Decoration of activated carbon nanotubes with copper and nickel

Abstract

Activated carbon nanotubes were used as precursors for preparing copper- and nickel-decorated nanotubes. The nature of the activated and decorated nanotubes was studied using high-resolution transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The inert surface of oxidized nanotubes was activated by the introduction of catalytic nuclei via a two-step sensitization - activation method and a single-step activation approach. The activated nanotubes catalyze metal deposition specifically onto their surfaces upon immersion in electroless plating baths. Both methods give tubes decorated with nickel. In addition, copper decoration was achieved for the first time. In the two-step sensitization-activation method, the extent of metal decoration was found to be dependent on the age of the sensitizing solution. Densely decorated nanotubes were obtained after three days of sensitizer aging. The single-step activation approach has previously not been applied to carbon nanotube substrates. Our results show that this method is an efficient and simple means of achieving carbon nanotube activation, with the activated tubes showing a high surface coverage of Pd-Sn catalytic nuclei. Electroless plating of such tubes readily results in nanotubes fully coated with nickel and copper.