Fapyane Deby, Revsbech Niels Peter
Aarhus University Centre for Water Technology (WATEC), Department of Biology, Aarhus University, Ny Munkegade 114, 8000 Aarhus C, Denmark.
ACS Sens. 2020 Aug 28;5(8):2604-2610. doi: 10.1021/acssensors.0c01071. Epub 2020 Aug 6.
Knowledge about the microscale distribution of CO is essential in many environmental and technical settings, and electrochemical CO sensing may be optimized to yield such information. The performance of a Clark-type CO sensor was greatly improved by adding 20% dimethylformamide (DMF) to the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide (EMIM-DCA) previously used as an electrolyte. The addition of DMF resulted in a much faster response to increasing (95% response of about 100 s) or decreasing CO concentration, a negligible interference from low concentrations of NO, and a signal temperature dependence similar to that of O microsensors. The use of 80% EMIM-DCA/20% DMF as an electrolyte leads to CO reduction at -0.72 V (vs standard hydrogen electrode), reducing the overpotential by 0.2 V as compared to the use of 100% EMIM-DCA. The CO microsensor has a calculated limit of detection of 0.5 Pa CO, and sensors optimized for high sensitivity exhibited a linear response within the range of 0-4.6 kPa (0-1.7 mM) CO. A set of four sensors exhibited no noticeable change of zero current and CO sensitivity during 4 months of continuous polarization.
在许多环境和技术场景中，了解一氧化碳（CO）的微观分布至关重要，并且可以优化电化学CO传感以获取此类信息。通过向先前用作电解质的离子液体1-乙基-3-甲基咪唑二氰胺（EMIM-DCA）中添加20%的二甲基甲酰胺（DMF），Clark型CO传感器的性能得到了极大改善。添加DMF后，对CO浓度增加（约100秒内95%的响应）或降低的响应速度大大加快，低浓度NO的干扰可忽略不计，并且信号温度依赖性与O微传感器类似。使用80%的EMIM-DCA/20%的DMF作为电解质会导致在-0.72 V（相对于标准氢电极）时CO发生还原，与使用100%的EMIM-DCA相比，过电位降低了0.2 V。该CO微传感器计算得出的检测限为0.5 Pa CO，针对高灵敏度优化的传感器在0-4.6 kPa（0-1.7 mM）CO范围内呈现线性响应。一组四个传感器在连续极化4个月期间，零电流和CO灵敏度没有明显变化。
