Abstract Nanocrystalline pure and potassium doped α-Fe2−x KxO3−δ (x = 0.03, 0.05) fiber optic gas sensors are proposed for sensing acetone, ethanol, methanol, and ammonia at room temperature. The nanostructured pure α-Fe2O3 and potassium doped α-Fe2−x KxO3−δ (x = 0.03, 0.05) were synthesized by conventional co-precipitation method and crystallite sizes were determined to be 6.02 nm for pure, 5.79 nm for 3%K-Fe2O3 and 3.97 nm for 5%K-Fe2O3. Synthesized nanostructures were characterized using characterization tools such as powder X-Ray Diffraction (XRD) for Structural phase composition, Fourier Transform Infrared Spectroscopy (FTIR) for functional group analysis and Scanning Electron Microscopy (SEM) for surface morphology, Energy-dispersive X-ray spectroscopy (EDX) for elemental analysis. UV–Vis spectroscopy showed optical characteristic properties exhibiting significant variation in absorbance for 5%K-Fe2O3. The gas sensitivity and selectivity characteristics were investigated for pure and doped materials. Time response of 5%K-Fe2O3 for all gases was taken. 5%K-Fe2O3 showed good gas selectivity and higher sensitivity towards acetone gas and gave relatively faster response. These substantiated the influence of potassium doping in α-Fe2O3 nanostructure.

中文翻译：

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钾掺杂 α-Fe2O3 纳米结构的光学、光谱和光纤气体传感

摘要 纳米晶纯和钾掺杂的 α-Fe2-x KxO3-δ (x = 0.03, 0.05) 光纤气体传感器被提议用于在室温下检测丙酮、乙醇、甲醇和氨。纳米结构的纯 α-Fe2O3 和掺杂钾的 α-Fe2-x KxO3-δ (x = 0.03, 0.05) 通过常规共沉淀法合成，微晶尺寸确定为纯 6.02 nm，3% K 为 5.79 nm -Fe2O3 和 3.97 nm（对于 5%K-Fe2O3）。使用表征工具表征合成的纳米结构，例如用于结构相组成的粉末 X 射线衍射 (XRD)、用于官能团分析的傅立叶变换红外光谱 (FTIR) 和用于表面形态的扫描电子显微镜 (SEM)、能量色散 X 射线用于元素分析的光谱 (EDX)。UV-Vis 光谱显示出光学特性，对 5%K-Fe2O3 的吸光度表现出显着变化。研究了纯材料和掺杂材料的气体灵敏度和选择性特性。对所有气体采用 5%K-Fe2O3 的时间响应。5%K-Fe2O3 表现出良好的气体选择性和对丙酮气体的更高灵敏度，并给出相对较快的响应。这些证实了钾掺杂对 α-Fe2O3 纳米结构的影响。