Evaluation of Photocatalytic Efficiency of WO3, NiWO3 and rGO/NiWO3 Nanoparticles

In this study, we synthesized and analyzed tungsten trioxide (WO₃), nickel tungstate (NiWO₃), and rGO/NiWO₃ nanocomposites as photocatalysts to degrade methylene blue (MB) dye under natural sunlight. Various tests, including XRD, FT-IR, UV-DRS, FE-SEM, EDAX, HR-TEM, and XPS, confirmed the successful synthesis and stability of the materials. XRD showed that WO₃ and NiWO₃ had monoclinic and cubic structures, with crystallite sizes of 12.85 nm, 33.58 nm, and 59.59 nm for rGO/NiWO₃. FE-SEM and HR-TEM images revealed a layered rGO structure with well-dispersed NiWO₃ particles. UV-DRS results showed band gaps of 1.08, 1.03, and 1.01 eV for WO₃, NiWO₃, and rGO/NiWO₃, respectively. The photocatalytic test showed that rGO/NiWO₃ achieved 89.7% Methylene Blue degradation efficiency. The degradation followed pseudo-first-order kinetics, with the highest rate constant for rGO/NiWO₃ (2.064 × 10⁻⁴ min⁻¹). These results suggest that the rGO/NiWO₃ nanocomposite has great potential for photocatalytic environmental cleanup, especially in wastewater treatment.