Solid-Liquid Interfaces

Theoretical Investigation of Heterogeneous Catalysis at the Solid-Liquid Interface for the Conversion of Lignocellulosic Biomass Model Molecules
The research objectives of this research program are to significantly enhance our molecular understanding of the specific effect of a liquid solvent on the activity and selectivity of a heterogeneous catalyst and to test the hypothesis that computational catalysis tools can be developed that explicitly account for the liquid-phase environment and that are still efficient enough to play a significant role in the rational design of novel heterogeneous catalysts with exceptional activity and selectivity  for the liquid-phase conversion of lignocellulosic biomass into fuels and chemicals.

A key roadblock in the computational investigation of chemical reactions at a solid-liquid interface stems from the need to properly account for the liquid-phase environment which often requires the simulation of systems of at least a few hundred atoms and which necessitates accounting for the effect of dynamic fluctuations in the complex liquid on the reaction rate of elementary processes at a catalyst surface. While AIMD approaches can, in principle, be used for such investigations, current computer technology and resources are not sufficient for the systematic investigation of various reaction pathways relevant for the conversion of more complex systems with these techniques.  In fact, we hypothesize that for the foreseeable future, alternative approaches have to be developed that are nearly as accurate as AIMD but that are computationally multiple (5-7) orders of magnitude less expensive so that large systems can be studied over long time scales.  It is one of our main goals in the research program to develop and validate such a highly efficient and accurate computational method for the prediction of the kinetics of reactions at a solid-liquid interface based on a QM/MM and implicit solvation approach for metal surfaces.

Selected References:
"Hybrid Quantum Mechanics/Molecular Mechanics Solvation Scheme for Computing Free Energies of Reactions at Metal-Water Interfaces," M. Faheem, A. Heyden, J. Chem. Theory Comput. 10, 3354-3368 (2014).

"Solvent Effects on the Hydrodeoxygenation of Propanoic Acid over Pd (111) Model Surfaces," S. Behtash, J. Lu, M. Faheem, A. Heyden, Green Chemistry 16, 605-616 (2014).

"New Implicit Solvation Scheme for Solid Surfaces," M. Faheem, S. Suthirakun, A. Heyden, J. Phys. Chem. C 116, 22458-22462 (2012).