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Quantitating the surface-strain dominated oxygen-reduction activity of monolayer Pt shell catalysts (Press Release)

Release Date
10 Apr, 2013
  • BL01B1 (XAFS)
  • BL14B2 (Engineering Science Research II)
  • BL37XU (Trace Element Analysis)
-A valuable methodology to remarkably decrease Pt usage for polymer electrolyte fuel cells-

Kyoto University

A research group led by Yoshiharu Uchimoto (professor), Yuki Orikasa (assistant professor), and Xiaoming Wang (research associate) of the Graduate School of Human and Environmental Studies, Kyoto University, for the first time in the world, has proposed a valuable quantitative methodology to guide the development of low-loading monolayer Pt catalysts for polymer electrolyte membrane fuel cells (PEMFCs), cooperating with Prof. Nagahiro Hoshi’s lab in the graduate school of engineering of Chiba University and the researchers in Ishifuku Metal Industry.

This study aims to the quantitative methodology to evaluate the lattice strain of monolayer Pt shell on core nanoparticles, which is a great challenge in optimizing the catalytic activity of monolayer Pt shell catalysts due to the short-range ordering structure of monolayer Pt atoms on different core facets. Based on monolayer Pt atoms on different single crystal facets, they use EXAFS to reveal the intrinsic structural correlation among monolayer Pt atoms on different core facets. And then, they proposed a general structural model of monolayer Pt atoms on different core facets for fitting EXAFS signal to obtain the quantitative lattice strain. Further, they demonstrate this quantitative methodology can directly evaluate the eventual catalytic activity. The great significance in this work is that it can guide the development of monolayer Pt shell catalysts, such as ascertaining the complete strain-activity correlation, predicting the optimal lattice strain, and leading the synthetic control. It is expected that the most efficient monolayer Pt shell catalysts with the cost-optimal levels will be realized to accelerate the commercialization of PEMFCs.

The results of this research were published online as a communication in Journal of the American Chemical Society on 5 April 2013.

Publication:
"Quantitating the Lattice Strain Dependence of Monolayer Pt Shell Activity toward Oxygen Reduction"
Xiaoming Wang 1, Yuki Orikasa 1, Yuki Takesue 2, Hideo Inoue 3, Masashi Nakamura 2, Taketoshi Minato 4, Nagahiro Hoshi 2, and Yoshiharu Uchimoto 1
1Graduate School of Human and Environmental Studies, Kyoto University, 2Graduate School of Engineering, Chiba University, 3Ishifuku Metal Industry Limited Company, 4Office of Society-Academia Collaboration for Innovation, Kyoto University
Journal of the American Chemical Society 135 (16) 5938-5941, Published online 05 April 2013

<<Figures>>

Fig. 1 Schematics of Pt nanoparticle catalyst and core-shell catalyst
Fig. 1 Schematics of Pt nanoparticle catalyst and core-shell catalyst

The amount of Pt can be markedly reduced using Pt only for the outermost layer of the nanoparticle catalyst.

Fig. 2 Schematic illustrating model system and different core-shell catalysts
Fig. 2 Schematic illustrating model system and different core-shell catalysts

Experiments using the model system enable the analysis of Pt bonding using the same method for any model. This analysis method was applied to a complicated core-shell catalyst in this research.

Fig. 3 Correlation between activity of core-shell catalyst and Pt-Pt bond length
Fig. 3 Correlation between activity of core-shell catalyst and Pt-Pt bond length


For more information, please contact:
  Prof. Yoshiharu Uchimoto (Graduate School of Human and Environmental Studies, Kyoto University)

  Assistant prof. Yuki Orikasa (Graduate School of Human and Environmental Studies, Kyoto University)
    E-mail : mail1
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