Nitrogen species in few-layer graphene produced by thermal exfoliation of fluorinated graphite intercalation compounds

Abstract

Few-layer graphene materials have been produced by decomposition of fluorinated graphite intercalated with acetonitrile (CH3CN) or isopropylamine ((CH3)2CHNH2) in the conditions of thermal shock. Electronic structure of the samples before and after exfoliation was studied using near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopy. Analysis of the spectroscopic data revealed the same set of nitrogen species in both exfoliation products that indicates decomposition of the intercalated molecules to the atomic state. Most of the nitrogen atoms were incorporated at the edges of graphene layers in pyridinic and protonated nitrogen forms. A difference in the electrochemical performance of the graphene materials was related with the exfoliation degree and the defect density in the graphene layers. Schematic representation of a process of thermal exfoliation of acetonitrile-intercalated fluorinated graphite.