Highly Sensitive Capacitive Gas Sensing at Ionic Liquid–Electrode Interfaces

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• 作者：Zhe Wang ; Min Guo ; Xiaoyi Mu ; Soumyo Sen ; Thomas Insley ; Andrew J. Mason ; Petr Král ; Xiangqun Zeng
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：February 2, 2016
• 年：2016
• 卷：88
• 期：3
• 页码：1959-1964
• 全文大小：503K
• ISSN：1520-6882

文摘

We have developed an ultrasensitive gas-detection method based on the measurement of a differential capacitance of electrified ionic liquid (IL) electrode interfaces in the presence and absence of adsorbed gas molecules. The observed change of differential capacitance has a local maximum at a certain potential that is unique for each type of gas, and its amplitude is related to the concentration of the gas molecules. We establish and validate this gas-sensing method by characterizing SO₂ detection at ppb levels with less than 1.8% signal from other interfering species (i.e., CO₂, O₂, NO₂, NO, SO₂, H₂O, H₂, and cyclohexane, tested at the same concentration as SO₂). This study opens a new avenue of utilizing tunable electrified IL–electrode interfaces for selective sensing of molecules with a kinetic size resolution of 0.1 ?.