Bulk Phosphorus-Doped Graphitic Carbon

Abstract

A direct synthetic route to a tunable range of phosphorus-doped graphitic carbon materials is demonstrated via the reaction of benzene and phosphorus trichloride in a closed reactor at elevated temperatures (800–1050 °C). Graphitic materials of continuously variable composition PCx up to a limit of approximately x = 5 are accessible, where phosphorus is incorporated both substitutionally within the graphite lattice and as stabilized P4 molecules. Higher temperatures result in a more ordered graphitic lattice, while the maximum phosphorus content is not observed to diminish. Lower temperatures and higher initial phosphorus content in the reaction mixture are shown to correlate with higher structural disorder. Phosphorus incorporation within directly synthesized PCx, as both a substitutional dopant and in the form of interstitial, stabilized molecular P4, is demonstrated to occur with little oxygen contamination in the bulk (<4 atom %), motivating promising future applications in fuel cells and alkali metal-ion batteries.