Activity enhancement of Pt nanoparticle catalysts by the ion-irradiated carbon supports; Clarification of the interfacial structures by XAFS measurements

Kimata, Tetsuya*; Kakitani, Kenta*; Yamamoto, Shunya*; Taguchi, Tomitsugu*; Matsumura, Daiju   ; Shimoyama, Iwao   ; Iwase, Akihiro*; Kobayashi, Tomohiro*; Yamaki, Tetsuya*; Terai, Takayuki*

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.