High-energy ball-milling preparation and characterization of Ln2O3−graphite nanocomposites

Abstract The combination of lanthanide species with graphite and related carbon nanomaterials (including graphene and graphene oxide) is a pathway to hybrid materials and nanocomposites with unique properties. Mechanical processing (MP) is an especially efficient and attractive way to generate such nanostructured materials, since it results in progressive exfoliation of graphite and can yield a variety of carbon nanostructures with sp2 hybridization, derived from the graphene building blocks. However, the knowledge of how lanthanides interact with graphite upon MP is very scarce. The goal of the present study was to obtain composites of graphite and selected Ln2O3 oxides (Ln = La, Eu, Gd and Lu) via high-energy ball-milling. According to scanning electron microscopy and X-ray diffraction analysis, the materials obtained can be qualified as nanocomposites, combining nanosized graphite and Ln2O3 particles, whose size depends on particular lanthanide species. The nanocomposites were characterized by using Raman, fluorescence and X-ray photoelectron spectroscopy, as well as thermogravimetric and differential thermal analysis. Density functional theory calculations were employed to provide an insight into the strength of interactions of Ln3+ ions with graphene sheets as the structural elements of graphite, as well as the distribution of charge and spin density depending on a particular lanthanide.