Silver-nanoparticle-decorated multiwalled carbon nanotubes prepared by poly(dopamine) functionalization and ultraviolet irradiation

A novel procedure was demonstrated for the preparation of carbon nanotubes (CNTs) decorated with silver nanoparticles through poly(dopamine) (PDA) surface functionalization and ultraviolet (UV) irradiation. The CNT surfaces were first functionalized by a bio-inspired PDA layer. X-ray photoelectron spectroscopy (XPS) results showed that PDA layer with thicknesses in nanometers were formed on the outer surfaces of the CNTs. With the immersion of the PDA-coated CNTs (CNTs-PDA) into a silver plating bath, the silver ions attached to the CNTs-PDA surfaces were reduced in situ to silver nanoparticles by using the N-containing groups and reducing ability of PDA. The dense silver nanoparticles were further decorated on the CNTs-PDA surfaces under UV irradiation. High-resolution transmission electron microscopy (HRTEM) images showed that the spherical silver nanoparticles were about 3-4 nm in diameter and uniformly distributed on the outer surfaces of the CNTs. The distance between the nanoparticles was less than 10 nm. The as-prepared silver-decorated CNTs-PDA nanocomposites had excellent electrical conductivity, with a surface conductivity of up to 340 S/cm.