1. Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan, Advanced Research Laboratory, Hitachi, Ltd, Ohmika-cho, 7-1-1, Ibaraki, Japan, Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan, Institute of Materials Chemistry, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland, and Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4, Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103, Japan