Exploring the Ability of α- Fe2O3 Nanoplate-Reduced Graphene Oxide Composites to Catalyze OER and Dye Degradation

Abstract

Through the study of reduced graphene oxide, hexagonal hematite (α- Fe2O3 ) nanoplates, and a composite made by combining them, this thesis addresses two important environmental issues: catalysis of the oxygen evolution reaction (OER) and the degradation of methylene blue (MB) dye under light exposure. OER is important because it is the more energy-intensive half reaction in water splitting, a process by which hydrogen can be renewably produced and later used to provide energy. MB is commonly used in industrial processes, later ending up as a pollutant in natural bodies of water. OER and MB degradation both hinge on the formation of hydroxyl radicals, which occurs when water molecules get oxidized. Hematite is known to have a band gap which gives it the ability to absorb a broad spectrum of visible light wavelengths, making it a good candidate for study in solar applications. However, it has low efficiency for water oxidation, due largely to the fast recombination rate of its photo-generated electron-hole pairs. RGO, known for its high conductivity, is thought to have the ability to decrease recombination rates by permitting the electrons of hematite nanoplates to travel further from their holes when the nanoplates are anchored to the rGO sheet. In order to explore this hypothesis, electrocatalytic, photoelectrocatalytic, and photocatalytic experiments were carried out. It was found that the hematite nanoplates have negligible reactivity under light and that the rGO has significant reactivity to light, as well as superior ability to catalyze OER and degrade MB without the presence of incident light. Throughout the experimentation process, electrode fabrication remained a challenge.