Efficient sunlight-assisted degradation of organic dyes using V2O3/g-C3N4 nanocomposite catalyst

This study reports the synthesis of vanadium oxide (V2O3) and graphitic carbon nitride (g-C3N4) nanocomposite for simple sunlight-assisted degradation of Methylene Blue(MB) and Rhodamine B (RhB) dyes. Herein, the V2O3 and g-C3N4 are synthesized via hydrothermal and thermal decomposition techniques, respectively. X-ray diffraction (XRD) analysis confirms the formation of the rhombohedral and hexagonal structures of V2O3 and g-C3N4 in the nanocomposite, respectively, while scanning electron microscopy (SEM) reveals the sheet-like morphology of g-C3N4 and V2O3 nanoparticles. The optical band gap of the nanocomposite is estimated as 1.89 eV using a Tauc's plot generated from UV–Vis reflectance spectroscopy. The as-synthesized nanocomposite exhibits an excellent dye degradation efficacy displaying a 100 % degradation of RhB and 90 % degradation of MB dyes within 1 h of exposure to daylight. This performance is attributed to the synergistic effect of the V2O3/g-C3N4 nanocomposite wherein the composite benefits from the large surface area and high visible light adsorption of g-C3N4, combined with the active catalytic sites of the rhombohedral V2O3 structure, resulting in its high efficiency for photocatalytic dye degradation. Scavenger studies confirm the hydroxyl (.OH) radicals and oxygen (O2−.) radicals as the primary reactive species in the degradation process MB. Furthermore, the catalyst exhibited remarkable stability over three cycles of photocatalysis thus confirming its utility for real-time environmental remediation applications.