A Comparative Study on the Structural and Optical Properties of NiMoO4 Nanomaterials Synthesized by Hydrothermal and Solvothermal Route

Abstract In the present work, a transition metal‐based ternary oxide of NiMoO 4 nanomaterials is prepared by both hydrothermal and solvothermal methods with various synthesis conditions. Structural evolution as a function of increase in calcination temperature is also discussed. Scanning electron microscope (SEM) analysis presents the surface morphology of as‐prepared samples with an apparent change in the particle size under different synthesis conditions. Energy Dispersive X‐ray spectroscopy (EDAX) analysis confirms the chemical composition of the nanomaterials. Structural analysis by X‐Ray powder Diffraction (XRD) exhibits the formation of 𝛼 and β‐phase of NiMoO 4 and further pure 𝛼‐phase is observed at calcination temperature of 650 °C. Fourier Transform Infrared spectroscopy (FTIR) indicates various functional groups present in NiMoO 4 sample. UV–vis absorption spectra present a broad peak around 220–450 nm. A direct and indirect energy band gap of ≈2.2 and ≈1.9 eV, respectively is calculated for NiMoO 4 nanomaterials synthesized at 180 and 220 °C for 24 h and calcinated at 650 °C. NiMoO 4 nanomaterials and their composites find an application as electrode materials in supercapacitor.