Electrochemical properties of bamboo-shaped multiwalled carbon nanotubes generated by solid state pyrolysis

We report herein on an electrochemical study of bamboo-shaped multiwalled carbon nanotubes (BMWCNTs) that were synthesized by a simple and efficient solid state pyrolysis method. Cyclic voltammetry was used to evaluate the electrochemical behavior of BWCNTs in 0.1 M KCl containing 5 mM of K4Fe(CN)6. The electron transfer rates of as-synthesized bamboo-shaped multiwalled carbon nanotubes and commercial hollow multiwalled CNTs were evaluated and compared. Among the studied electrodes, BMWCNTs showed a faster electron transfer rate, as compared with the other electrodes. The higher electron transfer kinetics can be attributed to the surface oxide functional groups. IR, Raman, XPS, and electrochemical studies showed that the as-synthesized carbon nanotubes exhibit some functional groups on BMWCNTs. This phenomenon can be attributed to the larger amount of exposed edge planes in the as-prepared BMWCNTs, as compared with the ordinary multiwalled carbon nanotubes. The capacitive properties of BMWCNTs electrodes were studied in 1 M KNO3 using cyclic voltammetry with the scan rates ranging from 25 to 500 mV/s. The specific capacitance of the BMWCNTs electrodes were 11.5 and 6.7 F/g with scan rates of 25 and 500 mV/s, respectively.