Rational construction of g-C3N4/SnO2/CoFe2O4 dual Z-scheme system as a potential scaffold for fluorescence sensing and visible light driven photocatalytic degradation of lethal pollutants

Mimicking the natural photosynthesis process, novel direct dual Z-scheme CN/SnO2/CoFe2O4 heterostructures with different weight ratios (CN/SnO2:CoFe2O4 be 1:1, 2:1 and 1:2; namely CSnCo-1, CSnCo-0.5 and CSnCo-2, respectively) were successfully fabricated and employed for photocatalytic degradation of anthracycline drug, doxorubicin (DXR) and aromatic compound, p-nitrophenol (PNP) and fluorescence detection of heavy metal ion, Hg2+; DXR and PNP. CSnCo-0.5 displayed exceptional photocatalytic capability having pseudo first order rate constant values 5.60, 3.02, 1.23 and 1.38 times higher for DXR; and 4.2, 3.0, 1.18 and 1.12 times higher for PNP in comparison to CN, CSn-20, CSnCo-1 and CSnCo-2, respectively. UV–vis DRS study, photoluminescence spectra and electrochemical impedance results inveterate the formation of direct dual Z-scheme charge transfer, which is beneficial for boosting photocatalytic performance of the system. Additionally, CSnCo-0.5 proved to be highly selective and sensitive for the FL sensing of Hg2+, DXR and PNP with detection limits as low as 0.57 µM, 0.05 µM and 0.63 µM, respectively. Further, sensor provided good analytical performance in real water samples.