Ethanol-sensing performance of tin dioxide octahedral nanocrystals with exposed high-energy {111} and {332} facets

Abstract

Tin dioxide octahedral nanocrystals with exposed high-energy {111} and {332} facets were hydrothermally synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). Gas sensors were fabricated from the prepared SnO₂ nanocrystals and applied to ethanol-sensing tests. Octahedral SnO₂ {332} exhibited a maximum response of 2200 under an ethanol concentration of 800 ppm at 250 °C with a response time of 1.5 s and a recovery time of 32.5 s, whereas SnO₂ {111} exhibited a maximum response of 179 at 360 °C with a response time of 9.5 s and a recovery time of 6.7 s. The sensing mechanisms responsible for SnO₂ nanocrystals to ethanol vapor are discussed.