In this work, we theoretically investigated the friction mechanism of hexagonal MoS2 (a well-known lamellar compound) using a computational chemistry method. First, we determined several parameters for molecular dynamics simulations via accurate quantum chemistry calculations and MoS 2 and MoS2-X Oxstructures were successfully reproduced. We also show that the simulated Raman spectrum and peak shift on X-ray diffraction patterns were in good agreement with those of experiment. The atomic interactions between MoS2 sheets were studied by using a hybrid quantum chemical/classical molecular dynamics method. We found that the predominant: interaction between two sulfur layers in different MoS2 sheets was Coulombic repulsion, which directly affects the MoS2 lubrication. MoS2 sheets adsorbed on a nascent: iron substrate reduced friction further due to much larger Coulombic repulsive interactions. Friction for the oxygen-containing MoS2 sheets was influenced by not only the Coulomb repulsive interaction but also the atomic-scale roughness of the MoS2/ MoS2 sliding interface.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry