Amplifying the receptor function on Ba0.9La0.1FeO3-SnO2 composite particle surface for high sensitivity toward ethanol gas sensing

Abstract

Composite particles of Ba0.9La0.1FeO3 (BLF) and SnO2 have been designed to amplify the receptor function of semiconductor gas sensor and achieve high sensitivity toward volatile organic compound gases. During operation, the sensor was driven under double-pulse mode (DP-mode) that includes high-temperature preheating. According to the temperature programmed desorption measurement, oxygen desorption from the BLF-SnO2 composite occurred at lower temperatures than that from SnO2, and the amount of oxygen desorption was also larger. Under the DP-mode, the electrical resistance of BLF-SnO2 was significantly higher than that of SnO2, because BLF acted as an oxygen supplier to increase effective oxygen concentration in the sensing layer. In addition, temperature programmed reaction measurement revealed that ethanol desorbed from BLF, and that the total amount of ethanol desorption and combustion on BLF-SnO2 was larger than that on SnO2. Thus, the sensor response to ethanol based on ethanol combustion reaction was enhanced when using BLF-SnO2 under the DP-mode, especially the sensor response to 1 ppm ethanol showed 143 at the preheating and measurement temperatures of 400 °C and 250 °C, respectively. This enhanced response was attributed to the condensation of oxygen and ethanol under the DP-mode, with BLF playing the role of oxygen and ethanol provider. Thus, compositing BLF with SnO2 significantly amplified the receptor function of the sensing material, and such materials design could lead to improved sensitivity.