Construction of 1D/2D α-Fe₂O₃/SnO₂ Hybrid Nanoarrays for Sub-ppm Acetone Detection

Exhaled acetone is one of the representative biomarkers for the noninvasive diagnosis of type-1 diabetes. In this work, we have applied a facile two-step chemical bath deposition method for acetone sensors based on α-Fe₂O₃/SnO₂ hybrid nanoarrays (HNAs), where one-dimensional (1D) FeOOH nanorods are in situ grown on the prefabricated 2D SnO₂ nanosheets for on-chip construction of 1D/2D HNAs. After annealing in air, ultrafine α-Fe₂O₃ nanorods are homogenously distributed on the surface of SnO₂ nanosheet arrays (NSAs). Gas sensing results show that the α-Fe₂O₃/SnO₂ HNAs exhibit a greatly enhanced response to acetone (3.25 at 0.4 ppm) at a sub-ppm level compared with those based on pure SnO₂ NSAs (1.16 at 0.4 ppm) and pure α-Fe₂O₃ nanorods (1.03 at 0.4 ppm), at an operating temperature of 340°C. The enhanced acetone sensing performance may be attributed to the formation of α-Fe₂O₃-SnO₂ n-n heterostructure with 1D/2D hybrid architectures. Moreover, the α-Fe₂O₃/SnO₂ HNAs also possess good reproducibility and selectivity toward acetone vapor, suggesting its potential application in breath acetone analysis.