Abstract:Two-dimensional (2D) materials are materials consisting of a single or a few layers of atoms. Owing to their outstanding physical, mechanical and chemical properties, 2D materials bring new horizons to the development of atomically thin solid lubricants with exceptional performances. In addition, the unique and simple topological structure of 2D materials also render them ideal objects for exploring the origins/mechanisms of friction. In this paper, the friction and wear properties of 2D materials at the nanoscale are reviewed. According to the mode of relative motions, frictional behavior of both inter-layer sliding and surface sliding are presented and their underlying physical mechanisms are elaborated based on current understandings. We also discuss the factors that influence the frictional behavior of 2D materials and present a few typical strategies of friction tuning. In addition to friction, different mechanisms associated with nanoscale wear processes of 2D materials are examined and illustrated. Finally, we briefly summarize the progress and give an outlook in tribological study of 2D materials.