Highly improved photocatalytic degradation of rhodamine B over BiGa Fe O solid solutions under visible light irradiation.

In this work, BiGa Fe O (0 ≤ ≤ 1.2) solid solutions were prepared the traditional high-temperature solid-state reaction. The Le Bail fitting on the powder X-ray diffraction patterns shows that these solid solutions were successfully synthesized. Scanning electron microscopy showed that the BiGaFeO sample was composed of sub-micron particle crystallites. Energy dispersive spectroscopy analysis and X-ray photoelectron spectroscopy were used to identify that the Fe element is trivalent when doping into the crystal structure. Ultraviolet-visible diffused reflectance spectra suggested that the bandgap of BiGaFeO is narrower than that of the undoped BiGaO sample. Three strategies, including Fe doping, addition of HO, and loading of the cocatalyst, were utilized to improve the photocatalytic degradation activity. The optimum photocatalytic performance was obtained over 2.5 wt% Cu/BiGaFeO sample in 20 ppm RhB aqueous solution (containing 1.5 mL HO) under visible light irradiation. Its photodegradation rate is 8.0 times that of BiGaO containing 0.5 mL HO. The 2.5 wt% Cu/BiGaFeO photocatalyst remained stable and active even after four cycles. Also, its photocatalytic conversion efficiency for RhB was nearly 100%, which was achieved in 3 hours. The photocatalytic mechanism indicated that ·OH and h played an important role in the photocatalytic degradation reaction.