One-step synthesis of metal nanoparticle/carbon nanotube hybrids by thermal plasmas of electrical wire explosion

Carbon nanotubes (CNTs) have exhibited excellent physical, chemical, and mechanical properties due to their unique structure, and become a research focus in recent years. To cope with different application scenarios and enhance the technological potential of CNTs, they need to be interfaced with other materials, like metal nanoparticles. In order to efficiently synthesize CNTs-based nanohybrids with different inorganic particles/clusters, we proposed a one-step synthesis approach based on the concept of confined electrical explosion. By executing electrical explosion of Cu and/or Al wires in a CNTs-containing tube, hundreds of Joules of electric energy can be instantaneously deposited in small space of several milliliter, leading to intense plasma-material interactions. By establishing a combined multi-physical diagnostic system, electrical and optical parameters during the reaction process are measured, and dynamic interactions between plasma and carbon nanotubes are captured using high-speed photography. It is observed the dense metallic plasma can occupy the confined space and heat up to several thousand Kelven within several $\mu \mathrm{s}$, along with the formation of plasma turbulence punching CNTs samples. Later, drastic heat and mass transfer happened between the “hot” plasma and “cold” CNTs. As a result, CNTs are sufficiently dissociated and ionized metal vapor quenched in the vicinity of tube surface. SEM and XPS/XRD are used to characterize the morphology and composition of the post-explosion products. Nanoparticles with characteristic diameter less than 100 nm have been observed on surface or inside the nanotube. Compared to $\mathrm{Cu}, \mathrm{Al}$ nanoparticles exhibit a more uniform and dense distribution, even completely covering the nanotube surface.