Structure, morphology and electronic properties of l-phenylalanine edge-functionalized graphite platelets through Friedel–Crafts acylation reaction

Abstract

In this study, in order to develop functionalized graphite without damaging the graphitic basal plane, graphite was edge-selectively functionalized with biosafe L-phenylalanine amino acid through direct Friedel–Crafts acylation reaction in polyphosphoric acid/phosphorus pentoxide medium. This technique led to graft amino acid moieties to the defective sites (mostly sp² C–H) located mainly on the edges of graphite via electrophilic substitution reaction. The presence of L-phenylalanine attached onto the graphite edge was confirmed by using elemental analysis, X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis. In addition, the covalent functionalization was confirmed by Fourier transform infrared spectroscopy, XPS, and Raman spectroscopy. Additionally, cyclic voltammetry was used to investigate the electrochemical behavior of edge functionalized graphite.