Abstract To analyze the sensing performance of the TiO2 nanotube (TiNT) array film gas sensor to H2S at low working temperature, the free-standing Fe-doped TiNT array films were synthesized using the one-step anodic oxidation method followed by immersion and annealing processes. The results obtained from the field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectra and ultraviolet–visible spectra methods indicate that the lattice of TiO2 was doped by iron ions. Subsequently, compared with undoped TiO2, the response intensity, response and recovery times of the gas sensor based on Fe-doped TiNT array film to 50 ppm H2S at 100 °C were improved. Furthermore, the improved selectivity and stability to H2S were also obtained with the Fe-doped TiNT gas sensor. Finally, based on the Density Functional Theory (DFT), the band structure of Fe-doped TiO2 and the electronic density of states of H2S and the compared gases are calculated and used for the systematical analysis of sensing and selectivity mechanisms of the Fe-doped TiNT gas sensor at low working temperature.

中文翻译：

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低温H2S气敏自支撑Fe掺杂TiO2纳米管阵列薄膜的合成及密度泛函理论研究

摘要 为分析低工作温度下 TiO2 纳米管 (TiNT) 阵列薄膜气体传感器对 H2S 的传感性能，采用一步阳极氧化法、浸渍和退火工艺合成了自支撑 Fe 掺杂的 TiNT 阵列薄膜。 . 从场发射扫描电子显微镜、X 射线衍射、X 射线光电子能谱和紫外-可见光谱方法获得的结果表明，TiO2 的晶格被铁离子掺杂。随后，与未掺杂的 TiO2 相比，基于 Fe 掺杂的 TiNT 阵列薄膜的气体传感器在 100°C 下对 50 ppm H2S 的响应强度、响应和恢复时间都有所提高。此外，Fe 掺杂的 TiNT 气体传感器还提高了对 H2S 的选择性和稳定性。最后，基于密度泛函理论（DFT），