(6cn) Computational Chemistry for Better Catalysis

My research interests consist of using modern computational chemistry methods, particularly density functional theory, to assist in the development of new materials for energy production that minimize harmful effects to the environment. Understanding the catalytic reactions that take place over several oxide metals has been the motivation for my research, and I plan to use this knowledge to build on future research. I would like to further study the photoreactivity of TiO₂, and especially the reactivity of TiO₂ nanostructures.

The focus of my graduate research at Purdue University was the modeling of ceria, CeO₂, as a catalyst and support in the water-gas shift (WGS) reaction. This reaction is important because it removes CO, which is a poison to proton exchange membrane (PEM) fuel cells, while producing H₂. I used density functional theory to simulate the doping of ceria with transition metals[1], and examined on the effect of these dopants on the reaction mechanisms. As part of this research I also studied the adsorption and reaction of several pertinent surface species, such as CO, H₂O, formates, and carbonates. My results showed that doping of ceria significantly changes the electronic structure of the surface, which enhances the WGS reactivity. Recent work has involved understanding the interactions of methanol and formaldehyde with ceria[2][3]. I also had experience modeling Pt and surface reconstruction removal by O₂ adsorption[4].

My current position as a post-doctoral researcher at the Pacific Northwest National Laboratory involves studying TiO₂ for photocatalytic purposes. TiO₂, titania, is used for pollutant molecule degradation, and also has the possibility for solar energy production. Charged species (electrons and holes) are created upon light adsorption, and can react with surface adsorbates. I have developed an atomic-level model for transport of these charge carriers[5][6], as well as modeled TiO₂ interfaces[7] that are crucial for charge transfer between nanoparticles. In collaboration with experiment I am also examining the adsorption and reactivity of carboxylic acids on TiO₂. Carboxylic acids are reasonably photo-active, so represent a prototypical reactant. Other projects involve the adsorption and migration of transition metal clusters over γ-alumina, Al₂O₃, an important industrial catalyst support.

[1] N. A. Deskins, A. Phatak, F. Ribeiro, K. T. Thomson, Transition Metal Doping of Ceria and Subsequent Reduction from First-Principles Simulation, Submitted to Journal of Physical Chemistry C.

[2] D. Mei, N. A. Deskins, M. Dupuis, Q. Ge, Methanol Adsorption on the Clean CeO₂(111) Surface : A Density Functional Theory Study, Journal of Physical Chemistry C, 111, 10514-10522 (2007).

[3] D. Mei, N. A. Deskins, M. Dupuis, A Density Functional Theory Study of Formaldehyde Adsorption on Ceria, Accepted in Surface Science.

[4] N. A. Deskins, J. Lauterbach and K. T. Thomson, Lifting the Pt{100} surface reconstruction through oxygen adsorption: A density functional theory analysis, Journal of Chemical Physics, 122, 184709 (2005).

[5] N. A. Deskins, M. Dupuis, Electron Transport via Polaron Hopping in Bulk TiO₂: Density Functional Theory Characterization, Physical Review B, 75, 195212 (2007).

[6] N.A. Deskins, M. Dupuis, Intrinsic Hole Migration in TiO₂, In preparation

[7] N. A. Deskins, S. Kerisit, K. M. Rosso, M. Dupuis, Molecular Dynamics Characterization of Rutile-Anatase Interfaces [Cover Article], Journal of Physical Chemistry C, 111, 9290-9298 (2007).