A gap exists in understanding heterogeneous catalysis between a cluster of a few atoms and a periodic slab model; reactions catalyzed by transition-metal-containing nanoparticles are still not well understood. In this presentation, we provide a multiscale modelling approach to study benzene hydrogenation on molybdenum carbide nanoparticles (MCNPs) in the process of in-situ heavy oil upgrading. The QM DFTB method is coupled with an MM force field to yield a quantum mechanical/molecular mechanical (QM/MM) model describing the reactants, the nanoparticles and the surroundings. Umbrella sampling (US) was employed to calculate the free energy profiles for benzene hydrogenation in a model aromatic solvent under realistic conditions. Comparisons are made with the traditional methodologies; the results reveal new features of the metallic MCNPs. Under working conditions, rather than being rigid, they are very flexible due to the entropic contributions of the MCNPs and the solvent, which greatly affect the free energy profiles.
The colloquium will be held by:
Prof. Dennis Salahub, University of Calgary, Canada (Link to homepage)
Where: Lecture Hall in Research III
When: 13:00 h - 14:15 h
Host: Prof. Dr. Ulrich Kleinekathöfer, Professor of Physics, Dept. of Physics & Earth Sciences
Email: u.kleinekathoefer [at] jacobs-university.de, Tel: +49 421 200-3523,
Link to Homepage: http://ukleinekat.user.jacobs-university.de