Investigation of methane oxidation by palladium-based catalyst via ReaxFF Molecular Dynamics simulation

CH₄ oxidations by Pd-based catalyst with and without oxygen coating were studied using ReaxFF Molecular Dynamics simulations. Results revealed the complete dynamic process of the catalytic oxidations at the atomic delineating the underlying mechanisms both qualitatively and quantitatively. Oxygen molecules were easier to be adsorbed on both bare and oxygen-coated Pd surfaces than CH₄. Comparison of the adsorptive dissociation of CH₄ over Pd nanoparticles with various levels of oxygen coverage showed that it was easier for the adsorptive dissociation of CH₄ on oxygen-coated Pd nanoparticles than on bare ones at low temperatures. The CH₄ dissociation rate increased with increasing temperature and is sensitive to the level of oxygen coverage on the surface. Additionally the activation energies for the adsorptive dissociation of CH₄ were determined by fixed-temperature simulations from 400 K to 1000 K through the changes of CH₄ concentration.