Enhanced electrocatalytic activity of nitrogen-doped multi-walled carbon nanotubes towards the oxygen reduction reaction in alkaline media

Abstract

In this work multi-walled carbon-nanotubes (MWCNTs) were doped with nitrogen using cyanamide (CM) or dicyandiamide (DCDA). To incorporate nitrogen into the CNT structure, high-temperature pyrolysis in an inert atmosphere was performed. For surface characterisation of nitrogen-doped CNTs (NCNTs) X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used. According to the results of XPS analysis, nitrogen was successfully incorporated into the carbon nanotube network. The electrocatalytic activity of NCNT catalysts for oxygen reduction reaction (ORR) in alkaline media was examined using the rotating disk electrode (RDE) and linear sweep voltammetry (LSV) measurements. The NCNT-DCDA material showed a better ORR performance than the NCNT-CM catalyst. The RDE results reveal that the NCNT materials studied could be considered as interesting alternatives to Pt-based catalysts in alkaline membrane fuel cells.