@article{oai:uec.repo.nii.ac.jp:00008918,
 author = {Kaneko, Takuma and Samjeské, Gabor and Nagamatsu, Shin-ichi and Higashi, Kotaro and Sekizawa, Oki and Takao, Shinobu and Yamamoto, Takashi and Zhao, Xiao and Sakata, Tomohiro and Uruga, Tomoya and Iwasawa, Yasuhiro},
 issue = {42},
 journal = {The Journal of Physical Chemistry C},
 month = {Oct},
 note = {The structural kinetics (rate constants for electronic and structural transformations) of the Pt charging/discharging, Pt–Pt bond dissociation/re-formation, and Pt–O bond formation/dissociation of Pt/Ketjenblack, Pt/acetylene black, and Pt/multiwalled carbon nanotube cathode catalysts in polymer electrolyte fuel cell (PEFC) membrane electrode assemblies (MEAs) under transient potential operations (0.4 VRHE → 1.4 VRHE → 0.4 VRHE) has been studied by in situ/operando time-resolved quick X-ray absorption fine structure (QXAFS; 100 ms/spectrum), while measuring electrochemical currents/charges in the MEAs under the potential operations. From the systematic QXAFS analysis for potential-dependent surface structures and rate constants (k and k′) for the transformations of Pt nanoparticles under the operations (0.4 VRHE → 1.4 VRHE and 1.4 VRHE → 0.4 VRHE), respectively, we have found the structural kinetics (k′Pt–O and k′valence) controlling the oxygen reduction reaction (ORR) activity and also the structural kinetics (k′Pt–Pt/kPt–Pt) reflecting the durability of the cathode catalysts. The relaxation time of the Pt–Pt bond re-formation and Pt–O bond dissociation processes in the activated MEAs was also suggested to predict the relative durability of similar kinds of cathode catalysts. The in situ time-resolved XAFS analysis provided direct information on the key structural kinetics of the Pt/C catalysts themselves for thorough understanding of the cathode catalysis toward PEFC improvement.},
 pages = {24250--24264},
 title = {Key Structural Kinetics for Carbon Effects on the Performance and Durability of Pt/Carbon Cathode Catalysts in Polymer Electrolyte Fuel Cells Characterized by In Situ Time-Resolved X-ray Absorption Fine Structure},
 volume = {120},
 year = {2016}
}