Molecular Dynamics Simulation Of Oxygen Adsorption On Transition Metal Surfaces

In the field of heterogeneous catalysis, the interaction of atoms and molecules on transition metallic surfaces has become an important issue. With the development of chemical industry, physicists and chemists have been interested in the subject of the interaction between gaseous molecules and metallic surfaces. Theoretical study on it from the atomic, molecular point of view can not only help us get the micro-dynamic information of surface adsorption but also help understand the interaction mechanism between the adsorbent and metallic surface.Oxygen atoms adsorbed on the low-index surfaces and stepped surfaces of transition metal Rh, oxygen molecules adsorbed on the low-index surfaces of transition metal Rh, Pt have been studied with molecular dynamics simulation. The calculation results are excellent agreement with experiments. In the mean time, they predict some important information that have not been observed.A key factor in molecular dynamics simulation is the accuracy of interatomic potentials. On the adsorbate and substrate interaction, we use Sutton-Chen many-body potential to describe the Rh-Rh, Pt-Pt interaction; Use Morse potential to describe the interaction of O-Rh, O-Pt; Lennard-Jones potential is applied to describe the interaction of intermolecular O-O and Harmonic potential is applied to describe the interaction of intramolecular O-O. A rational force field was built by using these potentials and critical characteristics of O-Rh system were obtained. It concluded that though the O atom adsorbed on the low-index surfaces or stepped surfaces, the O atom is easily adsorbed on the highest symmetry adsorption sites. It means that, on the stepped surface, the oxygen atom preferred to occupy the interface position between step and terrace, and with the increases of platform width, the combination can lower here. In addition, we study the interaction of molecular oxygen on transition metal Rh, Pt by using the built force field, received the nature of the critical point of oxygen molecules adsorption on metal Rh, Pt surfaces. When increases the coverage of oxygen, the oxygen molecules multilayer adsorption on metal surfaces, the metal surfaces reconstruction, and the bond of oxygen molecules lengthened.