(138e) Enhanced Photocatalytic Activity in Dye Degradation By Uct Mesoporous Iron Oxides

Photocatalytic dye degradation is an effective way to remove pollutant dyes in water. The UCT mesoporous materials, synthesized by the state-of-the-art sol-gel based inversed micelle method, can provide tunable structural properties, such as surface area, pore size and volume, and crystallinity. In this study, mesoporous iron oxides in different phases, 2-line ferrihydrite, α-Fe₂O₃, γ-Fe₂O₃, and, Fe₃O₄, have been prepared by changing the synthesis conditions, such as reaction temperature and calcination process. The increased reaction temperature was shown to increase the pore size due to the redox reactions between the as-made iron(III) oxide and the surface NO_x/carboxyl groups. When calcined in a nitrogen atmosphere, Fe(II) species could form Fe₃O₄ phase. The mesoporous iron oxides with different phases have been applied to orange II degradation under visible light irradiation as Fenton catalysts. All the synthesized mesoporous iron oxides show higher photocatalytic activity than commercial Fe₂O₃ in the orange II degradation reaction. Mesoporous 2-line ferrihydrite presents the highest reaction rate constant (0.0258 min^-1), which is mainly attributed to its large surface area. The recyclability study indicates that the activity of the synthesized mesoporous iron oxides can be maintained for at least 3 times recycles.