Microwave-Assisted Synthesis of Chalcopyrite/Silver Phosphate Composites with Enhanced Degradation of Rhodamine B under Photo-Fenton Process

A new composite by coupling chalcopyrite (CuFeS(2)) with silver phosphate (Ag(3)PO(4)) (CuFeS(2)/Ag(3)PO(4)) was proposed by using a cyclic microwave heating method. The prepared composites were characterized by scanning and transmission electron microscopy and X-ray diffraction, Fourier-transform infrared, UV–Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Under optimum conditions and 2.5 W irradiation (wavelength length > 420 nm, power density = 0.38 Wcm(−2)), 96% of rhodamine B (RhB) was degraded by CuFeS(2)/Ag(3)PO(4) within a 1 min photo-Fenton reaction, better than the performance of Ag(3)PO(4) (25% degradation within 10 min), CuFeS(2) (87.7% degradation within 1 min), and mechanically mixed CuFeS(2)/Ag(3)PO(4) catalyst. RhB degradation mainly depended on the amount of hydroxyl radicals generated from the Fenton reaction. The degradation mechanism of CuFeS(2)/Ag(3)PO(4) from the photo-Fenton reaction was deduced using a free radical trapping experiment, the chemical reaction of coumarin, and photocurrent and luminescence response. The incorporation of CuFeS(2) in Ag(3)PO(4) enhanced the charge separation of Ag(3)PO(4) and reduced Ag(3)PO(4) photocorrosion as the photogenerated electrons on Ag(3)PO(4) were transferred to regenerate Cu(2+)/Fe(3+) ions produced from the Fenton reaction to Cu(+)/Fe(2+) ions, thus simultaneously maintaining the CuFeS(2) intact. This demonstrates the synergistic effect on material stability. However, hydroxyl radicals were produced by both the photogenerated holes of Ag(3)PO(4) and the Fenton reaction of CuFeS(2) as another synergistic effect in catalysis. Notably, the degradation performance and the reusability of CuFeS(2)/Ag(3)PO(4) were promoted. The practical applications of this new material were demonstrated from the effective performance of CuFeS(2)/Ag(3)PO(4) composites in degrading various dyestuffs (90–98.9% degradation within 10 min) and dyes in environmental water samples (tap water, river water, pond water, seawater, treated wastewater) through enhanced the Fenton reaction under sunlight irradiation.