Reduced Graphene Oxide/WO₃ Nanorod Composites for Photocatalytic Degradation of Methylene Blue under Sunlight Irradiation

The addition of reduced graphene oxide (rGO) into semiconducting metal oxide nanomaterials is a trending material that has been used in a wide range of applications to improve the efficiency of metal oxides. In this present work, we synthesize rGO/WO3 nanohybrids via a simple one-step hydrothermal route. During the hydrothermal treatment, the subsequent in situ reduction of GO into rGO occurred in Millipore water without using any surfactant or reducing agents. A high-resolution transmission electron microscope investigated the morphology of the prepared samples. The phase formation was confirmed by X-ray diffraction pattern and Raman spectroscopy. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) dye under sunlight irradiation. From the results, the WR3 (i.e., WO3 + 30 mg GO) shows a higher catalytic activity for MB degradation. The constant rate values of WR3 (i.e., WO3 + 30 mg GO) also increased to ∼6.5 times compared to WO3. The enhanced catalytic activity of the prepared samples is due to the synergistic effect induced electron–hole recombination delay in the nanocomposites, which is confirmed from the photoluminescence spectroscopy. To probe the active species involved in photocatalysis, in situ scavenger studies were done. A two-route photocatalytic mechanism was proposed to explain the photocatalytic reaction.