1. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
2. International Research Center for Soft Matter; Beijing University of Chemical Technology; Beijing 100029 P. R. China
3. Department of Chemical Engineering; Cambridge University; Cambridge CB2 3RA UK
4. School of Chemical, Biological, and Environmental Engineering; Oregon State University; Corvallis OR 97331 USA
5. Solar Fuels Laboratory; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
6. Energy Research Institute @ Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore