L_x‐β‐NiMoO₄ (L = None, Al, V, Fe, Co) Nanocomposites: Facile Solid‐State Synthesis, Magnetic, Optical, and Electrochemical Properties

Abstract

Synthesis of a class of Lx‐β‐NiMoO4 (L = None, Al, V, Fe, Co) nanocomposites by a facile one‐step solid‐state route at 700, 800, and 900 °C for 8 h is introduced in the present study. The physical and electrochemical properties of the fabricated compounds are studied by X‐ray powder diffraction (XRPD), field‐emission scanning electron microscope, energy‐dispersive X‐ray spectroscopy, Fourier‐transform infrared spectroscopy, UV‐vis, vibrating sampling magnetometer (VSM), and cyclic voltammetry (CV) analyses. XRPD patterns associated with Rietveld analysis data performed by the FullProf program confirm that the as‐prepared samples are crystallized in the β polymorph monoclinic NiMoO4 crystal system. The magnetic property investigated by VSM analysis data shows that the fabricated samples have ferromagnetic behavior. It is found that the highest Ms value is obtained when Fe3+ is doped into the NiMoO4 crystal system. The smallest direct band gap energy (Eg) is obtained for V‐doped NiMoO4 nanocomposite. The electrochemical property of the prepared NiMoO4 nanocomposites is studied by CV analysis. The data confirm that NiMoO4 can be used in energy storage applications. An impedance spectroscopy plot of NiMoO4 reveals that the Z value is about 30 Ω cm−2. The slope of the curve is near to 90° representing a good capacitance behavior of NiMoO4.

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

“…The FTIR peaks around 650 cm −1 may be attributed to Mo─O─Ni vibrations, whereas the low frequency peaks around 440–460 cm −1 can be ascribed to the presence of MoO and NiO, building group of NiMoO 4 . [ 39,40 ]…”

“…The FTIR peaks around 650 cm −1 may be attributed to Mo─O─Ni vibrations, whereas the low frequency peaks around 440-460 cm −1 can be ascribed to the presence of MoO and NiO, building group of NiMoO 4 . [39,40] FTIR spectra of NiMoO 4 nanomaterials synthesized at 180 and 220 °C for 24 h by hydrothermal method and followed by calcination at 450 and 650 °C are as shown in Figure 8. The peaks at around 3400 cm −1 and 1640 cm −1 corresponding to the O─H bending and O─H stretching vibrations, respectively show widening and intensity decrease as a function of increase in calcination temperature, hence indicating the reduction in the water content in the samples at higher temperatures.…”