1. Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
2. Department of Chemistry, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, United Kingdom
3. College of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
4. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
6. Walter Schottky Institute and Physics Department, Technische Universität München, 85748 Garching, Germany