Hilde Krahl als Dunja, Szenenfoto, Brustbild, in: Gustav Ucicky: Der Postmeister (Wien Film)

Signatur des Originals: S 36/F10864

Dorit Kreysler als Marga Frisch, Szenenfoto, Brustbild, in: Erich von Neusser: Der Herr Schwiegerpapa (Film)

Signatur des Originals: S 36/F10874

Irene von Meyendorff als Octavia, Rollenbild, Hüftbild, in: Veit Harlan: Opfergang (Film)

Signatur des Originals: S 36/F10977

Heinz Rühmann als Peter Trost, Szenenfoto, in: Kurt Hoffmann: Ich vertraue dir meine Frau an (Film)

Signatur des Originals: S 36/F11076

Jacques Catelain als Oktavian, Elly Felicie als Sophie, Szenenfoto, Kniestück, in: Robert Wiene/Richard Strauss: Der Rosenkavalier, Dresden, 1926 (Pan-Film)

Signatur des Originals: S 36/F11995

Oxygen Reduction Reaction on Pt Overlayers Deposited onto a Gold Film: Ligand, Strain, and Ensemble Effect

We study the oxygen reduction reaction (ORR), the catalytic process occurring at the cathode in fuel cells, on Pt layers prepared by electrodeposition onto an Au substrate. Using a nominal Pt layer by layer deposition method previously proposed, imperfect layers of Pt on Au are obtained. The ORR on deposited Pt layers decreases with increasing Pt thickness. In the submonolayer region, however, the ORR activity is superior to that of bulk Pt. Using density functional theory (DFT) calculations, we correlate the observed activity trend to strain, ligand, and ensemble effects. At submonolayer coverage certain atom configurations weaken the binding energies of reaction intermediates due to a ligand and ensemble effect, thus effectively increasing the ORR activity. At higher Pt coverage the activity is governed by a strain effect, which lowers the activity by decreasing the oxidation potential of water. This study is a nice example of how the influence of strain, ligand, and ensemble effects on the ORR can be deconvoluted.