(239f) Multiscale Kmc-DFT Simulation On Bimetallic Catalysts

Multiscale KMC-DFT Simulation on Bimetallic Catalysts

Wei Guo¹, Michail Stamatakis^1,2 and Dionisios G. Vlachos¹*

¹Center for Catalytic Science and Technology, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA

²Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK

* vlachos@udel.edu

Bimetallic catalysts have provided an opportunity for designing more active, stable and less expensive materials than the individual, pure metals catalysts. However, the reaction mechanism and the dynamics of the catalyst during catalytic reaction are not yet fully understood. The effect of fine microstructure of Ni clusters on catalyst reactivity remains elusive. Here we have developed a multiscale approach to simulate the nitrogen desorption from Ni clusters of different sizes and shapes on Pt(111) (Ni/Pt). We employed density functional theory (DFT) calculations to model the coverage dependent N binding energies on a variety of Ni/Pt configurations, and presented a model based on local coordination environment of Ni neighbors around a nitrogen atom ¹. Then the energetics of adsorption, surface diffusion, association and desorption of atomic N on Ni/Pt catalysts are incorporated into a recently developed kinetic Monte Carlo (KMC) framework to simulate the temperature-programed desorption (TPD) spectra of nitrogen on Ni /Pt ². This is the first study of first-principles KMC simulation on bimetallic catalysts that provides a conceptual platform for accounting for complex microstructure on kinetics. Our simulation framework can be employed to understand the structure sensitivity in catalysis and eventually tune bimetallic catalytic materials for complex chemistries.

1.            W. Guo and D. G. Vlachos, J Chem Phys 138(17), 174702 (2013).

2.            W. Guo, M. Stamatakis and D. G. Vlachos, Submitted (2013).