Ultrasensitive Detection of Mold Biomarker 1-Octen-3-ol Using AuPt Nanocluster-Sensitized WO ₃ Gas Sensor for On-Site Grain Safety Monitoring

Expanding the detection targets and application scope of the gas sensor is highly significant. For instance, the selective and rapid detection of trace levels of 1-octen-3-ol, a volatile compound produced by fungal metabolic activity, is crucial for grain safety monitoring, yet it remains a major technical challenge. Herein, an AuPt alloy nanocluster-sensitized WO 3 chemiresistive gas sensor is developed for the detection of volatile 1-octen-3-ol, which exhibits an ultralow detection limit (12 ppb), good selectivity, and long-term stability (60 days). It effectively identifies various mold species infecting grain, including A. flavus, A. niger, R. stolonifer, P. citrinum, and A. alternata . The exceptional sensing performance stems from the strategic decoration of WO 3 with AuPt alloy nanoclusters. Modulation of the d -band center of noble metal strengthens the orbital overlap with the π* orbital of 1-octen-3-ol, while simultaneously promoting oxygen adsorption and dissociation on the sensing surface. The generated active oxygen species migrate from the nanoclusters to the WO 3 surface via oxygen spillover, significantly enhancing the kinetics of the gas-solid interfacial redox reaction. This study extends the application of chemiresistive gas sensors to grain mold monitoring by developing a high-performance 1-octen-3-ol sensor based on noble metal nanocluster-sensitized semiconductor metal oxides.