In
this study, we explore the synthesis and gas-sensing capabilities
of zinc stannate (Zn2SnO4) in three morphologiesspherical
nanoparticles, urchins, and octahedronsaiming to investigate
the influence of morphology on sensing properties. The fabricated
devices exhibit a significant resistance decrease upon exposure to
NO2 at room temperature (24 °C), indicating p-type
sensing behavior. Among these morphologies, the spherical nanoparticle-based
sensor exhibits the highest sensor response of 57% to 6 ppm of NO2, outperforming urchins and octahedrons by approximately 1.2
and 4.1 times, respectively. This superior performance, with response
and recovery times of 6.3 s and 224 s, is attributed to enhanced redox
reactions from a larger surface area and a higher proportion of oxygen
interstitials. The spherical nanoparticle-based sensor also demonstrates
exceptional selectivity for NO2 over SO2, CO,
NH3, and CH4, with a detection limit of 200
ppb. Furthermore, the sensor exhibits excellent reversibility with
only 2% variation across 20 consecutive test cycles and demonstrates
remarkable long-term stability, with a performance fluctuation of
approximately 2.3% over 63 days without significant degradation.