硫醇吸附挥发性有机气体 (VOCs) 的气敏机理. (Chinese)

Gas-sensing mechanism of thiol adsorption of volatile organic compounds (VOCs). (English)

Chemi-resistance sensors play an important role in air quality, food detection and human respiration detection. The gas-sensing mechanism analysis of the adsorption between the modifier, thiol, on the sensor and the volatile organic compounds (VOCs) to be detected is an important means to select the thiol and predict the adsorption capacity and specificity. In this paper, two common thiols, 11-mercapto-1-undecyl alcohol (MUD) and 4-methoxybenzyl mercaptan (MTT), and six typical VOCs (ethanol ETN, isopropanol IPA, acetone ACN, n-hexane HXN, toluene TLN, benzaldehyde BND) were selected, based on density functional theory (DFT), the surface electrostatic potential (ESP) was calculated and the gas adsorption model was established. The adsorption energy was calculated in the gas adsorption model, and the weak interaction was analyzed to explain the mechanism of gas adsorption from a microscopic point of view. The experimental results show that MUD molecules with hydroxyl groups can adsorb gases with hydroxyl groups (such as ETN, IPA) in the form of hydrogen bonds, and have a strong selective effect; MTT molecules with benzene rings and gas molecules with benzene ring structure (such as TLN, BND) will form π-π stacking between benzene rings during adsorption, and the adsorption is based on dispersion interaction, which indicating that MTT molecules have a strong adsorption effect on gases with benzene ring structure. The study found that the strength of its dispersion interaction adsorption is related to the absolute value of the surface ESP of the molecule. In this paper, the gas-sensing mechanism of gas adsorption by sensor surface modifiers is explored, and theoretical guidance is provided for the selection of surface modifiers and the prediction of experimental results. [ABSTRACT FROM AUTHOR]

化学电阻气体传感器对于空气质量, 食品检测和人体呼吸有着重要作用. 传感器上修饰物硫醇与待测的 VOCs 之间吸附的气敏机理分析是选择硫醇, 预测吸附能力与特异性的重要手段. 本文选取了11-巯基-1-十-醇 (MUD) 和4-甲氧基苄硫醇 (MTT) 两种常见的硫醇与六种典型的VOCs (乙醇ETN, 异丙醇IPA, 丙酮ACN, 正己烷HXN, 甲苯TLN, 苯甲醛 BND), 基于密度泛函理论 (DFT), 计算其表面静电势 (ESP) 并建立气体吸附模型. 在气体吸附模型的基础上计算其吸附能, 并分析其弱相互作用, 从微观角度解释气体吸附的作用机理. 实验结果表明, 具有羟基的MUD分子对同样有羟基的气体 (如 ETN, IPA) 能够以氢键的方式吸附, 具有较强的选择效果；具有苯环的MTT分子与具有苯环结构的气体分子 (如TLN, BND) 吸附时会在苯环之间形成π-π堆积, 基于色散作用进行吸附, 这表明MTT 分子对具有苯环结构的气体有着较强的吸附作用. 研究发现其色散作用吸附的强弱与分子的表面ESP绝对值有关. 本文对于传感器表面修饰物吸附气体的气敏机理进行了探究, 并对表面修饰物的选择和实验结果预测提供了理论指导. [ABSTRACT FROM AUTHOR]

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