RF sputtering as a tool for plasma treating and metal decoration

Multiwalled carbon nanotubes were functionalized and decorated with metal or bi-metallic nanoparticles by employing an RF sputtering machine. First, CNTs were functionalized in oxygen + argon plasma and then decorated with Au, Pt or Au/Pt. The size and density of the metal nanoparticles on the nanotube surface could be controlled by the process parameters such as power and deposition time. Structure morphology and chemical composition of the different hybrid materials were characterized by means of TEM and EDX. EDX reveals the presence of oxygen species grafted to CNTs functionalized in oxygen + argon plasma and TEM shows that the average diameter of nanoparticles is 2 nm. Particle size and distribution remain stable upon thermal treatment. The gas sensing properties of these materials have been studied.