Mixed oxides consisting of BaTiO3 and a metal oxide were studied as a new type of CO2 gas sensor based on capacitance changes. Small changes in the capacitance of a metal oxide caused by carbonation are amplified by mixing with BaTiO3, probably due to an enhancement of the barrier-layer capacitor. The CO2 sensing characteristics of mixed-oxide capacitors depend strongly on the operating frequency as well as on the operating temperature. Among the compositions investigated in this study, CuOBaTiO3 is the most sensitive to CO2. The combination CuOBaTiO3 selectively responds to carbon dioxide and can discriminate CO2 concentrations from 100 to 20 000 ppm.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry