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

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.