rGO/ V 2 O 5 nanowire composites were synthesized via a green hydrothermal process, and the effect of hydrothermal duration on their morphology and photocatalytic performance was systematically evaluated. The composite prepared at 36 h exhibited the most uniform nanowire architecture and the strongest interfacial coupling. Under simulated solar irradiation, this sample achieved 95.5% degradation of methylene blue (20 mg/L) within 240 min, significantly outperforming pristine V 2 O 5 . Radical-trapping experiments confirmed that superoxide radicals (O 2 •− ) and photogenerated holes (h⁺) are the primary active species, whereas hydroxyl radicals (•OH) contribute marginally. A mechanism is proposed in which photoexcited electrons transfer from V 2 O 5 to rGO, where rGO acts as an electron sink that suppresses electron–hole recombination and promotes O 2 reduction to O 2 •− ,thereby accelerating pollutant degradation into CO 2 , H 2 O, and inorganic ions. These results demonstrate the synergistic effect of rGO–V₂O₅ coupling and highlight a sustainable strategy for developing efficient photocatalysts for environmental remediation.
Thi et al. (Fri,) studied this question.