Frequency selective gas sensing performance of Ti/TiO₂ nanosheets/Au sensor is presented in this communication. The device was tested over the frequency range of 0.05–225 kHz with peak to peak amplitude of 0.5 V at the temperature ranging from 50 to 225°C under the exposure of acetone, ethanol, and methanol. The optimum sensor response towards acetone, ethanol, and methanol was recorded to be at resonant frequencies of 0.7 kHz, 0.4 kHz, and 0.3 kHz, respectively. Resonant frequency shifts under gas exposure with respect to that in the air were correlated with the change in dielectric (${\mathrm{\epsilon }}_{\mathrm{r}}$) at the nanosheets surfaces and interfaces. Over the tested frequency range order of capacitive change was found to be methanol > ethanol > acetone. Such gas response has been correlated with the degree of polarization of the analytes at the nanosheets surfaces and edges. Equivalent circuit model correlating capacitive and resistive contribution of the nanosheets have been analysed with the help of impedance spectroscopy in complex plane. Optimum capacitive response magnitude (CRM) was found to be ∼ 199%, 252%, and 256% towards 50 ppm of acetone, ethanol, and methanol, respectively. The fastest response time and recovery time of ∼ 24/14 s, 10/3 s, and 17/11 s were recorded for acetone, ethanol, and methanol, respectively.

本通讯介绍了 Ti/ TiO ₂纳米片/Au 传感器的频率选择性气体传感性能。该器件在 0.05–225 kHz 的频率范围内进行了测试，峰峰值幅度为 0.5 V，温度范围为 50 至 225°C，暴露于丙酮、乙醇和甲醇。记录到对丙酮、乙醇和甲醇的最佳传感器响应分别为 0.7 kHz、0.4 kHz 和 0.3 kHz 的共振频率。气体暴露下相对于空气中的谐振频率变化与介电常数的变化相关（${\mathrm{\epsilon }}_{\mathrm{r}}$) 在纳米片表面和界面处。在测试的频率范围内发现电容变化的顺序是甲醇 > 乙醇 > 丙酮。这种气体响应与纳米片表面和边缘处分析物的极化程度相关。借助复平面阻抗谱分析了与纳米片的电容和电阻贡献相关的等效电路模型。对于 50 ppm 的丙酮、乙醇和甲醇，最佳电容响应幅度 (CRM) 分别为 199%、252% 和 256%。丙酮、乙醇和甲醇的最快响应时间和恢复时间分别为 24/14 秒、10/3 秒和 17/11 秒。