Biomimetic Synthesis of Copper/Polydopamine‐Functionalized Oxygenated Carbon Nitride Composites and Their Application as Lubricants.

The wet chemical reduction method was used to modify polydopamine (PDA) functionalized oxygenated carbon nitride (O‐g‐C3N4) nanosheets to prepare in situ growth of Cu nanoparticles (Cu NPs) decorated on nanosheets. The PDA attached to the surface of O‐g‐C3N4 provided a uniformly distributed platform for copper nanoparticles. It also provided rich functional groups and provided good conditions for the dispersion of Cu/PDA/O‐g‐C3N4 in pure oil. Through TEM testing, Cu NPs with a diameter of 5–10 nm were evenly distributed on the PDA/O‐g‐C3N4 nanosheets. Through the sliding test on the steel surface, it was obvious that adding 0.2 wt % Cu/PDA/O‐g‐C3N4 to pure oil had a lowest coefficient of friction. In addition, the wear marks on the surface of Cu/PDA/O‐g‐C3N4 steel discs were studied with an optical microscope and a three‐dimensional profiler and its wear resistance was better than Cu NPs, O‐g‐C3N4 and Cu/O‐g‐C3N4. [ABSTRACT FROM AUTHOR]