Radial ZnO nanorods decorating Co3O4 nanoparticles for highly selective and sensitive detection of the 3-hydroxy-2-butanone biomarker

Indirectly monitoring Listeria monocytogenes (LMs) via gas sensor detecting metabolites 3-hydroxy-2-butanone (3H-2B) biomarker is a newly-emerged strategy. However, such sensors are required to simultaneously endow with outstanding selectivity, high sensitivity and ppb-level detection limit, which remains technologically challenging. Herein, we have developed highly selective and sensitive 3H-2B sensors with zinc oxide nanorods decorated with cobaltosic oxide nanoparticles (ZnO NRs / Co3O4 NPs), which have been synthesized by an optimized hydrothermal and annealing process. Specifically, the ZnO NRs / Co3O4 NPs exhibit ultrahigh sensitivity toward 5 ppm 3H-2B (Ra / Rg = 550 at 260 oC). Meanwhile, the sensor prototypes enable to detect as low as 10 ppb 3H-2B, show excellent long-term stability, and present remarkable selectivity through interfering selectivity survey and principal component analysis (PCA). Such outstanding sensing performance is attributed to the the modulated electron depletion layer by n / p heterojunction and abundant gas diffusion pathways of radial architectures, which is testified via electrochemical impedance spectroscopy test, Mott-Schottky measurement and ultraviolet-visible absorption analysis. Our highly selective and sensitive ZnO NRs / Co3O4 NPs are potential in real-time detection of 3H-2B biomarker of LMs.