1. School of Engineering; the University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
2. Japan Technological Research Association of Artificial Photosynthetic Chemical Process; 2-11-9 Iwamotocho, Chiyoda-ku Tokyo 101-0032 Japan
3. Faculty of Engineering; Shinshu University; 4-17-1 Wakasato Nagano 380-8553 Japan