| AVS 63rd International Symposium & Exhibition | |
| Fundamental Discoveries in Heterogeneous Catalysis Focus Topic | Wednesday Sessions |
| Session HC+NS+SS-WeA |
| Session: | Nanoscale Surface Structures in Heterogeneously Catalyzed Reactions |
| Presenter: | Mahdi Ahmadi, University of Central Florida |
| Authors: | M. Ahmadi, University of Central Florida F. Behafarid, University of Central Florida B. Roldan Cuenya, Ruhr-University Bochum, Germany |
| Correspondent: | Click to Email |
Strong metal-support interaction (SMSI) is expected to occur for this system under reducing environments
such as vacuum and H2. Since the morphology of NPs depends on their surface energy and their interaction
with the support, investigating the shape of NPs could be an excellent pathway to understand the metal
support interactions. In this study we have investigated the in situ shape evolution of TiO2 supported Pt NP
using grazing incidence small angle X-ray scattering (GISAXS) during annealing in H2 environment. The
size selected Pt NPs with an initial spherical shape were synthesized via inverse micelle encapsulation
method. The sample was step annealed up to 700°C in H2 environment and the onset for NPs faceting was
found to be 600°C. Annealing at a higher temperature (700°C) did not cause any further change in NPs
structure. The presence of a sharp scattering ray at 45° with respect to the surface normal indicates the (110)
facet to be the dominant side facet for Pt NPs and the top and interfacial facets to be Pt(100). These features
point out that the shape of Pt NPs supported on TiO2 under hydrogen environments is pyramidal. The
specific shape of Pt NPs are discussed based on the SMSI phenomenon.