Heterojunction ethanol gas sensor based on LaCoO3/SnO2 nanomaterials
SnO2 nanoparticles were prepared using a hydrothermal method,and LaCoO3 and LaCoO3/SnO2 nan-oparticles were successfully synthesized using the sol-gel method.A sensor device for the rapid detection of eth-anol gas was developed using alumina ceramic tubes as substrates and SnO2 and LaCoO3/SnO2 nanoparticles as sensing materials.Characterization techniques such as XRD,BET,and XPS were used to analyze the micro-structure and elemental composition of LaCoO3,SnO2,and LaCoO3/SnO2.The enhancement mechanism of the heterojunction LaCoO3/SnO2 for ethanol gas sensitivity was explained from the perspective of the energy band structure of LaCoO3 and SnO2.Compared to the SnO2 sensor,LaCoO3/SnO2 showed significant improvements in gas sensitivity response,response time,and selectivity.At the optimal working temperature of 250℃,the re-sponse of LaCoO3/SnO2 to ethanol gas(20 μg/m3)was 90.3,with response and recovery time of 6.5 s and 10.2 s respectively,and a minimum detection limit of 2.0 μg/m3,demonstrating good gas sensitivity,selectivi-ty,and anti-interference performance.The enhancement of gas sensing performance of LaCoO3/SnO2 is attribu-ted to the heterojunction formed by LaCoO3 and its larger specific surface area.
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