Synthesis of GdFeO3/alpha-Fe2O3 heterostructure with enhanced photo-Fenton-like performance for organic pollutant degradation

The synergistic effects of photo-Fenton-like oxidation and heterostructure photocatalysis are highly beneficial for wastewater treatment. In this work, photo-Fenton-like GdFeO3 (GFO)/alpha-Fe2O3 catalysts with Z-scheme hetero-structures were successfully fabricated via a facile ultrasonic method and then characterized using X-ray diffraction, transmission electron microscopy (TEM), field emission scanning electron microscopy, high-resolution TEM, ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron microscopy, photo-current analysis, and electron impedance spectroscopy. The heterostructure with a GFO/Fe ratio of 3:7 showed the highest photocatalytic activity during degradation of organic pollutants, and adding small amounts of H2O2 increased its visible-light-driven catalytic activity by 9.5, 2.3, and 16.4 times that of rhodamine B, methylene blue, and tetracycline, respectively. The catalytic results were significantly improved due to the synergy of the Z-scheme heterostructure and photo-Fenton-like oxidation. The results indicate that an appropriate composition ratio can accelerate the conversion rate of surface equivalent to Fe3+ to equivalent to Fe2+ and promote the separation of electron-holes that can form more reaction active sites. Furthermore, a possible photocatalytic mechanism associated with the GFO/Fe composite was proposed using an electron spin resonance test and active-species trapping experiments. Overall, this work presents an important synthesis route for photo-Fenton-like catalysts that can degrade organic pollutants in wastewater.