Hollow semiconductor oxide micro-/nanomaterials can provide significant advantages for gas sensing by facilitating the diffusion of target gases and the surface reaction. In this study, we report the synthesis of hollow NiFe₂O₄ microspindles through an as-developed metal–organic framework (MOF) route, which involves two steps: the preparation of Ni/Fe bimetallic MOF solid microspindle precursors and their subsequent transformation to the final materials via an annealing treatment in the air. The hollow NiFe₂O₄ microspindles were demonstrated to be composed of primary nano-building particles and abundant deep pores in the hollowed-out shells. Furthermore, in synergy with the large specific surface area, hollow interior, and abundant surface oxygen species, as expected, the gas sensor based on the hollow NiFe₂O₄ microspindles delivered a high sensitivity of 52.8 towards 200 ppm acetone vapor as well as good selectivity and cyclic stability at a low working temperature (120 °C). Finally, the sensing mechanism for the gas sensing behavior was also proposed. The high-performance sensing behavior towards acetone suggests that the as-fabricated sensor can be a promising candidate for environmental monitoring; thus, this study paves the way towards the efficient fabrication of advanced gas sensors on the basis of metal oxides derived from appropriate MOF precursors in the future.

中文翻译：

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源自Ni / Fe双金属MOF的 空心NiFe ₂ O _4微主轴，可在低工作温度下实现高灵敏度的丙酮传感†

中空的半导体氧化物微/纳米材料可通过促进目标气体的扩散和表面反应，为气体传感提供显着的优势。在这项研究中，我们报告了通过已开发的金属-有机骨架（MOF）路线合成空心NiFe ₂ O _4微锭的过程，该过程涉及两个步骤：Ni / Fe双金属MOF固体微锭前体的制备及其随后的转化为最终材料通过空气中的退火处理。空心NiFe ₂ O ₄事实证明，微主轴是由初级纳米结构颗粒和空心壳中丰富的深孔组成的。此外，与预期的大比表面积，中空内部和丰富的表面氧种类协同作用，基于中空NiFe ₂ O ₄的气体传感器微锭对200 ppm的丙酮蒸气具有52.8的高灵敏度，并且在低工作温度（120°C）下具有良好的选择性和循环稳定性。最后，提出了气体感应行为的感应机制。对丙酮的高性能传感行为表明，制成的传感器可以作为环境监测的有前途的候选者。因此，这项研究为将来基于适当的MOF前驱物衍生的金属氧化物有效地制造先进的气体传感器铺平了道路。