Synergistically enhanced solar light‐driven degradation of hazardous food colorants by ultrasonically derived MgFe₂O₄/S‐doped g‐C₃N₄ nanocomposite: A Z‐scheme system‐based heterojunction approach

Abstract

Magnesium ferrite/sulfur‐doped graphitic nitride (MFO/SCNNS) heterostructure has been developed via sonication‐assisted deposition of zero‐dimensional MFO over the surface of two‐dimensional SCN nanosheets. Additionally, the prepared nanocomposite material has been characterized by several analytical characterization techniques including XRD, Fourier transform infrared (FT‐IR), high‐resolution transmission electron microscopy (HR‐TEM), selected‐area electron diffraction (SAED), energy‐dispersive spectrometry (EDS), Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM), UV–Vis. spectroscopy, electron spin resonance(ESR), and X‐ray photoelectron spectroscopy (XPS) which indicated the existence of strong interfacial interactions via heterojunction formation between MFO and SCNNS. The as prepared nanocomposite, especially MFO:SCNNS (1:1) (having 1:1 mass ratio of MFO to SCNNS), offered impressive photo‐response for the complete degradation of Erythrosine B and Indigo Carmine within 30 min under direct solar light irradiation. The enhanced photoactivity of the MFO:SCNNS (1:1) was also confirmed by the photoluminescence, photocurrent and electrochemical impedance spectroscopy. The Mott–Schottky analysis also depicts the formation of p‐n heterojunction at the interface of MFO and SCNNS, responsible for the enhanced photoactivity. Additionally, the degradation process has also been studied using mass spectrometry, UV–Vis, and ESR spectral analysis. The trapping experiments were also conducted to confirm the formation of active radical species during the photodegradation reaction. Furthermore, the nanocomposite photocatalytic material offered excellent stability and reusability and thus can serve as an effective candidate for environmental remediation application such as real waste water treatment.