La-doped SnO ₂ /ZnO brush-distributed nanostructure for enhancing ethanol sensing performance

This study reports the development of a brush-distributed metal oxide nanostructure, in which zinc oxide (ZnO) nanorods are grown on electrospun lanthanum (La)-doped tin oxide (SnO 2 ) nanofibers for enhanced ethanol sensing. The La-doped SnO 2 nanofibers are firstly fabricated through electrospinning followed by calcination treatment. La incorporation significantly enhances the sensing performance of the pure SnO 2 nanofibers by facilitating dehydrogenation and oxidation of hydrocarbon, while simultaneously increasing the number of active sites on the surface of semiconductor oxides. The ZnO nanorods are then grown on the La-doped SnO 2 nanofibers to form the La-doped SnO 2 /ZnO brush-distributed nanostructures via hydrothermal method. The incorporation of ZnO plays a dominant role in enhancing the sensing performance of the La-doped SnO 2 nanofibers by generating additional oxygen vacancies and increasing the specific surface area. The La-doped SnO 2 /ZnO brush-distributed nanostructures were comprehensively characterized in terms of its morphology, structure, and composition using FESEM, XRD, and EDS analyses. The experimental results showed that the optimal sensing performance was observed for the La-doped SnO 2 /ZnO brush-distributed nanostructures with 2 mol% La, which achieved a sensitivity of 10.77 in response to 100 ppm ethanol at an operating temperature of 300 ℃. The ethanol gas sensor exhibited a response time of 8 s and a recovery time of 20 s.