SYNTHESES, CHARACTERIZATIONS AND TESTINGS OF CARBON NANOFIBRE FOR HYDROGEN ADSORPTION STUDIES

Renewable energy (RE) has been declared as the fifth fuel of Malaysia in addition to oil, gas, coal and hydropower. One of REs which is hydrogen has become an alternative fuel for transportation to replace petroleum. For sufficient hydrogen storage, the system requires an inexpensive, safe, low weight tank, comparable in to a gasoline tank with capability of quick loading and unloading hydrogen fuel. Carbon nanomaterials have been nominated as one of the best medium to store hydrogen due to its light weight, low cost production depending upon types of synthesis methods, non-toxic and can be generated with improvement in its storage capacity. The research work focuses on the development of carbon nanofibers by using chemical vapor deposition method. The development of catalysts such as iron (III) oxide and nickel (II) oxide for the synthesis of carbon nanofibers (CNFs) has also been investigated. The capacity of the developed materials in hydrogen adsorption is tested at 298K and the pressure is up to 100 bar using gravimetric measurement technique. Sample imaging observations using field emission electron microscopy (FESEM) and transmission electron microscopy (TEM) indicate that the synthesized CNFs have both platelet and herringbone structure with little carbon nanotubes (CNTs). Iron-based catalyst CNF (Fe-C) samples have diameter size of 170 nm while nickel-based catalyst CNF (Ni-C) has diameter size of 200 nm. Specific BET surface area of Fe-C and Ni-C are 92.34 m²/g and 45.96 m²/g, respectively. Both analysis which are energy-dispersive X-ray (EDX) and thermogravimetric proved that purity of Fe-C is between 88% to 95% while purity of Ni-C is ranges from 95% to 97%. For iron-based catalyst CNF, the highest uptake is 0.46 wt % at 70 bar and for nickel-based catalyst CNF, the highest uptake is 1.76 wt % at 70 bar.