PNNL

Abstract

In this communication, we report on the specific role of the Alp sites in Pt sintering over ?-Al2O3 support. On the basis of HR-STEM and EXAFS results that showed a bimodal distribution of Pt clusters on ?-Al2O3 during Pt sintering under high-temperature calcination conditions, high-level density functional theory (DFT) calculations were performed to investigate the interactions of atomic Pt and PtO on ?-Al2O3 at different coverages. In agreement with experimental observations, DFT calculations indicate that the sintering processes are both thermodynamically and kinetically hindered by strong interactions of atomic Pt and PtO with the Alp sites on the ?-Al2O3 support. Therefore, increasing the quantity of (100) facets of ?-Al2O3, on which the Alp sites reside, may provide a way to control the sintering of ?-Al2O3-supported Pt catalysts. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.