Potentiometric CO2 Sensor Using Li+ Ion Conducting Li3PO4 Thin Film Electrolyte

Sensors

Whyo Sub Noh¹  L. Satyanarayana² 

[1] Department of Material Science and Engineering, Chosun University, Gwangju 501-759, Korea;Research Institute of Energy Resources Technology, Chosun University, Gwangju 501-759, Korea

关键词: Thin film;    Thick film;    Potentiometric CO₂ sensor;    Li⁺ ion electrolyte;   

DOI  :  10.3390/s5110465

来源: mdpi

【 摘 要 】

Li⁺ ion conducting Li₃PO₄ thin film electrolytes with thickness 300nm, 650nm and 1.2μm were deposited on Al₂O₃ substrate at room temperature by thermal evaporation method. Reference and sensing electrodes were printed on Au interfaces by conventional screen printing technique. The overall dimension of the sensor was 3 × 3 mm and of electrodes were 1 × 1.5 mm each. The fabricated solid state potentiometric CO₂ sensors of type: CO₂, O₂, Au, Li₂TiO₃-TiO₂| Li₃PO₄ |Li₂CO₃, Au, CO₂, O₂ have been investigated for CO₂ sensing properties. The electromotive force (emf) and Δemf/dec values of the sensors are dependent on the thickness of the electrolyte film. 1.2μm thickness deposited sensor has shown good sensing behavior than the sensors with less thickness. The Δemf values of the sensor are linearly increased up to 460°C operating temperature and became stable above 460°C. Between 460-500°C temperatures region the sensor has reached an equilibrium state and the experimentally obtained Δemf values are about 80% of the theoretically calculated values. A Nernst's slope of -61mV/decade has been obtained between 250 to 5000 ppm of CO₂ concentration at 500°C temperature. The sensor is suitable for ease of mass production in view of its miniaturization and cost effectiveness after some further improvement.

【 授权许可】

Unknown   
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