1D/2D MnWO4 nanorods anchored on g-C3N4 nanosheets for enhanced photocatalytic degradation ofloxacin under visible light irradiation

Herein, MnWO4 nanorods coupled with g-C3N4 nanosheets were fabricated by a simple hydrothermal method, followed by an ultrasonication method. Morphological features, chemical composition, optical properties and crystallographic information of the prepared materials were obtained using SEM-EDX, TEM, XRD, XPS, FT-IR, UV-vis DRS, and PL techniques. The synthesized MnWO4@g-C3N4 nanocomposite displayed excellent photocatalytic activity towards ofloxacin (OFX) under visible light irradiation. Moreover, the influence of reaction parameters such as the catalyst dosage, pollutant concentration and presence of inorganic anions (Cl-, CO32- and SO42-), was investigated during the photocatalytic process. Notably, among the inorganic anions, SO42- and CO32- significantly hampered OFX degradation, while Cl- ions showed minimal effect on the degradation process. The apparent rate constant for MnWO4@g-C3N4 from first order kinetics was 3.5 and 4.8 times higher than that of pure g-C3N4 and MnWO4, respectively. Based on the obtained results, the possible charge transfer mechanism was proposed. The enhanced photocatalytic performance of the binary nanocomposite could be ascribed to the synergistic effect between MnWO4 nanorods and g-C3N4 nanosheets resulting in efficient visible light utilization and inhibition of the charge carrier recombination. This work demonstrates the potential application of MnWO4@g-C3N4 nanostructures in the photocatalytic removal of emerging pollutants in water.