Fe3O4-NiO core-shell composites: Hydrothermal synthesis and toluene sensing properties

Fe3O4-NiO core-shell composites were prepared via a simple one-step hydrothermal method. The synthesis was conducted in water-ethanol-butanol mixed solvent without any templates. The structure and morphology of the composites were characterized by X-Ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FESEM). The results showed that these porous architectures were assembled from Fe3O4 sphere core and NiO flower-like shells. To demonstrate the use of the composites, a chemical gas sensor has been fabricated and investigated for toluene detection. The sensor exhibits excellent toluene sensing performances in terms of high response, superior selectivity, and rapid response-recovery.