RF-PECVD growth and nitrogen plasma functionalization of CNTs on copper foil for electrochemical applications

• Effect of intermediate buffer layers on the growth of CNTs on copper is studied.
• CNTs were functionalized with nitrogen groups using a nitrogen plasma treatment.
• After the treatment the carbon nanotubes present an increase in structural disorder.
• Electrochemical study was done using CNTs/Cu as electrodes and LiClO4 as electrolyte.
• Nitrogen plasma treated CNTs show an increase in the specific capacitance.

This work describes an efficient way to improve the adhesion, growth rate and density of CNTs on copper substrate using radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD). The adhesion of an alumina buffer layer to the copper substrate is critical for the successful growth of CNTs. Hydrogen plasma was performed on the copper substrate to reduce copper oxide from the surface. The effect of two intermediate layers (Ti, Ni), as individual or in combination, between alumina and copper substrate on the CNT growth has been investigated. Furthermore, a nitrogen plasma treatment was carried out to functionalize the obtained CNTs. Electrochemical measurements were performed using CNTs grown on a copper substrate as electrodes and LiClO4 as electrolyte. The specific capacitance of the obtained electrodes increases from 49 up to 227 Fg− 1 for untreated and nitrogen-plasma treated CNTs at a scan rate of 10 mVs− 1, respectively.