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Kimata, Tetsuya*; Kakitani, Kenta*; Yamamoto, Shunya*; Shimoyama, Iwao; Matsumura, Daiju; Iwase, Akihiro*; Mao, W.*; Kobayashi, Tomohiro*; Yamaki, Tetsuya*; Terai, Takayuki*
Physical Review Materials (Internet), 6(3), p.035801_1 - 035801_7, 2022/03
Times Cited Count：7 Percentile：50.07(Materials Science, Multidisciplinary)
irradiationOkazaki, Hiroyuki*; Kakitani, Kenta*; Kimata, Tetsuya*; Idesaki, Akira*; Koshikawa, Hiroshi*; Matsumura, Daiju; Yamamoto, Shunya*; Yamaki, Tetsuya*
Journal of Chemical Physics, 152(12), p.124708_1 - 124708_5, 2020/03
Times Cited Count：5 Percentile：26.06(Chemistry, Physical)Kakitani, Kenta*; Kimata, Tetsuya*; Yamaki, Tetsuya*; Yamamoto, Shunya*; Matsumura, Daiju; Taguchi, Tomitsugu*; Terai, Takayuki*
Radiation Physics and Chemistry, 153, p.152 - 155, 2018/12
Times Cited Count：4 Percentile：34.14(Chemistry, Physical)Kakitani, Kenta*; Kimata, Tetsuya*; Yamaki, Tetsuya; Yamamoto, Shunya; Terai, Takayuki*; Kobayashi, Tomohiro*
no journal, ,
Platinum (Pt) nanoparticles with high oxygen reduction reaction (ORR) activity have been required for applications to polymer electrolyte fuel cells. We prepared the Pt nanoparticles on a glassy carbon (GC) substrate irradiated with 380 keV Ar
to tune the electronic structure of Pt nanoparticles and enhance the ORR activity. Rotating disk electrode measurements demonstrated that the Pt nanoparticles exhibited 2.5 times higher current density on the irradiated GC substrate than on the non-irradiated one. This improvement of the activity could be attributed to the formation of Pt-C bonding at the Pt/GC interface.
Kimata, Tetsuya*; Kakitani, Kenta*; Yamamoto, Shunya*; Taguchi, Tomitsugu*; Matsumura, Daiju; Shimoyama, Iwao; Iwase, Akihiro*; Kobayashi, Tomohiro*; Yamaki, Tetsuya*; Terai, Takayuki*
no journal, ,
Quite recently, the Pt nanoparticles on the Ar-ion-irradiated glassy carbon (GC) substrate have been found to exhibit high oxygen reduction reaction (ORR) activity due to electronic and structural effects through the irradiation lattice defects in the support. We performed X-ray absorption fine structure (XAFS) measurements to investigate the interface between GC and the Pt nanoparticles. The extended X-ray absorption fine structure at the Pt L
edge demonstrated that the Pt-Pt bond length in the Pt nanoparticles was shorter on the Ar-ion-irradiated GC substrate than on the non-irradiated one. Therefore, the electronic interaction at the interface would modify the atomic structure of the supported Pt nanoparticles, thereby improving their ORR activity. This invited talk, called the JSAP young scientist presentation award speech, reviews what our strategy of the XAFS measurements should be for the mechanistic understanding of the GC/Pt-nanoparticle interface and enhanced ORR activity.
-irradiated carbon supportKakitani, Kenta*; Kimata, Tetsuya*; Yamaki, Tetsuya*; Yamamoto, Shunya*; Taguchi, Tomitsugu*; Shimoyama, Iwao; Matsumura, Daiju; Iwase, Akihiro*; Kobayashi, Tomohiro*; Terai, Takayuki*; et al.
no journal, ,
Pt nanoparticles (NPs) on the Ar-irradiated carbon support were found highly active for the oxygen reduction reaction (ORR). This suggests that irradiation defects of the support would affect Pt NPs, but the mechanism of the activity improvement has not been clear. We performed here transmission electron microscopy and X-ray absorption near edge structure (XANES) measurements to investigate the effect of the Pt NP-support interface in terms of the size and chemical states of the Pt NPs. The Pt NPs were prepared on the glassy carbon substrate by sputter deposition; their sizes were 5.1 and 3.8 nm on the 380 keV Ar-irradiated and pristine substrates, respectively. In XANES spectra at Pt M
and L edges, the peak intensity was lower for the irradiated sample, indicating the suppression of Pt oxidation by the irradiation defects. Accordingly, fast kinetics originating from this interfacial chemical-state change, not an increase in the particle size, can explain the high ORR activity.
