1. Research Centre for Artificial Photosynthesis (ReCAP), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
2. Innovative Research Excellence, Power unit & Energy, Honda R&D Co., Ltd., 4630 Shimotakanezawa, Haga-Machi, Hagagun, Tochigi 321-3393, Japan
3. Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan