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Solar fuels production from water splitting with sunlight
thesisposted on 2022-03-28, 14:16 authored by Kyle Chen
With the increase in the depletion of fossil fuel resources and its accompanying harmful environmental effects, a clean, efficient and portable fuel is in need of development. As a result, hydrogen fuel has attracted much attention because of its favourable characteristics, but due to its limiting technology to produce it, hydrogen fuel is not widely used. Photocatalytic water splitting is a recent development that can potentially lead to an economical and efficient process to produce hydrogen. The power that drives this technology is sunlight, an environmentally free and renewable resource, making it a valuable approach to producing hydrogen fuel in the future. This thesis aims to conduct further work on the development of an efficient photocatalyst, which initiates the splitting of water into hydrogen and oxygen.The project fabricated iron oxide/carbon nitride nanotubes (FeOx/C3N4 NTs, and then tested its hydrogen generation performance, by emitting artificial visible-light on the chemical product submerged in water. The results showed an increase in photocatalytic performance as compared to the bulk graphitic C3N4, and C3N4 NTs by itself. In essence, the nanoparticles, FeOx, reduced the negative effect of recombinant rate and increased the visible-light absorption capacity. In addition, different weight percentages of FeOx/C3N4 NTs were synthesised (1 wt%, 3 wt%, 5 wt%, 7 wt% and 9 wt%). The photocatalytic test determined the optimum weight percentage for hydrogen evolution is 5 wt%. Any subsequent testing wt% values that were either above of below 5 wt% showed a reduction in hydrogen production. The morphological structure of the synthesised FeOx/C3N4 NTs was characterised by TEM, while its crystal phase was determined by the XRD. TEM images proved that FeOx particles are indeed anchored on the C3N4 NTs. However, many agglomerated on the NT surface, suggesting that the adopted method was not successful in synthesisin distinct NPs adhered onto the host photocatalyst. XRD results showed evidence of Fe3O4, Fe2O3 and Fe NPs. UV-vis absorption and PL spectra analysis showed that the hybrid photocatalyst is a visible-light driven photocatalyst and has a low recombination rate when exposed to visible light.