Synthesis and characterization of nanosheet NiMoO4 powder as a highly efficient and reusable catalyst for environmental remediation

The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an aqueous solution at room temperature. The physical properties of NiMoO4 are investigated using several techniques, such as X-ray diffraction (XRD), which perfectly fits the crystalline alpha-form of NiMoO4. Moreover, scanning electron microscope (SEM) images show nanosheet-like particles. The atomic force microscopy (AFM) measurements reveal high roughness of the particle's surface. Furthermore, the investigations into the main electronic levels of alpha-NiMoO4 suggest a strong UV-visible light absorption. The optical band gap is found to be about 2.36 eV. Then, the photocatalytic activity of the synthesized NiMoO4 nanoparticles (NPs) is tested against methylene blue (MB) dye as a pollutant model. The obtained results reveal good capacity of MB degradation even in the dark. It exhibits a degradation efficiency up to 87% within 60 min, under visible-light illumination, and 44% in the dark. The photocatalytic stability of NiMoO4 NPs is studied as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider alpha-NiMoO4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.