Hollow Pentagonal-Cone-Structured SnO2 Architectures Assembled with Nanorod Arrays for Low-Temperature Ethanol Sensing

Three-dimensional (3D) hierarchical hollow pentagonal-conestructured SnO2 nanorod array assemblies (HPCSNAs) were synthesized by a facile ultrasound-assisted hydrothermal approach in the absence of any substrates and surfactants. The hollow geometry appears to be a regular pentagonal-cone architecture constructed by five cones, which is further self-assembled from SnO2 nanorod arrays, demonstrating a complex self-construction to multiple formation mechanisms. The gas sensor based on the as-prepared SnO2 nanoarray assemblies exhibits excellent gas response, commendable response-recovery properties, and low-limit gas detection (as low as 1 ppm) for ethanol detection at a lower working temperature of 220 degrees C. The perfect sensing performance could be attributed to the numerous gas transport channels, the large volume space, and the potential barriers at nanorod/nanorod junctions of the unique 3D HPCSNAs.