| AVS 55th International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF-MoA |
| Session: | ALD: Functionalization and Surface Chemistry |
| Presenter: | J.W. Elam, Argonne National Lab. |
| Authors: | J.W. Elam, Argonne National Lab. S.T. Christensen, Northwestern U. F.A. Rabufetti, Northwestern U. W. Setthapun, Argonne National Lab. B. Lee, Argonne National Lab. Z. Feng, Northwestern U. P.C. Stair, Argonne National Lab. & Northwestern U. C.L. Marshall, Argonne National Lab. K.R. Poeppelmeier, Northwestern U. M.J. Bedzyk, Argonne National Lab. & Northwestern U. M.C. Hersam, Northwestern U. |
| Correspondent: | Click to Email |
Platinum supported on metal oxide surfaces has important technological applications in oxidative dehydrogenation catalysis, photocatalysis, and in catalytic converters. The atomic layer deposition (ALD) of Pt on oxide surfaces is unusual because it proceeds via nucleation, growth and coalescence of islands in contrast to the layer-by-layer behavior typically observed during the ALD of metal oxides. This natural tendency towards agglomeration combined with the ability to infiltrate porous materials makes ALD Pt an attractive method for preparing catalysts on high surface area supports. In this presentation, I will describe our recent work exploring Pt ALD on strontium titanate (STO) surfaces including both single crystal STO(001) substrates as well as novel STO nanocubes prepared by hydrothermal methods. We use a broad variety of methods to characterize these samples including atomic force microscopy, scanning- and transmission-electron microscopy, grazing incidence small angle X-ray scattering, X-ray reflectivity, X-ray fluorescence, and extended X-ray absorption fine structure measurements. These ex situ measurements are complemented by in situ quartz crystal microbalance and quadrupole mass spectrometer studies examining the mechanism of Pt ALD. These measurements clearly reveal the nucleation and growth of nm-sized Pt clusters on the STO surfaces where the Pt cluster size is controlled by the number of Pt ALD cycles. These Pt clusters are remarkably active for catalyzing the oxidation of hydrocarbons as demonstrated by propane light-off studies. The Pt clusters are very stable on the STO surfaces at temperatures up to 400-500°C, but sinter when heated to 800°C in vacuum.