Structural and gas sensing properties of sol–gel synthesized Zn-doped nickel ferrite nanoparticles

Zn-doped nickel ferrite nanoparticles (Ni1-xZnxFe2O4, x = 0.0, 0.01, and 0.03) were synthesised via the sol–gel method to investigate their structural properties and gas-sensing performance for acetone and isopropyl alcohol (IPA) at room temperature. The research team confirmed the successful synthesis of a pure cubic spinel structure using X-ray diffraction (XRD), which showed no secondary phases. Incorporating more zinc into the material reduced the crystallite size from 34 to 28 nm, as measured using the Modified Scherrer formula. Spinel formation was also validated by FTIR spectroscopy, which detected its characteristic vibrational bands. Furthermore, FESEM imaging showed the material consisted of uniformly distributed, spherical nanoparticles averaging 45 nm in size. The Vander Pauw technique confirmed the p-type semiconducting behavior of the samples. Gas-sensing studies were conducted for acetone and IPA at concentrations ranging from 1 to 200 ppm. The Ni0.99Zn0.01Fe2O4 sample exhibited the best sensing performance, with Rg/Ra ratios of 38.39 and 53.32 at 200 ppm for acetone and IPA, respectively. This superior performance was attributed to the optimal balance between the particle size, number of active sites, and porosity. The response and recovery times were concentration-dependent, with faster response times observed at lower concentrations. Excellent reproducibility was demonstrated over 15 cycles at 100 ppm for both gas types. Selectivity towards IPA over acetone was observed for all samples, with Ni0.99Zn0.01Fe2O4 showing the highest selectivity. The enhanced sensing performance of Zn-doped nickel ferrite nanoparticles, particularly Ni0.99Zn0.01Fe2O4, makes them promising candidates for the detection of acetone and IPA at room temperature, with potential applications in the early diagnosis of diabetes and kidney malfunction. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026.