The Development of New Type of Carbon Dioxide Gas Sensor Based on Lithium Conductor

基于锂导体的新型二氧化碳气体传感器的研制

基本信息

批准号：
02555163
负责人：
ADACHI Gin-ya
金额：
$ 8.51万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

The object of this research is to develop a portable carbon dioxide gas sensor by using a solid electrolyte based on lithium ionic conductor. The electromotive force (EMF) measurements were carried out with several CO_2 gas concentrations. The sensor was set up by using LiTi_2 (PO_4)_3+0.2Li_3PO_4 sintered material as the solid electrolyte, Li_2CO_3 as the detecting electrode, and CaCO_3 as the reference electrode. The measured EMF was in good agreement with the calculated EMF for the gas content from 80 ppm to 1 %. The response time was within several minutes.In a practical application, this type of sensor is expected to be installed in exhaust gas atmosphere. The influence of several gases coexistence with carbon dioxide was investigated. No influence was observed with NO_2 gas copresence from 100 ppm to 450 ppm. This is beca. Mse that lithium nitrate decomposes at the operating temperature of 650ﾟC. The EMF value becomes lower than the calculated EMF even at the SO_2 gas content of 20 ppm. This is ascribed to the formation of lithium sulfate on the electrolyte surface.One another gas should be investigated is water vapor. The sensor can detect the C0_2 concentration from 1000 ppm to 1 % at the water vapor concentration of 0-220g/m^3. The EMF output decreses in the CO_2 gas content lower than 1000 ppm. This phenomenon occurs by the chemical reaction between water vapor and lithium carbonate. In order to lower the operating temperature from 650ﾟC, several electrodes were selected as candidates. The sensor can detect the CO_2 gas concentration from 100 ppm. to 1 % at 350ﾟC in the case that Li_2CO_3-K_2CO_3-Na_2CO_3 eutectic mature was applied as the electrode.

本研究的目的是使用基于锂离子导体的固体电解质开发便携式二氧化碳气体传感器，并使用LiTi_2（）对多种CO_2气体浓度进行电动势（EMF）测量。以PO_4)_3+0.2Li_3PO_4烧结材料为固体电解质,Li_2CO_3为检测电极,CaCO_3为参比电极。对于气体含量从 80 ppm 到 1%，EMF 与计算的 EMF 非常吻合，响应时间在几分钟之内。在实际应用中，这种类型的传感器预计会受到安装在废气气氛中的影响。研究了几种气体与二氧化碳共存时，NO_2 气体在 100 ppm 至 450 ppm 范围内的共存情况，没有观察到影响。工作温度为 650°C，即使 SO_2 气体含量为 20 ppm，EMF 值也会低于计算的 EMF。这是由于电解质表面形成了硫酸锂。另一种需要研究的气体是水蒸气。传感器在水蒸气浓度0-220g/m^3时可检测1000ppm至1%的CO_2浓度。 EMF输出。 CO_2气体含量降低到低于1000 ppm 这种现象是由水蒸气和碳酸锂之间的化学反应引起的。为了将工作温度从650°C降低，选择了多个电极作为候选传感器。在 350°C 的情况下，气体浓度从 100 ppm 降至 1 %。采用Li_2CO_3-K_2CO_3-Na_2CO_3共晶成熟物作为电极。