Modeling of hydrocarbon cracking reactions on iron assisted zeolite using ReaxFF reactive force field method

Numerical computations were performed to develop a ReaxFF potential that can describe the chemical events related to the cracking of hydrocarbon fuels over an iron assisted aluminosilicate catalysts. Force field parameters for various interatomic interactions were trained against a DFT data set consisting of equations of states, heats of formation and binding energies. The accuracy of force field parameters was tested by comparing the ReaxFF activation energy barriers for various cracking reactions with DFT calculations. These reactions consisted of cracking of 1-butene and propane on aluminum assisted zeolite ring, dehydrogenation of propane on Fe(100) surface and propane cracking on Fe ₁₃ cluster inside ZSM5 zeolite. Effect of various impurities on the stability of zeolite framework was evaluated by computing melting point of doped ZSM5 zeolite. Molecular Dynamics (MD) simulations indicate that iron lowers the cracking temperature and cracks saturated hydrocarbons into smaller fragments by C-C bond fission and dehydrogenation mechanisms.