Hierarchical Assembly of α-Fe2O3 Nanosheets on SnO2 Hollow Nanospheres with Enhanced Ethanol Sensing Properties

We present the preparation of a hierarchical nanoheterostructure consisting of inner SnO2 hollow spheres (SHS) surrounded by an outer alpha-Fe2O3 nanosheet (FNS). Deposition of the FNS on the SHS outer surface was achieved by a facile microwave hydrothermal reaction to generate a double-shell SHS@ENS nanostructure. Such a composite with novel heterostructure acted as a sensing material for gas sensors. Significantly, the hierarchical composites exhibit excellent sensing performance toward ethanol, which is superior to the single component (SHS), mainly because of the synergistic effect and heterojunction.