Exploring Oxygen-Doped g-C₃N₄ Supported NiS Nanocomposites for Enhanced Photocatalytic Removal of Contaminants from Aqueous Medium

This study outlines the synthesis of a novel ternary NiS/O@g-C₃N₄ (NOC) nanocomposite via a simple hydrothermal process. Various techniques such as X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the nanocomposites. The NOC nanocomposite had an average crystallite size of 7.8 nm and an average diameter of 14.628 nm. The characterization results revealed that oxygen acts as an electron acceptor and charge transfer medium, which delays charge recombination and enhances the photodegradation efficiency of NOC. The photocatalytic property of the synthesized nanomaterial was investigated for the degradation of Congo Red (CR) and Rhodamine B (RhB) dyes. The NOC composite demonstrated impressive photocatalytic activity, achieving 92.29% and 99.5% degradation of CR and RhB within 50 and 60 min, respectively, in aqueous solutions, via the H₂O₂-assisted Advanced Oxidation Process (AOP). The degradation kinetics followed a pseudo-first-order kinetic model for both dyes. Furthermore, the NOC photocatalyst retained nearly 80% of its activity after five cycles, demonstrating high regeneration efficiency. These findings are encouraging for applications such as wastewater treatment and environmental remediation.