High porosity [Formula: see text]-Fe2O3 has attracted a lot of attention due to its exceptional structure. In this paper, nanoflake assembled hierarchical porous flower-like [Formula: see text]-Fe2O3 was prepared by hydrothermal and calcination methods without any additional templates. Scanning electron microscopy (SEM) morphological characterization results show that with the increase of calcination temperature (400∘C, 450∘C, 500∘C, 550∘C, 600∘C), pores appeared. However, the results of nitrogen adsorption show that the specific surface area of the [Formula: see text]-Fe2O3 reaches the maximum value (52.19[Formula: see text]m2/g) when the calcination temperature is 500∘C. The gas sensing performance of flower-like [Formula: see text]-Fe2O3 with different calcination temperature is compared, interestingly, with the increase of calcination temperature, the response of the samples increased first and then decreased, and reached the maximum value (44.2–100 parts per million (ppm) acetone) when the calcination temperature was 500∘C. The minimum concentration for acetone was 200 ppb (response value is 2.0). Moreover, calcined at 500∘C, hierarchical porous [Formula: see text]-Fe2O3 has a fast response recovery (4/25 s) and low working temperature (210∘C). These excellent gas sensing properties are mainly due to porous structure, large specific surface area, and oxygen vacancies on the surface, which make it a promising material for acetone sensors.

中文翻译：

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Nanoflake 组装分层多孔花状 α-Fe2O3，具有大比表面积，用于增强丙酮传感

高孔隙率【公式：见正文】-Fe2○3由于其独特的结构而引起了广泛的关注。本文将纳米薄片组装成分层多孔花状[分子式：见正文]-Fe2○3由水热法和煅烧法制备，无需任何额外模板。扫描电镜（SEM）形态表征结果表明，随着煅烧温度的升高（400∘C, 450∘C, 500∘C, 550∘C, 600∘C)、出现气孔。然而，氮吸附的结果表明[公式：见正文]-Fe的比表面积2○3达到最大值（52.19[公式：见正文]m2/g) 煅烧温度为 500∘C. 花状[分子式：见正文]-Fe的气敏性能2○3对比不同煅烧温度，有趣的是，随着煅烧温度的升高，样品的响应先增大后减小，在煅烧温度为 500 时达到最大值（44.2-100 ppm 丙酮）∘C. 丙酮的最低浓度为 200 ppb（响应值为 2.0）。此外，在 500∘C、分级多孔【公式：见正文】-Fe2○3具有快速响应恢复 (4/25 s) 和低工作温度 (210∘C）。这些优异的气体传感性能主要归功于多孔结构、大比表面积和表面上的氧空位，使其成为丙酮传感器的一种很有前途的材料。