[1] Natl Univ Singapore, Dept Chem, Singapore 117543, Singapore
[2] Natl Univ Singapore, Dept Mat Sci & Engn, NUSNNI NanoCore, Singapore 117576, Singapore
[3] King Abdullah Univ Sci & Technol, KAUST Catalysis Ctr, Thuwal 239556900, Saudi Arabia
[4] King Abdullah Univ Sci & Technol, Div Phys Sci & Engn, Thuwal 239556900, Saudi Arabia
[5] ASTAR, Inst Mat Res & Engn, Singapore 117602, Singapore