Functionalization of multiwall carbon nanotubes with nitrogen containing polyelectrolyte by a simple method

Commercially available multiwall carbon nanotubes (MWCNTs) have been functionalized with poly(diallyl dimethylammonium) chloride (PDDA), a nitrogen containing polyelectrolyte by a simple on-off ultrasonication method. The results obtained from Raman and X-ray photoelectron spectroscopy (XPS) studies confirm the functionalization of MWCNTs with PDDA. An up- shift in the positions of C1s XPS peak and a down-shift in the positions of the N1s XPS peak, has been observed along with an up-shift in the G-peak position in the Raman spectra, which suggest the occurrence of inter-molecular charge transfer from carbon atoms in MWCNTs to N+ centres in PDDA. The preliminary linear sweep voltammetry (LSV) results show good electrocatalytic activity of MWCNTs functionalized with nitrogen containing polyelectrolyte, which is comparable to the results with platinum based electrodes. Thus, MWCNTs non-covalently functionalized with a nitrogen containing polyelectrolyte (PDDA) by a simple on-off ultrasonication method could be advantageous for developing efficient metal-free electrocatalysts for the oxygen reduction reaction (ORR).