Influence of low-dimension carbon-based electrodes on the performance of SnO₂ nanofiber gas sensors at room temperature

Room-temperature NO₂ gas sensors are fabricated by employing tin oxide (SnO₂) nanofibers (NFs) as sensing layers and low-dimension carbon nanomaterials, including single-walled carbon nanotubes (SWCNTs) and reduced graphene oxide (rGO), as conductive interdigital electrodes (IDEs). The morphology characteristics and gas sensing performance of rGO IDEs-SnO₂ and SWCNTs IDEs-SnO₂ gas sensors have been investigated. The results demonstrate that the response of rGO IDEs based sensors achieves 90.0% after been exposed to 12 ppm NO₂, which is superior to the responses of Ti/Au and SWCNTs IDEs based sensors (55.1% and 16.7%, respectively). The rGO IDEs-SnO₂ sensor exhibits excellent sensitivity, large recovery capability and repeatability, and high selectivity at room temperature. The sensing mechanism of such prominent performance has also been analyzed, revealing that the outstanding properties could be attributed to a large number of active adsorption sites, the formation of a p-n heterojunction and a large effective contact area between the two-dimensional rGO nanosheets and the tube-shaped SnO₂ NFs. This work helps to build up a potential platform to explore effective electrodes for future novel NO₂ gas sensors in practical gas sensing applications.