Evaluation of O-terminated sustainable EC-MXene as solid lubricant

MXenes are a class of two‐dimensional materials (2DM) with high industrial potential due to their excellent properties and compositional diversity. Due to their outstanding surface chemistry, easy to shear capability and their ability to form low‐friction and wear‐resistant tribofilms, MXenes have been intensively investigated as solid lubricants in recent years. However, production involving HF acid still poses a potential hazard to workers and the environment. Therefore, we have syn‐ thesised Ti3C2Tx MXenes via a sustainable electrochemical method and studied their tribological performance using a reciprocating ball‐on‐disk nanotribometer with contact pressure of 0.3 GPa. We spray‐coated delaminated MXenes on steel substrate and tested in ambient conditions using three different counterbodies: Si3N4, Al2O3 and Steel AISI 52100. Additionally, we investigated load influence on tribological properties of EC‐MXenes. Chemical properties of EC‐MXenes, coat‐ ings and wear tracks are investigated using several techniques: light microscopy, 3D microscopy, scanning electron microscopy with energy dispersive electron spectroscopy (SEM/EDX), Raman spectroscopy and low energy ion scattering (LEIS). With this work, we have demonstrated that sus‐ tainably sourced MXenes, which are predominantly oxygen terminated, can be exceptionally stable under friction and have excellent tribological properties, which are manifested in a low coefficient of friction and great chemical stability.