Tribological properties of surface-functionalized Zr-based MOF as a lubricant additive

•Tetradecylphosphonic acid (TDPA) modified zirconium-based MOF was prepared as a lubricant additive in soybean oil.•TDPA modification can significantly improve the aggregation of Zr-MOF.•TDPA-Zr-MOF shows excellent anti-friction and anti-wear properties.•The lubrication properties of TDPA-Zr-MOF are attributed to the rolling effect and the formation of a tough protective film. The development of novel high-performance lubricants is of great significance to reduce energy consumption and save energy. Herein, we report a zirconium-based MOF functionalized with tetradecylphosphonic acid (TDPA-Zr-MOF), as a lubricant additive in soybean oil (SO). The tribological properties of TDPA-Zr-MOF were systematically measured by a four-ball test machine, which showed that soybean oil with TDPA-Zr-MOF exhibit better tribological properties compared with pure soybean oil. The friction coefficient and wear scar diameter are significantly reduced, both of which can be decreased by more than 35%. Based on the analysis of morphology and chemical composition of the worn surface, it is concluded that the excellent anti-friction and anti-wear properties of TDPA-Zr-MOF attributed to rolling effect and protective film effect.