CO2 sensing properties and mechanism of PrFeO3 and NdFeO3 thick film sensor

• Published in: Journal of rare earths 2019-01, Vol.37 (1), p.80-87
• Main Authors: Chen, Yanping, Wang, Dandan, Qin, Hongwei, Zhang, Heng, Zhang, Zhongli, Zhou, Guangjun, Gao, Chengyong, Hu, Jifan
• Format: Article
• Language: English
• Subjects: CO2; Gas sensors; Perovskite; Rare earths; Sensing mechanism
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2018.06.007

The CO2 sensing of PrFeO3 and NdFeO3 sensors were investigated. Experimental results show that the resistances for PrFeO3 and NdFeO3 in CO2 gas are larger than those in air and the responses for PrFeO3 and NdFeO3 sensors increase with an increase in room-temperature relative humidity. When exposed to 1000 ppm CO2, the response of PrFeO3 thick film based on nano-powders annealed at 700 °C can reach 8.44 at 160 °C for the background of wet air with 58% of room-temperature relative humidity (RH), which is much larger than the corresponding value (3.03) in wet air with 25% RH. The sensing response S of NdFeO3 thick-film sensor based on nano-powders annealed at 600 °C to 3000 ppm CO2 at the operating temperature 200 °C can reach 2.36 for the background of wet air with 72% RH, which is larger than the corresponding value (1.83) in the air with 25% RH. Compared with other CO2 sensing materials, the PrFeO3 sensor has larger response at lower operating temperature for CO2 gas and may be used as a new CO2 sensing material. When exposed 1000 ppm of CO2, the corresponding responses were 3.03 and 2.38 at operating temperatures of 160 and 180 °C. PrFeO3 exhibits good response and recovery properties for CO2. The response time and recovery time of PrFeO3 sensor at 180 °C to 5000 ppm CO2 are 441 and 98 s, respectively. [Display omitted]