سنسور گاز دی اکسید کربن بر اساس الکترولیت جامد برای کنترل کیفیت هوا

A practical CO2 gas sensor for air quality control is developed by using a combination of a Na3Zr2Si2PO12 (NASICON) as a solid electrolyte and Li2CO3 as a carbonate phase. The sensor's electromotive force (emf) shows a linear relationship with the logarithm of CO2 concentration. Zeolite is chosen as a filter material in order to minimize the effect of interfering gases on the sensor's emf and shows very little sensor response deterioration to CO2. Under continuous energizing, both the emf and a change in the emf (defined as Δemf) are stable over a period of 2 years. However, after the sensor is exposed to a high humidity atmosphere in an unpowered state, the emf decreases, but Δemf stays constant. A new data selection method for renewing the standard of the emf is investigated in order to monitor CO2 concentration using Δemf. The output of the CO2 monitor corresponds to a conventional non-dispersive infrared (NDIR) analyzer.

Recently, accurate measurement of CO2 concentration in offices and houses has become widespread, as CO2 is a good indicator of air quality pollution. Although infrared spectroscopic analyzers are commonly used in this field, they have several disadvantages such as their large size and high cost, so there is a need to develop inexpensive and maintenance-free CO2 sensors. To provide these needs, solid-electrolyte type CO2 sensors composed of a solid electrolyte and a carbonate phase have been developed [1], [2] and [3]. In this study, we have produced a practical CO2 gas sensor with a platinum heater and a new zeolite filter. A CO2 monitor utilizing this sensor was developed and tested in an office.

A practical solid-electrolyte type CO2 sensor was developed. The sensor's emf showed a linear relationship with the logarithm of the CO2 concentration and was only slightly effected by interfering gases through the use of a new zeolite filter. The sensor's emf showed a tendency to decrease after being exposed to a high humidity atmosphere in an unpowered state, but Δemf stayed fairly stable. The CO2 monitor calculated the CO2 concentration through Δemf using the new data selection method. The output of this monitor corresponded to a conventional NDIR analyzer during a field test in an office. As a result, a new CO2 sensor for air quality control could be realized.