Research Of CeO₂-based Mixed Potential Acetone Gas Sensor

In this article,Ce O₂-based mixed potential type gas sensor attached with sensing electrodes?SE?consisting of perovskite-type composite oxides has been developed for acetone detection.The acetone sensor was made of chip structure.The sensor took CeO₂solid electrolyte as substrate material,Pt as reference electrode and perovskite oxide composite as sensing electrode material.The sensing property of SEs plays an important role in developing the response of mixed potential sensors.A-site of the perovskite-type composite oxides?ABO₃?determine the properties of the materials.Therefore,the research focus of this paper is to develop high-performance perovskite sensitive electrode materials suitable for making CeO₂ based mixed potential acetone sensor.Therefore,there were two major study contents in this paper as follows:1.La_1-xSr_xCoO₃ was used as sensing electrode,CeO₂ based mixed potential acetone sensor was made.The La_1-xSr_xCoO₃?x=0.1,0.2,0.3 and 0.5?sensing electrode materials were synthesized by citric acid complex method.When x=0.2,the response value??V?of the sensor attached with La_0.8Sr_0.2CoO₃ exhibited the highest sensitivity among the sensors.The respose of the sensor was sectionally linearly changed with the logarithm of acetone concentration within the ranges of 1–5ppm and 5–50ppm,and the sensitivities were-26 and-49mV/decade,respectively.In addition,the influence of sintering temperature on the performance of the sensor was studied.In the three temperature sintered materials at 800,1000 and 1200?,the sensor attached with La_0.8Sr_0.2CoO₃-SE sintered at 1000?clearly exhibited the highest response.To validate the proposed mixed potential model,the polarization curves of sensors attached with La_1-xSr_xCoO₃-SEs were measured.It can be seen that among the four curves,the slope of the curve for the sensor attached with La_0.8Sr_0.2CoO₃ was the largest one,which indicated that the anodic activity of this sensor was the highest,and La_0.8Sr_0.2CoO₃ had the best electrochemically catalytic activity among the La_1-x-x Sr_xCoO₃ materials.Moreover,the sensor also displayed other excellent sensing characteristics,such as good stability,good repeatability and selectivity.2.The Mn perovskite?MMnO₃?sensing electrode material was developed,and the influence of different A elements on the gas sensing properties of the sensor was studied.The choice of M is Sr,Ca,La and Sm.The prepared materials were characterized by XRD and SEM.The morphology of the sensitive electrode materials was characterized by fieldemission scanning electron microscopy?FESEM?.It is found that the SrMnO₃ has the smallest particles and the pores of this material are uniform.It indicated that SrMnO₃may be the best sensing material among these materials.The sensor attached with SrMnO₃-SE sntered at 1000?shows the best response to 20 ppm acetone,which was-49mV.The sensitivity of the device to 1–50 ppm acetone is-38 mV/decade.The typical90%response and recovery times of the sensor attached with SrMnO₃-SE are only 2s and6s.In addition,the sensor has good stability and repeatability.Besides,the sensor performed a good reproducibility and stability.In this article,two high-performance sensitive electrode materials La_0.8Sr_0.2CoO₃and SrMnO₃ have been developed through a series of studies.The mixed potential acetone sensor in this paper has the characteristics of high sensitivity,good repeatability,strong stability and acceptable selectivity.It was a big process to the detection of acetone both in atmosphere environment and microenvionment in diagnosis of diabetes.