Abstract

The continuous discharge of dye-contaminated wastewater from industrial operations is a major environmental hazard,
demanding the development of effective and long-term cleanup techniques. In this work, graphene oxide (GO) and GO-nickel
oxide (NiO) nanocomposites were produced and comprehensively tested for photocatalytic efficiency in the breakdown of
organic dyes using visible light irradiation. The structural and morphological properties of the synthesized materials were
investigated using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (EDS), confirming
the successful formation of GO-NiO nanocomposites with uniform dispersion of NiO nanoparticles on GO sheets. Optical
investigation demonstrated that the GO-NiO nanocomposite has a lower band gap, leading to increased visible light absorption.
Photocatalytic investigations revealed that the GO-NiO nanocomposite exhibited considerably greater degradation efficiency
than virgin GO, owing to enhanced charge separation and reduced electron-hole recombination arising from strong interfacial
contacts. The degradation process exhibited pseudo-first-order kinetics, indicating positive reaction dynamics. Furthermore, the
nanocomposite demonstrated remarkable stability and reusability after many catalytic cycles. Overall, the findings demonstrate
the efficacy and sustainability of GO-NiO nanocomposites as photocatalysts for environmental remediation by degrading organic
contaminants in aqueous environments.