Jump to main content
Jump to site search

Issue 23, 2016
Previous Article Next Article

Efficiency and long-term durability of a nitrogen-doped single-walled carbon nanotube electrocatalyst synthesized by defluorination-assisted nanotube-substitution for oxygen reduction reaction

Author affiliations

Abstract

Nitrogen-doped carbon nanomaterials are known to be excellent electrocatalysts for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells. In this study, we used a new and simple post-doping synthesis method to prepare nitrogen-doped single-walled carbon nanotubes (SWCNTs) by reacting fluorinated SWCNTs with ammonia gas at 300–600 °C. The structure and morphology of the Nx°C-doped SWCNTs (x: reaction temperature) synthesized by the defluorination-assisted nanotube-substitution reaction were characterized. Their levels of nitrogen doping (1.38–3.04 at%) are fairly high, with enriched pyridinic- and pyrrolic-nitrogen species. Their electrochemical catalytic activity for ORR in 0.5 M H2SO4 was evaluated by cyclic voltammetry and linear sweep voltammetry, and their catalytic durability was assessed in load-potential cycle tests. For the Nx°C-doped SWCNTs, the peak and the onset potential (Epeak and Eonset, respectively) shifted towards the positive and the current density (j@E1/2) at the half-wave potential (E1/2) increased with increasing reaction temperature. The Eonset values of N500°C- and N600°C-doped SWCNTs were +0.51 V while that of the non-fluorinated hc-SWCNTs was +0.16 V. The number of electrons transferred per oxygen molecule (n) in ORR was determined to be 2.32–3.64 at the potential of −0.3 V. The ORR catalytic activity was evaluated comprehensively through the measured parameters Epeak, Eonset, n, and j@E1/2. The N500°C-doped SWCNTs possessed the highest ORR catalytic activity. After 11 000 cycles in the load-potential test, its current density remained at 93% of the initial value, indicating better durability than platinum nanoparticles supported on carbon black (Pt–C).

Graphical abstract: Efficiency and long-term durability of a nitrogen-doped single-walled carbon nanotube electrocatalyst synthesized by defluorination-assisted nanotube-substitution for oxygen reduction reaction

Back to tab navigation

Supplementary files

Publication details

The article was received on 01 Apr 2016, accepted on 11 May 2016 and first published on 12 May 2016


Article type: Paper
DOI: 10.1039/C6TA02722A
Citation: J. Mater. Chem. A, 2016,4, 9184-9195
  •   Request permissions

    Efficiency and long-term durability of a nitrogen-doped single-walled carbon nanotube electrocatalyst synthesized by defluorination-assisted nanotube-substitution for oxygen reduction reaction

    K. Yokoyama, S. Yokoyama, Y. Sato, K. Hirano, S. Hashiguchi, K. Motomiya, H. Ohta, H. Takahashi, K. Tohji and Y. Sato, J. Mater. Chem. A, 2016, 4, 9184
    DOI: 10.1039/C6TA02722A

Search articles by author

Spotlight

Advertisements