Nanoprecise spontaneous coating of carbon nanotubes with a europium hydroxide layer
A protocol for ultrathin nanoprecise coating of individual multiwall carbon nanotubes with amorphous europium hydroxide was developed. The nanocoated carbon nanotubes were successfully prepared by in situ deposition of europium hydroxide in the aqueous suspension by means of dative bonds to oxygen containing groups on the surface of a multiwall carbon nanotube. The coating layer was found to be very uniform, and its thickness was controlled by time of deposition with nanometer precision. The products were characterized by high-resolution transmission electron microscopy (HR-TEM), TEM/energy-dispersive X-ray spectroscopy (TEM/EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and conductivity and current-voltage measurements. The ultrathin europium hydroxide could electrically insulate individual multiwall carbon nanotubes.