Efficient photocatalytic degradation of indigo carmine dye by CoFe2O4@g-C3N4 nanocomposite

Semiconductor-based photocatalysts are potential candidates to efficiently control pollution and reduce noxious organic contaminants from wastewater. The present research is devoted to fabricating of semiconducting nanocomposite material for the photodegradation of indigo carmine (IC) as a model organic pollutant. A facile eco-friendly method was adopted to synthesize cobalt ferrite nanoparticles (CoFe 2 O 4 ) from their precursors using Pimpinella anisum extract as a reducing and capping agent and then coupled to graphitic carbon nitride (g-C 3 N 4 ) to achieve CoFe 2 O 4 @g-C 3 N 4 composite. X-ray diffraction analysis confirmed the formation of both phases in the composite with a mean crystallite size (≈ 29 nm) for CoFe 2 O 4 . In contrast, the chemical composition obtained by EDS and XPS techniques revealed the presence of Co, Fe, O, C, and N. Consequently, the CoFe 2 O 4 @g-C 3 N 4 heterostructure reduced the indirect band gap from 2.82 to 2.33 eV, thereby improving visible-light absorption. The optical band gap of pure CoFe nanoparticles was found to be ∼3.20 eV, and more direct and increases the surface area to ≈ 59 cm 2 . g -1 . The CoFe 2 O 4 , g-C 3 N 4 , and CoFe 2 O 4 @g-C 3 N 4 were tested for the degradation of the IC under visible light illumination. The nanocomposite exhibits excellent photocatalytic performance towards the IC degradation, reaching 100% within 60 min. The synergism of CoFe 2 O 4 and g-C 3 N 4 within the CoFe 2 O 4 @g-C 3 N 4 heterostructure resulted in a lessened energy band gap, hindered electron/hole pair recombination, and improved both electrons and holes viability for the photodegradation through the formation of active radicals, and consequently an enhancement of dye photodegradation.