A systematic empirical study on the synthesis of turbostratic nanoscale graphene produced via chamber detonation of gaseous hydrocarbon precursors

Abstract

A systematic study on the formation and characterization of detonation carbon using various hydrocarbon precursors is presented. All precursors share similar trends in product yields with the requirement of oxygen/carbon ratio (O/C) ≤ 1.0 to produce solid carbon, and the detonation data indicating that a minimum temperature and pressure of 2300 ± 150 K and 13 ± 1 atm, respectively, are both required to produce solid carbon with graphene morphology. These two results form a theoretical model that can be used to predict whether the reaction will form a soot or a graphene before the experiment takes place. Characterizations such as Raman, XRD, TEM, etc. are used to systematically distinguish the solid carbon produced between soot, graphene, and graphite. The resulting graphene product is a turbostratic nanoscale graphene with 5-30 layers depending on the O/C ratio and precursor, and can be industrially scaled up to produce kg/day quantities at low cost. Differing O/C ratios produce graphenes with different properties that we call low O/C and high O/C graphene. Syngas is also produced as a byproduct for O/C mixtures ≤ 1.0, and there are low-to-zero solid carbon yields for O/C mixtures > 1.0 which instead produce carbon monoxide and hydrogen, an appealing industry reaction in the process of being scaled up.