AVS 64th International Symposium & Exhibition
    Surface Science Division Friday Sessions
       Session SS+HC-FrM

Paper SS+HC-FrM7
Ab-Initio Study of Low Index Surface Planes of γ-Al2O3 and their Interface with Pt

Friday, November 3, 2017, 10:20 am, Room 24

Session: Recent Advances in the Chemistry and Physics of Interfaces
Presenter: Kofi Oware Sarfo, Oregon State University
Authors: K. Oware Sarfo, Oregon State University
A.L. Clauser, Oregon State University
Z.L. McClure, Oregon State University
M. Santala, Oregon State University
L. Árnadóttir, Oregon State University
Correspondent: Click to Email
Metal/metal oxide interfaces are important because of their substantial impact on the composite properties of materials in a vast range of scientific and technological applications. Historically, metal oxides have been used as thermal barriers to protect metals from thermal degeneration in high temperature environments. Metal/oxide interfaces are important in applications such as protective coatings for metal medical implants, in electronic devices, and in heterogeneous catalysis mostly as catalyst support. γ-Al2O3 is a common catalyst support due to its high surface area, which enables fine dispersal of metal catalysts, such as Pt, Pd, Ru, and Rh. The structure and metal/metal oxide interactions at the interface of these materials can significantly impact the electronic and mechanical properties of the catalyst and the support. In this work, we combine theoretical and experimental approaches to study the nature of the metal/metal oxide interface between γ-Al2O3 and Pt. The theoretical approach utilized density functional theory (DFT) to study the structure and atomistic interactions at the interface. To determine the effect of the environment on the stability of different surface termination, we calculate the surface energy of three different low index planes and possible terminations of γ-Al2O3 as a function of partial pressures of oxygen at the experimental fabrication temperature (1100K). The (100) surface plane of γ-Al2O3 was found to be most stable and the (111) surface plane had the highest surface energy corresponding to lowest stability due to its highly polar structure. The stoichiometric terminations were found to be the most stable for the (100) and (110) planes at all partial pressures of oxygen, while the most stable termination of the (111) plane transitions from the stoichiometric surface to an oxygen rich surface termination at higher partial pressures of oxygen. This provides the basis for the experimental study of the atomic structure of the interface between γ-Al2O3 and Pt nanoparticles.