[1] Univ Kebangsaan Malaysia, Fuel Cell Inst, Bangi 43600, Selangor, Malaysia
[2] Univ Kebangsaan Malaysia, Sch Chem Sci & Food Technol, Fac Sci & Technol, Bangi 43600, Selangor, Malaysia
[3] Univ Kebangsaan Malaysia, Fac Sci & Technol, Sch Appl Phys, Bangi 43600, Selangor, Malaysia