Surface Oxidation and Electron Transfer of MoS2 During Friction

The oxidation and electron transfer on the surface of MoS2during friction are studied by means of electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS). As the results, it is inferred that Mo4+changed to Mo6+ions in the friction failure process of MoS2 via Mo5+ion intermediate. The complexity of the oxidation process on the surface of MoS2during friction has also been noticed. Moreover, there exist a variety of chemical states of Mo during the oxidation process, and the oxidation of Mo is characteristic of single electron transfer in the Mo4d orbit.