Synergistic enhancement of methylene blue degradation using r-GO supported ZrO2 under UV-Vis irradiation: An efficient photocatalytic approach for wastewater treatment

This study offers a comprehensive examination of the synthesis and utilization of zirconium oxide incorporated reduced graphene oxide (ZrO 2 /r-GO) nanocomposites aimed at the photocatalytic degradation of methylene blue dye under UV light. A detailed analysis of the morphology and photocatalytic features of the synthesized photocatalyst was investigated through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL), thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) analysis. Analytical techniques clearly confirmed that ZrO 2 particles were successfully incorporated on the surfaces of reduced graphene oxide (r-GO). HR-TEM images revealed a strong interconnection between r-GO and ZrO 2 , with observed lattice spacing corresponding to the ZrO 2 (111) plane, thereby confirming their close structural integration. The results corresponded closely with the XRD analysis, confirming the cubic crystalline structure of ZrO 2 . The results indicated that the combined effect of r-GO and ZrO 2 in prepared ZrO 2 /r-GO-10 nanocomposite significantly enhanced the adsorption-photodegradation efficiency, achieving a 91% removal of methylene blue within a 100 min time frame. This performance represents a significant increase in the pseudo-first-order kinetic rate constant over pristine ZrO 2 , which achieved a degradation efficiency was less compared to the rGO-ZrO 2 nanocomposites due to its uniqeidentical conditions, thereby clearly demonstrating a powerful synergistic effect between r-GO and ZrO 2 . Furthermore, the degradation process of methylene blue with the synthesized catalyst was consistent with a pseudo-first-order kinetics model. The superoxide (*O 2 − ) radical plays a significant role in the degradation mechanism of methylene blue dye in an aqueous environment. The findings reveal the impressive photocatalytic abilities of ZrO 2 /r-GO nanocomposites, suggesting their significant potential for effective remediation of organic dyes in water systems.