Highly active ZnO modified g-C3N4 Nanocomposite for dye degradation under UV and Visible Light with enhanced stability and antimicrobial activity

•ZnO/g-C3N4 nanocomposite was synthesized by facile thermal condensation method.•ZnO particles sandwiched within g-C3N4 exhibit higher photoactivity and stability.•The photocatalytic mechanism of ZnO/g-C3N4 in degrading DB dye were discussed.•The antibacterial activity and reusability studies are examined for ZnO/g-C3N4.

The ZnO/g-C3N4 nanocomposite photocatalyst have been synthesized by a facile single step thermal condensation route. The results indicate the formation of uniformly dispersed ZnO particles into the g-C3N4 sheet and that was further confirmed by characterization using X-ray diffraction (XRD), Field-emission scanning electron microscope (FESEM) with energy-dispersive X-ray spectrometry (EDS), High-resolution transmission electron microscope (HRTEM), Fourier transform infrared (FTIR) spectra, Raman spectroscopy and UV-vis diffuse reflectance spectroscopy (DRS). Further, this novel photo-catalytically active nanocomposites was utilized for the degradation of textile dye Direct Blue 199 under UV and visible irradiation. The results showed that photocatalytic activity of the ZnO/g-C3N4 nanocomposite was much higher than that of pure g-C3N4 via photodegradation of Direct Blue 199 under irradiation. The kinetic constant of dye over ZnO/g-C3N4 (1:3 ratio) was 2.4 to 3 times higher than that of pure g-C3N4. The gC3N4 support in the composite, promote the carrier utilization efficiency by accepting the photoexcited electrons from ZnO. The developed ZnO/g-C3N4 nanocomposite was found to be stable up to five cycles with excellent stability in dye degradation. Moreover, the nanocomposite showed improved antibacterial activity against both Gram-negative and Gram-positive bacteria (Escherichia coli and Staphylococcus aureus).