Modulation of ZnFe2O4/ZnO heterostructure for enhanced triethylamine sensing performance.

The emerging in-plane heterostructures exhibit unique structure properties, attracting considerable attention in the gas sensors. However, the insight of the structure difference between in-plane and out-plane heterojunctions as well as the structure-activity relationship are still ambiguous. Herein, a novel in-plane ZnFe 2 O 4 /ZnO heterojunction (ZnFe 2 O 4 /ZnO-1) is designed for the efficient detection of triethylamine, which exhibits superior sensing performance with high selectivity and fast response/recovery, and the sensing response (R a /R g =424.07, 50 ppm) is 3.66 folds higher than the out-plane ZnFe 2 O 4 /ZnO heterojunction (ZnFe 2 O 4 /ZnO-2). Moreover, multiple structure analysis and DFT calculations reveal numerous grain boundaries form in ZnFe 2 O 4 /ZnO-1, and the lattice strain, d -band electronic structure, surface oxygen species as well as the surface acidity exhibit great difference with ZnFe 2 O 4 /ZnO-2. Notably, the formation of in-plane heterojunctions facilitates the generation of abundant surface O 2 - (ad) species and large amounts of Lewis acid sites, as well as the upshift of d -band center, which contributes to the enhanced triethylamine sensing performance. Our work illustrates the structure-activity relationship between in-plane and out-plane heterojunctions, and paves the way for the design of novel heterostructure for detecting harmful volatile organic compounds. • The in-plane ZnFe 2 O 4 /ZnO heterostructures have been successfully synthesized. • The in-plane material exhibits superior sensing performance to TEA at 120 °C. • The structural differences between in-plane and out-plane are investigated. • The structure-activity relationship of ZnFe 2 O 4 /ZnO-1 to TEA sensing is illustrated. • The surface O 2 -(ad) species, Lewis acid and the upshift of d -band center contribute to the sensing performance. [ABSTRACT FROM AUTHOR]