Surface-tailored PdPt/ZnO mesoporous concave nanocages for highly active sensing of 3-hydroxy-2-butanone biomarker

Gas sensors for detecting foodborne pathogen biomarkers offer a promising approach to enhance food safety monitoring. However, sensors based on conventional sensing materials often lack the requisite sensitivity for trace-level pathogen metabolites. Herein, PdPt/ZnO hollow concave nanocages are rationally designed through a surface-tailored strategy to achieve rapid and ultrasensitive detection of the Listeria monocytogenes biomarker 3-hydroxy-2-butanone at ultralow concentrations. The representative 1%PdPt/ZnO-based sensor exhibits superior sensing properties: high response (R a /R g  = 92.8@5 ppm), rapid response/recovery kinetics (14/15 s), ultralow detection limit (20 ppb), excellent selectivity, and over 30-day stability at an operating temperature of 150 °C. The combination of ex-situ / in-situ characterization and DFT calculations reveals that the hollow concave nanocage morphology synergistically activated by PdPt bimetallic sites dramatically increases active site density, accelerates oxygen diffusion, and lowers the reaction energy barrier, thereby enabling the efficient adsorption and conversion of oxygen species and 3-hydroxy-2-butanone. Crucially, the sensor enables rapid response of Listeria monocytogenes in actual food samples and distinguishes it from other foodborne pathogens, demonstrating its significant potential for accurate, real-time, and non-invasive monitoring of Listeria monocytogenes contamination.