Simulation Projects

The Group's research involves applying molecular and atomistic simulations to predict the outcome of chemical reactions in highly non-ideal environments, on surfaces, and at interfaces. Quantifying and understanding the behavior of chemical reactions from a purely experimental standpoint can be difficult. However, advanced Monte Carlo simulation methods and electronic structure calculations are ideally suited for acquiring detailed thermodynamic and kinetic information of many chemical systems.

  • Carbon Nanotubes
  • Metal-Support Interactions in Catalysis
  • Adsorption
  • Atomic Layer Deposition
  • Fuel Cell Catalysis
  • Interfacial Systems

    • Nanotube bundle - with defects

    		Carbon nanotubes are amazing structures that have been been discovered just over a decade ago, and there has been a great deal of interest in using these carbonaceous cylinders in applications such as electronic materials, adsorption, and catalysis. In order to facilitate discoveries in these fields of research, the group is currently simulating various chemical reactions in structurally perfect and defective nanotubes, guiding the detailed optimization of adsorption and reaction in the materials.
    A major goal in catalysis is for the catalyst to maintain its activity during reacting conditions, which may include high temperatures, high or low pH, interactions with adsorbates, or the presence of an electrical current in electrochemical applications. Harsh reacting conditions may quickly result in a loss of chemical activity, due to catalyst poisoning, sintering, or dissolution of the catalyst or its support material. In order to maintain activity, these detrimental processes must be mitigated, either by tightly controlling the reaction conditions or by altering the intrinsic properties of the catalyst/support material. Here, we are using computational methods to understand how the interactions between metal clusters and carbon support materials might be manipulated in order to preserve or enhance catalyst function.
    The influence of surface chemistry on adsorption and reaction have also been studied by our group. We are interested in controlling surface chemistry to manuiplate adsorption behavior and ultimately optimize reaction conversion at the nanometer length scale.
    We are interested in using molecular simulation and other computational techniques to gain theoretical insights into Atomic Layer Deposition (ALD) at the atomic scale. The information of the atomic processes and energies involved is gathered using ab initio calculations. Based on the ab initio results, the dominant kinetic processes occurring on the surface can be modeled simultaneously using the Kinetic Monte Carlo (KMC) technique, while preserving the atomic structural details of the system. We are collaborating with experimentalists to test and refine the models developed. With QCP, ATR-FTIR and TPD techniques, several quantities can be acquired and directly compared with the simulations.
    Our group is currently involved in modeling studies related to fuel cell catalysis. The goal of our modeling efforts is to provide guidance to experimentalists working in the area of material synthesis. The objective of this collaborative project is to elucidate the mechanism by which the catalyst and its support perform their function, via a combined experimental and multiscale simulation approach. We are currently investigating both PEM and SOFC fuel cells.
    We know that the behavior of a chemical reaction depends upon its local environment. The interfaces between vapor-liquid and liquid-liquid phases create regions with unique properties (at nanometer length scales) which differ from either of the adjoining phases. It has been shown that these interfacial regions strongly influence not only reaction kinetics but also the equilibrium conversions of chemical reactions. We intend to identify the factors most important to these systems, quantitatively describe how the reactions are affected, and suggest routes for controlling interfacial conversion.
    Funding for our research group has been generously been provided by:

  • National Science Foundation CAREER Award
  • Office of Naval Research
  • Department of Energy
  • PNNL Molecular Science Computing Facility (MSCF)
  • NCSA/TeraGrid Computing Resources
  • The University of Alabama