Synthesis and characterizations of graphene–copper nanocomposites and their antifriction application

In this work, a facile one-pot reduction method was used to prepare graphene–copper nanocomposites using graphite oxide and copper sulfate. The nanocomposites were characterized by transmission electron microscope, X-ray diffraction, Raman spectrum, thermal gravimetric analysis, UV–vis analysis and Fourier transform infrared spectrum. It was found that the as-synthesized graphene sheets have few layers and less defects with oxygen functional group on it. The copper nanoparticles with an average diameter of 20 nm were uniformly deposited on the graphene sheets. The aggregation of the copper nanoparticles was effectively prevented. The nanocomposites can evenly disperse in base oil. The antifriction performance of the base oil added with GNS–Cu was firstly investigated. It was found that the GNS–Cu nanocomposites as additive in proper ratio showed better antifriction properties with an improvement of the load-carrying capacity by 50%.