Study on Photocatalytic Degradation of Acid Red 73 by Fe3O4@TiO2 Exposed (001) Facets
Li Sun, Quan Zhou, Jiaheng Mao, Xingyu Ouyang, Zhigang Yuan, Xiaoxiang Song, Wenbang Gong, Shunqi Mei, Wei Xu
Abstract
Water pollution can be treated through the photocatalytic reaction of TiO2 or TiO2 compounds. A solvothermal method was used to prepare Fe3O4 and Fe3O4@TiO2 composite photocatalyst with (001) high-energy facets exposed in the anatase phase. TiO2 and Fe3O4@TiO2 were characterized by field emission scanning electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy, X-ray diffraction spectroscopy and Raman spectroscopy. It was found that the composite Fe3O4@TiO2 can reduce the band gap and maintain a certain proportion of (001) high-energy facet exposure. The band gaps of Fe3O4@TiO2 and TiO2 are 2.5 eV and 2.9 eV, respectively. The exposure percentages of (001) facets of Fe3O4@TiO2 and TiO2 are about 25.2% and 12.1%, respectively. Fe3O4@TiO2 was used for photocatalytic degradation of Acid Red 73, and it was found that Fe3O4@TiO2 could improve the efficiency of photocatalytic degradation of Acid Red 73. The photocatalytic degradation rates of Fe3O4@TiO2 and TiO2 at 24 min were 93.56% and 74.47%, respectively. The cycle experiment of photocatalytic degradation of Acid Red 73 by Fe3O4@TiO2 showed that at the fifth cycle, the rate of dye degradation decreased to 77.05%, but the rate of dye degradation can reach more than 90% after self-cleaning treatment. The photocatalytic degradation mechanism is explained by the energy band theory and the first-order kinetic equation model.