Structural and Morphological Characterization of the Expanded Graphite Obtained by Ball Milling and HF Leaching

Abstract

In this research, expanded graphite (EG) was successfully fabricated using a simple ball milling process followed by hydrofluoric (HF, 10 wt. %) leaching. The effect of ball milling time (0-15 h) and leaching time (1-24 h) on the exfoliation of graphite were examined by XRD and Raman spectroscopy. Furthermore, the morphological evaluation of the obtained expanded graphite samples was carried out by scanning electron microscopy (SEM). The XRD results of the ball-milled and HF treated samples showed a slight peak shift and broadening of (002) plane for expanded graphitein in comparison to the precursor and HF-treated samples. Moreover, the intensity of the (002) planes remarkably decreased by the ball milling process but remained constant after HF treatment. Raman spectra of the samples confirmed the ordering process only in HF-treated specimens. Moreover, the intensity ratio of 2D1 to 2D2 band gradually increased with enhancing the HF treatment time up to 5 hrs, indicating a decrement in the number of graphite layers by leaching in the HF solution