Experimental Studies of Fundamental Molecule-Particle Interactions and Reactions on Iron Metal and Oxide Surfaces
EMSL Project ID
40023
Abstract
We will employ a novel 'atom-dropping' approach to explore the reactivity Fe and Fe oxides with environmentally relevant species. Iron oxides will be deposited directly via evaporation or created by landing Fe atoms into multilayers of water and oxygen. TPD studies of the final reaction products will be complemented by infrared reflection adsorption spectroscopy (IRAS), which will provide valuable information about the reactive intermediates and remediation pathways. The initial reactive step between iron and many species (chlorocarbons, water) appears to be the formation of an Fe insertion complex that has been predicted by theory. Indirect evidence for the complex comes from TPD and XPS experiments. We propose to find direct evidence for the insertion complex using FTIR spectroscopy. To enhance the infrared signal we will use repeated layers of Fe and the reactant to create a molecular parfait. In addition, the experiment will be designed to optimize the FTIR detection of the 1000 to 700 cm-1 region. Iron oxides will be deposited directly via evaporation or created by landing Fe atoms into multilayers of water and oxygen. We will investigate the growth and structural characteristics of nanoporous Fe oxide films grown via reactive ballistic deposition (RBD). We expect these nanoporous Fe oxide films to exhibit high surface areas relative to a flat substrate. The relative surface area and binding site distribution in the films will be followed as a function of annealing temperature. This study will then investigate the reactivity of these films towards O2, H2O, and CHxCl4-x. Reactivity studies will employ TPD and IRAS, and the subsequent effect of these adsorbates on surface area and binding site distribution will be monitored by rare gas physisorption. This proposal is designed to provide a fundamental, molecular-level understanding of the chemistry and reactions of iron metal and metal oxide particles and surfaces. The focus is on advancing this understanding by using molecular and nano-scale systems and inventing novel experimental methods to resolve the complexities inherently limiting the understanding of processes in real-world environments. Such detailed molecular-level studies are germane to DOE programs in environmental restoration and remediation, waste processing, and contaminant fate and transport.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-06
End Date
2012-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Parkinson GS, Z Dohnalek, RS Smith, and BD Kay. 2010. "Reactivity of Fe0 Atoms with mixed CCI4 and D2O films over FeO (111)." Journal of Physical Chemistry C 114(40):17136-17141. doi:10.1021/jp103896k.