Visible light-degradation of azo dye methyl orange using TiO₂/β-FeOOH as a heterogeneous photo-Fenton-like catalyst

In this study, a novel TiO₂/β-FeOOH composite photocatalyst was synthesized by a hydrothermal method. X-ray diffraction, Fourier transform infrared spectrum, UV-vis diffuse reflectance spectra and scanning electron microscopy (SEM) were used to characterize the composite photocatalyst. The photocatalytic activity of the prepared composite photocatalyst was evaluated in a heterogeneous photo-Fenton-like process using methyl orange (MO) as target pollutant. The TiO₂/β-FeOOH composites exhibited higher photocatalytic activity than pure β-FeOOH and TiO₂ under visible-light irradiation. The enhanced photocatalytic activity can be ascribed to the formation of TiO₂/β-FeOOH heterostructure, which plays an important role in expanding the photoactivity to the visible light region and in effectively prolonging the lifetime of photoinduced electrons and holes. Further investigation revealed that the 25TiO₂/β-FeOOH composite synthesized with the TiO₂/Fe³⁺ in a mole ratio of 25:75 showed the highest catalytic activity.