Solar light-induced degradation of hazardous organic pollutants using Diospyros kaki mediated green synthesized zirconium doped nickel oxide-zinc oxide nanocomposite

Abstract

This study explores an eco-friendly route using Diospyros kaki leaves extract as a stabilizing and reducing agent for the fabrication of 0.5% and 1% Zr-NiO/ZnO NCs. The fabricated samples were characterized using x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), energy-dispersive x-ray (EDX) and transmission electron microscopy (TEM). The physicochemical analysis confirmed the successful fabrication of zirconium-doped NiO/ZnO (Zr-NiO/ZnO NCs) NCs. UV-DRS study showed the widening of the band gap from 3.43 eV to 3.66 eV with the increase in the amount of dopant from 0.5% to 1%. The SEM and TEM micrographs revealed the formation of nanostructures having irregular morphologies which were unevenly distributed. Furthermore, EDX results showed the characteristic signal of zirconium, nickel, zinc, and oxygen in the sample which confirmed the successful formation of Zr-NiO/ZnO NCs. The photocatalytic activity of Zr-NiO/ZnO NCs was evaluated by performing degradation of brilliant green (BG) and 4-nitrophenol (4-NP) under direct solar light, which showed enhanced photocatalytic performance. The 0.5%Zr-NiO/ZnO NC demonstrated enhanced performance (86.4% degradation of BG and 89% degradation of 4-NP) as compared to 1% Zr-NiO/ZnO NC (67% and 51% of BG and 4-NP respectively) which can be related to lower band gap and less agglomeration of nanostructures.