Synthesis and photocatalytic degradation of Methylene Blue dye using graphene oxide quantum dots (GOQDs)

Abstract

Graphene oxide quantum dots (GOQDs) were synthesized using a modified Hummers method combined with a hydrothermal process to evaluate their photocatalytic efficiency in degrading Methylene Blue (MB) dye. Characterization of GOQDs was performed using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis) spectroscopy, and Raman spectroscopy. TEM analysis revealed uniformly distributed quantum dots with diameters ranging from 5 to 10 nm. FTIR and Raman spectra confirmed the presence of characteristic functional groups and vibrational modes of graphene oxide. UV-Vis spectroscopy determined the optical band gap of GOQDs to be approximately 3.3 eV, indicating their suitability for visible light activation. Photocatalytic experiments demonstrated that GOQDs effectively degraded a 10 mg/L MB solution, achieving complete degradation after 210 minutes under fluorescent light at an initial pH of 6,42. These results highlight the potential of GOQDs as efficient photocatalysts for organic dye removal under visible light, offering a promising solution for wastewater treatment applications.