Rhodium-decorated MWCNTs for detecting organic vapours

In this paper, we describe a new approach for the development of a vapour sensor based on carbon nanotubes decorated with rhodium nanoparticles for detecting organic compounds. The morphology of treated multiwall carbon nanotubes was studied by means of high-resolution transmission electron microscopy (TEM) and the composition by X-ray photoelectron spectroscopy (XPS). Various aromatic and non-aromatic vapours were tested. For non-aromatic vapours, the response kinetics shows that these species are chemisorbed at the surface of carbon nanotubes. On the other hand, with aromatic vapours, the kinetics shows a physisorption behaviour. Also, the developed sensor shows lower sensitivity for non-aromatic than for aromatic vapours. The drift in sensor response remained below 10% after two months of sensor operation, which shows the high stability of the rhodium-carbon nanotubes film.