基于DFT的氮参杂TiO₂ (101)检测H2S的气敏特性研究

Study on Gas Sensing Characteristics of Nitrogen Doped TiO₂ (101) for Detecting H2S Based on DFT

摘要: SF₆绝缘气体作为电力系统中最重要的气体绝缘介质之一，具有灭弧能力强、无毒等突出优点。但其在设备内部绝缘缺陷产生的局部放电作用下，会分解生成包括SO₂F₂，SO₂和H₂S在内的几种特征物质，降低SF₆气体绝缘性能。而通过化学气体传感器检测SF₆特征分解组分，实现气体绝缘设备故障诊断与在线监测技术，已被认为是估算电气工程中绝缘设备运行状态的可行方法。研究发现TiO₂纳米管传感器对SF₆分解组分H₂S具有良好的响应，因此TiO₂纳米管传感器具有增强的敏感性和对气体分子的响应。本文基于密度泛函理论方法模拟了SF₆分解组分H₂S在N掺杂TiO₂上的吸附特性。结果表明，N-TiO₂对H₂S的敏感性较好，吸附后电导率发生明显变化。

Abstract: As one of the most important gas insulation media in power system, SF₆ insulating gas has the outstanding advantages of strong arc extinguishing ability and non-toxic. Under the action of partial discharge caused by the internal insulation defects of the equipment, several characteristic substances, including SO₂F₂, SO₂ and H₂S, will be decomposed and generated, which will reduce the insulation performance of SF₆ gas. By detecting SF₆ characteristic decomposition components by chemical gas sensor, fault diagnosis and on-line monitoring technology of gas insulation equipment has been considered as a feasible method to estimate the running state of insulation equipment in electrical engineering. The study found that N-TiO₂ sensor has a good response to the H₂S of SF₆ decomposition components, so N-TiO₂ sensor has enhanced sensitivity and response to gas molecules. The adsorption characteristics of SF₆ decomposition component H₂S on N doping TiO₂ are simulated based on density functional theory method. The results show that the sensitivity of the N-TiO₂ to the H₂S is good, and the conductivity changes obviously after adsorption.