Niobium-based catalysts prepared by reactive radio-frequency magnetron sputtering and arc plasma methods as non-noble metal cathode catalysts for polymer electrolyte fuel cells

Ryohji Ohnishi, Masao Katayama, Kazuhiro Takanabe, Jun Kubota, Kazunari Domen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Two vacuum methods, reactive radio-frequency (RF) magnetron sputtering and arc plasma deposition, were used to prepare niobium-based catalysts for an oxygen reduction reaction (ORR) as non-noble metal cathodes for polymer electrode fuel cells (PEFCs). Thin films with various N and O contents, denoted as NbOx and Nb-O-N, were prepared on glassy carbon plates by RF magnetron sputtering with controlled partial pressures of oxygen and nitrogen. Electrochemical measurements indicated that the introduction of the nitrogen species into the thin film resulted in improved ORR activity compared to the oxide-only film. Using an arc plasma method, niobium was deposited on highly oriented pyrolytic graphite (HOPG) substrates, and the sub-nanoscale surface morphology of the deposited particles was investigated using scanning tunneling microscopy (STM). To prepare practical cathode catalysts, niobium was deposited on carbon black (CB) powders by arc plasma method. STM and transmission electron microscopy observations of samples on HOPG and CB indicated that the prepared catalysts were highly dispersed at the atomic level. The onset potential of oxygen reduction on Nb-O-N/CB was 0.86V vs. a reversible hydrogen electrode, and the apparent current density was drastically improved by the introduction of nitrogen.

Original languageEnglish (US)
Pages (from-to)5393-5400
Number of pages8
JournalElectrochimica Acta
Volume55
Issue number19
DOIs
StatePublished - Jul 30 2010

Keywords

  • Arc plasma
  • Niobium
  • Non-noble metal cathode
  • Oxygen reduction reaction
  • PEFC

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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