2016年11月
Particle-size effect of Pt cathode catalysts on durability in fuel cells
NANO ENERGY
- ,
- ,
- ,
- 巻
- 29
- 号
- 開始ページ
- 323
- 終了ページ
- 333
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.nanoen.2016.02.016
- 出版者・発行元
- ELSEVIER SCIENCE BV
Monodisperse Pt nanoparticles with three different sizes (d=2, 3, and 4 nm, each with a very narrow standard deviation sigma(d) of 10%) supported on carbon black (CB) were prepared by the nanocapsule method. Four kinds of 50 wt%-Pt loaded catalysts [Pt-2 nm/CB, Pt-3 nm/CB, Pt-4 nm/CB, and a commercial Pt-2 nm/CB (sigma(d)=20%)] were subjected to an accelerated durability test comprising standard potential step cycles between 0.6 V and 1.0 V vs. RHE, which simulates load cycles for fuel cell vehicles, in N-2-purged 0.1 M HClO4 solution at 65 degrees C. The oxygen reduction reaction (ORR) activity and H2O2 yield at these catalysts were evaluated from the hydrodynamic voltammograms in O-2-saturated 0.1 M HClO4 solution at 65 degrees C by the use a multi-channel flow double electrode technique. At the beginning of testing (BOT), all catalysts exhibited the identical value of kinetically-controlled area-specific activity (j(k)), and the kinetically-controlled mass activity (MA(k)) was proportional to the electrochemically active area (ECA). With increasing the number of potential step cycles, the MAk values of all catalysts decreased due to the reduction of the ECA, as a result of particle growth, but the jk values were nearly unchanged irrespective of such particle growth. After 30,000 cycles, at which each MAk (or ECA) had reached a stable value (end of testing, EOT), the smallest Pt catalyst (our Pt-2nm/CB) still maintained the highest MAk, which was a factor of approximately two higher than those of Pt. nm/CB and the commercial Pt-2nm/CB. Contrary to the common view, Pt nanoparticles as small as 2 nm were found to be quite durable, maintaining high performance from the BOT to EOT, as long as they were uniform in size (sigma(d) <= 10%) and highly dispersed over the whole surface of the carbon support. (C) 2016 Elsevier Ltd. All rights reserved.
- リンク情報
- ID情報
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- DOI : 10.1016/j.nanoen.2016.02.016
- ISSN : 2211-2855
- eISSN : 2211-3282
- Web of Science ID : WOS:000389624100024