One‐ and Two‐Dimensional Inorganic Crystals inside Inorganic Nanotubes

Abstract

AbstractVarious inorganic salts can be encapsulated inside the comparatively narrow (0.8–2 nm) hollow core of single‐walled carbon nanotubes (SWNTs) by molten phase capillary wetting. A new synthetic strategy is presented allowing the formation of one dimensional (1D) inorganic crystals or core–shell nanotubular structures by using multiwall WS2 nanotubes as host templates. Molten phase wetting with CsIresults in the formation of 1D crystal structures inside WS2 nanocapillaries with a Moiré pattern. The relatively large diameter of the WS2 nanotube (with inner and outer diameters of ca. 10 and 20 nm, respectively), allows a conformal folding of the guest PbI2 layers (PbI2@WS2 core–shell nanotubes) on the interior wall of the WS2 nanotube‐template, thus leading to relatively defect‐free core–shell inorganic nanotubular structures, which have not been previously observed within carbon nanotubes (CNTs). Core–shell WS2@MoS2 nanotubes can be obtained by the gas‐phase reaction of MoCl5 with sulfur in the presence of WS2 nanotubes. The mechanism of imbibition/solidification of the molten salt into the hollow cores of MoS2 nanotubes has been studied by molecular dynamics simulations, showing major differences between layered compounds and those with quasi‐isotropic structure. Theoretical considerations also show the conditions for the stability of such core–shell 1D nanostructures. These new strategies can open up many possibilities for the synthesis of new nanotubular structures.