Graphite and Bismuth Selenide under Electrical Explosion in Confined Environment: Exfoliation, Phase Transition, and Surface Decoration

Abstract

AbstractElectrical explosion, characterized by ultrafast atomization and quenching rate (dT/dt ≈ 1010–1012 K s–1) of the sample, is a unique approach for “one‐step” synthesis of nanomaterials. Experiments are carried out with layered graphite and Bi2Se3 under the action of electrical explosion in a confined reaction tube. High‐speed photography and electrophysical diagnostics are applied to characterize dynamic processes. SEM and EDS are used to characterize surface micro‐morphology of reaction products. The layered materials are first exfoliated to thin nanosheets/nanocrystals by shock waves and turbulent flow of the explosion. As the ionized explosion products (>10 000 K) contacts the sample, intense heat transfer happens, simultaneously atomizing the sample and quenching the plasmas. As a result, nanoparticles grow on the surface of thin sheets, forming “dot‐sheet” structure. The size distribution of the nanoparticles typically ranges from 10 to 100 nm, following Log‐normal distribution. The dotted graphite nanosheets gather together and form a stacked/cabbage‐like structure. By contrast, Bi2Se3 case accompanies with chemical reactions, causing surface corrosion and showing more possibilities: nanocrystals and nanotubes growth on different areas of the sample.