Synthesis and characterization of graphene from palm oil on nickel substrate via thermal chemical vapour deposition / Salifairus Mohammad Jafar

In recent decades, the discovery of carbon nanotube and fullerene has effectively opened up a new dimension in materials technology and science. The breakthrough discovered that graphene is a new two-dimensional carbon allotrope has greatly expanded research in this area. The challenges for scientists are to produce uniform graphene and scalable production to be used in the industry. Graphene is traditionally manufactured from fossil fuels that are highly poisonous, such as methane, acetylene and ethanol, benzene, xylene, and toluene, among other things. The cost of these precursors is high, and their supply has been decreasing for several decades due to the fact that they are non-renewable resources. In this research includes the synthesis of graphene using a process of thermal chemical vapour deposition, carbon precursor (palm oil) and techniques of characterisation used. The overview of the synthesis variations and graphene characterisation techniques will be discussed in this thesis. The Nickel substrate was used in this experiment because it is high carbon solubility materials, which mean as many as carbon atoms could deposited on the substrate surface before cooling down process occur. Raman spectra have demonstrated the annealing time at 15 minutes was the optimized time to synthesis the graphene. The G and 2D band were at 1594 cm-1 and 2703 cm-1, respectively. At 15 minutes annealing time, the ratio of ID/IG was the lowest value compared to other deposition temperature. The ratio showed that synthesized graphene at this deposition temperature is high quality graphene. It was supported by the XRD pattern, at 15 minutes, the FWHM of [200] was 0.21° and it was the lowest value compared to other synthesis time. The surface roughness showed high value at 15 minutes which is 296 nm. The FESEM images shown the graphene sheets grown at the edge of the grain. The deposited graphene was not uniform due to the grain boundaries between nickel grain at different phase. The synthesized graphene was shown in the HRTEM images, and the graphitic layers was observed. The percentage of reflectance in UV-VIS spectra was observed at lower than 40% in the range between 200 and 300 nm. There are three significant parameter that has been set to synthesis high quality graphene which are deposition temperature, synthesis time and annealing time. The graphene deposited from palm oil as a precursor had the potential to be a low-cost, eco-friendly, and renewable material.