Ultrasensitive Detection of Mold Biomarker 1-Octen-3-ol Using AuPt Nanocluster-Sensitized WO3 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 WO3 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 WO3 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 WO3 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.