Effect of Combustion Fuel on Phase, Morphology and Band Gap Energy of MgO Nanoparticles Prepared via Self-Propagating Combustion (SPC) Method

In this study, MgO nanoparticles (MgO-NPs) were synthesized using the self-propagating combustion (SPC) method. Different fuels which are triethanolamine, glycine, and citric acid were employed to investigate their effects on the phase, morphology, particle size and band gap energy of MgO-NPs. The resulting samples were named MgO-TRI (triethanolamine), MgO-GLY (glycine), and MgO-CA (citric acid), respectively. This method is simple, produces uniform powder, and is capable of yielding large quantities of the final product. Pure MgO-NPs was obtained at the temperature of 600 ℃ for 12 hours. The nanoparticles produced exhibit agglomerated and irregular rounded particle size (26.43 nm) using triethanolamine as fuel followed by citric acid (51.50 nm) and glycine (90.44 nm). The band gap energy of the produced MgO-NPs ranging from 5.81 eV to 6.20 eV are much lower than their micron-sized counterpart (7.8 eV). Due to having the smallest particle size, MgO-TRI sample has the lowest band gap energy followed by MgO-CA and MgO-GLY which have bigger particle size. This shows that the band gap energy of materials is affected by the size of particles. The findings indicated that the tuning of band gap energy of synthesized nanomaterials suiting the desired applications can be executed by varying the fuels. From this study, triethanolamine is evidenced to be the most effective fuel for SPC method as it produces the smallest particle size producing MgO-NPs with the lowest band gap energy compared to other fuels.