Ultrasonication-assisted uniform decoration of carbon nanotubes by various particles with controlled size and loading

We demonstrate the uniform decoration of carbon nanotubes (CNTs) with in situ produced species from different reactions with the aid of high intensity ultrasound. The process is simple, rapid, and does not require any pretreatment of the nanotubes. A variety of nanoparticles (NPs), such as metals, and/or metal oxides with uniformity in size, have been deposited on nanotube surfaces. As a model system, Pd NP-decorated CNT samples were prepared and characterized by spectroscopic and microscopic techniques. The size of the Pd NPs was tailored in the range 2.8–6.0 nm by manipulating their loading level on the nanotubes which could be as high as 50 wt.%. By controlling both the sonic power intensity and precursor concentration, the size of particles can be tuned at a given load content. The mechanistic implications regarding the nanotube decoration were discussed.