In Situ Hydrothermal Synthesis of NiMnWO Nanoheterostructure for Enhanced Photodegradation of Methyl Orange.

The monoclinic nanocrystalline NiMnWO heterostructure has been successfully synthesized by the hydrothermal technique for achieving better sensitive and photocatalytic performances. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis), and photoluminescence (PL) spectroscopy have been employed to investigate their structural, microstructural, and optical properties. Mn-ion incorporation in the NiWO lattice reduces the particle size of the sample compared with the pure undoped NiWO sample, which has been confirmed from the transmission electron microscope image. The Tauc plot of the NiMnWO sample exhibits a significant decrease in bandgap energy compared with the pure undoped NiWO sample due to the quantum confinement effect. Finally, the material was explored as a photocatalyst for the degradation of methyl orange (MO) dye from wastewater under visible light irradiation. Various reaction parameters such as pH, catalyst dose, reaction time, and kinetics of the photodegradation were studied using the batch method. The results showed that the NiMnWO is highly efficient (94.51%) compared with undoped NiWO (65.45%). The rate of photodegradation by NiMnWO (0.067) was found to be 1.06 times higher than the undoped NiWO (0.062).