电流型二氧化碳气敏微电极的研究

An Amperometric Gas-sensing Microelectrode for the Determination of Carbon Dioxide

本文提出并用微电极技术建立了基于室温下直接阴极还原CO_2的电流型二氧化碳气敏微电极.微CO_2电极体系由金(或铂)微工作电极、Ag/AgCl对电极(兼作参比电极)、含有非水电解质[二甲基亚砜(DMSO)和四乙基氯化铵(0.1mol·L^(-1))的支持芯及透气膜构成.该电极在0～100%CO_2的整个浓度范围内有良好的线性响应关系,与现有的CO_2气敏器件比较,它具有灵敏度高、响应速度快、工作稳定和整体性好等特性.这类采用非水电解质的电流型气敏微电极能被开发应用于室温检测其它非电化学活性气体.文中还根据微电极工作原理讨论了这种气敏器件的响应机制.

An ampere-metric carbon dioxide gas-sensing microelectrode based on the direct cathodic reduction of CO2 at room temperature was presented and fabricated by microelectrode technigue. The CO2 microelectrode system consists of a gold (or platinum) microelectrode as the working electrode, anAg/Agcl electrode as the counter electrode and the reference electrode, supporting wicks containing dimethylsulphoxide (DMSO) and tetraethyl ammonium chloride (0.1 mol·L-1) as electrolyte, and a gas Pmeable membrane. This linear relationship between the cathodic limiting current and the CO2 percent in the CO2/N2 mixture were found to be psatisfactory over the concentration range of 0-100%. Compared with other CO2-sensing devices, this proposed amperometric CO2 device has some features, such as high sensitivity, fast response rate, long-term stability in operation and compact body. Furthermore, this amperometric gas-sensing microelectrode with nonagueous electrolyte can be used for the detecti onof electrochemical inactive gases at room temgerature. The reonse mech anism of such gas-sensing microelectrode is proposed.