Atomic Level Investigation of the Phase Stability of Transition Metal Surfaces Under Reactive Environment
EMSL Project ID
48177
Abstract
Atomic level understanding of transition metal surfaces (in particular the surfaces of metal nano-particles) is critical for developing a structure-property relationship in a range of scientific disciplines including catalysis, materials science or solid-state physics. The goal of this project is to investigate the surfaces of Platinum group metal nanoparticles during their exposure to elevated temperatures and reactive oxidizing environments. The specific questions we are going to address in this work are: 1) what are the structural characteristics of the low index surfaces of metal particles and how these characteristic change with particle size, temperature and gas pressure, 2) what is the mechanism of oxidation 3) what is the role of support material on phase stability of metal nanoparticles. The experiments proposed in this work will be performed with an aberration corrected environmental transmission electron microscope (E-TEM) that utilizes a recently built gas delivery unit that allows us to accurately control gas mixture compositions and flow rates and seamless switching between gases, while maintaining atomic resolution imaging. Selected samples will be also studied using an aberration corrected scanning transmission electron microscope (STEM) in combination with compositional mapping using electron energy loss spectroscopy (EELS), and other techniques such as X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, to obtain information on the electronic structure of the metal nano-particles. An import aspect of this work will be quantifying the bonding environment in the surface oxide, and derivation of surface energies with the use of Density Functional Theory (DFT) methods.
Project Details
Start Date
2014-01-20
End Date
2014-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Ewbank JL, L Kovarik, FZ Diallo, and C Sievers. "Effect of Metal Support Interactions in Ni/Al2O3 Catalysts with Low Metal Loading for Methane Dry Reforming." Applied Catalysis A: General. doi:10.1016/j.apcata.2015.01.029