[1] Univ Tokyo, Dept Chem, Grad Sch Sci, Bunkyo Ku, Tokyo 1130033, Japan
[2] Toyota Motor Co Ltd, Fuel Cell Syst Dev Ctr, Shizuoka 4101193, Japan
[3] Toyota Cent Res & Dev Labs Inc, Nagakute, Aichi 4801192, Japan
[4] Tottori Univ, Fac Engn, Dept Mat Sci, Tottori 6808552, Japan
[5] Japan Synchrotron Radiat Res Inst Kouto, Sayo, Hyogo 6795198, Japan
[6] High Energy Accelerator Res Org, Photon Factory, Inst Mat Struct Sci, Tsukuba, Ibaraki 3050801, Japan