Mechanistic and electrochemical investigation of solar light driven organic pollutant degradation using SrFe12O19/NiO Z-scheme heterojunctions

This research aimed to explore a novel and straightforward precipitation-based synthesis method for fabricating a NiO/ SrFe₁₂O₁₉ p-n heterojunction nanocomposite photocatalyst. Several characterization techniques were employed for evaluating the materials' properties: FTIR for functional groups, SEM for morphology, EDX for elemental composition, UV-DRS for bandgap energy, and EIS for charge transfer resistance, PL for recombination studies, XPS for surface chemical states, and XRD for crystalline phases. This work investigated the photocatalytic activity and reusability of the nanocomposite for the removal of rhodamine B (RhB) (cationic) dye and ibuprofen drug under solar light irradiation. To determine the ideal photodegradation conditions, intrinsic reaction parameters such as catalyst loading, solution pH, and beginning pollutant concentration and agitation of time were investigated. A binary NiO/SrFe₁₂O₁₉ catalyst with a 0.60 mg loading at pH 3.5 destroyed 93% of 60ppm RhB dye after 100 min of solar light irradiation. Furthermore, for ibuprofen degradation, at pH 7, catalyst dose 0.75 mg, pollutant concentration 10 ppm, and irradiation time 120 min, the composite showed 75% removal efficiency under solar light. Moreover, this composite catalyst demonstrated exceptional chemical stability and reusability, removing 60% of the RhB dye and 41% of ibuprofen after four recycling runs.Scavenger tests demonstrated that photogenerated holes (h⁺) and superoxide free radicals (^·O₂) are the primary reactive species causing degradation. This study gives information on the creation of highly effective nanomaterials for removing dyes from wastewater, as well as a possible reaction mechanism.