Ammonia-sensing characteristics of Pt and SiO2 doped SnO2 materials

Improvement in ammonia gas sensing behavior by polypyrrole/multi-walled carbon nanotubes composites

“…The gas sensing device was prepared by using two Pt electrodes and a SiO 2 plate, as shown in previous work [27,28]. This measurement was performed in a stainless steel chamber with a volume of 1500 cm 3 . The chamber was connected to gas cylinders (NH 3 and air).…”

“…The gas feeding rate was kept constant at 500 sccm in all cases. The change in electrical resistance was measured at 298 ± 1 K. When the electrical resistance was stable under the NH 3 ). PPy and other conductive polymers have, therefore, also been classified as organic metals.…”

“…Ammonia (NH 3 ) is a kind of gas with high toxicity. The detection of NH 3 is necessary and important for environmental monitoring and chemical control in industrial, agricultural, and medical fields.…”

“…The detection of NH 3 is necessary and important for environmental monitoring and chemical control in industrial, agricultural, and medical fields. For example, the maximum NH 3 concentration allowed at the industrial working place is 25 ppm for 8 h exposure, and 35 ppm over a 10 min period [1].…”

“…Therefore, a sensitive NH 3 gas sensor must be developed for the detection of lower NH 3 concentration below these limits. NH 3 gas sensors based on conventional materials such as SnO 2 [3], TiO 2 [4], In 2 O 3 [5], WO 3 [6], and ZnO [7] have been developed with good responsiveness and selectivity, and fast response-recovery, that can be used in detecting the lower level presence of NH 3 gas. However, these NH 3 gas sensors are fabricated using metal oxides which operate effectively at temperature ranges between 150 and 400 o C, resulting in both high power consumption and complexities in integration.…”