Designing of nickel cobalt molybdate/multiwalled carbon nanotube composites for suppression of electromagnetic radiation

Abstract

One-dimensional nanorod structures of cobalt molybdate, nickel cobalt molybdate and nickel cobalt molybdate/multiwalled carbon nanotube composites have been effectively synthesized by mild hydrothermal method. The elemental analysis of prepared composite nanorods is studied by Fourier transform infrared and electron diffraction X-ray spectroscopy. Structures and morphologies of samples are characterized by X-ray diffraction and field emission scanning electron microscope. SEM morphology authenticates the development of nanorod structures of synthesized samples. The particles’ size attained by CoMoO4, NiCoMoO4 and NiCoMoO4/CNTs from SEM morphology is in the range of 45–65 nm, 75–85 nm and 100–125 nm. It is experiential that after Ni doping in CoMoO4 particle size is increased and constituent parts are transformed into consistent dimension with better morphology. The SEM image of NiCoMoO4/CNTs shows the thread-like structures that reveal the presence of carbon nanotubes in the composite. EMI shielding measurements were taken using pressed rectangular pellets of 2 mm thickness. The measured total electromagnetic interference (EMI) shielding efficiency (~ SET) of NiCoMoO4/CNTs is 48.84 dB in the Ku band (12.4–18.0 GHz), and involvement of SE due to the absorption of total EMI SE of the composite is larger than that of reflection. This is due to the development of strong conducting network through MWCNTs within divalent transition metal-doped metal–metal matrix. The obtained results suggest the usefulness of the composite for commercial use in far-field EMI shielding and suppression of electromagnetic radiation.