Novel reduced graphene oxide/ZnBi₂O₄ hybrid photocatalyst for visible light degradation of 2,4-dichlorophenoxyacetic acid

A new highly efficient rGO/ZnBi₂O₄ hybrid catalyst has been successfully synthesized through oxidation-reduction and co-precipitation methods, followed by heating at 450 °C. The obtained rGO/ZnBi₂O₄ catalyst was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The catalytic activity of rGO/ZnBi₂O₄ under visible light irradiation was tested using 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The rGO/ZnBi₂O₄ hybrid catalyst containing 2% rGO (2.0rGO/ZnBi₂O₄) showed the best catalytic performance. More than 90% of 2,4-D in a 30 mg/L solution was degraded after 120 min of visible light irradiation using 2.0rGO/ZnBi₂O₄ at 1.0 g/L concentration. Moreover, the 2.0rGO/ZnBi₂O₄ catalyst showed excellent stability over four consecutive cycles, with no significant changes in the photocatalytic degradation rate. This study demonstrated that rGO/ZnBi₂O₄ may be a promising, low-cost, and green photocatalyst for environmental remediation applications.