Gold Nanoparticles Partially Embedded in Ultrathin Anodic Alumina Films
Sprache des Titels:
Gold nanoparticles with diameters ranging from 3.2 to 9.7 nm were prepared on an ultrathin anodic aluminum film by means of molecular beam deposition. Coverages ranging from 17.9% to 48.5% and the subsequent anodic anodization behavior were studied. Further oxide growth does not completely cover the gold nanoparticles but takes place preferentially under the particles with a surprisingly low kinetic hindrance. The gold nanoparticles are electrically isolated from the substrate as demonstrated by the absence of electrocatalytic reactions on the gold surface. A strong surface charge phenomenon is observed, which increases with increasing gold coverage that yields an increase of the capacity up to the minimum potential required for further oxide formation.