Enhanced photocatalytic degradation of rhodamine B over Ag₃PO₄/Polyaniline/NiFe₂O₄ nanocomposite under solar light irradiation

In this study, a nanocomposite of Ag₃PO₄/Polyaniline(PANI)/NiFe₂O₄ was synthesized and studied on degradation of rhodamine B (RhB) in water under solar light irradiation. The nanocomposite was characterized using powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Ultraviolet–visible (UV–vis) differential reflectance spectroscopy (DRS). The best photocatalytic nanocomposite (Ag₃PO₄/3%PANI/10%NiFe₂O₄) showed six-fold higher degradation rate constant than of pristine Ag₃PO₄. Moreover, introduction of PANI/NiFe₂O₄ into Ag₃PO₄ significantly enhance the recyclability of the nanocomposite (stable after 3 cycles) whereas pristine Ag₃PO₄ degraded even after first cycle. Radical scavenger studies with t-butyl alcohol, disodium ethylenediaminetetraacetic acid, and ascorbic acid indicated that both holes and electron participate in the degradation of RhB. We hypothesized that the presence of PANI and NiFe₂O₄ in the nanocomposite enhanced its hole and electron transport, respectively, facilitating efficient electron–hole separation. Therefore, large number of holes accumulates in valance band of Ag₃PO₄ that enhanced the degradation of RhB dye in water under solar light irradiation.