Enhancement of ammonia gas sensing by metal oxide-polyaniline nanocomposite

Abstract

Ammonia (NH3) gas is an important chemical in many industries. Employees who work in those industrial areas may exposed to a certain concentration of NH3 which could cause various symptoms such as irritation of skin and eyes and problems in respiratory system. The development of new NH3 sensing material has drawn a great attention. In this study, porous tin dioxide nanofibers (SnO2 NFs) were successfully fabricated by an electrospinning technique. The SnO2 NFs were composited with polyaniline (PANI), conducting polymer and form tin dioxide nanofibers@polyaniline nanocomposite (SnO2 NFs@PANI). The morphology was characterized using SEM-EDS and XRD. The SnO2 NFs@PANI was examined and showed improving and desirable sensing for NH3 gas, which includes a good linearity response in a range of 0.4 - 100 ppm, and a detection limit of 12.4 ppb at room temperature. Furthermore, the present sensor also showed a rapid response and recovery rates of 87 s and 160 s, good selectivity, repeatability, long-term stability, and reproducibility to 10 ppm NH3 at room temperature. Furthermore, the gas sensing mechanisms of NH3 on SnO2 NFs@PANI were also discussed in detail. The enhanced sensing characteristics of nanocomposites were related to the morphology structure and p-n heterojunction between PANI and SnO2 NFs.