CO₂ gas sensors based on Yb_1-xCa_xFeO₃ nanocrystalline powders

张盼盼¹，秦宏伟²，张恒²，吕伟¹，胡季帆²

1. School of Chemistry and Chemical Engineering, Shandong University2. School of Physics, State Key Laboratory for Crystal Materials, Shandong University

摘 要：In this study, the Yb_1-xCa_xFeO₃（0≤x≤0.3） nanocrystalline powders were prepared by sol-gel method. We used the method of quantitative analysis to research the gas-sensitive properties for Yb_1-xCa_xFeO₃ to CO₂. Also, we investigated the effects of various factors on gas sensing properties by simple variable method. The doping of Ca could not only decrease the resistance of YbFeO₃, but also enhance its sensitivity to CO₂. When the Ca content x=0.2, Yb_1-xCa_xFeO₃ showed the best response to CO₂. The response Rg/Ra to 5000 ppm CO₂ for Yb_0.8Ca_0.2FeO₃ at its optimal temperature of 260 °C with the room temperature humidity of 28%RH was 1.85. The response and recovery time decreased with an increase of the operating temperature for Yb_0.8Ca_0.2FeO₃ sensor to 5000 ppm CO₂. Furthermore, with an increase of CO₂ concentration from 1000 to 50000 ppm, the response time of Yb_0.8Ca_0.2FeO₃ became shorter, and meanwhile the recovery time was longer. CO₂-sensing response for Yb_0.8Ca_0.2FeO₃ increased with the increase of relative humidity. The response for Yb_0.8Ca_0.2FeO₃ in the background of air（with the room temperature humidity of 39%RH） at 260 °C could reach 2.012 to 5000 ppm CO₂, which was larger than the corresponding value（1.16） in dry air.

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