1. School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
2. Institute of Chemical and Engineering Sciences A*STAR; 1 Pesek Road Singapore 627833 Singapore
3. Solar Fuel Laboratory; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
4. Energy Research Institute @ Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore