One-pot synthesis and improved sensing properties of hierarchical flowerlike SnO2 assembled from sheet and ultra-thin rod subunits

Self-assembled unusual SnO2 flowers have been synthesized by a facile one-pot hydrothermal route. FESEM and TEM reveal that these hierarchical SnO2 flowers, ranging from 600 to 900 nm in size, are composed of two types of building blocks, that is, nanosheets and nanorods. Experimental results obtained from the different growth stages demonstrate that the as-prepared SnO2 nanostructures exhibit an interesting time-dependent evolution of building blocks, from sheets to ultra-thin rods with diameters down to 5 nm. The possible formation mechanism for the hierarchical nanostructures with various architectures is presented on account of the self-assembled growth induced by Ostwald ripening. Furthermore, the as-prepared SnO2 nanosheets and nanorods exhibit improved acetone performances in comparison with hierarchical SnO2 nanosheets due to the additional presence of ultra-thin rodlike subunits. It is found that flowerlike SnO2 have a response of 11.4–50 ppm acetone at the optimal operating temperature of 310 °C, and the response and recovery time are within 1.6 and 7.0 s, respectively.