One-step synthesis of structural-controlled metal-graphene nanocomposites via flash atomization and plasma-assisted reactions of electrical explosion

Abstract

Metal-graphene nanocomposites are highly attractive for a wide range of structural and functional applications. One promising approach for their “one-step” synthesis is through electrical explosion, which utilizes high-electric-power pulses to achieve ultrafast heating/quenching rates (dT/dt ∼ 10^10 K/s) of current-carrying conductors. By performing electrical explosion of metallic wire in a graphite-powder-containing tube, hundreds of Joules can be instantaneously confined in 7-cm3 space, leading to intense plasma-material interactions. Our research has yielded two distinct metal-graphene assembly routes: the first involves the graphite nanosheets decorated with metallic nanoparticles (<100 nm-diameter), while the second concerns the nanometal core coated by graphene shell (<10 layers) along with onion-like carbon. Explosion-induced shockwave and its reflection exfoliate graphite powders and initiate turbulent-mixing of the flow field, allowing the atomized metal to quench on graphite nanosheets. Further increasing explosion energy to achieve oscillating-discharge for reaction, strong radiation and kinetic energy of plasmas will sublimate the graphite, cooling to core@shell structures.