Surface activity, with ReaxFF simulation

Study Surface Activity with ReaxFF Simulation 100... 

Traditional MD simulations can investigate the different residence times due to the hydrophobic property of the surface of the pores and then obtain different surface fluid transport coefficients and provide a reliable basis for the experimental design. Quantum chemical calculations can consider reactive molecules with different reaction mechanisms for the active surfice of pores the reactivity will also affect the transport fluid to some extent. MD simulation cannot reflect the chemical interaction between the particles and cannot simulate a chemical reaction, while quantum chemical calculations cannot be apphed to large systems. ReaxFF simulation method is a new simulation method rising in recent years it can simulate not only the transport process but also chemical reactions and can simulate transport and reaction in a large system at the same time, which can fill the gap between quantum chemistry and classical force field (empirical force field). It simulates the process with more reahstic method because we can not only obtain the transport properties of the fluid but also reflect a chemical reaction of fluid and the surface. 

Take hydrodesulfurization catalysis, for example. We used an active Ti02 as the catalytic support to load the active species for catalysis. Till now, there are many works devoted to research the hydrodesulfurization catalysis mechanism by DFT and experiment, and the reaction pathway of hydrodesulfurization has been figured out. DFT was almost focused on the simulation of the active site. For example, Raybaud et al investigated the interaction of the reactants and intermediate with the M0S2 or NiMoS catalyst by DFT (Dupont et al, 2011). Also, they studied the interaction between active species and support (Costa et al, 2007). However, there was litde work on the interaction of reactants or resultants with catalytic support. The ReaxFF method can be apphed to investigate the reaction on Ti02. It can combine the effect of surface and the effect of transport into reaction process so that the reaction time and the transport time can be separately studied to find out the key influence factor. 

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