Fabrication of N, P, F Co-Doped MXene Nanosheets with Ionic Liquid-Assisted Carbonization as an Efficient Lubricant Additive

Herein, nitrogen, phosphorus, and fluorine codoped MXene (N,P,F-MXene) was synthesized via thermal treatment using 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]) as the doping precursor. Comprehensive characterization confirmed the effective incorporation of nitrogen, phosphorus, and fluorine into the MXene lattice. Tribological testing revealed that N,P,F-MXene demonstrated excellent performance as an additive in lubrication, showing significantly reduced friction and wear. Specifically, it achieved an average COF of 0.109 and reduced wear volume by 62.5% versus the base oil. Furthermore, the N,P,F-MXene-based lubricant exhibited good adaptability under extreme operating conditions, sustaining stable tribological behavior over a broad load, frequency, and temperature range. Notably, its load capacity reached 500 N. Mechanistic analysis indicates that its superior performance originates from the synergistic effects of the physical filling and adsorption of N,P,F-MXene, coupled with the formation of a tribo-chemical film with low shear strength enriched with nitrogen/phosphorus/fluorine compounds and metal oxides in the friction process. This study provides an effective strategy for heteroatom doping of MXene and offers a promising pathway toward high-performance oil-based lubricant additives.