Metal–Organic Framework-Derived Porous NiFe₂O₄ Nanoboxes for Ethyl Acetate Gas Sensors

Detection of ethyl acetate (EtOAc) gas is important for human health and even the diagnosis of certain cancers. However, only a few materials were reported for EtOAc sensing. Herein, NiFe2O4 nanobox (NB) sensing materials with a porous hollow structure were prepared by annealing the self-sacrificed templates of hydrothermally synthesized metal–organic frameworks (MOFs). The superior selectivity of NiFe2O4 NB materials was observed toward EtOAc gas at low optimum working temperature. The response (Rg/Ra) of the NiFe2O4 NB-based sensor is 64.27 toward 200 ppm EtOAc at 120 °C, which is nearly three times greater than that of the sensor based on NiFe2O4 nanocubes (NCs) without a hollow structure. In addition, the NiFe2O4 NB-based sensor exhibited a limit of detection (LOD) of around 0.26 ppm. The enhanced gas sensing performance of the NiFe2O4 NB material may be associated with the unique porous hollow morphology and multiple surface element states, providing more active sites and facilitating the diffusion of gases. The NiFe2O4 NB material is expected to be a candidate material for EtOAc gas detection.