Constructing multi-layer Ti3C2Tx/rGO heterojunctions: Synergistic effect and unique lubrication mechanism

Two-dimensional materials, such as Ti3C2Tx and graphene oxide (GO), are considered candidates for a new generation of lubricating materials due to their unique physical and chemical properties. However, the dispersion stability of Ti3C2Tx and GO in non-polar oils is insufficient, hindering their potential as lubricating additives. Herein, 1,12-Dodecanediamine (DDM) was used as a bridge to connect Ti3C2Tx and GO, and to reduce graphene oxide (rGO) for forming the stacked two-dimensional multilayer Ti3C2Tx/rGO heterostructures. The multilayer Ti3C2Tx/rGO heterostructure exhibits excellent dispersion stability in PAO 20, ensuring its continuous integration into the tribo-interfaces throughout the friction process. The addition of 0.06 wt% multilayer Ti3C2Tx/rGO to the base oil reduced the average friction coefficient and wear volume by 35.3% and 41.6%. The enhanced lubrication performance is mainly due to the unique multilayer heterostructure of Ti3C2Tx/rGO. During friction, the disintegration of Ti3C2Tx into small fragments effectively safeguards the structural integrity of rGO, thereby facilitating the formation of a robust and smooth multilayer lubrication film. Additionally, Ti3C2Tx is adhered to the wear surface in smaller sizes or evolved into the form of Ti oxides. The emergence of this new composite material is not only expected to solve the problem of insufficient performance of traditional lubricating materials under extreme conditions, but also laid the foundation for expanding the application of two-dimensional materials in the field of lubrication.