Extreme condition nanocarbon formation under air and argon atmospheres during detonation of composition B-3

Novel nanocarbons synthesized by extreme conditions produce products with various chemical and physical properties. Herein through high explosive detonation of Composition B-3 (40% TNT, 60% RDX), pressures and temperatures not classically attainable in laboratory syntheses provide access to interesting carbon allotropes. For example, detonations of Composition B-3 are regularly used to synthesize the now commercially-available nanodiamond (3-5 nm spherical diamond particles) through quenching of the detonation by ice collars at high pressures and temperatures. Detonation conditions of Composition B-3, in this study, were modified by altering the atmosphere (air versus Ar) without quenching, consequently directing nanocarbon formation. X-ray scattering and microscopy elucidate that detonations performed in air produced spherical hollow core-shell nanocarbons, whereas detonations in Ar produced elongated nanocarbons. Although morphology bifurcates, spectroscopy reveals that both major detonation products are comprised of sp2 hybridized carbon. As expected from air atmosphere detonations, surface functionalization is dominated by CO bonding. The absence of oxygen in the Ar atmosphere detonations may propagate extended sheets of graphene that either stack together due to electrostatics or fold upon itself. This work demonstrates that modification of the detonation atmosphere provides an alternative route for the production of new and interesting nanocarbons.

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