Defect sites induced activation of oxygen species for enhanced 3-hydroxy-2-butanone sensing based on ZnIn2S4/In2O3 heterostructure

Defect sites in heterostructures play a vital role in optimizing interfacial charge separation efficiency and carrier migration behavior, which enhance surface reaction dynamics. However, the effect of defect sites on modulation of electronic structure and oxygen activation is still ambiguous. Herein, we successfully construct in-plane ZnIn 2 S 4 /In 2 O 3 heterostructures by partial in-situ oxidation strategy and the surface properties can be precisely tuned by treating at individual temperatures. Notably, the in-plane ZnIn 2 S 4 /In 2 O 3 heterostructure which is treated in air at 425 °C exhibits outstanding sensing performance towards acetoin (R a /R g  = 248.6 for 50 ppm acetoin at 180 °C), a biomarker of Listeria monocytogenes, with rapid response and recovery dynamic (18/183 s), along with excellent reliability and sensing stability. Detailed characterization and DFT calculation indicate that in-plane heterostructures possess numerous grain boundaries, thereby modulating the p-orbitals electronic structure of oxygen atom and promoting the formation of reactive oxygen species (O − (ad)). Moreover, the built-in electric field further also facilitates the electron transfer, further contributing to the enhanced sensing performance for 3-hydroxy-2-butanone.