Practical capacitive type CO2 sensor using CeO2/BaCO3/CuO ceramics

Shogo Matsubara, Shinichiro Kaneko, Shinji Morimoto, Shoichi Shimizu, Tatsumi Ishihara, Yusaku Takita

Research output: Contribution to journalConference articlepeer-review

33 Citations (Scopus)


A practical capacitive type CO2 sensor composed of CeO2/BaCO3/CuO mixed oxides has been developed for the IAQ (indoor air quality) monitoring system. Sensing detectors were fabricated as follows. The pressed pellets of CeO2/BaCO3/CuO mixed oxides were sintered at 800-900 °C for 5 h, then RuO2 electrode was formed on both sides of the pellets. In order to study CO2 sensing characteristics, the capacitance of detector was measured at 550 °C with an LCR meter. The sensitivity of Cat2%CO(2)/Cin-air was measured to be -2.5 dB. They showed good stability in CO2 sensitivity at 85 °C and 90% RH test for 1500 h. The sensor unit with an oscillation circuit using this detector was developed, and its monitoring characteristics were studied. It was shown that the sensitivity change was negligible between 0% RH and 60% RH at 30 °C. The measurement error of CO2 sensor was within 200 ppm in the humidity range of 40-90% RH, and within 30 ppm/°C in the temperature range of 5-50 °C. A CO2 concentration profile monitored in an office by the developed sensor unit showed good agreement with that monitored by an NDIR type sensor. These results suggest that the developed CO2 sensor unit may be applicable to indoor quality monitoring systems. The alumina substrate, which integrates the sensing detector of 1.6*1.2*0.5 mm3 and the printed-film heater, is small (3.6*2.8*0.4 mm3) and need no damp proofing, so that small size and low cost of the sensor can be easily attained.

Original languageEnglish
Pages (from-to)128-132
Number of pages5
JournalSensors and Actuators, B: Chemical
Issue number1
Publication statusPublished - Jun 30 2000
Externally publishedYes
EventIMCS-7: 7th International Meeting on Chemical Sensors - Beijing, China
Duration: Jul 27 1998Jul 30 1998

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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