Hydrogen peroxide-assisted photocatalytic dye degradation over reduced graphene oxide integrated ZnCr₂O₄ nanoparticles

Zinc chromite nanoparticles (NPs) and zinc chromite-reduced graphene oxide (ZnCr₂O₄-rGO) nanocomposite have been synthesized by the combined effects of reflux condensation and calcination processes. The structural properties were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible studies, etc. Structural morphology was investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) that indicate the formation of particles in the nanometer regime. The presence of the elements Zn, Cr, O and C has been confirmed by energy-dispersive X-ray spectroscopy (EDX) images which show the purity of the synthesized products. The photocatalytic activities of both as-prepared samples under visible light irradiation were investigated in presence of hydrogen peroxide (H₂O₂) and the results show that ZnCr₂O₄-rGO nanocomposite has a quite higher photo-activity response than virgin ZnCr₂O₄ NPs. The enhanced photo response indicates that, in ZnCr₂O₄, the photo-induced electrons favor to transfer to the rGO surface and the recombination of electron-hole pairs inhibited for which it results in the significantly increased photocatalytic activity for the ZnCr₂O₄-rGO photocatalyst and this phenomenon is also supported by the band gap value and photoluminescence results. Our outcomes demonstrate that ZnCr₂O₄-rGO nanocomposite is a more promising material to build up an efficient photocatalyst for waste water treatment.