Thiourea-assistant growth of In₂O₃ porous pompon assembled from 2D nanosheets for enhanced ethanol sensing...

The flower-like porous In₂O₃ pompon assembled from two-dimensional (2D) nanosheets was synthesized through a simple thiourea-assistant hydrothermal method following the annealed process. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images manifest that the In₂O₃ pompon possesses a clear porous structure with a nanosheet thickness of about 37.5 nm. Further, we compare the performance of intermediate products (In₂S₃, In₂S₃/In₂O₃) and In₂O₃ nanostructures as ethanol detection gas sensors. The fabrication of In₂O₃-based sensors exhibits enhanced ethanol sensing performance than that of In₂S₃/In₂O₃-based and In₂S₃-based sensors, which is mainly attributed to more chemical oxygen and oxygen vacancies on the material surface. The In₂O₃-based sensors for ethanol detection revealed a wide linear range from 2 ppm to 100 ppm, meanwhile the corresponding detection limits (LOD) as low as ~0.4 ppm at 260 °C. And the In₂O₃-based sensors also exhibit superior repeatability and reliable selectivity. The simple fabrication strategy of 2D nanosheets-assembled flower-like In₂O₃ porous pompon may facilitate other ethanol gas sensors production and other 2D metal oxide semiconductor materials-based sensors preparation.