Chapter 7: Modeling Nanocatalytic Reactions with DFTB/MM-MD and DFTB-NMD

Nanoparticles represent a very important class of catalytic materials in chemical industry. Due to their dynamic nature in high temperature and complex working conditions, understanding the chemical reactions catalyzed by nanoparticles poses a challenge for both experimental and theoretical studies. In this chapter, we introduce two methods based on density functional tight-binding (DFTB) to address this problem: DFTB/molecular mechanics molecular dynamics (DFTB/MM-MD) and DFTB nanoreactor MD (NMD). Using the benzene hydrogenation reaction in the oil sands upgrading as an example, we have shown that the DFTB/MM-MD approach is capable of modeling elementary reactions catalyzed by nanoparticles in complex environments, with the entropic effect and environment effect explicitly considered. The DFTB-NMD approach, on the other hand, can predict the major reaction pathways for catalytic reactions on nanoparticles that form complicated reaction networks. With these methods, we expect that much understanding can be obtained for the catalytic reactions on nanoparticles in complex environments.