Bimetallic organic framework-derived porous Co₃O₄/Fe₂O₃ nanosheets for acetone sensing

Bimetallic organic frameworks (Bi-MOFs) are increasingly recognized as highly suitable precursors for developing composite gas sensors based on metal oxide semiconductors (MOS). In this work, we synthesized a Co/Fe-bimetallic organic framework (Co/Fe-Bi-MOF) via an ion-exchange strategy, which was subsequently calcined to obtain porous Co₃O₄/Fe₂O₃ nanosheet heterostructures. The prepared porous Co₃O₄/Fe₂O₃ nanosheet heterojunction sensing material exhibits excellent acetone gas-sensing performance. At 190 °C, the porous Co₃O₄/Fe₂O₃ nanosheet heterojunction material demonstrates remarkable sensitivity to 100 ppm acetone, with a response nearly three times higher than that of pure Co₃O₄, along with fast response and recovery times and a practical detection limit as low as 1 ppm. Furthermore, the porous Co₃O₄/Fe₂O₃ nanosheet heterojunction material also displays outstanding performance characteristics, including reversibility, repeatability, long-term stability, selectivity, and exceptional humidity resistance. Based on various characterization data and DFT simulation results, the enhanced acetone sensitivity is primarily attributed to the synergistic effects arising from the heterojunction structure, large specific surface area, and micro-mesoporous framework. This study provides a promising strategy for developing innovative gas sensors derived from Bi-MOFs.