Well-designed g-C₃N₄ nanosheet incorporated Ag loaded Er_0.05La_0.95FeO₃ heterojunctions for isoamyl alcohol detection

Because the volatile content of isoamyl alcohol increases sharply on the seventh day of wheat mildew infection, isoamyl alcohol can be used as an early biomarker of wheat mildew infection. Currently, only a few sensors for isoamyl alcohol detection have been reported, and these sensors still suffer from low sensitivity and poor moisture resistance. Herein, the isoamyl alcohol sensitivity of 5 at% Er@LaFeO₃ (ELFO) was enhanced by loading Ag nanoparticles on the surface of the ELFO microspheres, while the optimal operating temperature was reduced. The moisture resistance of Ag/ELFO was improved by the incorporation of g-C₃N₄ nanosheets (NSs) on the surface of Ag/ELFO through electrostatic self-assembly. Given the requirements for practical applications in grain granaries, the sensing behavior of a Ag/ELFO-based sensor incorporating g-C₃N₄ NSs at 20% relative humidity (RH) was systematically studied, and the sensor demonstrated excellent repeatability, long-term stability, and superior selectivity (791 at 50 ppm) for isoamyl alcohol with a low limit of detection (LOD = 75 ppb). Furthermore, the practical results obtained for wheat at different mildew stages further confirmed the potential of the g-C₃N₄/Ag/ELFO-based sensor for monitoring the early mildew stage of wheat. This work may offer guidance for enhancing the moisture resistance of gas-sensitive materials through the strategy of employing composite nanomaterials.