1. Division of Material Science and Engineering, Faculty of Engineering, Hokkaido University,
Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
2. Department
of Applied Chemistry, Graduate Course of Urban Environmental Sciences, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachiohji, Tokyo 192-0397, Japan
3. Research Center for Artificial Photosynthesis, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachiohji, Tokyo 192-0397 Japan