Catalyst-free growth of carbon nanotube arrays directly on Inconel® substrates for electrochemical carbon-based electrodes†
Vertically aligned carbon nanotubes (VACNTs) were grown directly on a pretreated Inconel® metallic substrate by thermal chemical vapor deposition without the need of catalyst addition. This experimental approach allows the substrate surface to act as both the catalyst and support for the CNTs growth therefore enhancing the connection between the two. It was found that uniformly dispersed and densely packed nano-sized, intrinsic catalytic particles, generated during the annealing pretreatment, allow the growth of the vertically aligned CNTs. Scanning electron microscopy, transmission electron microscopy and Raman spectroscopy were used to assess the quality and the nature of the formed CNTs. Electrochemical measurements were performed to evaluate the possibility to use the Inconel/VACNTs system as an electrode material. As a proof of concept, the capacitive behavior of the VACNTs arrays coupled to the Inconel substrate as the active electrode material and the current collector, respectively, in supercapacitors is demonstrated.