This study concerns the preparation of sprayed binary molybdenum oxide, MoO$_3$, thin films and ternary and quaternary derivatives by alloying. The characterization of their physical properties was carried out by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, spectrophotometry and impedancemetry. It appears from the electrical study that the great value of resistance R corresponds to the NiMoO$_4$ thin films. The equivalent ac circuit of these films is composed by a parallel resistor R and capacitor C connected together. This work also focused on the photocatalysis process applied to the studied samples. Under solar irradiation, the photocatalytic application was tested in terms of the degradation reaction of wastewater containing methylene blue. Under similar experimental conditions, the NiMoO$_4$ thin film shows a higher rate of degradation than the other thin layers.

Semiconductor photocatalysts, especially nickel molybdenum oxide with a monoclinic structure, have been frequently used to address environmental pollution issues. Many advantages have been discovered for photocatalytic applications using this material, so, in this study, we have studied the physical properties of NiMoO$_4$ thin film prepared using the spray approach. The structural properties have been characterized by X-ray diffraction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The structural analysis shows a monoclinic structure with space group C$_2$/m and a grain size equal to 150 nm. In addition, the optical measurements show direct optical transitions with a bandgap equal to 3.56 eV, revealed by an ellipsometric spectroscopy study. Using a spectroscopy impedance analysis, we have also investigated the frequency relaxation phenomenon and determined the activation energy, which was equal to 1.16 eV. Finally, the photocatalytic degradation of methylene blue was performed on this thin layer under sunlight irradiation. The monoclinic structure and possible defects in the lattices were used to discuss the effective photocatalytic activity.