1. O. Sato and T. Iyoda, Kanagawa Academy of Science and Technology, Tokyo Institute of Polytechnics, 1583 Iiyama Atsugi, Kanagawa 243-02, Japan.
2. A. Fujishima, Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113, Japan.
3. K. Hashimoto, Kanagawa Academy of Science and Technology, Tokyo Institute of Polytechnics, Kanagawa 243-02, and Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113, Japan.