Nearly Monodispersed Multifunctional NiCo₂O₄ Spinel Nanoparticles: Magnetism, Infrared Transparency, and Radiofrequency Absorption

Abstract

We report low temperature synthesis of nearly monodispersed NiCo2O4 nanoparticles by a combustion method utilizing glycine as a fuel and nitrate as oxidizer. An appropriate glycine-to-metal nitrate molar ratio favors the formation of nearly monodispersed NiCo2O4 nanoparticles. We discuss the relevant synthesis chemistry and their detailed characterization using different techniques such as X-ray diffraction, high resolution transmission electron microscopy, superconducting quantum interference device magnetometry, and Fourier transform infrared spectroscopy. We also show the interesting evolution of the phase and magnetic properties of such nanoparticles upon annealing treatment. Importantly, these nanoparticles show a high (∼83%) infrared transparency that is useful for specific solar and fuel cell electrode applications as well as significant radiofrequency (RF) absorption causing substantial heating of their aqueous dispersion that should have potential applications for magnetic hyperthermia.

Effect of Co/Ni ratios in cobalt nickel mixed oxide catalysts on methane combustion

“…Theoretically, CoNi (67:33) should form 100 wt% NiCo2O4 phase; however, it contains the mixture of 78 wt% NiCo2O4 phase and 22 wt% NiO phase based on the MAUD analysis. The formation of NiO phase orginates from the thermal decomposition of NiCo2O4 spinel phase above 400 °C during calcination process [38][39][40].…”

Nickel Cobaltite Nanostructures for Photoelectric and Catalytic Applications

“…Therefore, morphologically controllable synthetic methods aiming for well-defi ned nanocrystals are the primary step. So far, the main synthesis strategies include liquid-phase co-precipitation, [ 43,70 ] hydro-and solvothermal routes, [ 1,41,71 ] microwave-assisted methods, [ 72 ] electrodeposition methods, [ 32 ] electrospinning methods, [ 73 ] high-temperture [ 23,24,69 ] [ 30 ] mesoporous hollow sub-microspheres, [ 70 ] and hollow crossed nanocubes. [ 74 ] Microspheres ( Figure 2 a) and hollow sub-microspheres (Figure 2 b) (Figure 2d,e), [ 25,45 ] nanowires (Figure 2 f,g), [ 43 ] and nanotubes (Figure 2 h), [ 46 ] whose lateral dimensions are in the range of several hundred nanometers to several 2 Ti foil electrocatalytic oxygen evolution [11] nanowire arrays co-precipitation route Ni(NO 3 ) 2 , Co(NO 3 ) 2 − oxygen reduction reaction, electrocatalytic oxygen evolution [56] www.small-journal.com micrometers.…”

“…[ 23 ] The magnetic properties and saturation magnetization of NiCo 2 O 4 can also be tuned by annealing, [ 24 ] morphology, [ 25 ] and components. [ 26 ] Iliev and co-workers have reported that epitaxial NiCo 2 O 4 fi lms deposited at temperatures lower than 450 °C are ferrimagnetic, and those grown at elevated temperatures are nonmagnetic.…”

High‐Performance NiCo2O4 Nanofilm Photodetectors Fabricated by an Interfacial Self‐Assembly Strategy

“…[ 16 ] Many researches have focused studies on the electrocatalytic activity, [ 17 ] ferromagnetic properties, [ 18 ] and application in the negative electrode of lithium-ion battery. [ 19 ] Furthermore, NiCo 2 O 4 can also be a promising material for photodetectors due to its proper bandgap of ≈ 2.1 eV.…”