Catalytic activity of highly durable Pt/CNT catalysts covered with hydrophobic silica layers for the oxygen reduction reaction in PEFCs

Sakae Takenaka, Hiroaki Miyamoto, Yutaka Utsunomiya, Hideki Matsune, Masahiro Kishida

Research output: Contribution to journalArticle

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Abstract

Carbon nanotube-supported Pt catalysts (Pt/CNT) for the cathode in a polymer electrolyte fuel cell (PEFC) were covered with silica layers using tetraethoxysilane (TEOS) and also methyltriethoxysilane (MTEOS) to improve the catalyst durability under the severe conditions at the PEFC cathode. Both the silica-coated Pt/CNT catalysts had excellent durability for potential cycling between 0.6 and 1.0 V (vs RHE) in N2-purged 0.1 M HClO4 electrolyte, while Pt/CNT without silica coating was significantly deactivated due to an increase of the Pt metal particle size. Silica-coated Pt/CNT prepared from MTEOS had similar activity for the oxygen reduction reaction as Pt/CNT without silica coating, whereas the silica coverage obtained with TEOS slightly reduced the catalytic activity of the Pt/CNT catalyst. The silica layers prepared from MTEOS are more hydrophobic than those prepared from TEOS due to the presence of methyl groups. In addition, the silica layers prepared from MTEOS have larger pores than those prepared from TEOS. The hydrophobic silica layers with larger pores in the silica-coated Pt/CNT do not inhibit the diffusion of the reactants (oxygen) and the discharge of the products (water) during the oxygen reduction reaction.

Original languageEnglish
Pages (from-to)774-783
Number of pages10
JournalJournal of Physical Chemistry C
Volume118
Issue number2
DOIs
Publication statusPublished - Jan 16 2014

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Silicon Dioxide
catalytic activity
Catalyst activity
carbon nanotubes
Silica
Oxygen
silicon dioxide
catalysts
Catalysts
oxygen
Polymers
Electrolytes
electrolytes
durability
fuel cells
Fuel cells
Durability
Cathodes
cell cathodes
porosity

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Catalytic activity of highly durable Pt/CNT catalysts covered with hydrophobic silica layers for the oxygen reduction reaction in PEFCs. / Takenaka, Sakae; Miyamoto, Hiroaki; Utsunomiya, Yutaka; Matsune, Hideki; Kishida, Masahiro.

In: Journal of Physical Chemistry C, Vol. 118, No. 2, 16.01.2014, p. 774-783.

Research output: Contribution to journalArticle

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