ZnWO 4 /f-MWCNTs Nanocomposite for H 2 S Gas Sensor with Fast Response and Recovery: Mechanism Study and Application for Detecting Fish Spoilage

Hydrogen sulfide (H₂S), a characteristic byproduct of sulfur-containing amino acid decomposition during fish spoilage, serves as a critical freshness indicator and poses substantial food safety risks. This study develops a novel H₂S gas sensor using a ZnWO₄/f-MWCNTs nanocomposite synthesized via one-step hydrothermal method. The incorporated functionalized multiwalled carbon nanotubes (f-MWCNTs) improve the sensing material's conductivity, dispersion stability, and gas adsorption capacity. XRD, XPS, FTIR, SEM, TEM, and BET analyses verify the composite's successful synthesis and optimal physicochemical properties. The ZnWO₄/f-MWCNTs sensor demonstrates exceptional H₂S detection at 120 °C, achieving a response value of 18.67 (Ra/Rg) to 50 ppm of H₂S with fast response/recovery times (14 s/30 s) and excellent selectivity against interferents. Real-time monitoring of fish spoilage further confirms its practical utility, highlighting the sensor's potential for meat freshness assessment and food safety applications.