-charge coefficient, Ï, quantifies the response of the surface stress - a fundamental property of solid surfaces - to the addition or removal of superficial electric charge. So far, all experiments have found Ï negative at clean metal surfaces. Here we report in situ dilatometry experiments on nanoporous gold samples prepared by dealloying. The results reveal a large reversible elastic contraction during the anodic part of cyclic potential scans. The behavior, which indicates an abnormal positive sign of Ï, can be linked to a monolayer of strongly adsorbed oxygen formed during dealloying, and to the extraordinarily small (1-2Â nm) structure scale of the material while the oxide is in place. After cathodic reduction, Ï reverts to the conventional, negative sign of the clean metal surface. We discuss the sign of Ï in relation to the electronic screening at metallic and oxide-covered surfaces.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Hai-Jun Jin, Smrutiranjan Parida, Dominik Kramer, Jörg Weissmüller,